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dl |
1.1 |
/* |
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jsr166 |
1.31 |
* Copyright 1997-2007 Sun Microsystems, Inc. All Rights Reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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1.1 |
* |
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jsr166 |
1.31 |
* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Sun designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Sun in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
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* CA 95054 USA or visit www.sun.com if you need additional information or |
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* have any questions. |
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dl |
1.1 |
*/ |
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package java.util; |
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import java.io.Serializable; |
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import java.io.ObjectOutputStream; |
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import java.io.IOException; |
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import java.lang.reflect.Array; |
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/** |
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* This class consists exclusively of static methods that operate on or return |
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* collections. It contains polymorphic algorithms that operate on |
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* collections, "wrappers", which return a new collection backed by a |
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* specified collection, and a few other odds and ends. |
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* |
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* <p>The methods of this class all throw a <tt>NullPointerException</tt> |
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* if the collections or class objects provided to them are null. |
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* |
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* <p>The documentation for the polymorphic algorithms contained in this class |
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* generally includes a brief description of the <i>implementation</i>. Such |
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* descriptions should be regarded as <i>implementation notes</i>, rather than |
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* parts of the <i>specification</i>. Implementors should feel free to |
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* substitute other algorithms, so long as the specification itself is adhered |
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* to. (For example, the algorithm used by <tt>sort</tt> does not have to be |
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* a mergesort, but it does have to be <i>stable</i>.) |
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* |
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* <p>The "destructive" algorithms contained in this class, that is, the |
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* algorithms that modify the collection on which they operate, are specified |
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* to throw <tt>UnsupportedOperationException</tt> if the collection does not |
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* support the appropriate mutation primitive(s), such as the <tt>set</tt> |
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* method. These algorithms may, but are not required to, throw this |
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* exception if an invocation would have no effect on the collection. For |
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* example, invoking the <tt>sort</tt> method on an unmodifiable list that is |
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* already sorted may or may not throw <tt>UnsupportedOperationException</tt>. |
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* |
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jsr166 |
1.4 |
* <p>This class is a member of the |
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1.28 |
* <a href="{@docRoot}/../technotes/guides/collections/index.html"> |
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1.1 |
* Java Collections Framework</a>. |
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* |
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* @author Josh Bloch |
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* @author Neal Gafter |
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* @see Collection |
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* @see Set |
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* @see List |
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* @see Map |
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1.1 |
* @since 1.2 |
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*/ |
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public class Collections { |
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// Suppresses default constructor, ensuring non-instantiability. |
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private Collections() { |
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} |
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// Algorithms |
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/* |
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* Tuning parameters for algorithms - Many of the List algorithms have |
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* two implementations, one of which is appropriate for RandomAccess |
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* lists, the other for "sequential." Often, the random access variant |
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* yields better performance on small sequential access lists. The |
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1.7 |
* tuning parameters below determine the cutoff point for what constitutes |
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1.1 |
* a "small" sequential access list for each algorithm. The values below |
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* were empirically determined to work well for LinkedList. Hopefully |
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* they should be reasonable for other sequential access List |
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* implementations. Those doing performance work on this code would |
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* do well to validate the values of these parameters from time to time. |
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* (The first word of each tuning parameter name is the algorithm to which |
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* it applies.) |
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*/ |
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private static final int BINARYSEARCH_THRESHOLD = 5000; |
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private static final int REVERSE_THRESHOLD = 18; |
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private static final int SHUFFLE_THRESHOLD = 5; |
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private static final int FILL_THRESHOLD = 25; |
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private static final int ROTATE_THRESHOLD = 100; |
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private static final int COPY_THRESHOLD = 10; |
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private static final int REPLACEALL_THRESHOLD = 11; |
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private static final int INDEXOFSUBLIST_THRESHOLD = 35; |
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/** |
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* Sorts the specified list into ascending order, according to the |
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* <i>natural ordering</i> of its elements. All elements in the list must |
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* implement the <tt>Comparable</tt> interface. Furthermore, all elements |
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* in the list must be <i>mutually comparable</i> (that is, |
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* <tt>e1.compareTo(e2)</tt> must not throw a <tt>ClassCastException</tt> |
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* for any elements <tt>e1</tt> and <tt>e2</tt> in the list).<p> |
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* |
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* This sort is guaranteed to be <i>stable</i>: equal elements will |
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* not be reordered as a result of the sort.<p> |
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* |
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* The specified list must be modifiable, but need not be resizable.<p> |
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* |
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* The sorting algorithm is a modified mergesort (in which the merge is |
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* omitted if the highest element in the low sublist is less than the |
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* lowest element in the high sublist). This algorithm offers guaranteed |
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jsr166 |
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* n log(n) performance. |
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dl |
1.1 |
* |
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* This implementation dumps the specified list into an array, sorts |
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* the array, and iterates over the list resetting each element |
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* from the corresponding position in the array. This avoids the |
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* n<sup>2</sup> log(n) performance that would result from attempting |
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* to sort a linked list in place. |
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* |
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* @param list the list to be sorted. |
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* @throws ClassCastException if the list contains elements that are not |
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jsr166 |
1.33 |
* <i>mutually comparable</i> (for example, strings and integers). |
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dl |
1.1 |
* @throws UnsupportedOperationException if the specified list's |
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jsr166 |
1.33 |
* list-iterator does not support the <tt>set</tt> operation. |
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dl |
1.1 |
* @see Comparable |
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*/ |
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public static <T extends Comparable<? super T>> void sort(List<T> list) { |
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jsr166 |
1.33 |
Object[] a = list.toArray(); |
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Arrays.sort(a); |
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ListIterator<T> i = list.listIterator(); |
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for (int j=0; j<a.length; j++) { |
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i.next(); |
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i.set((T)a[j]); |
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} |
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dl |
1.1 |
} |
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/** |
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* Sorts the specified list according to the order induced by the |
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* specified comparator. All elements in the list must be <i>mutually |
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* comparable</i> using the specified comparator (that is, |
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* <tt>c.compare(e1, e2)</tt> must not throw a <tt>ClassCastException</tt> |
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* for any elements <tt>e1</tt> and <tt>e2</tt> in the list).<p> |
148 |
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* |
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* This sort is guaranteed to be <i>stable</i>: equal elements will |
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* not be reordered as a result of the sort.<p> |
151 |
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* |
152 |
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* The sorting algorithm is a modified mergesort (in which the merge is |
153 |
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* omitted if the highest element in the low sublist is less than the |
154 |
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* lowest element in the high sublist). This algorithm offers guaranteed |
155 |
jsr166 |
1.4 |
* n log(n) performance. |
156 |
dl |
1.1 |
* |
157 |
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* The specified list must be modifiable, but need not be resizable. |
158 |
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* This implementation dumps the specified list into an array, sorts |
159 |
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* the array, and iterates over the list resetting each element |
160 |
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* from the corresponding position in the array. This avoids the |
161 |
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* n<sup>2</sup> log(n) performance that would result from attempting |
162 |
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* to sort a linked list in place. |
163 |
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* |
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* @param list the list to be sorted. |
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* @param c the comparator to determine the order of the list. A |
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* <tt>null</tt> value indicates that the elements' <i>natural |
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* ordering</i> should be used. |
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* @throws ClassCastException if the list contains elements that are not |
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jsr166 |
1.33 |
* <i>mutually comparable</i> using the specified comparator. |
170 |
dl |
1.1 |
* @throws UnsupportedOperationException if the specified list's |
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jsr166 |
1.33 |
* list-iterator does not support the <tt>set</tt> operation. |
172 |
dl |
1.1 |
* @see Comparator |
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*/ |
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public static <T> void sort(List<T> list, Comparator<? super T> c) { |
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jsr166 |
1.33 |
Object[] a = list.toArray(); |
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Arrays.sort(a, (Comparator)c); |
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ListIterator i = list.listIterator(); |
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for (int j=0; j<a.length; j++) { |
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i.next(); |
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i.set(a[j]); |
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} |
182 |
dl |
1.1 |
} |
183 |
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184 |
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185 |
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/** |
186 |
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* Searches the specified list for the specified object using the binary |
187 |
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* search algorithm. The list must be sorted into ascending order |
188 |
jsr166 |
1.25 |
* according to the {@linkplain Comparable natural ordering} of its |
189 |
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* elements (as by the {@link #sort(List)} method) prior to making this |
190 |
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* call. If it is not sorted, the results are undefined. If the list |
191 |
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* contains multiple elements equal to the specified object, there is no |
192 |
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* guarantee which one will be found. |
193 |
dl |
1.1 |
* |
194 |
jsr166 |
1.25 |
* <p>This method runs in log(n) time for a "random access" list (which |
195 |
dl |
1.1 |
* provides near-constant-time positional access). If the specified list |
196 |
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* does not implement the {@link RandomAccess} interface and is large, |
197 |
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* this method will do an iterator-based binary search that performs |
198 |
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* O(n) link traversals and O(log n) element comparisons. |
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* |
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* @param list the list to be searched. |
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* @param key the key to be searched for. |
202 |
dl |
1.2 |
* @return the index of the search key, if it is contained in the list; |
203 |
jsr166 |
1.33 |
* otherwise, <tt>(-(<i>insertion point</i>) - 1)</tt>. The |
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* <i>insertion point</i> is defined as the point at which the |
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* key would be inserted into the list: the index of the first |
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* element greater than the key, or <tt>list.size()</tt> if all |
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* elements in the list are less than the specified key. Note |
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* that this guarantees that the return value will be >= 0 if |
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* and only if the key is found. |
210 |
dl |
1.1 |
* @throws ClassCastException if the list contains elements that are not |
211 |
jsr166 |
1.33 |
* <i>mutually comparable</i> (for example, strings and |
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* integers), or the search key is not mutually comparable |
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* with the elements of the list. |
214 |
dl |
1.1 |
*/ |
215 |
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public static <T> |
216 |
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int binarySearch(List<? extends Comparable<? super T>> list, T key) { |
217 |
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if (list instanceof RandomAccess || list.size()<BINARYSEARCH_THRESHOLD) |
218 |
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return Collections.indexedBinarySearch(list, key); |
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else |
220 |
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return Collections.iteratorBinarySearch(list, key); |
221 |
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} |
222 |
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private static <T> |
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int indexedBinarySearch(List<? extends Comparable<? super T>> list, T key) |
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{ |
226 |
jsr166 |
1.33 |
int low = 0; |
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int high = list.size()-1; |
228 |
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229 |
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while (low <= high) { |
230 |
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int mid = (low + high) >>> 1; |
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Comparable<? super T> midVal = list.get(mid); |
232 |
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int cmp = midVal.compareTo(key); |
233 |
dl |
1.1 |
|
234 |
jsr166 |
1.33 |
if (cmp < 0) |
235 |
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low = mid + 1; |
236 |
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else if (cmp > 0) |
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high = mid - 1; |
238 |
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else |
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return mid; // key found |
240 |
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} |
241 |
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return -(low + 1); // key not found |
242 |
dl |
1.1 |
} |
243 |
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244 |
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private static <T> |
245 |
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int iteratorBinarySearch(List<? extends Comparable<? super T>> list, T key) |
246 |
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{ |
247 |
jsr166 |
1.33 |
int low = 0; |
248 |
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int high = list.size()-1; |
249 |
dl |
1.1 |
ListIterator<? extends Comparable<? super T>> i = list.listIterator(); |
250 |
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251 |
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while (low <= high) { |
252 |
jsr166 |
1.25 |
int mid = (low + high) >>> 1; |
253 |
dl |
1.1 |
Comparable<? super T> midVal = get(i, mid); |
254 |
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int cmp = midVal.compareTo(key); |
255 |
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256 |
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if (cmp < 0) |
257 |
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low = mid + 1; |
258 |
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else if (cmp > 0) |
259 |
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high = mid - 1; |
260 |
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else |
261 |
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return mid; // key found |
262 |
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} |
263 |
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return -(low + 1); // key not found |
264 |
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} |
265 |
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266 |
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/** |
267 |
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* Gets the ith element from the given list by repositioning the specified |
268 |
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* list listIterator. |
269 |
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*/ |
270 |
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private static <T> T get(ListIterator<? extends T> i, int index) { |
271 |
jsr166 |
1.33 |
T obj = null; |
272 |
dl |
1.1 |
int pos = i.nextIndex(); |
273 |
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if (pos <= index) { |
274 |
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do { |
275 |
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obj = i.next(); |
276 |
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} while (pos++ < index); |
277 |
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} else { |
278 |
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do { |
279 |
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obj = i.previous(); |
280 |
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} while (--pos > index); |
281 |
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} |
282 |
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return obj; |
283 |
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} |
284 |
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|
285 |
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/** |
286 |
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* Searches the specified list for the specified object using the binary |
287 |
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* search algorithm. The list must be sorted into ascending order |
288 |
jsr166 |
1.25 |
* according to the specified comparator (as by the |
289 |
|
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* {@link #sort(List, Comparator) sort(List, Comparator)} |
290 |
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* method), prior to making this call. If it is |
291 |
dl |
1.1 |
* not sorted, the results are undefined. If the list contains multiple |
292 |
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* elements equal to the specified object, there is no guarantee which one |
293 |
jsr166 |
1.25 |
* will be found. |
294 |
dl |
1.1 |
* |
295 |
jsr166 |
1.25 |
* <p>This method runs in log(n) time for a "random access" list (which |
296 |
dl |
1.1 |
* provides near-constant-time positional access). If the specified list |
297 |
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* does not implement the {@link RandomAccess} interface and is large, |
298 |
|
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* this method will do an iterator-based binary search that performs |
299 |
|
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* O(n) link traversals and O(log n) element comparisons. |
300 |
|
|
* |
301 |
|
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* @param list the list to be searched. |
302 |
|
|
* @param key the key to be searched for. |
303 |
jsr166 |
1.25 |
* @param c the comparator by which the list is ordered. |
304 |
|
|
* A <tt>null</tt> value indicates that the elements' |
305 |
jsr166 |
1.33 |
* {@linkplain Comparable natural ordering} should be used. |
306 |
dl |
1.2 |
* @return the index of the search key, if it is contained in the list; |
307 |
jsr166 |
1.33 |
* otherwise, <tt>(-(<i>insertion point</i>) - 1)</tt>. The |
308 |
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* <i>insertion point</i> is defined as the point at which the |
309 |
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* key would be inserted into the list: the index of the first |
310 |
|
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* element greater than the key, or <tt>list.size()</tt> if all |
311 |
|
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* elements in the list are less than the specified key. Note |
312 |
|
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* that this guarantees that the return value will be >= 0 if |
313 |
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* and only if the key is found. |
314 |
dl |
1.1 |
* @throws ClassCastException if the list contains elements that are not |
315 |
jsr166 |
1.33 |
* <i>mutually comparable</i> using the specified comparator, |
316 |
|
|
* or the search key is not mutually comparable with the |
317 |
|
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* elements of the list using this comparator. |
318 |
dl |
1.1 |
*/ |
319 |
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public static <T> int binarySearch(List<? extends T> list, T key, Comparator<? super T> c) { |
320 |
|
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if (c==null) |
321 |
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return binarySearch((List) list, key); |
322 |
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|
323 |
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if (list instanceof RandomAccess || list.size()<BINARYSEARCH_THRESHOLD) |
324 |
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return Collections.indexedBinarySearch(list, key, c); |
325 |
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else |
326 |
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return Collections.iteratorBinarySearch(list, key, c); |
327 |
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} |
328 |
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|
329 |
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private static <T> int indexedBinarySearch(List<? extends T> l, T key, Comparator<? super T> c) { |
330 |
jsr166 |
1.33 |
int low = 0; |
331 |
|
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int high = l.size()-1; |
332 |
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|
333 |
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while (low <= high) { |
334 |
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int mid = (low + high) >>> 1; |
335 |
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T midVal = l.get(mid); |
336 |
|
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int cmp = c.compare(midVal, key); |
337 |
dl |
1.1 |
|
338 |
jsr166 |
1.33 |
if (cmp < 0) |
339 |
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low = mid + 1; |
340 |
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else if (cmp > 0) |
341 |
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high = mid - 1; |
342 |
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else |
343 |
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return mid; // key found |
344 |
|
|
} |
345 |
|
|
return -(low + 1); // key not found |
346 |
dl |
1.1 |
} |
347 |
|
|
|
348 |
|
|
private static <T> int iteratorBinarySearch(List<? extends T> l, T key, Comparator<? super T> c) { |
349 |
jsr166 |
1.33 |
int low = 0; |
350 |
|
|
int high = l.size()-1; |
351 |
dl |
1.1 |
ListIterator<? extends T> i = l.listIterator(); |
352 |
|
|
|
353 |
|
|
while (low <= high) { |
354 |
jsr166 |
1.25 |
int mid = (low + high) >>> 1; |
355 |
dl |
1.1 |
T midVal = get(i, mid); |
356 |
|
|
int cmp = c.compare(midVal, key); |
357 |
|
|
|
358 |
|
|
if (cmp < 0) |
359 |
|
|
low = mid + 1; |
360 |
|
|
else if (cmp > 0) |
361 |
|
|
high = mid - 1; |
362 |
|
|
else |
363 |
|
|
return mid; // key found |
364 |
|
|
} |
365 |
|
|
return -(low + 1); // key not found |
366 |
|
|
} |
367 |
|
|
|
368 |
|
|
private interface SelfComparable extends Comparable<SelfComparable> {} |
369 |
|
|
|
370 |
|
|
|
371 |
|
|
/** |
372 |
|
|
* Reverses the order of the elements in the specified list.<p> |
373 |
|
|
* |
374 |
|
|
* This method runs in linear time. |
375 |
|
|
* |
376 |
|
|
* @param list the list whose elements are to be reversed. |
377 |
|
|
* @throws UnsupportedOperationException if the specified list or |
378 |
jsr166 |
1.4 |
* its list-iterator does not support the <tt>set</tt> operation. |
379 |
dl |
1.1 |
*/ |
380 |
|
|
public static void reverse(List<?> list) { |
381 |
|
|
int size = list.size(); |
382 |
|
|
if (size < REVERSE_THRESHOLD || list instanceof RandomAccess) { |
383 |
|
|
for (int i=0, mid=size>>1, j=size-1; i<mid; i++, j--) |
384 |
|
|
swap(list, i, j); |
385 |
|
|
} else { |
386 |
|
|
ListIterator fwd = list.listIterator(); |
387 |
|
|
ListIterator rev = list.listIterator(size); |
388 |
|
|
for (int i=0, mid=list.size()>>1; i<mid; i++) { |
389 |
jsr166 |
1.33 |
Object tmp = fwd.next(); |
390 |
dl |
1.1 |
fwd.set(rev.previous()); |
391 |
|
|
rev.set(tmp); |
392 |
|
|
} |
393 |
|
|
} |
394 |
|
|
} |
395 |
|
|
|
396 |
|
|
/** |
397 |
|
|
* Randomly permutes the specified list using a default source of |
398 |
|
|
* randomness. All permutations occur with approximately equal |
399 |
|
|
* likelihood.<p> |
400 |
|
|
* |
401 |
|
|
* The hedge "approximately" is used in the foregoing description because |
402 |
|
|
* default source of randomness is only approximately an unbiased source |
403 |
|
|
* of independently chosen bits. If it were a perfect source of randomly |
404 |
|
|
* chosen bits, then the algorithm would choose permutations with perfect |
405 |
|
|
* uniformity.<p> |
406 |
|
|
* |
407 |
|
|
* This implementation traverses the list backwards, from the last element |
408 |
|
|
* up to the second, repeatedly swapping a randomly selected element into |
409 |
|
|
* the "current position". Elements are randomly selected from the |
410 |
|
|
* portion of the list that runs from the first element to the current |
411 |
|
|
* position, inclusive.<p> |
412 |
|
|
* |
413 |
|
|
* This method runs in linear time. If the specified list does not |
414 |
|
|
* implement the {@link RandomAccess} interface and is large, this |
415 |
|
|
* implementation dumps the specified list into an array before shuffling |
416 |
|
|
* it, and dumps the shuffled array back into the list. This avoids the |
417 |
|
|
* quadratic behavior that would result from shuffling a "sequential |
418 |
|
|
* access" list in place. |
419 |
|
|
* |
420 |
|
|
* @param list the list to be shuffled. |
421 |
|
|
* @throws UnsupportedOperationException if the specified list or |
422 |
jsr166 |
1.4 |
* its list-iterator does not support the <tt>set</tt> operation. |
423 |
dl |
1.1 |
*/ |
424 |
|
|
public static void shuffle(List<?> list) { |
425 |
jsr166 |
1.9 |
if (r == null) { |
426 |
|
|
r = new Random(); |
427 |
|
|
} |
428 |
dl |
1.1 |
shuffle(list, r); |
429 |
|
|
} |
430 |
jsr166 |
1.9 |
private static Random r; |
431 |
dl |
1.1 |
|
432 |
|
|
/** |
433 |
|
|
* Randomly permute the specified list using the specified source of |
434 |
|
|
* randomness. All permutations occur with equal likelihood |
435 |
|
|
* assuming that the source of randomness is fair.<p> |
436 |
|
|
* |
437 |
|
|
* This implementation traverses the list backwards, from the last element |
438 |
|
|
* up to the second, repeatedly swapping a randomly selected element into |
439 |
|
|
* the "current position". Elements are randomly selected from the |
440 |
|
|
* portion of the list that runs from the first element to the current |
441 |
|
|
* position, inclusive.<p> |
442 |
|
|
* |
443 |
|
|
* This method runs in linear time. If the specified list does not |
444 |
|
|
* implement the {@link RandomAccess} interface and is large, this |
445 |
|
|
* implementation dumps the specified list into an array before shuffling |
446 |
|
|
* it, and dumps the shuffled array back into the list. This avoids the |
447 |
|
|
* quadratic behavior that would result from shuffling a "sequential |
448 |
|
|
* access" list in place. |
449 |
|
|
* |
450 |
|
|
* @param list the list to be shuffled. |
451 |
|
|
* @param rnd the source of randomness to use to shuffle the list. |
452 |
|
|
* @throws UnsupportedOperationException if the specified list or its |
453 |
|
|
* list-iterator does not support the <tt>set</tt> operation. |
454 |
|
|
*/ |
455 |
|
|
public static void shuffle(List<?> list, Random rnd) { |
456 |
|
|
int size = list.size(); |
457 |
|
|
if (size < SHUFFLE_THRESHOLD || list instanceof RandomAccess) { |
458 |
|
|
for (int i=size; i>1; i--) |
459 |
|
|
swap(list, i-1, rnd.nextInt(i)); |
460 |
|
|
} else { |
461 |
|
|
Object arr[] = list.toArray(); |
462 |
|
|
|
463 |
|
|
// Shuffle array |
464 |
|
|
for (int i=size; i>1; i--) |
465 |
|
|
swap(arr, i-1, rnd.nextInt(i)); |
466 |
|
|
|
467 |
|
|
// Dump array back into list |
468 |
|
|
ListIterator it = list.listIterator(); |
469 |
|
|
for (int i=0; i<arr.length; i++) { |
470 |
|
|
it.next(); |
471 |
|
|
it.set(arr[i]); |
472 |
|
|
} |
473 |
|
|
} |
474 |
|
|
} |
475 |
|
|
|
476 |
|
|
/** |
477 |
|
|
* Swaps the elements at the specified positions in the specified list. |
478 |
|
|
* (If the specified positions are equal, invoking this method leaves |
479 |
|
|
* the list unchanged.) |
480 |
|
|
* |
481 |
|
|
* @param list The list in which to swap elements. |
482 |
|
|
* @param i the index of one element to be swapped. |
483 |
|
|
* @param j the index of the other element to be swapped. |
484 |
|
|
* @throws IndexOutOfBoundsException if either <tt>i</tt> or <tt>j</tt> |
485 |
|
|
* is out of range (i < 0 || i >= list.size() |
486 |
|
|
* || j < 0 || j >= list.size()). |
487 |
|
|
* @since 1.4 |
488 |
|
|
*/ |
489 |
|
|
public static void swap(List<?> list, int i, int j) { |
490 |
jsr166 |
1.33 |
final List l = list; |
491 |
|
|
l.set(i, l.set(j, l.get(i))); |
492 |
dl |
1.1 |
} |
493 |
|
|
|
494 |
|
|
/** |
495 |
|
|
* Swaps the two specified elements in the specified array. |
496 |
|
|
*/ |
497 |
|
|
private static void swap(Object[] arr, int i, int j) { |
498 |
|
|
Object tmp = arr[i]; |
499 |
|
|
arr[i] = arr[j]; |
500 |
|
|
arr[j] = tmp; |
501 |
|
|
} |
502 |
|
|
|
503 |
|
|
/** |
504 |
|
|
* Replaces all of the elements of the specified list with the specified |
505 |
|
|
* element. <p> |
506 |
|
|
* |
507 |
|
|
* This method runs in linear time. |
508 |
|
|
* |
509 |
|
|
* @param list the list to be filled with the specified element. |
510 |
|
|
* @param obj The element with which to fill the specified list. |
511 |
|
|
* @throws UnsupportedOperationException if the specified list or its |
512 |
jsr166 |
1.33 |
* list-iterator does not support the <tt>set</tt> operation. |
513 |
dl |
1.1 |
*/ |
514 |
|
|
public static <T> void fill(List<? super T> list, T obj) { |
515 |
|
|
int size = list.size(); |
516 |
|
|
|
517 |
|
|
if (size < FILL_THRESHOLD || list instanceof RandomAccess) { |
518 |
|
|
for (int i=0; i<size; i++) |
519 |
|
|
list.set(i, obj); |
520 |
|
|
} else { |
521 |
|
|
ListIterator<? super T> itr = list.listIterator(); |
522 |
|
|
for (int i=0; i<size; i++) { |
523 |
|
|
itr.next(); |
524 |
|
|
itr.set(obj); |
525 |
|
|
} |
526 |
|
|
} |
527 |
|
|
} |
528 |
|
|
|
529 |
|
|
/** |
530 |
|
|
* Copies all of the elements from one list into another. After the |
531 |
|
|
* operation, the index of each copied element in the destination list |
532 |
|
|
* will be identical to its index in the source list. The destination |
533 |
|
|
* list must be at least as long as the source list. If it is longer, the |
534 |
|
|
* remaining elements in the destination list are unaffected. <p> |
535 |
|
|
* |
536 |
|
|
* This method runs in linear time. |
537 |
|
|
* |
538 |
|
|
* @param dest The destination list. |
539 |
|
|
* @param src The source list. |
540 |
|
|
* @throws IndexOutOfBoundsException if the destination list is too small |
541 |
|
|
* to contain the entire source List. |
542 |
|
|
* @throws UnsupportedOperationException if the destination list's |
543 |
|
|
* list-iterator does not support the <tt>set</tt> operation. |
544 |
|
|
*/ |
545 |
|
|
public static <T> void copy(List<? super T> dest, List<? extends T> src) { |
546 |
|
|
int srcSize = src.size(); |
547 |
|
|
if (srcSize > dest.size()) |
548 |
|
|
throw new IndexOutOfBoundsException("Source does not fit in dest"); |
549 |
|
|
|
550 |
|
|
if (srcSize < COPY_THRESHOLD || |
551 |
|
|
(src instanceof RandomAccess && dest instanceof RandomAccess)) { |
552 |
|
|
for (int i=0; i<srcSize; i++) |
553 |
|
|
dest.set(i, src.get(i)); |
554 |
|
|
} else { |
555 |
|
|
ListIterator<? super T> di=dest.listIterator(); |
556 |
jsr166 |
1.33 |
ListIterator<? extends T> si=src.listIterator(); |
557 |
dl |
1.1 |
for (int i=0; i<srcSize; i++) { |
558 |
|
|
di.next(); |
559 |
|
|
di.set(si.next()); |
560 |
|
|
} |
561 |
|
|
} |
562 |
|
|
} |
563 |
|
|
|
564 |
|
|
/** |
565 |
|
|
* Returns the minimum element of the given collection, according to the |
566 |
|
|
* <i>natural ordering</i> of its elements. All elements in the |
567 |
|
|
* collection must implement the <tt>Comparable</tt> interface. |
568 |
|
|
* Furthermore, all elements in the collection must be <i>mutually |
569 |
|
|
* comparable</i> (that is, <tt>e1.compareTo(e2)</tt> must not throw a |
570 |
|
|
* <tt>ClassCastException</tt> for any elements <tt>e1</tt> and |
571 |
|
|
* <tt>e2</tt> in the collection).<p> |
572 |
|
|
* |
573 |
|
|
* This method iterates over the entire collection, hence it requires |
574 |
|
|
* time proportional to the size of the collection. |
575 |
|
|
* |
576 |
|
|
* @param coll the collection whose minimum element is to be determined. |
577 |
|
|
* @return the minimum element of the given collection, according |
578 |
|
|
* to the <i>natural ordering</i> of its elements. |
579 |
|
|
* @throws ClassCastException if the collection contains elements that are |
580 |
jsr166 |
1.33 |
* not <i>mutually comparable</i> (for example, strings and |
581 |
|
|
* integers). |
582 |
dl |
1.1 |
* @throws NoSuchElementException if the collection is empty. |
583 |
|
|
* @see Comparable |
584 |
|
|
*/ |
585 |
|
|
public static <T extends Object & Comparable<? super T>> T min(Collection<? extends T> coll) { |
586 |
jsr166 |
1.33 |
Iterator<? extends T> i = coll.iterator(); |
587 |
|
|
T candidate = i.next(); |
588 |
dl |
1.1 |
|
589 |
jsr166 |
1.6 |
while (i.hasNext()) { |
590 |
jsr166 |
1.33 |
T next = i.next(); |
591 |
|
|
if (next.compareTo(candidate) < 0) |
592 |
|
|
candidate = next; |
593 |
|
|
} |
594 |
|
|
return candidate; |
595 |
dl |
1.1 |
} |
596 |
|
|
|
597 |
|
|
/** |
598 |
|
|
* Returns the minimum element of the given collection, according to the |
599 |
|
|
* order induced by the specified comparator. All elements in the |
600 |
|
|
* collection must be <i>mutually comparable</i> by the specified |
601 |
|
|
* comparator (that is, <tt>comp.compare(e1, e2)</tt> must not throw a |
602 |
|
|
* <tt>ClassCastException</tt> for any elements <tt>e1</tt> and |
603 |
|
|
* <tt>e2</tt> in the collection).<p> |
604 |
|
|
* |
605 |
|
|
* This method iterates over the entire collection, hence it requires |
606 |
|
|
* time proportional to the size of the collection. |
607 |
|
|
* |
608 |
|
|
* @param coll the collection whose minimum element is to be determined. |
609 |
|
|
* @param comp the comparator with which to determine the minimum element. |
610 |
|
|
* A <tt>null</tt> value indicates that the elements' <i>natural |
611 |
|
|
* ordering</i> should be used. |
612 |
|
|
* @return the minimum element of the given collection, according |
613 |
|
|
* to the specified comparator. |
614 |
|
|
* @throws ClassCastException if the collection contains elements that are |
615 |
jsr166 |
1.33 |
* not <i>mutually comparable</i> using the specified comparator. |
616 |
dl |
1.1 |
* @throws NoSuchElementException if the collection is empty. |
617 |
|
|
* @see Comparable |
618 |
|
|
*/ |
619 |
|
|
public static <T> T min(Collection<? extends T> coll, Comparator<? super T> comp) { |
620 |
|
|
if (comp==null) |
621 |
|
|
return (T)min((Collection<SelfComparable>) (Collection) coll); |
622 |
|
|
|
623 |
jsr166 |
1.33 |
Iterator<? extends T> i = coll.iterator(); |
624 |
|
|
T candidate = i.next(); |
625 |
dl |
1.1 |
|
626 |
jsr166 |
1.6 |
while (i.hasNext()) { |
627 |
jsr166 |
1.33 |
T next = i.next(); |
628 |
|
|
if (comp.compare(next, candidate) < 0) |
629 |
|
|
candidate = next; |
630 |
|
|
} |
631 |
|
|
return candidate; |
632 |
dl |
1.1 |
} |
633 |
|
|
|
634 |
|
|
/** |
635 |
|
|
* Returns the maximum element of the given collection, according to the |
636 |
|
|
* <i>natural ordering</i> of its elements. All elements in the |
637 |
|
|
* collection must implement the <tt>Comparable</tt> interface. |
638 |
|
|
* Furthermore, all elements in the collection must be <i>mutually |
639 |
|
|
* comparable</i> (that is, <tt>e1.compareTo(e2)</tt> must not throw a |
640 |
|
|
* <tt>ClassCastException</tt> for any elements <tt>e1</tt> and |
641 |
|
|
* <tt>e2</tt> in the collection).<p> |
642 |
|
|
* |
643 |
|
|
* This method iterates over the entire collection, hence it requires |
644 |
|
|
* time proportional to the size of the collection. |
645 |
|
|
* |
646 |
|
|
* @param coll the collection whose maximum element is to be determined. |
647 |
|
|
* @return the maximum element of the given collection, according |
648 |
|
|
* to the <i>natural ordering</i> of its elements. |
649 |
|
|
* @throws ClassCastException if the collection contains elements that are |
650 |
jsr166 |
1.33 |
* not <i>mutually comparable</i> (for example, strings and |
651 |
dl |
1.1 |
* integers). |
652 |
|
|
* @throws NoSuchElementException if the collection is empty. |
653 |
|
|
* @see Comparable |
654 |
|
|
*/ |
655 |
|
|
public static <T extends Object & Comparable<? super T>> T max(Collection<? extends T> coll) { |
656 |
jsr166 |
1.33 |
Iterator<? extends T> i = coll.iterator(); |
657 |
|
|
T candidate = i.next(); |
658 |
dl |
1.1 |
|
659 |
jsr166 |
1.6 |
while (i.hasNext()) { |
660 |
jsr166 |
1.33 |
T next = i.next(); |
661 |
|
|
if (next.compareTo(candidate) > 0) |
662 |
|
|
candidate = next; |
663 |
|
|
} |
664 |
|
|
return candidate; |
665 |
dl |
1.1 |
} |
666 |
|
|
|
667 |
|
|
/** |
668 |
|
|
* Returns the maximum element of the given collection, according to the |
669 |
|
|
* order induced by the specified comparator. All elements in the |
670 |
|
|
* collection must be <i>mutually comparable</i> by the specified |
671 |
|
|
* comparator (that is, <tt>comp.compare(e1, e2)</tt> must not throw a |
672 |
|
|
* <tt>ClassCastException</tt> for any elements <tt>e1</tt> and |
673 |
|
|
* <tt>e2</tt> in the collection).<p> |
674 |
|
|
* |
675 |
|
|
* This method iterates over the entire collection, hence it requires |
676 |
|
|
* time proportional to the size of the collection. |
677 |
|
|
* |
678 |
|
|
* @param coll the collection whose maximum element is to be determined. |
679 |
|
|
* @param comp the comparator with which to determine the maximum element. |
680 |
|
|
* A <tt>null</tt> value indicates that the elements' <i>natural |
681 |
|
|
* ordering</i> should be used. |
682 |
|
|
* @return the maximum element of the given collection, according |
683 |
|
|
* to the specified comparator. |
684 |
|
|
* @throws ClassCastException if the collection contains elements that are |
685 |
jsr166 |
1.33 |
* not <i>mutually comparable</i> using the specified comparator. |
686 |
dl |
1.1 |
* @throws NoSuchElementException if the collection is empty. |
687 |
|
|
* @see Comparable |
688 |
|
|
*/ |
689 |
|
|
public static <T> T max(Collection<? extends T> coll, Comparator<? super T> comp) { |
690 |
|
|
if (comp==null) |
691 |
|
|
return (T)max((Collection<SelfComparable>) (Collection) coll); |
692 |
|
|
|
693 |
jsr166 |
1.33 |
Iterator<? extends T> i = coll.iterator(); |
694 |
|
|
T candidate = i.next(); |
695 |
dl |
1.1 |
|
696 |
jsr166 |
1.6 |
while (i.hasNext()) { |
697 |
jsr166 |
1.33 |
T next = i.next(); |
698 |
|
|
if (comp.compare(next, candidate) > 0) |
699 |
|
|
candidate = next; |
700 |
|
|
} |
701 |
|
|
return candidate; |
702 |
dl |
1.1 |
} |
703 |
|
|
|
704 |
|
|
/** |
705 |
|
|
* Rotates the elements in the specified list by the specified distance. |
706 |
|
|
* After calling this method, the element at index <tt>i</tt> will be |
707 |
|
|
* the element previously at index <tt>(i - distance)</tt> mod |
708 |
|
|
* <tt>list.size()</tt>, for all values of <tt>i</tt> between <tt>0</tt> |
709 |
|
|
* and <tt>list.size()-1</tt>, inclusive. (This method has no effect on |
710 |
|
|
* the size of the list.) |
711 |
|
|
* |
712 |
|
|
* <p>For example, suppose <tt>list</tt> comprises<tt> [t, a, n, k, s]</tt>. |
713 |
|
|
* After invoking <tt>Collections.rotate(list, 1)</tt> (or |
714 |
|
|
* <tt>Collections.rotate(list, -4)</tt>), <tt>list</tt> will comprise |
715 |
|
|
* <tt>[s, t, a, n, k]</tt>. |
716 |
|
|
* |
717 |
|
|
* <p>Note that this method can usefully be applied to sublists to |
718 |
|
|
* move one or more elements within a list while preserving the |
719 |
|
|
* order of the remaining elements. For example, the following idiom |
720 |
|
|
* moves the element at index <tt>j</tt> forward to position |
721 |
|
|
* <tt>k</tt> (which must be greater than or equal to <tt>j</tt>): |
722 |
|
|
* <pre> |
723 |
|
|
* Collections.rotate(list.subList(j, k+1), -1); |
724 |
|
|
* </pre> |
725 |
|
|
* To make this concrete, suppose <tt>list</tt> comprises |
726 |
|
|
* <tt>[a, b, c, d, e]</tt>. To move the element at index <tt>1</tt> |
727 |
|
|
* (<tt>b</tt>) forward two positions, perform the following invocation: |
728 |
|
|
* <pre> |
729 |
|
|
* Collections.rotate(l.subList(1, 4), -1); |
730 |
|
|
* </pre> |
731 |
|
|
* The resulting list is <tt>[a, c, d, b, e]</tt>. |
732 |
jsr166 |
1.4 |
* |
733 |
dl |
1.1 |
* <p>To move more than one element forward, increase the absolute value |
734 |
|
|
* of the rotation distance. To move elements backward, use a positive |
735 |
|
|
* shift distance. |
736 |
|
|
* |
737 |
|
|
* <p>If the specified list is small or implements the {@link |
738 |
|
|
* RandomAccess} interface, this implementation exchanges the first |
739 |
|
|
* element into the location it should go, and then repeatedly exchanges |
740 |
|
|
* the displaced element into the location it should go until a displaced |
741 |
|
|
* element is swapped into the first element. If necessary, the process |
742 |
|
|
* is repeated on the second and successive elements, until the rotation |
743 |
|
|
* is complete. If the specified list is large and doesn't implement the |
744 |
|
|
* <tt>RandomAccess</tt> interface, this implementation breaks the |
745 |
|
|
* list into two sublist views around index <tt>-distance mod size</tt>. |
746 |
|
|
* Then the {@link #reverse(List)} method is invoked on each sublist view, |
747 |
|
|
* and finally it is invoked on the entire list. For a more complete |
748 |
|
|
* description of both algorithms, see Section 2.3 of Jon Bentley's |
749 |
|
|
* <i>Programming Pearls</i> (Addison-Wesley, 1986). |
750 |
|
|
* |
751 |
|
|
* @param list the list to be rotated. |
752 |
|
|
* @param distance the distance to rotate the list. There are no |
753 |
|
|
* constraints on this value; it may be zero, negative, or |
754 |
|
|
* greater than <tt>list.size()</tt>. |
755 |
|
|
* @throws UnsupportedOperationException if the specified list or |
756 |
jsr166 |
1.4 |
* its list-iterator does not support the <tt>set</tt> operation. |
757 |
dl |
1.1 |
* @since 1.4 |
758 |
|
|
*/ |
759 |
|
|
public static void rotate(List<?> list, int distance) { |
760 |
|
|
if (list instanceof RandomAccess || list.size() < ROTATE_THRESHOLD) |
761 |
jsr166 |
1.32 |
rotate1(list, distance); |
762 |
dl |
1.1 |
else |
763 |
jsr166 |
1.32 |
rotate2(list, distance); |
764 |
dl |
1.1 |
} |
765 |
|
|
|
766 |
|
|
private static <T> void rotate1(List<T> list, int distance) { |
767 |
|
|
int size = list.size(); |
768 |
|
|
if (size == 0) |
769 |
|
|
return; |
770 |
|
|
distance = distance % size; |
771 |
|
|
if (distance < 0) |
772 |
|
|
distance += size; |
773 |
|
|
if (distance == 0) |
774 |
|
|
return; |
775 |
|
|
|
776 |
|
|
for (int cycleStart = 0, nMoved = 0; nMoved != size; cycleStart++) { |
777 |
|
|
T displaced = list.get(cycleStart); |
778 |
|
|
int i = cycleStart; |
779 |
|
|
do { |
780 |
|
|
i += distance; |
781 |
|
|
if (i >= size) |
782 |
|
|
i -= size; |
783 |
|
|
displaced = list.set(i, displaced); |
784 |
|
|
nMoved ++; |
785 |
|
|
} while(i != cycleStart); |
786 |
|
|
} |
787 |
|
|
} |
788 |
|
|
|
789 |
|
|
private static void rotate2(List<?> list, int distance) { |
790 |
|
|
int size = list.size(); |
791 |
|
|
if (size == 0) |
792 |
jsr166 |
1.4 |
return; |
793 |
dl |
1.1 |
int mid = -distance % size; |
794 |
|
|
if (mid < 0) |
795 |
|
|
mid += size; |
796 |
|
|
if (mid == 0) |
797 |
|
|
return; |
798 |
|
|
|
799 |
|
|
reverse(list.subList(0, mid)); |
800 |
|
|
reverse(list.subList(mid, size)); |
801 |
|
|
reverse(list); |
802 |
|
|
} |
803 |
|
|
|
804 |
|
|
/** |
805 |
|
|
* Replaces all occurrences of one specified value in a list with another. |
806 |
|
|
* More formally, replaces with <tt>newVal</tt> each element <tt>e</tt> |
807 |
|
|
* in <tt>list</tt> such that |
808 |
|
|
* <tt>(oldVal==null ? e==null : oldVal.equals(e))</tt>. |
809 |
|
|
* (This method has no effect on the size of the list.) |
810 |
|
|
* |
811 |
|
|
* @param list the list in which replacement is to occur. |
812 |
|
|
* @param oldVal the old value to be replaced. |
813 |
|
|
* @param newVal the new value with which <tt>oldVal</tt> is to be |
814 |
|
|
* replaced. |
815 |
|
|
* @return <tt>true</tt> if <tt>list</tt> contained one or more elements |
816 |
|
|
* <tt>e</tt> such that |
817 |
|
|
* <tt>(oldVal==null ? e==null : oldVal.equals(e))</tt>. |
818 |
|
|
* @throws UnsupportedOperationException if the specified list or |
819 |
jsr166 |
1.4 |
* its list-iterator does not support the <tt>set</tt> operation. |
820 |
dl |
1.1 |
* @since 1.4 |
821 |
|
|
*/ |
822 |
|
|
public static <T> boolean replaceAll(List<T> list, T oldVal, T newVal) { |
823 |
|
|
boolean result = false; |
824 |
|
|
int size = list.size(); |
825 |
|
|
if (size < REPLACEALL_THRESHOLD || list instanceof RandomAccess) { |
826 |
|
|
if (oldVal==null) { |
827 |
|
|
for (int i=0; i<size; i++) { |
828 |
|
|
if (list.get(i)==null) { |
829 |
|
|
list.set(i, newVal); |
830 |
|
|
result = true; |
831 |
|
|
} |
832 |
|
|
} |
833 |
|
|
} else { |
834 |
|
|
for (int i=0; i<size; i++) { |
835 |
|
|
if (oldVal.equals(list.get(i))) { |
836 |
|
|
list.set(i, newVal); |
837 |
|
|
result = true; |
838 |
|
|
} |
839 |
|
|
} |
840 |
|
|
} |
841 |
|
|
} else { |
842 |
|
|
ListIterator<T> itr=list.listIterator(); |
843 |
|
|
if (oldVal==null) { |
844 |
|
|
for (int i=0; i<size; i++) { |
845 |
|
|
if (itr.next()==null) { |
846 |
|
|
itr.set(newVal); |
847 |
|
|
result = true; |
848 |
|
|
} |
849 |
|
|
} |
850 |
|
|
} else { |
851 |
|
|
for (int i=0; i<size; i++) { |
852 |
|
|
if (oldVal.equals(itr.next())) { |
853 |
|
|
itr.set(newVal); |
854 |
|
|
result = true; |
855 |
|
|
} |
856 |
|
|
} |
857 |
|
|
} |
858 |
|
|
} |
859 |
|
|
return result; |
860 |
|
|
} |
861 |
|
|
|
862 |
|
|
/** |
863 |
|
|
* Returns the starting position of the first occurrence of the specified |
864 |
|
|
* target list within the specified source list, or -1 if there is no |
865 |
|
|
* such occurrence. More formally, returns the lowest index <tt>i</tt> |
866 |
|
|
* such that <tt>source.subList(i, i+target.size()).equals(target)</tt>, |
867 |
|
|
* or -1 if there is no such index. (Returns -1 if |
868 |
|
|
* <tt>target.size() > source.size()</tt>.) |
869 |
|
|
* |
870 |
|
|
* <p>This implementation uses the "brute force" technique of scanning |
871 |
|
|
* over the source list, looking for a match with the target at each |
872 |
|
|
* location in turn. |
873 |
|
|
* |
874 |
|
|
* @param source the list in which to search for the first occurrence |
875 |
|
|
* of <tt>target</tt>. |
876 |
|
|
* @param target the list to search for as a subList of <tt>source</tt>. |
877 |
|
|
* @return the starting position of the first occurrence of the specified |
878 |
|
|
* target list within the specified source list, or -1 if there |
879 |
|
|
* is no such occurrence. |
880 |
|
|
* @since 1.4 |
881 |
|
|
*/ |
882 |
|
|
public static int indexOfSubList(List<?> source, List<?> target) { |
883 |
|
|
int sourceSize = source.size(); |
884 |
|
|
int targetSize = target.size(); |
885 |
|
|
int maxCandidate = sourceSize - targetSize; |
886 |
|
|
|
887 |
|
|
if (sourceSize < INDEXOFSUBLIST_THRESHOLD || |
888 |
|
|
(source instanceof RandomAccess&&target instanceof RandomAccess)) { |
889 |
|
|
nextCand: |
890 |
|
|
for (int candidate = 0; candidate <= maxCandidate; candidate++) { |
891 |
|
|
for (int i=0, j=candidate; i<targetSize; i++, j++) |
892 |
|
|
if (!eq(target.get(i), source.get(j))) |
893 |
|
|
continue nextCand; // Element mismatch, try next cand |
894 |
|
|
return candidate; // All elements of candidate matched target |
895 |
|
|
} |
896 |
|
|
} else { // Iterator version of above algorithm |
897 |
|
|
ListIterator<?> si = source.listIterator(); |
898 |
|
|
nextCand: |
899 |
|
|
for (int candidate = 0; candidate <= maxCandidate; candidate++) { |
900 |
|
|
ListIterator<?> ti = target.listIterator(); |
901 |
|
|
for (int i=0; i<targetSize; i++) { |
902 |
|
|
if (!eq(ti.next(), si.next())) { |
903 |
|
|
// Back up source iterator to next candidate |
904 |
|
|
for (int j=0; j<i; j++) |
905 |
|
|
si.previous(); |
906 |
|
|
continue nextCand; |
907 |
|
|
} |
908 |
|
|
} |
909 |
|
|
return candidate; |
910 |
|
|
} |
911 |
|
|
} |
912 |
|
|
return -1; // No candidate matched the target |
913 |
|
|
} |
914 |
|
|
|
915 |
|
|
/** |
916 |
|
|
* Returns the starting position of the last occurrence of the specified |
917 |
|
|
* target list within the specified source list, or -1 if there is no such |
918 |
|
|
* occurrence. More formally, returns the highest index <tt>i</tt> |
919 |
|
|
* such that <tt>source.subList(i, i+target.size()).equals(target)</tt>, |
920 |
|
|
* or -1 if there is no such index. (Returns -1 if |
921 |
|
|
* <tt>target.size() > source.size()</tt>.) |
922 |
|
|
* |
923 |
|
|
* <p>This implementation uses the "brute force" technique of iterating |
924 |
|
|
* over the source list, looking for a match with the target at each |
925 |
|
|
* location in turn. |
926 |
|
|
* |
927 |
|
|
* @param source the list in which to search for the last occurrence |
928 |
|
|
* of <tt>target</tt>. |
929 |
|
|
* @param target the list to search for as a subList of <tt>source</tt>. |
930 |
|
|
* @return the starting position of the last occurrence of the specified |
931 |
|
|
* target list within the specified source list, or -1 if there |
932 |
|
|
* is no such occurrence. |
933 |
|
|
* @since 1.4 |
934 |
|
|
*/ |
935 |
|
|
public static int lastIndexOfSubList(List<?> source, List<?> target) { |
936 |
|
|
int sourceSize = source.size(); |
937 |
|
|
int targetSize = target.size(); |
938 |
|
|
int maxCandidate = sourceSize - targetSize; |
939 |
|
|
|
940 |
|
|
if (sourceSize < INDEXOFSUBLIST_THRESHOLD || |
941 |
|
|
source instanceof RandomAccess) { // Index access version |
942 |
|
|
nextCand: |
943 |
|
|
for (int candidate = maxCandidate; candidate >= 0; candidate--) { |
944 |
|
|
for (int i=0, j=candidate; i<targetSize; i++, j++) |
945 |
|
|
if (!eq(target.get(i), source.get(j))) |
946 |
|
|
continue nextCand; // Element mismatch, try next cand |
947 |
|
|
return candidate; // All elements of candidate matched target |
948 |
|
|
} |
949 |
|
|
} else { // Iterator version of above algorithm |
950 |
|
|
if (maxCandidate < 0) |
951 |
|
|
return -1; |
952 |
|
|
ListIterator<?> si = source.listIterator(maxCandidate); |
953 |
|
|
nextCand: |
954 |
|
|
for (int candidate = maxCandidate; candidate >= 0; candidate--) { |
955 |
|
|
ListIterator<?> ti = target.listIterator(); |
956 |
|
|
for (int i=0; i<targetSize; i++) { |
957 |
|
|
if (!eq(ti.next(), si.next())) { |
958 |
|
|
if (candidate != 0) { |
959 |
|
|
// Back up source iterator to next candidate |
960 |
|
|
for (int j=0; j<=i+1; j++) |
961 |
|
|
si.previous(); |
962 |
|
|
} |
963 |
|
|
continue nextCand; |
964 |
|
|
} |
965 |
|
|
} |
966 |
|
|
return candidate; |
967 |
|
|
} |
968 |
|
|
} |
969 |
|
|
return -1; // No candidate matched the target |
970 |
|
|
} |
971 |
|
|
|
972 |
|
|
|
973 |
|
|
// Unmodifiable Wrappers |
974 |
|
|
|
975 |
|
|
/** |
976 |
|
|
* Returns an unmodifiable view of the specified collection. This method |
977 |
|
|
* allows modules to provide users with "read-only" access to internal |
978 |
|
|
* collections. Query operations on the returned collection "read through" |
979 |
|
|
* to the specified collection, and attempts to modify the returned |
980 |
|
|
* collection, whether direct or via its iterator, result in an |
981 |
|
|
* <tt>UnsupportedOperationException</tt>.<p> |
982 |
|
|
* |
983 |
|
|
* The returned collection does <i>not</i> pass the hashCode and equals |
984 |
|
|
* operations through to the backing collection, but relies on |
985 |
|
|
* <tt>Object</tt>'s <tt>equals</tt> and <tt>hashCode</tt> methods. This |
986 |
|
|
* is necessary to preserve the contracts of these operations in the case |
987 |
|
|
* that the backing collection is a set or a list.<p> |
988 |
|
|
* |
989 |
|
|
* The returned collection will be serializable if the specified collection |
990 |
jsr166 |
1.4 |
* is serializable. |
991 |
dl |
1.1 |
* |
992 |
|
|
* @param c the collection for which an unmodifiable view is to be |
993 |
jsr166 |
1.33 |
* returned. |
994 |
dl |
1.1 |
* @return an unmodifiable view of the specified collection. |
995 |
|
|
*/ |
996 |
|
|
public static <T> Collection<T> unmodifiableCollection(Collection<? extends T> c) { |
997 |
jsr166 |
1.33 |
return new UnmodifiableCollection<T>(c); |
998 |
dl |
1.1 |
} |
999 |
|
|
|
1000 |
|
|
/** |
1001 |
|
|
* @serial include |
1002 |
|
|
*/ |
1003 |
|
|
static class UnmodifiableCollection<E> implements Collection<E>, Serializable { |
1004 |
jsr166 |
1.33 |
private static final long serialVersionUID = 1820017752578914078L; |
1005 |
dl |
1.1 |
|
1006 |
jsr166 |
1.33 |
final Collection<? extends E> c; |
1007 |
dl |
1.1 |
|
1008 |
jsr166 |
1.33 |
UnmodifiableCollection(Collection<? extends E> c) { |
1009 |
dl |
1.1 |
if (c==null) |
1010 |
|
|
throw new NullPointerException(); |
1011 |
|
|
this.c = c; |
1012 |
|
|
} |
1013 |
|
|
|
1014 |
jsr166 |
1.33 |
public int size() {return c.size();} |
1015 |
|
|
public boolean isEmpty() {return c.isEmpty();} |
1016 |
|
|
public boolean contains(Object o) {return c.contains(o);} |
1017 |
|
|
public Object[] toArray() {return c.toArray();} |
1018 |
|
|
public <T> T[] toArray(T[] a) {return c.toArray(a);} |
1019 |
dl |
1.1 |
public String toString() {return c.toString();} |
1020 |
|
|
|
1021 |
jsr166 |
1.33 |
public Iterator<E> iterator() { |
1022 |
|
|
return new Iterator<E>() { |
1023 |
|
|
private final Iterator<? extends E> i = c.iterator(); |
1024 |
|
|
|
1025 |
|
|
public boolean hasNext() {return i.hasNext();} |
1026 |
|
|
public E next() {return i.next();} |
1027 |
|
|
public void remove() { |
1028 |
|
|
throw new UnsupportedOperationException(); |
1029 |
dl |
1.1 |
} |
1030 |
jsr166 |
1.33 |
}; |
1031 |
dl |
1.1 |
} |
1032 |
|
|
|
1033 |
jsr166 |
1.33 |
public boolean add(E e) { |
1034 |
|
|
throw new UnsupportedOperationException(); |
1035 |
dl |
1.1 |
} |
1036 |
jsr166 |
1.33 |
public boolean remove(Object o) { |
1037 |
|
|
throw new UnsupportedOperationException(); |
1038 |
dl |
1.1 |
} |
1039 |
|
|
|
1040 |
jsr166 |
1.33 |
public boolean containsAll(Collection<?> coll) { |
1041 |
|
|
return c.containsAll(coll); |
1042 |
dl |
1.1 |
} |
1043 |
jsr166 |
1.33 |
public boolean addAll(Collection<? extends E> coll) { |
1044 |
|
|
throw new UnsupportedOperationException(); |
1045 |
dl |
1.1 |
} |
1046 |
jsr166 |
1.33 |
public boolean removeAll(Collection<?> coll) { |
1047 |
|
|
throw new UnsupportedOperationException(); |
1048 |
dl |
1.1 |
} |
1049 |
jsr166 |
1.33 |
public boolean retainAll(Collection<?> coll) { |
1050 |
|
|
throw new UnsupportedOperationException(); |
1051 |
dl |
1.1 |
} |
1052 |
jsr166 |
1.33 |
public void clear() { |
1053 |
|
|
throw new UnsupportedOperationException(); |
1054 |
dl |
1.1 |
} |
1055 |
|
|
} |
1056 |
|
|
|
1057 |
|
|
/** |
1058 |
|
|
* Returns an unmodifiable view of the specified set. This method allows |
1059 |
|
|
* modules to provide users with "read-only" access to internal sets. |
1060 |
|
|
* Query operations on the returned set "read through" to the specified |
1061 |
|
|
* set, and attempts to modify the returned set, whether direct or via its |
1062 |
|
|
* iterator, result in an <tt>UnsupportedOperationException</tt>.<p> |
1063 |
|
|
* |
1064 |
|
|
* The returned set will be serializable if the specified set |
1065 |
jsr166 |
1.4 |
* is serializable. |
1066 |
dl |
1.1 |
* |
1067 |
|
|
* @param s the set for which an unmodifiable view is to be returned. |
1068 |
|
|
* @return an unmodifiable view of the specified set. |
1069 |
|
|
*/ |
1070 |
|
|
public static <T> Set<T> unmodifiableSet(Set<? extends T> s) { |
1071 |
jsr166 |
1.33 |
return new UnmodifiableSet<T>(s); |
1072 |
dl |
1.1 |
} |
1073 |
|
|
|
1074 |
|
|
/** |
1075 |
|
|
* @serial include |
1076 |
|
|
*/ |
1077 |
|
|
static class UnmodifiableSet<E> extends UnmodifiableCollection<E> |
1078 |
jsr166 |
1.33 |
implements Set<E>, Serializable { |
1079 |
|
|
private static final long serialVersionUID = -9215047833775013803L; |
1080 |
dl |
1.1 |
|
1081 |
jsr166 |
1.33 |
UnmodifiableSet(Set<? extends E> s) {super(s);} |
1082 |
|
|
public boolean equals(Object o) {return o == this || c.equals(o);} |
1083 |
|
|
public int hashCode() {return c.hashCode();} |
1084 |
dl |
1.1 |
} |
1085 |
|
|
|
1086 |
|
|
/** |
1087 |
|
|
* Returns an unmodifiable view of the specified sorted set. This method |
1088 |
|
|
* allows modules to provide users with "read-only" access to internal |
1089 |
|
|
* sorted sets. Query operations on the returned sorted set "read |
1090 |
|
|
* through" to the specified sorted set. Attempts to modify the returned |
1091 |
|
|
* sorted set, whether direct, via its iterator, or via its |
1092 |
|
|
* <tt>subSet</tt>, <tt>headSet</tt>, or <tt>tailSet</tt> views, result in |
1093 |
|
|
* an <tt>UnsupportedOperationException</tt>.<p> |
1094 |
|
|
* |
1095 |
|
|
* The returned sorted set will be serializable if the specified sorted set |
1096 |
jsr166 |
1.4 |
* is serializable. |
1097 |
dl |
1.1 |
* |
1098 |
|
|
* @param s the sorted set for which an unmodifiable view is to be |
1099 |
jsr166 |
1.4 |
* returned. |
1100 |
dl |
1.1 |
* @return an unmodifiable view of the specified sorted set. |
1101 |
|
|
*/ |
1102 |
|
|
public static <T> SortedSet<T> unmodifiableSortedSet(SortedSet<T> s) { |
1103 |
jsr166 |
1.33 |
return new UnmodifiableSortedSet<T>(s); |
1104 |
dl |
1.1 |
} |
1105 |
|
|
|
1106 |
|
|
/** |
1107 |
|
|
* @serial include |
1108 |
|
|
*/ |
1109 |
|
|
static class UnmodifiableSortedSet<E> |
1110 |
jsr166 |
1.33 |
extends UnmodifiableSet<E> |
1111 |
|
|
implements SortedSet<E>, Serializable { |
1112 |
|
|
private static final long serialVersionUID = -4929149591599911165L; |
1113 |
dl |
1.1 |
private final SortedSet<E> ss; |
1114 |
|
|
|
1115 |
jsr166 |
1.33 |
UnmodifiableSortedSet(SortedSet<E> s) {super(s); ss = s;} |
1116 |
dl |
1.1 |
|
1117 |
|
|
public Comparator<? super E> comparator() {return ss.comparator();} |
1118 |
|
|
|
1119 |
|
|
public SortedSet<E> subSet(E fromElement, E toElement) { |
1120 |
|
|
return new UnmodifiableSortedSet<E>(ss.subSet(fromElement,toElement)); |
1121 |
|
|
} |
1122 |
|
|
public SortedSet<E> headSet(E toElement) { |
1123 |
|
|
return new UnmodifiableSortedSet<E>(ss.headSet(toElement)); |
1124 |
|
|
} |
1125 |
|
|
public SortedSet<E> tailSet(E fromElement) { |
1126 |
|
|
return new UnmodifiableSortedSet<E>(ss.tailSet(fromElement)); |
1127 |
|
|
} |
1128 |
|
|
|
1129 |
jsr166 |
1.33 |
public E first() {return ss.first();} |
1130 |
|
|
public E last() {return ss.last();} |
1131 |
dl |
1.1 |
} |
1132 |
|
|
|
1133 |
|
|
/** |
1134 |
|
|
* Returns an unmodifiable view of the specified list. This method allows |
1135 |
|
|
* modules to provide users with "read-only" access to internal |
1136 |
|
|
* lists. Query operations on the returned list "read through" to the |
1137 |
|
|
* specified list, and attempts to modify the returned list, whether |
1138 |
|
|
* direct or via its iterator, result in an |
1139 |
|
|
* <tt>UnsupportedOperationException</tt>.<p> |
1140 |
|
|
* |
1141 |
|
|
* The returned list will be serializable if the specified list |
1142 |
|
|
* is serializable. Similarly, the returned list will implement |
1143 |
|
|
* {@link RandomAccess} if the specified list does. |
1144 |
|
|
* |
1145 |
|
|
* @param list the list for which an unmodifiable view is to be returned. |
1146 |
|
|
* @return an unmodifiable view of the specified list. |
1147 |
|
|
*/ |
1148 |
|
|
public static <T> List<T> unmodifiableList(List<? extends T> list) { |
1149 |
jsr166 |
1.33 |
return (list instanceof RandomAccess ? |
1150 |
dl |
1.1 |
new UnmodifiableRandomAccessList<T>(list) : |
1151 |
|
|
new UnmodifiableList<T>(list)); |
1152 |
|
|
} |
1153 |
|
|
|
1154 |
|
|
/** |
1155 |
|
|
* @serial include |
1156 |
|
|
*/ |
1157 |
|
|
static class UnmodifiableList<E> extends UnmodifiableCollection<E> |
1158 |
jsr166 |
1.33 |
implements List<E> { |
1159 |
jsr166 |
1.32 |
private static final long serialVersionUID = -283967356065247728L; |
1160 |
jsr166 |
1.33 |
final List<? extends E> list; |
1161 |
|
|
|
1162 |
|
|
UnmodifiableList(List<? extends E> list) { |
1163 |
|
|
super(list); |
1164 |
|
|
this.list = list; |
1165 |
|
|
} |
1166 |
dl |
1.1 |
|
1167 |
jsr166 |
1.33 |
public boolean equals(Object o) {return o == this || list.equals(o);} |
1168 |
|
|
public int hashCode() {return list.hashCode();} |
1169 |
dl |
1.1 |
|
1170 |
jsr166 |
1.33 |
public E get(int index) {return list.get(index);} |
1171 |
|
|
public E set(int index, E element) { |
1172 |
|
|
throw new UnsupportedOperationException(); |
1173 |
|
|
} |
1174 |
|
|
public void add(int index, E element) { |
1175 |
|
|
throw new UnsupportedOperationException(); |
1176 |
|
|
} |
1177 |
|
|
public E remove(int index) { |
1178 |
|
|
throw new UnsupportedOperationException(); |
1179 |
|
|
} |
1180 |
|
|
public int indexOf(Object o) {return list.indexOf(o);} |
1181 |
|
|
public int lastIndexOf(Object o) {return list.lastIndexOf(o);} |
1182 |
|
|
public boolean addAll(int index, Collection<? extends E> c) { |
1183 |
|
|
throw new UnsupportedOperationException(); |
1184 |
|
|
} |
1185 |
|
|
public ListIterator<E> listIterator() {return listIterator(0);} |
1186 |
|
|
|
1187 |
|
|
public ListIterator<E> listIterator(final int index) { |
1188 |
|
|
return new ListIterator<E>() { |
1189 |
|
|
private final ListIterator<? extends E> i |
1190 |
|
|
= list.listIterator(index); |
1191 |
|
|
|
1192 |
|
|
public boolean hasNext() {return i.hasNext();} |
1193 |
|
|
public E next() {return i.next();} |
1194 |
|
|
public boolean hasPrevious() {return i.hasPrevious();} |
1195 |
|
|
public E previous() {return i.previous();} |
1196 |
|
|
public int nextIndex() {return i.nextIndex();} |
1197 |
|
|
public int previousIndex() {return i.previousIndex();} |
1198 |
|
|
|
1199 |
|
|
public void remove() { |
1200 |
|
|
throw new UnsupportedOperationException(); |
1201 |
dl |
1.1 |
} |
1202 |
jsr166 |
1.33 |
public void set(E e) { |
1203 |
|
|
throw new UnsupportedOperationException(); |
1204 |
dl |
1.1 |
} |
1205 |
jsr166 |
1.33 |
public void add(E e) { |
1206 |
|
|
throw new UnsupportedOperationException(); |
1207 |
dl |
1.1 |
} |
1208 |
jsr166 |
1.33 |
}; |
1209 |
|
|
} |
1210 |
dl |
1.1 |
|
1211 |
jsr166 |
1.33 |
public List<E> subList(int fromIndex, int toIndex) { |
1212 |
dl |
1.1 |
return new UnmodifiableList<E>(list.subList(fromIndex, toIndex)); |
1213 |
|
|
} |
1214 |
|
|
|
1215 |
|
|
/** |
1216 |
|
|
* UnmodifiableRandomAccessList instances are serialized as |
1217 |
|
|
* UnmodifiableList instances to allow them to be deserialized |
1218 |
|
|
* in pre-1.4 JREs (which do not have UnmodifiableRandomAccessList). |
1219 |
|
|
* This method inverts the transformation. As a beneficial |
1220 |
|
|
* side-effect, it also grafts the RandomAccess marker onto |
1221 |
|
|
* UnmodifiableList instances that were serialized in pre-1.4 JREs. |
1222 |
|
|
* |
1223 |
|
|
* Note: Unfortunately, UnmodifiableRandomAccessList instances |
1224 |
|
|
* serialized in 1.4.1 and deserialized in 1.4 will become |
1225 |
|
|
* UnmodifiableList instances, as this method was missing in 1.4. |
1226 |
|
|
*/ |
1227 |
|
|
private Object readResolve() { |
1228 |
|
|
return (list instanceof RandomAccess |
1229 |
jsr166 |
1.33 |
? new UnmodifiableRandomAccessList<E>(list) |
1230 |
|
|
: this); |
1231 |
dl |
1.1 |
} |
1232 |
|
|
} |
1233 |
|
|
|
1234 |
|
|
/** |
1235 |
|
|
* @serial include |
1236 |
|
|
*/ |
1237 |
|
|
static class UnmodifiableRandomAccessList<E> extends UnmodifiableList<E> |
1238 |
|
|
implements RandomAccess |
1239 |
|
|
{ |
1240 |
|
|
UnmodifiableRandomAccessList(List<? extends E> list) { |
1241 |
|
|
super(list); |
1242 |
|
|
} |
1243 |
|
|
|
1244 |
jsr166 |
1.33 |
public List<E> subList(int fromIndex, int toIndex) { |
1245 |
dl |
1.1 |
return new UnmodifiableRandomAccessList<E>( |
1246 |
|
|
list.subList(fromIndex, toIndex)); |
1247 |
|
|
} |
1248 |
|
|
|
1249 |
|
|
private static final long serialVersionUID = -2542308836966382001L; |
1250 |
|
|
|
1251 |
|
|
/** |
1252 |
|
|
* Allows instances to be deserialized in pre-1.4 JREs (which do |
1253 |
|
|
* not have UnmodifiableRandomAccessList). UnmodifiableList has |
1254 |
|
|
* a readResolve method that inverts this transformation upon |
1255 |
|
|
* deserialization. |
1256 |
|
|
*/ |
1257 |
|
|
private Object writeReplace() { |
1258 |
|
|
return new UnmodifiableList<E>(list); |
1259 |
|
|
} |
1260 |
|
|
} |
1261 |
|
|
|
1262 |
|
|
/** |
1263 |
|
|
* Returns an unmodifiable view of the specified map. This method |
1264 |
|
|
* allows modules to provide users with "read-only" access to internal |
1265 |
|
|
* maps. Query operations on the returned map "read through" |
1266 |
|
|
* to the specified map, and attempts to modify the returned |
1267 |
|
|
* map, whether direct or via its collection views, result in an |
1268 |
|
|
* <tt>UnsupportedOperationException</tt>.<p> |
1269 |
|
|
* |
1270 |
|
|
* The returned map will be serializable if the specified map |
1271 |
jsr166 |
1.4 |
* is serializable. |
1272 |
dl |
1.1 |
* |
1273 |
|
|
* @param m the map for which an unmodifiable view is to be returned. |
1274 |
|
|
* @return an unmodifiable view of the specified map. |
1275 |
|
|
*/ |
1276 |
|
|
public static <K,V> Map<K,V> unmodifiableMap(Map<? extends K, ? extends V> m) { |
1277 |
jsr166 |
1.33 |
return new UnmodifiableMap<K,V>(m); |
1278 |
dl |
1.1 |
} |
1279 |
|
|
|
1280 |
|
|
/** |
1281 |
|
|
* @serial include |
1282 |
|
|
*/ |
1283 |
|
|
private static class UnmodifiableMap<K,V> implements Map<K,V>, Serializable { |
1284 |
jsr166 |
1.33 |
private static final long serialVersionUID = -1034234728574286014L; |
1285 |
dl |
1.1 |
|
1286 |
jsr166 |
1.33 |
private final Map<? extends K, ? extends V> m; |
1287 |
dl |
1.1 |
|
1288 |
jsr166 |
1.33 |
UnmodifiableMap(Map<? extends K, ? extends V> m) { |
1289 |
dl |
1.1 |
if (m==null) |
1290 |
|
|
throw new NullPointerException(); |
1291 |
|
|
this.m = m; |
1292 |
|
|
} |
1293 |
|
|
|
1294 |
jsr166 |
1.33 |
public int size() {return m.size();} |
1295 |
|
|
public boolean isEmpty() {return m.isEmpty();} |
1296 |
|
|
public boolean containsKey(Object key) {return m.containsKey(key);} |
1297 |
|
|
public boolean containsValue(Object val) {return m.containsValue(val);} |
1298 |
|
|
public V get(Object key) {return m.get(key);} |
1299 |
|
|
|
1300 |
|
|
public V put(K key, V value) { |
1301 |
|
|
throw new UnsupportedOperationException(); |
1302 |
|
|
} |
1303 |
|
|
public V remove(Object key) { |
1304 |
|
|
throw new UnsupportedOperationException(); |
1305 |
|
|
} |
1306 |
|
|
public void putAll(Map<? extends K, ? extends V> m) { |
1307 |
|
|
throw new UnsupportedOperationException(); |
1308 |
|
|
} |
1309 |
|
|
public void clear() { |
1310 |
|
|
throw new UnsupportedOperationException(); |
1311 |
|
|
} |
1312 |
|
|
|
1313 |
|
|
private transient Set<K> keySet = null; |
1314 |
|
|
private transient Set<Map.Entry<K,V>> entrySet = null; |
1315 |
|
|
private transient Collection<V> values = null; |
1316 |
|
|
|
1317 |
|
|
public Set<K> keySet() { |
1318 |
|
|
if (keySet==null) |
1319 |
|
|
keySet = unmodifiableSet(m.keySet()); |
1320 |
|
|
return keySet; |
1321 |
|
|
} |
1322 |
dl |
1.1 |
|
1323 |
jsr166 |
1.33 |
public Set<Map.Entry<K,V>> entrySet() { |
1324 |
|
|
if (entrySet==null) |
1325 |
|
|
entrySet = new UnmodifiableEntrySet<K,V>(m.entrySet()); |
1326 |
|
|
return entrySet; |
1327 |
|
|
} |
1328 |
|
|
|
1329 |
|
|
public Collection<V> values() { |
1330 |
|
|
if (values==null) |
1331 |
|
|
values = unmodifiableCollection(m.values()); |
1332 |
|
|
return values; |
1333 |
|
|
} |
1334 |
|
|
|
1335 |
|
|
public boolean equals(Object o) {return o == this || m.equals(o);} |
1336 |
|
|
public int hashCode() {return m.hashCode();} |
1337 |
dl |
1.1 |
public String toString() {return m.toString();} |
1338 |
|
|
|
1339 |
|
|
/** |
1340 |
|
|
* We need this class in addition to UnmodifiableSet as |
1341 |
|
|
* Map.Entries themselves permit modification of the backing Map |
1342 |
|
|
* via their setValue operation. This class is subtle: there are |
1343 |
|
|
* many possible attacks that must be thwarted. |
1344 |
|
|
* |
1345 |
|
|
* @serial include |
1346 |
|
|
*/ |
1347 |
|
|
static class UnmodifiableEntrySet<K,V> |
1348 |
jsr166 |
1.33 |
extends UnmodifiableSet<Map.Entry<K,V>> { |
1349 |
|
|
private static final long serialVersionUID = 7854390611657943733L; |
1350 |
dl |
1.1 |
|
1351 |
|
|
UnmodifiableEntrySet(Set<? extends Map.Entry<? extends K, ? extends V>> s) { |
1352 |
jsr166 |
1.4 |
super((Set)s); |
1353 |
dl |
1.1 |
} |
1354 |
|
|
public Iterator<Map.Entry<K,V>> iterator() { |
1355 |
|
|
return new Iterator<Map.Entry<K,V>>() { |
1356 |
jsr166 |
1.33 |
private final Iterator<? extends Map.Entry<? extends K, ? extends V>> i = c.iterator(); |
1357 |
dl |
1.1 |
|
1358 |
|
|
public boolean hasNext() { |
1359 |
|
|
return i.hasNext(); |
1360 |
|
|
} |
1361 |
jsr166 |
1.33 |
public Map.Entry<K,V> next() { |
1362 |
|
|
return new UnmodifiableEntry<K,V>(i.next()); |
1363 |
dl |
1.1 |
} |
1364 |
|
|
public void remove() { |
1365 |
|
|
throw new UnsupportedOperationException(); |
1366 |
|
|
} |
1367 |
|
|
}; |
1368 |
|
|
} |
1369 |
|
|
|
1370 |
|
|
public Object[] toArray() { |
1371 |
|
|
Object[] a = c.toArray(); |
1372 |
|
|
for (int i=0; i<a.length; i++) |
1373 |
|
|
a[i] = new UnmodifiableEntry<K,V>((Map.Entry<K,V>)a[i]); |
1374 |
|
|
return a; |
1375 |
|
|
} |
1376 |
|
|
|
1377 |
|
|
public <T> T[] toArray(T[] a) { |
1378 |
|
|
// We don't pass a to c.toArray, to avoid window of |
1379 |
|
|
// vulnerability wherein an unscrupulous multithreaded client |
1380 |
|
|
// could get his hands on raw (unwrapped) Entries from c. |
1381 |
jsr166 |
1.33 |
Object[] arr = c.toArray(a.length==0 ? a : Arrays.copyOf(a, 0)); |
1382 |
dl |
1.1 |
|
1383 |
|
|
for (int i=0; i<arr.length; i++) |
1384 |
|
|
arr[i] = new UnmodifiableEntry<K,V>((Map.Entry<K,V>)arr[i]); |
1385 |
|
|
|
1386 |
|
|
if (arr.length > a.length) |
1387 |
|
|
return (T[])arr; |
1388 |
|
|
|
1389 |
|
|
System.arraycopy(arr, 0, a, 0, arr.length); |
1390 |
|
|
if (a.length > arr.length) |
1391 |
|
|
a[arr.length] = null; |
1392 |
|
|
return a; |
1393 |
|
|
} |
1394 |
|
|
|
1395 |
|
|
/** |
1396 |
|
|
* This method is overridden to protect the backing set against |
1397 |
|
|
* an object with a nefarious equals function that senses |
1398 |
|
|
* that the equality-candidate is Map.Entry and calls its |
1399 |
|
|
* setValue method. |
1400 |
|
|
*/ |
1401 |
|
|
public boolean contains(Object o) { |
1402 |
|
|
if (!(o instanceof Map.Entry)) |
1403 |
|
|
return false; |
1404 |
jsr166 |
1.32 |
return c.contains( |
1405 |
jsr166 |
1.33 |
new UnmodifiableEntry<Object,Object>((Map.Entry<?,?>) o)); |
1406 |
dl |
1.1 |
} |
1407 |
|
|
|
1408 |
|
|
/** |
1409 |
|
|
* The next two methods are overridden to protect against |
1410 |
|
|
* an unscrupulous List whose contains(Object o) method senses |
1411 |
|
|
* when o is a Map.Entry, and calls o.setValue. |
1412 |
|
|
*/ |
1413 |
|
|
public boolean containsAll(Collection<?> coll) { |
1414 |
|
|
Iterator<?> e = coll.iterator(); |
1415 |
|
|
while (e.hasNext()) |
1416 |
|
|
if (!contains(e.next())) // Invokes safe contains() above |
1417 |
|
|
return false; |
1418 |
|
|
return true; |
1419 |
|
|
} |
1420 |
|
|
public boolean equals(Object o) { |
1421 |
|
|
if (o == this) |
1422 |
|
|
return true; |
1423 |
|
|
|
1424 |
|
|
if (!(o instanceof Set)) |
1425 |
|
|
return false; |
1426 |
|
|
Set s = (Set) o; |
1427 |
|
|
if (s.size() != c.size()) |
1428 |
|
|
return false; |
1429 |
|
|
return containsAll(s); // Invokes safe containsAll() above |
1430 |
|
|
} |
1431 |
|
|
|
1432 |
|
|
/** |
1433 |
|
|
* This "wrapper class" serves two purposes: it prevents |
1434 |
|
|
* the client from modifying the backing Map, by short-circuiting |
1435 |
|
|
* the setValue method, and it protects the backing Map against |
1436 |
|
|
* an ill-behaved Map.Entry that attempts to modify another |
1437 |
|
|
* Map Entry when asked to perform an equality check. |
1438 |
|
|
*/ |
1439 |
|
|
private static class UnmodifiableEntry<K,V> implements Map.Entry<K,V> { |
1440 |
|
|
private Map.Entry<? extends K, ? extends V> e; |
1441 |
|
|
|
1442 |
|
|
UnmodifiableEntry(Map.Entry<? extends K, ? extends V> e) {this.e = e;} |
1443 |
|
|
|
1444 |
jsr166 |
1.33 |
public K getKey() {return e.getKey();} |
1445 |
dl |
1.1 |
public V getValue() {return e.getValue();} |
1446 |
|
|
public V setValue(V value) { |
1447 |
|
|
throw new UnsupportedOperationException(); |
1448 |
|
|
} |
1449 |
jsr166 |
1.33 |
public int hashCode() {return e.hashCode();} |
1450 |
dl |
1.1 |
public boolean equals(Object o) { |
1451 |
|
|
if (!(o instanceof Map.Entry)) |
1452 |
|
|
return false; |
1453 |
|
|
Map.Entry t = (Map.Entry)o; |
1454 |
|
|
return eq(e.getKey(), t.getKey()) && |
1455 |
|
|
eq(e.getValue(), t.getValue()); |
1456 |
|
|
} |
1457 |
|
|
public String toString() {return e.toString();} |
1458 |
|
|
} |
1459 |
|
|
} |
1460 |
|
|
} |
1461 |
|
|
|
1462 |
|
|
/** |
1463 |
|
|
* Returns an unmodifiable view of the specified sorted map. This method |
1464 |
|
|
* allows modules to provide users with "read-only" access to internal |
1465 |
|
|
* sorted maps. Query operations on the returned sorted map "read through" |
1466 |
|
|
* to the specified sorted map. Attempts to modify the returned |
1467 |
|
|
* sorted map, whether direct, via its collection views, or via its |
1468 |
|
|
* <tt>subMap</tt>, <tt>headMap</tt>, or <tt>tailMap</tt> views, result in |
1469 |
|
|
* an <tt>UnsupportedOperationException</tt>.<p> |
1470 |
|
|
* |
1471 |
|
|
* The returned sorted map will be serializable if the specified sorted map |
1472 |
jsr166 |
1.4 |
* is serializable. |
1473 |
dl |
1.1 |
* |
1474 |
|
|
* @param m the sorted map for which an unmodifiable view is to be |
1475 |
jsr166 |
1.4 |
* returned. |
1476 |
dl |
1.1 |
* @return an unmodifiable view of the specified sorted map. |
1477 |
|
|
*/ |
1478 |
|
|
public static <K,V> SortedMap<K,V> unmodifiableSortedMap(SortedMap<K, ? extends V> m) { |
1479 |
jsr166 |
1.33 |
return new UnmodifiableSortedMap<K,V>(m); |
1480 |
dl |
1.1 |
} |
1481 |
|
|
|
1482 |
|
|
/** |
1483 |
|
|
* @serial include |
1484 |
|
|
*/ |
1485 |
|
|
static class UnmodifiableSortedMap<K,V> |
1486 |
jsr166 |
1.33 |
extends UnmodifiableMap<K,V> |
1487 |
|
|
implements SortedMap<K,V>, Serializable { |
1488 |
|
|
private static final long serialVersionUID = -8806743815996713206L; |
1489 |
dl |
1.1 |
|
1490 |
|
|
private final SortedMap<K, ? extends V> sm; |
1491 |
|
|
|
1492 |
jsr166 |
1.33 |
UnmodifiableSortedMap(SortedMap<K, ? extends V> m) {super(m); sm = m;} |
1493 |
dl |
1.1 |
|
1494 |
|
|
public Comparator<? super K> comparator() {return sm.comparator();} |
1495 |
|
|
|
1496 |
|
|
public SortedMap<K,V> subMap(K fromKey, K toKey) { |
1497 |
|
|
return new UnmodifiableSortedMap<K,V>(sm.subMap(fromKey, toKey)); |
1498 |
|
|
} |
1499 |
|
|
public SortedMap<K,V> headMap(K toKey) { |
1500 |
|
|
return new UnmodifiableSortedMap<K,V>(sm.headMap(toKey)); |
1501 |
|
|
} |
1502 |
|
|
public SortedMap<K,V> tailMap(K fromKey) { |
1503 |
|
|
return new UnmodifiableSortedMap<K,V>(sm.tailMap(fromKey)); |
1504 |
|
|
} |
1505 |
|
|
|
1506 |
|
|
public K firstKey() {return sm.firstKey();} |
1507 |
|
|
public K lastKey() {return sm.lastKey();} |
1508 |
|
|
} |
1509 |
|
|
|
1510 |
|
|
|
1511 |
|
|
// Synch Wrappers |
1512 |
|
|
|
1513 |
|
|
/** |
1514 |
|
|
* Returns a synchronized (thread-safe) collection backed by the specified |
1515 |
|
|
* collection. In order to guarantee serial access, it is critical that |
1516 |
|
|
* <strong>all</strong> access to the backing collection is accomplished |
1517 |
|
|
* through the returned collection.<p> |
1518 |
|
|
* |
1519 |
|
|
* It is imperative that the user manually synchronize on the returned |
1520 |
|
|
* collection when iterating over it: |
1521 |
|
|
* <pre> |
1522 |
|
|
* Collection c = Collections.synchronizedCollection(myCollection); |
1523 |
|
|
* ... |
1524 |
|
|
* synchronized(c) { |
1525 |
|
|
* Iterator i = c.iterator(); // Must be in the synchronized block |
1526 |
|
|
* while (i.hasNext()) |
1527 |
|
|
* foo(i.next()); |
1528 |
|
|
* } |
1529 |
|
|
* </pre> |
1530 |
|
|
* Failure to follow this advice may result in non-deterministic behavior. |
1531 |
|
|
* |
1532 |
|
|
* <p>The returned collection does <i>not</i> pass the <tt>hashCode</tt> |
1533 |
|
|
* and <tt>equals</tt> operations through to the backing collection, but |
1534 |
|
|
* relies on <tt>Object</tt>'s equals and hashCode methods. This is |
1535 |
|
|
* necessary to preserve the contracts of these operations in the case |
1536 |
|
|
* that the backing collection is a set or a list.<p> |
1537 |
|
|
* |
1538 |
|
|
* The returned collection will be serializable if the specified collection |
1539 |
jsr166 |
1.4 |
* is serializable. |
1540 |
dl |
1.1 |
* |
1541 |
|
|
* @param c the collection to be "wrapped" in a synchronized collection. |
1542 |
|
|
* @return a synchronized view of the specified collection. |
1543 |
|
|
*/ |
1544 |
|
|
public static <T> Collection<T> synchronizedCollection(Collection<T> c) { |
1545 |
jsr166 |
1.33 |
return new SynchronizedCollection<T>(c); |
1546 |
dl |
1.1 |
} |
1547 |
|
|
|
1548 |
|
|
static <T> Collection<T> synchronizedCollection(Collection<T> c, Object mutex) { |
1549 |
jsr166 |
1.33 |
return new SynchronizedCollection<T>(c, mutex); |
1550 |
dl |
1.1 |
} |
1551 |
|
|
|
1552 |
|
|
/** |
1553 |
|
|
* @serial include |
1554 |
|
|
*/ |
1555 |
|
|
static class SynchronizedCollection<E> implements Collection<E>, Serializable { |
1556 |
jsr166 |
1.33 |
private static final long serialVersionUID = 3053995032091335093L; |
1557 |
dl |
1.1 |
|
1558 |
jsr166 |
1.33 |
final Collection<E> c; // Backing Collection |
1559 |
|
|
final Object mutex; // Object on which to synchronize |
1560 |
dl |
1.1 |
|
1561 |
jsr166 |
1.33 |
SynchronizedCollection(Collection<E> c) { |
1562 |
dl |
1.1 |
if (c==null) |
1563 |
|
|
throw new NullPointerException(); |
1564 |
jsr166 |
1.33 |
this.c = c; |
1565 |
dl |
1.1 |
mutex = this; |
1566 |
|
|
} |
1567 |
jsr166 |
1.33 |
SynchronizedCollection(Collection<E> c, Object mutex) { |
1568 |
|
|
this.c = c; |
1569 |
dl |
1.1 |
this.mutex = mutex; |
1570 |
|
|
} |
1571 |
|
|
|
1572 |
jsr166 |
1.33 |
public int size() { |
1573 |
|
|
synchronized(mutex) {return c.size();} |
1574 |
dl |
1.1 |
} |
1575 |
jsr166 |
1.33 |
public boolean isEmpty() { |
1576 |
|
|
synchronized(mutex) {return c.isEmpty();} |
1577 |
dl |
1.1 |
} |
1578 |
jsr166 |
1.33 |
public boolean contains(Object o) { |
1579 |
|
|
synchronized(mutex) {return c.contains(o);} |
1580 |
dl |
1.1 |
} |
1581 |
jsr166 |
1.33 |
public Object[] toArray() { |
1582 |
|
|
synchronized(mutex) {return c.toArray();} |
1583 |
dl |
1.1 |
} |
1584 |
jsr166 |
1.33 |
public <T> T[] toArray(T[] a) { |
1585 |
|
|
synchronized(mutex) {return c.toArray(a);} |
1586 |
dl |
1.1 |
} |
1587 |
|
|
|
1588 |
jsr166 |
1.33 |
public Iterator<E> iterator() { |
1589 |
dl |
1.1 |
return c.iterator(); // Must be manually synched by user! |
1590 |
|
|
} |
1591 |
|
|
|
1592 |
jsr166 |
1.33 |
public boolean add(E e) { |
1593 |
|
|
synchronized(mutex) {return c.add(e);} |
1594 |
dl |
1.1 |
} |
1595 |
jsr166 |
1.33 |
public boolean remove(Object o) { |
1596 |
|
|
synchronized(mutex) {return c.remove(o);} |
1597 |
dl |
1.1 |
} |
1598 |
|
|
|
1599 |
jsr166 |
1.33 |
public boolean containsAll(Collection<?> coll) { |
1600 |
|
|
synchronized(mutex) {return c.containsAll(coll);} |
1601 |
dl |
1.1 |
} |
1602 |
jsr166 |
1.33 |
public boolean addAll(Collection<? extends E> coll) { |
1603 |
|
|
synchronized(mutex) {return c.addAll(coll);} |
1604 |
dl |
1.1 |
} |
1605 |
jsr166 |
1.33 |
public boolean removeAll(Collection<?> coll) { |
1606 |
|
|
synchronized(mutex) {return c.removeAll(coll);} |
1607 |
dl |
1.1 |
} |
1608 |
jsr166 |
1.33 |
public boolean retainAll(Collection<?> coll) { |
1609 |
|
|
synchronized(mutex) {return c.retainAll(coll);} |
1610 |
dl |
1.1 |
} |
1611 |
jsr166 |
1.33 |
public void clear() { |
1612 |
|
|
synchronized(mutex) {c.clear();} |
1613 |
dl |
1.1 |
} |
1614 |
jsr166 |
1.33 |
public String toString() { |
1615 |
|
|
synchronized(mutex) {return c.toString();} |
1616 |
dl |
1.1 |
} |
1617 |
|
|
private void writeObject(ObjectOutputStream s) throws IOException { |
1618 |
jsr166 |
1.33 |
synchronized(mutex) {s.defaultWriteObject();} |
1619 |
dl |
1.1 |
} |
1620 |
|
|
} |
1621 |
|
|
|
1622 |
|
|
/** |
1623 |
|
|
* Returns a synchronized (thread-safe) set backed by the specified |
1624 |
|
|
* set. In order to guarantee serial access, it is critical that |
1625 |
|
|
* <strong>all</strong> access to the backing set is accomplished |
1626 |
|
|
* through the returned set.<p> |
1627 |
|
|
* |
1628 |
|
|
* It is imperative that the user manually synchronize on the returned |
1629 |
|
|
* set when iterating over it: |
1630 |
|
|
* <pre> |
1631 |
|
|
* Set s = Collections.synchronizedSet(new HashSet()); |
1632 |
|
|
* ... |
1633 |
|
|
* synchronized(s) { |
1634 |
|
|
* Iterator i = s.iterator(); // Must be in the synchronized block |
1635 |
|
|
* while (i.hasNext()) |
1636 |
|
|
* foo(i.next()); |
1637 |
|
|
* } |
1638 |
|
|
* </pre> |
1639 |
|
|
* Failure to follow this advice may result in non-deterministic behavior. |
1640 |
|
|
* |
1641 |
|
|
* <p>The returned set will be serializable if the specified set is |
1642 |
|
|
* serializable. |
1643 |
|
|
* |
1644 |
|
|
* @param s the set to be "wrapped" in a synchronized set. |
1645 |
|
|
* @return a synchronized view of the specified set. |
1646 |
|
|
*/ |
1647 |
|
|
public static <T> Set<T> synchronizedSet(Set<T> s) { |
1648 |
jsr166 |
1.33 |
return new SynchronizedSet<T>(s); |
1649 |
dl |
1.1 |
} |
1650 |
|
|
|
1651 |
|
|
static <T> Set<T> synchronizedSet(Set<T> s, Object mutex) { |
1652 |
jsr166 |
1.33 |
return new SynchronizedSet<T>(s, mutex); |
1653 |
dl |
1.1 |
} |
1654 |
|
|
|
1655 |
|
|
/** |
1656 |
|
|
* @serial include |
1657 |
|
|
*/ |
1658 |
|
|
static class SynchronizedSet<E> |
1659 |
jsr166 |
1.33 |
extends SynchronizedCollection<E> |
1660 |
|
|
implements Set<E> { |
1661 |
|
|
private static final long serialVersionUID = 487447009682186044L; |
1662 |
dl |
1.1 |
|
1663 |
jsr166 |
1.33 |
SynchronizedSet(Set<E> s) { |
1664 |
dl |
1.1 |
super(s); |
1665 |
|
|
} |
1666 |
jsr166 |
1.33 |
SynchronizedSet(Set<E> s, Object mutex) { |
1667 |
dl |
1.1 |
super(s, mutex); |
1668 |
|
|
} |
1669 |
|
|
|
1670 |
jsr166 |
1.33 |
public boolean equals(Object o) { |
1671 |
|
|
synchronized(mutex) {return c.equals(o);} |
1672 |
dl |
1.1 |
} |
1673 |
jsr166 |
1.33 |
public int hashCode() { |
1674 |
|
|
synchronized(mutex) {return c.hashCode();} |
1675 |
dl |
1.1 |
} |
1676 |
|
|
} |
1677 |
|
|
|
1678 |
|
|
/** |
1679 |
|
|
* Returns a synchronized (thread-safe) sorted set backed by the specified |
1680 |
|
|
* sorted set. In order to guarantee serial access, it is critical that |
1681 |
|
|
* <strong>all</strong> access to the backing sorted set is accomplished |
1682 |
|
|
* through the returned sorted set (or its views).<p> |
1683 |
|
|
* |
1684 |
|
|
* It is imperative that the user manually synchronize on the returned |
1685 |
|
|
* sorted set when iterating over it or any of its <tt>subSet</tt>, |
1686 |
|
|
* <tt>headSet</tt>, or <tt>tailSet</tt> views. |
1687 |
|
|
* <pre> |
1688 |
jsr166 |
1.4 |
* SortedSet s = Collections.synchronizedSortedSet(new TreeSet()); |
1689 |
dl |
1.1 |
* ... |
1690 |
|
|
* synchronized(s) { |
1691 |
|
|
* Iterator i = s.iterator(); // Must be in the synchronized block |
1692 |
|
|
* while (i.hasNext()) |
1693 |
|
|
* foo(i.next()); |
1694 |
|
|
* } |
1695 |
|
|
* </pre> |
1696 |
|
|
* or: |
1697 |
|
|
* <pre> |
1698 |
jsr166 |
1.4 |
* SortedSet s = Collections.synchronizedSortedSet(new TreeSet()); |
1699 |
dl |
1.1 |
* SortedSet s2 = s.headSet(foo); |
1700 |
|
|
* ... |
1701 |
|
|
* synchronized(s) { // Note: s, not s2!!! |
1702 |
|
|
* Iterator i = s2.iterator(); // Must be in the synchronized block |
1703 |
|
|
* while (i.hasNext()) |
1704 |
|
|
* foo(i.next()); |
1705 |
|
|
* } |
1706 |
|
|
* </pre> |
1707 |
|
|
* Failure to follow this advice may result in non-deterministic behavior. |
1708 |
|
|
* |
1709 |
|
|
* <p>The returned sorted set will be serializable if the specified |
1710 |
|
|
* sorted set is serializable. |
1711 |
|
|
* |
1712 |
|
|
* @param s the sorted set to be "wrapped" in a synchronized sorted set. |
1713 |
|
|
* @return a synchronized view of the specified sorted set. |
1714 |
|
|
*/ |
1715 |
|
|
public static <T> SortedSet<T> synchronizedSortedSet(SortedSet<T> s) { |
1716 |
jsr166 |
1.33 |
return new SynchronizedSortedSet<T>(s); |
1717 |
dl |
1.1 |
} |
1718 |
|
|
|
1719 |
|
|
/** |
1720 |
|
|
* @serial include |
1721 |
|
|
*/ |
1722 |
|
|
static class SynchronizedSortedSet<E> |
1723 |
jsr166 |
1.33 |
extends SynchronizedSet<E> |
1724 |
|
|
implements SortedSet<E> |
1725 |
dl |
1.1 |
{ |
1726 |
jsr166 |
1.33 |
private static final long serialVersionUID = 8695801310862127406L; |
1727 |
dl |
1.1 |
|
1728 |
|
|
final private SortedSet<E> ss; |
1729 |
|
|
|
1730 |
jsr166 |
1.33 |
SynchronizedSortedSet(SortedSet<E> s) { |
1731 |
dl |
1.1 |
super(s); |
1732 |
|
|
ss = s; |
1733 |
|
|
} |
1734 |
jsr166 |
1.33 |
SynchronizedSortedSet(SortedSet<E> s, Object mutex) { |
1735 |
dl |
1.1 |
super(s, mutex); |
1736 |
|
|
ss = s; |
1737 |
|
|
} |
1738 |
|
|
|
1739 |
jsr166 |
1.33 |
public Comparator<? super E> comparator() { |
1740 |
|
|
synchronized(mutex) {return ss.comparator();} |
1741 |
dl |
1.1 |
} |
1742 |
|
|
|
1743 |
|
|
public SortedSet<E> subSet(E fromElement, E toElement) { |
1744 |
jsr166 |
1.33 |
synchronized(mutex) { |
1745 |
dl |
1.1 |
return new SynchronizedSortedSet<E>( |
1746 |
|
|
ss.subSet(fromElement, toElement), mutex); |
1747 |
|
|
} |
1748 |
|
|
} |
1749 |
|
|
public SortedSet<E> headSet(E toElement) { |
1750 |
jsr166 |
1.33 |
synchronized(mutex) { |
1751 |
dl |
1.1 |
return new SynchronizedSortedSet<E>(ss.headSet(toElement), mutex); |
1752 |
|
|
} |
1753 |
|
|
} |
1754 |
|
|
public SortedSet<E> tailSet(E fromElement) { |
1755 |
jsr166 |
1.33 |
synchronized(mutex) { |
1756 |
dl |
1.1 |
return new SynchronizedSortedSet<E>(ss.tailSet(fromElement),mutex); |
1757 |
|
|
} |
1758 |
|
|
} |
1759 |
|
|
|
1760 |
|
|
public E first() { |
1761 |
jsr166 |
1.33 |
synchronized(mutex) {return ss.first();} |
1762 |
dl |
1.1 |
} |
1763 |
|
|
public E last() { |
1764 |
jsr166 |
1.33 |
synchronized(mutex) {return ss.last();} |
1765 |
dl |
1.1 |
} |
1766 |
|
|
} |
1767 |
|
|
|
1768 |
|
|
/** |
1769 |
|
|
* Returns a synchronized (thread-safe) list backed by the specified |
1770 |
|
|
* list. In order to guarantee serial access, it is critical that |
1771 |
|
|
* <strong>all</strong> access to the backing list is accomplished |
1772 |
|
|
* through the returned list.<p> |
1773 |
|
|
* |
1774 |
|
|
* It is imperative that the user manually synchronize on the returned |
1775 |
|
|
* list when iterating over it: |
1776 |
|
|
* <pre> |
1777 |
|
|
* List list = Collections.synchronizedList(new ArrayList()); |
1778 |
|
|
* ... |
1779 |
|
|
* synchronized(list) { |
1780 |
|
|
* Iterator i = list.iterator(); // Must be in synchronized block |
1781 |
|
|
* while (i.hasNext()) |
1782 |
|
|
* foo(i.next()); |
1783 |
|
|
* } |
1784 |
|
|
* </pre> |
1785 |
|
|
* Failure to follow this advice may result in non-deterministic behavior. |
1786 |
|
|
* |
1787 |
|
|
* <p>The returned list will be serializable if the specified list is |
1788 |
|
|
* serializable. |
1789 |
|
|
* |
1790 |
|
|
* @param list the list to be "wrapped" in a synchronized list. |
1791 |
|
|
* @return a synchronized view of the specified list. |
1792 |
|
|
*/ |
1793 |
|
|
public static <T> List<T> synchronizedList(List<T> list) { |
1794 |
jsr166 |
1.33 |
return (list instanceof RandomAccess ? |
1795 |
dl |
1.1 |
new SynchronizedRandomAccessList<T>(list) : |
1796 |
|
|
new SynchronizedList<T>(list)); |
1797 |
|
|
} |
1798 |
|
|
|
1799 |
|
|
static <T> List<T> synchronizedList(List<T> list, Object mutex) { |
1800 |
jsr166 |
1.33 |
return (list instanceof RandomAccess ? |
1801 |
dl |
1.1 |
new SynchronizedRandomAccessList<T>(list, mutex) : |
1802 |
|
|
new SynchronizedList<T>(list, mutex)); |
1803 |
|
|
} |
1804 |
|
|
|
1805 |
|
|
/** |
1806 |
|
|
* @serial include |
1807 |
|
|
*/ |
1808 |
|
|
static class SynchronizedList<E> |
1809 |
jsr166 |
1.33 |
extends SynchronizedCollection<E> |
1810 |
|
|
implements List<E> { |
1811 |
jsr166 |
1.32 |
private static final long serialVersionUID = -7754090372962971524L; |
1812 |
dl |
1.1 |
|
1813 |
jsr166 |
1.33 |
final List<E> list; |
1814 |
dl |
1.1 |
|
1815 |
jsr166 |
1.33 |
SynchronizedList(List<E> list) { |
1816 |
|
|
super(list); |
1817 |
|
|
this.list = list; |
1818 |
|
|
} |
1819 |
|
|
SynchronizedList(List<E> list, Object mutex) { |
1820 |
dl |
1.1 |
super(list, mutex); |
1821 |
jsr166 |
1.33 |
this.list = list; |
1822 |
dl |
1.1 |
} |
1823 |
|
|
|
1824 |
jsr166 |
1.33 |
public boolean equals(Object o) { |
1825 |
|
|
synchronized(mutex) {return list.equals(o);} |
1826 |
dl |
1.1 |
} |
1827 |
jsr166 |
1.33 |
public int hashCode() { |
1828 |
|
|
synchronized(mutex) {return list.hashCode();} |
1829 |
dl |
1.1 |
} |
1830 |
|
|
|
1831 |
jsr166 |
1.33 |
public E get(int index) { |
1832 |
|
|
synchronized(mutex) {return list.get(index);} |
1833 |
dl |
1.1 |
} |
1834 |
jsr166 |
1.33 |
public E set(int index, E element) { |
1835 |
|
|
synchronized(mutex) {return list.set(index, element);} |
1836 |
dl |
1.1 |
} |
1837 |
jsr166 |
1.33 |
public void add(int index, E element) { |
1838 |
|
|
synchronized(mutex) {list.add(index, element);} |
1839 |
dl |
1.1 |
} |
1840 |
jsr166 |
1.33 |
public E remove(int index) { |
1841 |
|
|
synchronized(mutex) {return list.remove(index);} |
1842 |
dl |
1.1 |
} |
1843 |
|
|
|
1844 |
jsr166 |
1.33 |
public int indexOf(Object o) { |
1845 |
|
|
synchronized(mutex) {return list.indexOf(o);} |
1846 |
dl |
1.1 |
} |
1847 |
jsr166 |
1.33 |
public int lastIndexOf(Object o) { |
1848 |
|
|
synchronized(mutex) {return list.lastIndexOf(o);} |
1849 |
dl |
1.1 |
} |
1850 |
|
|
|
1851 |
jsr166 |
1.33 |
public boolean addAll(int index, Collection<? extends E> c) { |
1852 |
|
|
synchronized(mutex) {return list.addAll(index, c);} |
1853 |
dl |
1.1 |
} |
1854 |
|
|
|
1855 |
jsr166 |
1.33 |
public ListIterator<E> listIterator() { |
1856 |
|
|
return list.listIterator(); // Must be manually synched by user |
1857 |
dl |
1.1 |
} |
1858 |
|
|
|
1859 |
jsr166 |
1.33 |
public ListIterator<E> listIterator(int index) { |
1860 |
|
|
return list.listIterator(index); // Must be manually synched by user |
1861 |
dl |
1.1 |
} |
1862 |
|
|
|
1863 |
jsr166 |
1.33 |
public List<E> subList(int fromIndex, int toIndex) { |
1864 |
|
|
synchronized(mutex) { |
1865 |
dl |
1.1 |
return new SynchronizedList<E>(list.subList(fromIndex, toIndex), |
1866 |
|
|
mutex); |
1867 |
|
|
} |
1868 |
|
|
} |
1869 |
|
|
|
1870 |
|
|
/** |
1871 |
|
|
* SynchronizedRandomAccessList instances are serialized as |
1872 |
|
|
* SynchronizedList instances to allow them to be deserialized |
1873 |
|
|
* in pre-1.4 JREs (which do not have SynchronizedRandomAccessList). |
1874 |
|
|
* This method inverts the transformation. As a beneficial |
1875 |
|
|
* side-effect, it also grafts the RandomAccess marker onto |
1876 |
|
|
* SynchronizedList instances that were serialized in pre-1.4 JREs. |
1877 |
|
|
* |
1878 |
|
|
* Note: Unfortunately, SynchronizedRandomAccessList instances |
1879 |
|
|
* serialized in 1.4.1 and deserialized in 1.4 will become |
1880 |
|
|
* SynchronizedList instances, as this method was missing in 1.4. |
1881 |
|
|
*/ |
1882 |
|
|
private Object readResolve() { |
1883 |
|
|
return (list instanceof RandomAccess |
1884 |
jsr166 |
1.33 |
? new SynchronizedRandomAccessList<E>(list) |
1885 |
|
|
: this); |
1886 |
dl |
1.1 |
} |
1887 |
|
|
} |
1888 |
|
|
|
1889 |
|
|
/** |
1890 |
|
|
* @serial include |
1891 |
|
|
*/ |
1892 |
|
|
static class SynchronizedRandomAccessList<E> |
1893 |
jsr166 |
1.33 |
extends SynchronizedList<E> |
1894 |
|
|
implements RandomAccess { |
1895 |
dl |
1.1 |
|
1896 |
|
|
SynchronizedRandomAccessList(List<E> list) { |
1897 |
|
|
super(list); |
1898 |
|
|
} |
1899 |
|
|
|
1900 |
jsr166 |
1.33 |
SynchronizedRandomAccessList(List<E> list, Object mutex) { |
1901 |
dl |
1.1 |
super(list, mutex); |
1902 |
|
|
} |
1903 |
|
|
|
1904 |
jsr166 |
1.33 |
public List<E> subList(int fromIndex, int toIndex) { |
1905 |
|
|
synchronized(mutex) { |
1906 |
dl |
1.1 |
return new SynchronizedRandomAccessList<E>( |
1907 |
|
|
list.subList(fromIndex, toIndex), mutex); |
1908 |
|
|
} |
1909 |
|
|
} |
1910 |
|
|
|
1911 |
jsr166 |
1.32 |
private static final long serialVersionUID = 1530674583602358482L; |
1912 |
dl |
1.1 |
|
1913 |
|
|
/** |
1914 |
|
|
* Allows instances to be deserialized in pre-1.4 JREs (which do |
1915 |
|
|
* not have SynchronizedRandomAccessList). SynchronizedList has |
1916 |
|
|
* a readResolve method that inverts this transformation upon |
1917 |
|
|
* deserialization. |
1918 |
|
|
*/ |
1919 |
|
|
private Object writeReplace() { |
1920 |
|
|
return new SynchronizedList<E>(list); |
1921 |
|
|
} |
1922 |
|
|
} |
1923 |
|
|
|
1924 |
|
|
/** |
1925 |
|
|
* Returns a synchronized (thread-safe) map backed by the specified |
1926 |
|
|
* map. In order to guarantee serial access, it is critical that |
1927 |
|
|
* <strong>all</strong> access to the backing map is accomplished |
1928 |
|
|
* through the returned map.<p> |
1929 |
|
|
* |
1930 |
|
|
* It is imperative that the user manually synchronize on the returned |
1931 |
|
|
* map when iterating over any of its collection views: |
1932 |
|
|
* <pre> |
1933 |
|
|
* Map m = Collections.synchronizedMap(new HashMap()); |
1934 |
|
|
* ... |
1935 |
|
|
* Set s = m.keySet(); // Needn't be in synchronized block |
1936 |
|
|
* ... |
1937 |
|
|
* synchronized(m) { // Synchronizing on m, not s! |
1938 |
|
|
* Iterator i = s.iterator(); // Must be in synchronized block |
1939 |
|
|
* while (i.hasNext()) |
1940 |
|
|
* foo(i.next()); |
1941 |
|
|
* } |
1942 |
|
|
* </pre> |
1943 |
|
|
* Failure to follow this advice may result in non-deterministic behavior. |
1944 |
|
|
* |
1945 |
|
|
* <p>The returned map will be serializable if the specified map is |
1946 |
|
|
* serializable. |
1947 |
|
|
* |
1948 |
|
|
* @param m the map to be "wrapped" in a synchronized map. |
1949 |
|
|
* @return a synchronized view of the specified map. |
1950 |
|
|
*/ |
1951 |
|
|
public static <K,V> Map<K,V> synchronizedMap(Map<K,V> m) { |
1952 |
jsr166 |
1.33 |
return new SynchronizedMap<K,V>(m); |
1953 |
dl |
1.1 |
} |
1954 |
|
|
|
1955 |
|
|
/** |
1956 |
|
|
* @serial include |
1957 |
|
|
*/ |
1958 |
|
|
private static class SynchronizedMap<K,V> |
1959 |
jsr166 |
1.33 |
implements Map<K,V>, Serializable { |
1960 |
|
|
private static final long serialVersionUID = 1978198479659022715L; |
1961 |
dl |
1.1 |
|
1962 |
jsr166 |
1.33 |
private final Map<K,V> m; // Backing Map |
1963 |
|
|
final Object mutex; // Object on which to synchronize |
1964 |
dl |
1.1 |
|
1965 |
jsr166 |
1.33 |
SynchronizedMap(Map<K,V> m) { |
1966 |
dl |
1.1 |
if (m==null) |
1967 |
|
|
throw new NullPointerException(); |
1968 |
|
|
this.m = m; |
1969 |
|
|
mutex = this; |
1970 |
|
|
} |
1971 |
|
|
|
1972 |
jsr166 |
1.33 |
SynchronizedMap(Map<K,V> m, Object mutex) { |
1973 |
dl |
1.1 |
this.m = m; |
1974 |
|
|
this.mutex = mutex; |
1975 |
|
|
} |
1976 |
|
|
|
1977 |
jsr166 |
1.33 |
public int size() { |
1978 |
|
|
synchronized(mutex) {return m.size();} |
1979 |
dl |
1.1 |
} |
1980 |
jsr166 |
1.33 |
public boolean isEmpty() { |
1981 |
|
|
synchronized(mutex) {return m.isEmpty();} |
1982 |
dl |
1.1 |
} |
1983 |
jsr166 |
1.33 |
public boolean containsKey(Object key) { |
1984 |
|
|
synchronized(mutex) {return m.containsKey(key);} |
1985 |
dl |
1.1 |
} |
1986 |
jsr166 |
1.33 |
public boolean containsValue(Object value) { |
1987 |
|
|
synchronized(mutex) {return m.containsValue(value);} |
1988 |
dl |
1.1 |
} |
1989 |
jsr166 |
1.33 |
public V get(Object key) { |
1990 |
|
|
synchronized(mutex) {return m.get(key);} |
1991 |
dl |
1.1 |
} |
1992 |
|
|
|
1993 |
jsr166 |
1.33 |
public V put(K key, V value) { |
1994 |
|
|
synchronized(mutex) {return m.put(key, value);} |
1995 |
dl |
1.1 |
} |
1996 |
jsr166 |
1.33 |
public V remove(Object key) { |
1997 |
|
|
synchronized(mutex) {return m.remove(key);} |
1998 |
dl |
1.1 |
} |
1999 |
jsr166 |
1.33 |
public void putAll(Map<? extends K, ? extends V> map) { |
2000 |
|
|
synchronized(mutex) {m.putAll(map);} |
2001 |
|
|
} |
2002 |
|
|
public void clear() { |
2003 |
|
|
synchronized(mutex) {m.clear();} |
2004 |
dl |
1.1 |
} |
2005 |
|
|
|
2006 |
jsr166 |
1.33 |
private transient Set<K> keySet = null; |
2007 |
|
|
private transient Set<Map.Entry<K,V>> entrySet = null; |
2008 |
|
|
private transient Collection<V> values = null; |
2009 |
dl |
1.1 |
|
2010 |
jsr166 |
1.33 |
public Set<K> keySet() { |
2011 |
dl |
1.1 |
synchronized(mutex) { |
2012 |
|
|
if (keySet==null) |
2013 |
|
|
keySet = new SynchronizedSet<K>(m.keySet(), mutex); |
2014 |
|
|
return keySet; |
2015 |
|
|
} |
2016 |
jsr166 |
1.33 |
} |
2017 |
dl |
1.1 |
|
2018 |
jsr166 |
1.33 |
public Set<Map.Entry<K,V>> entrySet() { |
2019 |
dl |
1.1 |
synchronized(mutex) { |
2020 |
|
|
if (entrySet==null) |
2021 |
jsr166 |
1.4 |
entrySet = new SynchronizedSet<Map.Entry<K,V>>(m.entrySet(), mutex); |
2022 |
dl |
1.1 |
return entrySet; |
2023 |
|
|
} |
2024 |
jsr166 |
1.33 |
} |
2025 |
dl |
1.1 |
|
2026 |
jsr166 |
1.33 |
public Collection<V> values() { |
2027 |
dl |
1.1 |
synchronized(mutex) { |
2028 |
|
|
if (values==null) |
2029 |
|
|
values = new SynchronizedCollection<V>(m.values(), mutex); |
2030 |
|
|
return values; |
2031 |
|
|
} |
2032 |
|
|
} |
2033 |
|
|
|
2034 |
jsr166 |
1.33 |
public boolean equals(Object o) { |
2035 |
dl |
1.1 |
synchronized(mutex) {return m.equals(o);} |
2036 |
|
|
} |
2037 |
jsr166 |
1.33 |
public int hashCode() { |
2038 |
dl |
1.1 |
synchronized(mutex) {return m.hashCode();} |
2039 |
|
|
} |
2040 |
jsr166 |
1.33 |
public String toString() { |
2041 |
|
|
synchronized(mutex) {return m.toString();} |
2042 |
dl |
1.1 |
} |
2043 |
|
|
private void writeObject(ObjectOutputStream s) throws IOException { |
2044 |
jsr166 |
1.33 |
synchronized(mutex) {s.defaultWriteObject();} |
2045 |
dl |
1.1 |
} |
2046 |
|
|
} |
2047 |
|
|
|
2048 |
|
|
/** |
2049 |
|
|
* Returns a synchronized (thread-safe) sorted map backed by the specified |
2050 |
|
|
* sorted map. In order to guarantee serial access, it is critical that |
2051 |
|
|
* <strong>all</strong> access to the backing sorted map is accomplished |
2052 |
|
|
* through the returned sorted map (or its views).<p> |
2053 |
|
|
* |
2054 |
|
|
* It is imperative that the user manually synchronize on the returned |
2055 |
|
|
* sorted map when iterating over any of its collection views, or the |
2056 |
|
|
* collections views of any of its <tt>subMap</tt>, <tt>headMap</tt> or |
2057 |
|
|
* <tt>tailMap</tt> views. |
2058 |
|
|
* <pre> |
2059 |
jsr166 |
1.4 |
* SortedMap m = Collections.synchronizedSortedMap(new TreeMap()); |
2060 |
dl |
1.1 |
* ... |
2061 |
|
|
* Set s = m.keySet(); // Needn't be in synchronized block |
2062 |
|
|
* ... |
2063 |
|
|
* synchronized(m) { // Synchronizing on m, not s! |
2064 |
|
|
* Iterator i = s.iterator(); // Must be in synchronized block |
2065 |
|
|
* while (i.hasNext()) |
2066 |
|
|
* foo(i.next()); |
2067 |
|
|
* } |
2068 |
|
|
* </pre> |
2069 |
|
|
* or: |
2070 |
|
|
* <pre> |
2071 |
jsr166 |
1.4 |
* SortedMap m = Collections.synchronizedSortedMap(new TreeMap()); |
2072 |
dl |
1.1 |
* SortedMap m2 = m.subMap(foo, bar); |
2073 |
|
|
* ... |
2074 |
|
|
* Set s2 = m2.keySet(); // Needn't be in synchronized block |
2075 |
|
|
* ... |
2076 |
|
|
* synchronized(m) { // Synchronizing on m, not m2 or s2! |
2077 |
|
|
* Iterator i = s.iterator(); // Must be in synchronized block |
2078 |
|
|
* while (i.hasNext()) |
2079 |
|
|
* foo(i.next()); |
2080 |
|
|
* } |
2081 |
|
|
* </pre> |
2082 |
|
|
* Failure to follow this advice may result in non-deterministic behavior. |
2083 |
|
|
* |
2084 |
|
|
* <p>The returned sorted map will be serializable if the specified |
2085 |
|
|
* sorted map is serializable. |
2086 |
|
|
* |
2087 |
|
|
* @param m the sorted map to be "wrapped" in a synchronized sorted map. |
2088 |
|
|
* @return a synchronized view of the specified sorted map. |
2089 |
|
|
*/ |
2090 |
|
|
public static <K,V> SortedMap<K,V> synchronizedSortedMap(SortedMap<K,V> m) { |
2091 |
jsr166 |
1.33 |
return new SynchronizedSortedMap<K,V>(m); |
2092 |
dl |
1.1 |
} |
2093 |
|
|
|
2094 |
|
|
|
2095 |
|
|
/** |
2096 |
|
|
* @serial include |
2097 |
|
|
*/ |
2098 |
|
|
static class SynchronizedSortedMap<K,V> |
2099 |
jsr166 |
1.33 |
extends SynchronizedMap<K,V> |
2100 |
|
|
implements SortedMap<K,V> |
2101 |
dl |
1.1 |
{ |
2102 |
jsr166 |
1.33 |
private static final long serialVersionUID = -8798146769416483793L; |
2103 |
dl |
1.1 |
|
2104 |
|
|
private final SortedMap<K,V> sm; |
2105 |
|
|
|
2106 |
jsr166 |
1.33 |
SynchronizedSortedMap(SortedMap<K,V> m) { |
2107 |
dl |
1.1 |
super(m); |
2108 |
|
|
sm = m; |
2109 |
|
|
} |
2110 |
jsr166 |
1.33 |
SynchronizedSortedMap(SortedMap<K,V> m, Object mutex) { |
2111 |
dl |
1.1 |
super(m, mutex); |
2112 |
|
|
sm = m; |
2113 |
|
|
} |
2114 |
|
|
|
2115 |
jsr166 |
1.33 |
public Comparator<? super K> comparator() { |
2116 |
|
|
synchronized(mutex) {return sm.comparator();} |
2117 |
dl |
1.1 |
} |
2118 |
|
|
|
2119 |
|
|
public SortedMap<K,V> subMap(K fromKey, K toKey) { |
2120 |
jsr166 |
1.33 |
synchronized(mutex) { |
2121 |
dl |
1.1 |
return new SynchronizedSortedMap<K,V>( |
2122 |
|
|
sm.subMap(fromKey, toKey), mutex); |
2123 |
|
|
} |
2124 |
|
|
} |
2125 |
|
|
public SortedMap<K,V> headMap(K toKey) { |
2126 |
jsr166 |
1.33 |
synchronized(mutex) { |
2127 |
dl |
1.1 |
return new SynchronizedSortedMap<K,V>(sm.headMap(toKey), mutex); |
2128 |
|
|
} |
2129 |
|
|
} |
2130 |
|
|
public SortedMap<K,V> tailMap(K fromKey) { |
2131 |
jsr166 |
1.33 |
synchronized(mutex) { |
2132 |
dl |
1.1 |
return new SynchronizedSortedMap<K,V>(sm.tailMap(fromKey),mutex); |
2133 |
|
|
} |
2134 |
|
|
} |
2135 |
|
|
|
2136 |
|
|
public K firstKey() { |
2137 |
jsr166 |
1.33 |
synchronized(mutex) {return sm.firstKey();} |
2138 |
dl |
1.1 |
} |
2139 |
|
|
public K lastKey() { |
2140 |
jsr166 |
1.33 |
synchronized(mutex) {return sm.lastKey();} |
2141 |
dl |
1.1 |
} |
2142 |
|
|
} |
2143 |
|
|
|
2144 |
|
|
// Dynamically typesafe collection wrappers |
2145 |
|
|
|
2146 |
|
|
/** |
2147 |
jsr166 |
1.32 |
* Returns a dynamically typesafe view of the specified collection. |
2148 |
|
|
* Any attempt to insert an element of the wrong type will result in an |
2149 |
|
|
* immediate {@link ClassCastException}. Assuming a collection |
2150 |
|
|
* contains no incorrectly typed elements prior to the time a |
2151 |
|
|
* dynamically typesafe view is generated, and that all subsequent |
2152 |
|
|
* access to the collection takes place through the view, it is |
2153 |
|
|
* <i>guaranteed</i> that the collection cannot contain an incorrectly |
2154 |
|
|
* typed element. |
2155 |
dl |
1.1 |
* |
2156 |
|
|
* <p>The generics mechanism in the language provides compile-time |
2157 |
|
|
* (static) type checking, but it is possible to defeat this mechanism |
2158 |
|
|
* with unchecked casts. Usually this is not a problem, as the compiler |
2159 |
|
|
* issues warnings on all such unchecked operations. There are, however, |
2160 |
|
|
* times when static type checking alone is not sufficient. For example, |
2161 |
|
|
* suppose a collection is passed to a third-party library and it is |
2162 |
|
|
* imperative that the library code not corrupt the collection by |
2163 |
|
|
* inserting an element of the wrong type. |
2164 |
|
|
* |
2165 |
|
|
* <p>Another use of dynamically typesafe views is debugging. Suppose a |
2166 |
jsr166 |
1.32 |
* program fails with a {@code ClassCastException}, indicating that an |
2167 |
dl |
1.1 |
* incorrectly typed element was put into a parameterized collection. |
2168 |
|
|
* Unfortunately, the exception can occur at any time after the erroneous |
2169 |
|
|
* element is inserted, so it typically provides little or no information |
2170 |
|
|
* as to the real source of the problem. If the problem is reproducible, |
2171 |
|
|
* one can quickly determine its source by temporarily modifying the |
2172 |
|
|
* program to wrap the collection with a dynamically typesafe view. |
2173 |
|
|
* For example, this declaration: |
2174 |
jsr166 |
1.32 |
* <pre> {@code |
2175 |
|
|
* Collection<String> c = new HashSet<String>(); |
2176 |
|
|
* }</pre> |
2177 |
dl |
1.1 |
* may be replaced temporarily by this one: |
2178 |
jsr166 |
1.32 |
* <pre> {@code |
2179 |
|
|
* Collection<String> c = Collections.checkedCollection( |
2180 |
|
|
* new HashSet<String>(), String.class); |
2181 |
|
|
* }</pre> |
2182 |
dl |
1.1 |
* Running the program again will cause it to fail at the point where |
2183 |
|
|
* an incorrectly typed element is inserted into the collection, clearly |
2184 |
|
|
* identifying the source of the problem. Once the problem is fixed, the |
2185 |
|
|
* modified declaration may be reverted back to the original. |
2186 |
|
|
* |
2187 |
|
|
* <p>The returned collection does <i>not</i> pass the hashCode and equals |
2188 |
|
|
* operations through to the backing collection, but relies on |
2189 |
jsr166 |
1.32 |
* {@code Object}'s {@code equals} and {@code hashCode} methods. This |
2190 |
dl |
1.1 |
* is necessary to preserve the contracts of these operations in the case |
2191 |
|
|
* that the backing collection is a set or a list. |
2192 |
|
|
* |
2193 |
|
|
* <p>The returned collection will be serializable if the specified |
2194 |
|
|
* collection is serializable. |
2195 |
|
|
* |
2196 |
jsr166 |
1.32 |
* <p>Since {@code null} is considered to be a value of any reference |
2197 |
|
|
* type, the returned collection permits insertion of null elements |
2198 |
|
|
* whenever the backing collection does. |
2199 |
|
|
* |
2200 |
dl |
1.1 |
* @param c the collection for which a dynamically typesafe view is to be |
2201 |
jsr166 |
1.32 |
* returned |
2202 |
|
|
* @param type the type of element that {@code c} is permitted to hold |
2203 |
dl |
1.1 |
* @return a dynamically typesafe view of the specified collection |
2204 |
|
|
* @since 1.5 |
2205 |
|
|
*/ |
2206 |
|
|
public static <E> Collection<E> checkedCollection(Collection<E> c, |
2207 |
|
|
Class<E> type) { |
2208 |
|
|
return new CheckedCollection<E>(c, type); |
2209 |
|
|
} |
2210 |
jsr166 |
1.4 |
|
2211 |
jsr166 |
1.32 |
@SuppressWarnings("unchecked") |
2212 |
|
|
static <T> T[] zeroLengthArray(Class<T> type) { |
2213 |
jsr166 |
1.33 |
return (T[]) Array.newInstance(type, 0); |
2214 |
jsr166 |
1.32 |
} |
2215 |
|
|
|
2216 |
dl |
1.1 |
/** |
2217 |
|
|
* @serial include |
2218 |
|
|
*/ |
2219 |
|
|
static class CheckedCollection<E> implements Collection<E>, Serializable { |
2220 |
|
|
private static final long serialVersionUID = 1578914078182001775L; |
2221 |
|
|
|
2222 |
|
|
final Collection<E> c; |
2223 |
|
|
final Class<E> type; |
2224 |
|
|
|
2225 |
|
|
void typeCheck(Object o) { |
2226 |
jsr166 |
1.32 |
if (o != null && !type.isInstance(o)) |
2227 |
|
|
throw new ClassCastException(badElementMsg(o)); |
2228 |
dl |
1.1 |
} |
2229 |
|
|
|
2230 |
jsr166 |
1.33 |
private String badElementMsg(Object o) { |
2231 |
|
|
return "Attempt to insert " + o.getClass() + |
2232 |
|
|
" element into collection with element type " + type; |
2233 |
|
|
} |
2234 |
jsr166 |
1.32 |
|
2235 |
dl |
1.1 |
CheckedCollection(Collection<E> c, Class<E> type) { |
2236 |
|
|
if (c==null || type == null) |
2237 |
|
|
throw new NullPointerException(); |
2238 |
|
|
this.c = c; |
2239 |
|
|
this.type = type; |
2240 |
|
|
} |
2241 |
|
|
|
2242 |
jsr166 |
1.32 |
public int size() { return c.size(); } |
2243 |
|
|
public boolean isEmpty() { return c.isEmpty(); } |
2244 |
|
|
public boolean contains(Object o) { return c.contains(o); } |
2245 |
|
|
public Object[] toArray() { return c.toArray(); } |
2246 |
|
|
public <T> T[] toArray(T[] a) { return c.toArray(a); } |
2247 |
|
|
public String toString() { return c.toString(); } |
2248 |
|
|
public boolean remove(Object o) { return c.remove(o); } |
2249 |
|
|
public void clear() { c.clear(); } |
2250 |
|
|
|
2251 |
jsr166 |
1.33 |
public boolean containsAll(Collection<?> coll) { |
2252 |
dl |
1.1 |
return c.containsAll(coll); |
2253 |
|
|
} |
2254 |
|
|
public boolean removeAll(Collection<?> coll) { |
2255 |
|
|
return c.removeAll(coll); |
2256 |
|
|
} |
2257 |
|
|
public boolean retainAll(Collection<?> coll) { |
2258 |
|
|
return c.retainAll(coll); |
2259 |
|
|
} |
2260 |
|
|
|
2261 |
jsr166 |
1.20 |
public Iterator<E> iterator() { |
2262 |
jsr166 |
1.33 |
final Iterator<E> it = c.iterator(); |
2263 |
|
|
return new Iterator<E>() { |
2264 |
|
|
public boolean hasNext() { return it.hasNext(); } |
2265 |
|
|
public E next() { return it.next(); } |
2266 |
|
|
public void remove() { it.remove(); }}; |
2267 |
|
|
} |
2268 |
jsr166 |
1.20 |
|
2269 |
jsr166 |
1.33 |
public boolean add(E e) { |
2270 |
jsr166 |
1.5 |
typeCheck(e); |
2271 |
|
|
return c.add(e); |
2272 |
dl |
1.1 |
} |
2273 |
|
|
|
2274 |
jsr166 |
1.32 |
private E[] zeroLengthElementArray = null; // Lazily initialized |
2275 |
dl |
1.1 |
|
2276 |
jsr166 |
1.33 |
private E[] zeroLengthElementArray() { |
2277 |
|
|
return zeroLengthElementArray != null ? zeroLengthElementArray : |
2278 |
|
|
(zeroLengthElementArray = zeroLengthArray(type)); |
2279 |
|
|
} |
2280 |
|
|
|
2281 |
|
|
@SuppressWarnings("unchecked") |
2282 |
|
|
Collection<E> checkedCopyOf(Collection<? extends E> coll) { |
2283 |
|
|
Object[] a = null; |
2284 |
|
|
try { |
2285 |
|
|
E[] z = zeroLengthElementArray(); |
2286 |
|
|
a = coll.toArray(z); |
2287 |
|
|
// Defend against coll violating the toArray contract |
2288 |
|
|
if (a.getClass() != z.getClass()) |
2289 |
|
|
a = Arrays.copyOf(a, a.length, z.getClass()); |
2290 |
|
|
} catch (ArrayStoreException ignore) { |
2291 |
|
|
// To get better and consistent diagnostics, |
2292 |
|
|
// we call typeCheck explicitly on each element. |
2293 |
|
|
// We call clone() to defend against coll retaining a |
2294 |
|
|
// reference to the returned array and storing a bad |
2295 |
|
|
// element into it after it has been type checked. |
2296 |
|
|
a = coll.toArray().clone(); |
2297 |
|
|
for (Object o : a) |
2298 |
|
|
typeCheck(o); |
2299 |
|
|
} |
2300 |
|
|
// A slight abuse of the type system, but safe here. |
2301 |
|
|
return (Collection<E>) Arrays.asList(a); |
2302 |
|
|
} |
2303 |
dl |
1.1 |
|
2304 |
jsr166 |
1.32 |
public boolean addAll(Collection<? extends E> coll) { |
2305 |
jsr166 |
1.33 |
// Doing things this way insulates us from concurrent changes |
2306 |
|
|
// in the contents of coll and provides all-or-nothing |
2307 |
|
|
// semantics (which we wouldn't get if we type-checked each |
2308 |
|
|
// element as we added it) |
2309 |
|
|
return c.addAll(checkedCopyOf(coll)); |
2310 |
dl |
1.1 |
} |
2311 |
|
|
} |
2312 |
|
|
|
2313 |
|
|
/** |
2314 |
|
|
* Returns a dynamically typesafe view of the specified set. |
2315 |
|
|
* Any attempt to insert an element of the wrong type will result in |
2316 |
jsr166 |
1.32 |
* an immediate {@link ClassCastException}. Assuming a set contains |
2317 |
dl |
1.1 |
* no incorrectly typed elements prior to the time a dynamically typesafe |
2318 |
|
|
* view is generated, and that all subsequent access to the set |
2319 |
|
|
* takes place through the view, it is <i>guaranteed</i> that the |
2320 |
|
|
* set cannot contain an incorrectly typed element. |
2321 |
|
|
* |
2322 |
|
|
* <p>A discussion of the use of dynamically typesafe views may be |
2323 |
jsr166 |
1.32 |
* found in the documentation for the {@link #checkedCollection |
2324 |
|
|
* checkedCollection} method. |
2325 |
dl |
1.1 |
* |
2326 |
|
|
* <p>The returned set will be serializable if the specified set is |
2327 |
|
|
* serializable. |
2328 |
|
|
* |
2329 |
jsr166 |
1.32 |
* <p>Since {@code null} is considered to be a value of any reference |
2330 |
|
|
* type, the returned set permits insertion of null elements whenever |
2331 |
|
|
* the backing set does. |
2332 |
|
|
* |
2333 |
dl |
1.1 |
* @param s the set for which a dynamically typesafe view is to be |
2334 |
jsr166 |
1.32 |
* returned |
2335 |
|
|
* @param type the type of element that {@code s} is permitted to hold |
2336 |
dl |
1.1 |
* @return a dynamically typesafe view of the specified set |
2337 |
|
|
* @since 1.5 |
2338 |
|
|
*/ |
2339 |
|
|
public static <E> Set<E> checkedSet(Set<E> s, Class<E> type) { |
2340 |
|
|
return new CheckedSet<E>(s, type); |
2341 |
|
|
} |
2342 |
jsr166 |
1.4 |
|
2343 |
dl |
1.1 |
/** |
2344 |
|
|
* @serial include |
2345 |
|
|
*/ |
2346 |
|
|
static class CheckedSet<E> extends CheckedCollection<E> |
2347 |
|
|
implements Set<E>, Serializable |
2348 |
|
|
{ |
2349 |
|
|
private static final long serialVersionUID = 4694047833775013803L; |
2350 |
|
|
|
2351 |
|
|
CheckedSet(Set<E> s, Class<E> elementType) { super(s, elementType); } |
2352 |
|
|
|
2353 |
jsr166 |
1.23 |
public boolean equals(Object o) { return o == this || c.equals(o); } |
2354 |
dl |
1.1 |
public int hashCode() { return c.hashCode(); } |
2355 |
|
|
} |
2356 |
|
|
|
2357 |
|
|
/** |
2358 |
jsr166 |
1.32 |
* Returns a dynamically typesafe view of the specified sorted set. |
2359 |
|
|
* Any attempt to insert an element of the wrong type will result in an |
2360 |
|
|
* immediate {@link ClassCastException}. Assuming a sorted set |
2361 |
|
|
* contains no incorrectly typed elements prior to the time a |
2362 |
|
|
* dynamically typesafe view is generated, and that all subsequent |
2363 |
|
|
* access to the sorted set takes place through the view, it is |
2364 |
|
|
* <i>guaranteed</i> that the sorted set cannot contain an incorrectly |
2365 |
|
|
* typed element. |
2366 |
dl |
1.1 |
* |
2367 |
|
|
* <p>A discussion of the use of dynamically typesafe views may be |
2368 |
jsr166 |
1.32 |
* found in the documentation for the {@link #checkedCollection |
2369 |
|
|
* checkedCollection} method. |
2370 |
dl |
1.1 |
* |
2371 |
|
|
* <p>The returned sorted set will be serializable if the specified sorted |
2372 |
|
|
* set is serializable. |
2373 |
|
|
* |
2374 |
jsr166 |
1.32 |
* <p>Since {@code null} is considered to be a value of any reference |
2375 |
|
|
* type, the returned sorted set permits insertion of null elements |
2376 |
|
|
* whenever the backing sorted set does. |
2377 |
|
|
* |
2378 |
dl |
1.1 |
* @param s the sorted set for which a dynamically typesafe view is to be |
2379 |
jsr166 |
1.32 |
* returned |
2380 |
|
|
* @param type the type of element that {@code s} is permitted to hold |
2381 |
dl |
1.1 |
* @return a dynamically typesafe view of the specified sorted set |
2382 |
|
|
* @since 1.5 |
2383 |
|
|
*/ |
2384 |
|
|
public static <E> SortedSet<E> checkedSortedSet(SortedSet<E> s, |
2385 |
|
|
Class<E> type) { |
2386 |
|
|
return new CheckedSortedSet<E>(s, type); |
2387 |
|
|
} |
2388 |
|
|
|
2389 |
|
|
/** |
2390 |
|
|
* @serial include |
2391 |
|
|
*/ |
2392 |
|
|
static class CheckedSortedSet<E> extends CheckedSet<E> |
2393 |
|
|
implements SortedSet<E>, Serializable |
2394 |
|
|
{ |
2395 |
|
|
private static final long serialVersionUID = 1599911165492914959L; |
2396 |
|
|
private final SortedSet<E> ss; |
2397 |
|
|
|
2398 |
|
|
CheckedSortedSet(SortedSet<E> s, Class<E> type) { |
2399 |
|
|
super(s, type); |
2400 |
|
|
ss = s; |
2401 |
|
|
} |
2402 |
|
|
|
2403 |
|
|
public Comparator<? super E> comparator() { return ss.comparator(); } |
2404 |
|
|
public E first() { return ss.first(); } |
2405 |
|
|
public E last() { return ss.last(); } |
2406 |
|
|
|
2407 |
|
|
public SortedSet<E> subSet(E fromElement, E toElement) { |
2408 |
jsr166 |
1.32 |
return checkedSortedSet(ss.subSet(fromElement,toElement), type); |
2409 |
dl |
1.1 |
} |
2410 |
|
|
public SortedSet<E> headSet(E toElement) { |
2411 |
jsr166 |
1.32 |
return checkedSortedSet(ss.headSet(toElement), type); |
2412 |
dl |
1.1 |
} |
2413 |
|
|
public SortedSet<E> tailSet(E fromElement) { |
2414 |
jsr166 |
1.32 |
return checkedSortedSet(ss.tailSet(fromElement), type); |
2415 |
dl |
1.1 |
} |
2416 |
|
|
} |
2417 |
|
|
|
2418 |
|
|
/** |
2419 |
|
|
* Returns a dynamically typesafe view of the specified list. |
2420 |
|
|
* Any attempt to insert an element of the wrong type will result in |
2421 |
jsr166 |
1.32 |
* an immediate {@link ClassCastException}. Assuming a list contains |
2422 |
dl |
1.1 |
* no incorrectly typed elements prior to the time a dynamically typesafe |
2423 |
|
|
* view is generated, and that all subsequent access to the list |
2424 |
|
|
* takes place through the view, it is <i>guaranteed</i> that the |
2425 |
|
|
* list cannot contain an incorrectly typed element. |
2426 |
|
|
* |
2427 |
|
|
* <p>A discussion of the use of dynamically typesafe views may be |
2428 |
jsr166 |
1.32 |
* found in the documentation for the {@link #checkedCollection |
2429 |
|
|
* checkedCollection} method. |
2430 |
|
|
* |
2431 |
|
|
* <p>The returned list will be serializable if the specified list |
2432 |
|
|
* is serializable. |
2433 |
dl |
1.1 |
* |
2434 |
jsr166 |
1.32 |
* <p>Since {@code null} is considered to be a value of any reference |
2435 |
|
|
* type, the returned list permits insertion of null elements whenever |
2436 |
|
|
* the backing list does. |
2437 |
dl |
1.1 |
* |
2438 |
|
|
* @param list the list for which a dynamically typesafe view is to be |
2439 |
|
|
* returned |
2440 |
jsr166 |
1.32 |
* @param type the type of element that {@code list} is permitted to hold |
2441 |
dl |
1.1 |
* @return a dynamically typesafe view of the specified list |
2442 |
|
|
* @since 1.5 |
2443 |
|
|
*/ |
2444 |
|
|
public static <E> List<E> checkedList(List<E> list, Class<E> type) { |
2445 |
|
|
return (list instanceof RandomAccess ? |
2446 |
|
|
new CheckedRandomAccessList<E>(list, type) : |
2447 |
|
|
new CheckedList<E>(list, type)); |
2448 |
|
|
} |
2449 |
|
|
|
2450 |
|
|
/** |
2451 |
|
|
* @serial include |
2452 |
|
|
*/ |
2453 |
jsr166 |
1.32 |
static class CheckedList<E> |
2454 |
jsr166 |
1.33 |
extends CheckedCollection<E> |
2455 |
|
|
implements List<E> |
2456 |
dl |
1.1 |
{ |
2457 |
jsr166 |
1.32 |
private static final long serialVersionUID = 65247728283967356L; |
2458 |
dl |
1.1 |
final List<E> list; |
2459 |
|
|
|
2460 |
|
|
CheckedList(List<E> list, Class<E> type) { |
2461 |
|
|
super(list, type); |
2462 |
|
|
this.list = list; |
2463 |
|
|
} |
2464 |
|
|
|
2465 |
jsr166 |
1.23 |
public boolean equals(Object o) { return o == this || list.equals(o); } |
2466 |
dl |
1.1 |
public int hashCode() { return list.hashCode(); } |
2467 |
|
|
public E get(int index) { return list.get(index); } |
2468 |
|
|
public E remove(int index) { return list.remove(index); } |
2469 |
|
|
public int indexOf(Object o) { return list.indexOf(o); } |
2470 |
|
|
public int lastIndexOf(Object o) { return list.lastIndexOf(o); } |
2471 |
|
|
|
2472 |
|
|
public E set(int index, E element) { |
2473 |
|
|
typeCheck(element); |
2474 |
|
|
return list.set(index, element); |
2475 |
|
|
} |
2476 |
|
|
|
2477 |
|
|
public void add(int index, E element) { |
2478 |
|
|
typeCheck(element); |
2479 |
|
|
list.add(index, element); |
2480 |
|
|
} |
2481 |
|
|
|
2482 |
|
|
public boolean addAll(int index, Collection<? extends E> c) { |
2483 |
jsr166 |
1.32 |
return list.addAll(index, checkedCopyOf(c)); |
2484 |
dl |
1.1 |
} |
2485 |
|
|
public ListIterator<E> listIterator() { return listIterator(0); } |
2486 |
|
|
|
2487 |
|
|
public ListIterator<E> listIterator(final int index) { |
2488 |
jsr166 |
1.33 |
final ListIterator<E> i = list.listIterator(index); |
2489 |
dl |
1.1 |
|
2490 |
jsr166 |
1.33 |
return new ListIterator<E>() { |
2491 |
dl |
1.1 |
public boolean hasNext() { return i.hasNext(); } |
2492 |
|
|
public E next() { return i.next(); } |
2493 |
|
|
public boolean hasPrevious() { return i.hasPrevious(); } |
2494 |
|
|
public E previous() { return i.previous(); } |
2495 |
|
|
public int nextIndex() { return i.nextIndex(); } |
2496 |
|
|
public int previousIndex() { return i.previousIndex(); } |
2497 |
jsr166 |
1.32 |
public void remove() { i.remove(); } |
2498 |
dl |
1.1 |
|
2499 |
jsr166 |
1.5 |
public void set(E e) { |
2500 |
|
|
typeCheck(e); |
2501 |
|
|
i.set(e); |
2502 |
dl |
1.1 |
} |
2503 |
|
|
|
2504 |
jsr166 |
1.5 |
public void add(E e) { |
2505 |
|
|
typeCheck(e); |
2506 |
|
|
i.add(e); |
2507 |
dl |
1.1 |
} |
2508 |
|
|
}; |
2509 |
|
|
} |
2510 |
|
|
|
2511 |
|
|
public List<E> subList(int fromIndex, int toIndex) { |
2512 |
|
|
return new CheckedList<E>(list.subList(fromIndex, toIndex), type); |
2513 |
|
|
} |
2514 |
|
|
} |
2515 |
|
|
|
2516 |
|
|
/** |
2517 |
|
|
* @serial include |
2518 |
|
|
*/ |
2519 |
|
|
static class CheckedRandomAccessList<E> extends CheckedList<E> |
2520 |
|
|
implements RandomAccess |
2521 |
|
|
{ |
2522 |
|
|
private static final long serialVersionUID = 1638200125423088369L; |
2523 |
|
|
|
2524 |
|
|
CheckedRandomAccessList(List<E> list, Class<E> type) { |
2525 |
|
|
super(list, type); |
2526 |
|
|
} |
2527 |
|
|
|
2528 |
|
|
public List<E> subList(int fromIndex, int toIndex) { |
2529 |
|
|
return new CheckedRandomAccessList<E>( |
2530 |
|
|
list.subList(fromIndex, toIndex), type); |
2531 |
|
|
} |
2532 |
|
|
} |
2533 |
|
|
|
2534 |
|
|
/** |
2535 |
jsr166 |
1.32 |
* Returns a dynamically typesafe view of the specified map. |
2536 |
|
|
* Any attempt to insert a mapping whose key or value have the wrong |
2537 |
|
|
* type will result in an immediate {@link ClassCastException}. |
2538 |
|
|
* Similarly, any attempt to modify the value currently associated with |
2539 |
|
|
* a key will result in an immediate {@link ClassCastException}, |
2540 |
|
|
* whether the modification is attempted directly through the map |
2541 |
|
|
* itself, or through a {@link Map.Entry} instance obtained from the |
2542 |
|
|
* map's {@link Map#entrySet() entry set} view. |
2543 |
dl |
1.1 |
* |
2544 |
|
|
* <p>Assuming a map contains no incorrectly typed keys or values |
2545 |
|
|
* prior to the time a dynamically typesafe view is generated, and |
2546 |
|
|
* that all subsequent access to the map takes place through the view |
2547 |
|
|
* (or one of its collection views), it is <i>guaranteed</i> that the |
2548 |
|
|
* map cannot contain an incorrectly typed key or value. |
2549 |
|
|
* |
2550 |
|
|
* <p>A discussion of the use of dynamically typesafe views may be |
2551 |
jsr166 |
1.32 |
* found in the documentation for the {@link #checkedCollection |
2552 |
|
|
* checkedCollection} method. |
2553 |
dl |
1.1 |
* |
2554 |
|
|
* <p>The returned map will be serializable if the specified map is |
2555 |
|
|
* serializable. |
2556 |
|
|
* |
2557 |
jsr166 |
1.32 |
* <p>Since {@code null} is considered to be a value of any reference |
2558 |
|
|
* type, the returned map permits insertion of null keys or values |
2559 |
|
|
* whenever the backing map does. |
2560 |
|
|
* |
2561 |
dl |
1.1 |
* @param m the map for which a dynamically typesafe view is to be |
2562 |
jsr166 |
1.32 |
* returned |
2563 |
|
|
* @param keyType the type of key that {@code m} is permitted to hold |
2564 |
|
|
* @param valueType the type of value that {@code m} is permitted to hold |
2565 |
dl |
1.1 |
* @return a dynamically typesafe view of the specified map |
2566 |
|
|
* @since 1.5 |
2567 |
|
|
*/ |
2568 |
jsr166 |
1.32 |
public static <K, V> Map<K, V> checkedMap(Map<K, V> m, |
2569 |
jsr166 |
1.33 |
Class<K> keyType, |
2570 |
dl |
1.1 |
Class<V> valueType) { |
2571 |
|
|
return new CheckedMap<K,V>(m, keyType, valueType); |
2572 |
|
|
} |
2573 |
|
|
|
2574 |
|
|
|
2575 |
|
|
/** |
2576 |
|
|
* @serial include |
2577 |
|
|
*/ |
2578 |
jsr166 |
1.32 |
private static class CheckedMap<K,V> |
2579 |
jsr166 |
1.33 |
implements Map<K,V>, Serializable |
2580 |
dl |
1.1 |
{ |
2581 |
|
|
private static final long serialVersionUID = 5742860141034234728L; |
2582 |
|
|
|
2583 |
|
|
private final Map<K, V> m; |
2584 |
|
|
final Class<K> keyType; |
2585 |
|
|
final Class<V> valueType; |
2586 |
|
|
|
2587 |
|
|
private void typeCheck(Object key, Object value) { |
2588 |
jsr166 |
1.32 |
if (key != null && !keyType.isInstance(key)) |
2589 |
|
|
throw new ClassCastException(badKeyMsg(key)); |
2590 |
|
|
|
2591 |
|
|
if (value != null && !valueType.isInstance(value)) |
2592 |
|
|
throw new ClassCastException(badValueMsg(value)); |
2593 |
dl |
1.1 |
} |
2594 |
|
|
|
2595 |
jsr166 |
1.33 |
private String badKeyMsg(Object key) { |
2596 |
|
|
return "Attempt to insert " + key.getClass() + |
2597 |
|
|
" key into map with key type " + keyType; |
2598 |
|
|
} |
2599 |
|
|
|
2600 |
|
|
private String badValueMsg(Object value) { |
2601 |
|
|
return "Attempt to insert " + value.getClass() + |
2602 |
|
|
" value into map with value type " + valueType; |
2603 |
|
|
} |
2604 |
jsr166 |
1.32 |
|
2605 |
dl |
1.1 |
CheckedMap(Map<K, V> m, Class<K> keyType, Class<V> valueType) { |
2606 |
|
|
if (m == null || keyType == null || valueType == null) |
2607 |
|
|
throw new NullPointerException(); |
2608 |
|
|
this.m = m; |
2609 |
|
|
this.keyType = keyType; |
2610 |
|
|
this.valueType = valueType; |
2611 |
|
|
} |
2612 |
|
|
|
2613 |
|
|
public int size() { return m.size(); } |
2614 |
|
|
public boolean isEmpty() { return m.isEmpty(); } |
2615 |
|
|
public boolean containsKey(Object key) { return m.containsKey(key); } |
2616 |
|
|
public boolean containsValue(Object v) { return m.containsValue(v); } |
2617 |
|
|
public V get(Object key) { return m.get(key); } |
2618 |
|
|
public V remove(Object key) { return m.remove(key); } |
2619 |
|
|
public void clear() { m.clear(); } |
2620 |
|
|
public Set<K> keySet() { return m.keySet(); } |
2621 |
|
|
public Collection<V> values() { return m.values(); } |
2622 |
jsr166 |
1.23 |
public boolean equals(Object o) { return o == this || m.equals(o); } |
2623 |
dl |
1.1 |
public int hashCode() { return m.hashCode(); } |
2624 |
|
|
public String toString() { return m.toString(); } |
2625 |
|
|
|
2626 |
|
|
public V put(K key, V value) { |
2627 |
|
|
typeCheck(key, value); |
2628 |
|
|
return m.put(key, value); |
2629 |
|
|
} |
2630 |
|
|
|
2631 |
jsr166 |
1.33 |
@SuppressWarnings("unchecked") |
2632 |
|
|
public void putAll(Map<? extends K, ? extends V> t) { |
2633 |
|
|
// Satisfy the following goals: |
2634 |
|
|
// - good diagnostics in case of type mismatch |
2635 |
|
|
// - all-or-nothing semantics |
2636 |
|
|
// - protection from malicious t |
2637 |
|
|
// - correct behavior if t is a concurrent map |
2638 |
|
|
Object[] entries = t.entrySet().toArray(); |
2639 |
|
|
List<Map.Entry<K,V>> checked = |
2640 |
|
|
new ArrayList<Map.Entry<K,V>>(entries.length); |
2641 |
|
|
for (Object o : entries) { |
2642 |
|
|
Map.Entry<?,?> e = (Map.Entry<?,?>) o; |
2643 |
|
|
Object k = e.getKey(); |
2644 |
|
|
Object v = e.getValue(); |
2645 |
|
|
typeCheck(k, v); |
2646 |
|
|
checked.add( |
2647 |
|
|
new AbstractMap.SimpleImmutableEntry<K,V>((K) k, (V) v)); |
2648 |
|
|
} |
2649 |
|
|
for (Map.Entry<K,V> e : checked) |
2650 |
|
|
m.put(e.getKey(), e.getValue()); |
2651 |
|
|
} |
2652 |
dl |
1.1 |
|
2653 |
|
|
private transient Set<Map.Entry<K,V>> entrySet = null; |
2654 |
|
|
|
2655 |
|
|
public Set<Map.Entry<K,V>> entrySet() { |
2656 |
|
|
if (entrySet==null) |
2657 |
|
|
entrySet = new CheckedEntrySet<K,V>(m.entrySet(), valueType); |
2658 |
|
|
return entrySet; |
2659 |
|
|
} |
2660 |
|
|
|
2661 |
|
|
/** |
2662 |
|
|
* We need this class in addition to CheckedSet as Map.Entry permits |
2663 |
|
|
* modification of the backing Map via the setValue operation. This |
2664 |
|
|
* class is subtle: there are many possible attacks that must be |
2665 |
|
|
* thwarted. |
2666 |
|
|
* |
2667 |
|
|
* @serial exclude |
2668 |
|
|
*/ |
2669 |
|
|
static class CheckedEntrySet<K,V> implements Set<Map.Entry<K,V>> { |
2670 |
jsr166 |
1.32 |
private final Set<Map.Entry<K,V>> s; |
2671 |
|
|
private final Class<V> valueType; |
2672 |
dl |
1.1 |
|
2673 |
|
|
CheckedEntrySet(Set<Map.Entry<K, V>> s, Class<V> valueType) { |
2674 |
|
|
this.s = s; |
2675 |
|
|
this.valueType = valueType; |
2676 |
|
|
} |
2677 |
|
|
|
2678 |
jsr166 |
1.32 |
public int size() { return s.size(); } |
2679 |
|
|
public boolean isEmpty() { return s.isEmpty(); } |
2680 |
|
|
public String toString() { return s.toString(); } |
2681 |
|
|
public int hashCode() { return s.hashCode(); } |
2682 |
|
|
public void clear() { s.clear(); } |
2683 |
dl |
1.1 |
|
2684 |
jsr166 |
1.32 |
public boolean add(Map.Entry<K, V> e) { |
2685 |
dl |
1.1 |
throw new UnsupportedOperationException(); |
2686 |
|
|
} |
2687 |
|
|
public boolean addAll(Collection<? extends Map.Entry<K, V>> coll) { |
2688 |
|
|
throw new UnsupportedOperationException(); |
2689 |
|
|
} |
2690 |
|
|
|
2691 |
|
|
public Iterator<Map.Entry<K,V>> iterator() { |
2692 |
jsr166 |
1.33 |
final Iterator<Map.Entry<K, V>> i = s.iterator(); |
2693 |
|
|
final Class<V> valueType = this.valueType; |
2694 |
dl |
1.1 |
|
2695 |
jsr166 |
1.33 |
return new Iterator<Map.Entry<K,V>>() { |
2696 |
dl |
1.1 |
public boolean hasNext() { return i.hasNext(); } |
2697 |
|
|
public void remove() { i.remove(); } |
2698 |
|
|
|
2699 |
|
|
public Map.Entry<K,V> next() { |
2700 |
jsr166 |
1.32 |
return checkedEntry(i.next(), valueType); |
2701 |
dl |
1.1 |
} |
2702 |
|
|
}; |
2703 |
|
|
} |
2704 |
|
|
|
2705 |
jsr166 |
1.33 |
@SuppressWarnings("unchecked") |
2706 |
dl |
1.1 |
public Object[] toArray() { |
2707 |
|
|
Object[] source = s.toArray(); |
2708 |
|
|
|
2709 |
|
|
/* |
2710 |
|
|
* Ensure that we don't get an ArrayStoreException even if |
2711 |
|
|
* s.toArray returns an array of something other than Object |
2712 |
|
|
*/ |
2713 |
|
|
Object[] dest = (CheckedEntry.class.isInstance( |
2714 |
|
|
source.getClass().getComponentType()) ? source : |
2715 |
|
|
new Object[source.length]); |
2716 |
|
|
|
2717 |
|
|
for (int i = 0; i < source.length; i++) |
2718 |
jsr166 |
1.32 |
dest[i] = checkedEntry((Map.Entry<K,V>)source[i], |
2719 |
jsr166 |
1.33 |
valueType); |
2720 |
dl |
1.1 |
return dest; |
2721 |
|
|
} |
2722 |
|
|
|
2723 |
jsr166 |
1.33 |
@SuppressWarnings("unchecked") |
2724 |
dl |
1.1 |
public <T> T[] toArray(T[] a) { |
2725 |
|
|
// We don't pass a to s.toArray, to avoid window of |
2726 |
|
|
// vulnerability wherein an unscrupulous multithreaded client |
2727 |
|
|
// could get his hands on raw (unwrapped) Entries from s. |
2728 |
jsr166 |
1.32 |
T[] arr = s.toArray(a.length==0 ? a : Arrays.copyOf(a, 0)); |
2729 |
dl |
1.1 |
|
2730 |
|
|
for (int i=0; i<arr.length; i++) |
2731 |
jsr166 |
1.32 |
arr[i] = (T) checkedEntry((Map.Entry<K,V>)arr[i], |
2732 |
jsr166 |
1.33 |
valueType); |
2733 |
dl |
1.1 |
if (arr.length > a.length) |
2734 |
jsr166 |
1.32 |
return arr; |
2735 |
dl |
1.1 |
|
2736 |
|
|
System.arraycopy(arr, 0, a, 0, arr.length); |
2737 |
|
|
if (a.length > arr.length) |
2738 |
|
|
a[arr.length] = null; |
2739 |
|
|
return a; |
2740 |
|
|
} |
2741 |
|
|
|
2742 |
|
|
/** |
2743 |
|
|
* This method is overridden to protect the backing set against |
2744 |
|
|
* an object with a nefarious equals function that senses |
2745 |
|
|
* that the equality-candidate is Map.Entry and calls its |
2746 |
|
|
* setValue method. |
2747 |
|
|
*/ |
2748 |
|
|
public boolean contains(Object o) { |
2749 |
|
|
if (!(o instanceof Map.Entry)) |
2750 |
|
|
return false; |
2751 |
jsr166 |
1.33 |
Map.Entry<?,?> e = (Map.Entry<?,?>) o; |
2752 |
|
|
return s.contains( |
2753 |
|
|
(e instanceof CheckedEntry) ? e : checkedEntry(e, valueType)); |
2754 |
dl |
1.1 |
} |
2755 |
|
|
|
2756 |
|
|
/** |
2757 |
jsr166 |
1.32 |
* The bulk collection methods are overridden to protect |
2758 |
|
|
* against an unscrupulous collection whose contains(Object o) |
2759 |
|
|
* method senses when o is a Map.Entry, and calls o.setValue. |
2760 |
dl |
1.1 |
*/ |
2761 |
jsr166 |
1.32 |
public boolean containsAll(Collection<?> c) { |
2762 |
jsr166 |
1.33 |
for (Object o : c) |
2763 |
jsr166 |
1.32 |
if (!contains(o)) // Invokes safe contains() above |
2764 |
dl |
1.1 |
return false; |
2765 |
|
|
return true; |
2766 |
|
|
} |
2767 |
|
|
|
2768 |
jsr166 |
1.33 |
public boolean remove(Object o) { |
2769 |
jsr166 |
1.32 |
if (!(o instanceof Map.Entry)) |
2770 |
|
|
return false; |
2771 |
jsr166 |
1.33 |
return s.remove(new AbstractMap.SimpleImmutableEntry |
2772 |
|
|
<Object, Object>((Map.Entry<?,?>)o)); |
2773 |
|
|
} |
2774 |
|
|
|
2775 |
|
|
public boolean removeAll(Collection<?> c) { |
2776 |
|
|
return batchRemove(c, false); |
2777 |
|
|
} |
2778 |
|
|
public boolean retainAll(Collection<?> c) { |
2779 |
|
|
return batchRemove(c, true); |
2780 |
|
|
} |
2781 |
|
|
private boolean batchRemove(Collection<?> c, boolean complement) { |
2782 |
|
|
boolean modified = false; |
2783 |
|
|
Iterator<Map.Entry<K,V>> it = iterator(); |
2784 |
|
|
while (it.hasNext()) { |
2785 |
|
|
if (c.contains(it.next()) != complement) { |
2786 |
|
|
it.remove(); |
2787 |
|
|
modified = true; |
2788 |
|
|
} |
2789 |
|
|
} |
2790 |
|
|
return modified; |
2791 |
|
|
} |
2792 |
jsr166 |
1.32 |
|
2793 |
dl |
1.1 |
public boolean equals(Object o) { |
2794 |
|
|
if (o == this) |
2795 |
|
|
return true; |
2796 |
|
|
if (!(o instanceof Set)) |
2797 |
|
|
return false; |
2798 |
|
|
Set<?> that = (Set<?>) o; |
2799 |
jsr166 |
1.32 |
return that.size() == s.size() |
2800 |
jsr166 |
1.33 |
&& containsAll(that); // Invokes safe containsAll() above |
2801 |
dl |
1.1 |
} |
2802 |
|
|
|
2803 |
jsr166 |
1.33 |
static <K,V,T> CheckedEntry<K,V,T> checkedEntry(Map.Entry<K,V> e, |
2804 |
|
|
Class<T> valueType) { |
2805 |
|
|
return new CheckedEntry<K,V,T>(e, valueType); |
2806 |
|
|
} |
2807 |
jsr166 |
1.32 |
|
2808 |
dl |
1.1 |
/** |
2809 |
|
|
* This "wrapper class" serves two purposes: it prevents |
2810 |
|
|
* the client from modifying the backing Map, by short-circuiting |
2811 |
|
|
* the setValue method, and it protects the backing Map against |
2812 |
|
|
* an ill-behaved Map.Entry that attempts to modify another |
2813 |
jsr166 |
1.32 |
* Map.Entry when asked to perform an equality check. |
2814 |
dl |
1.1 |
*/ |
2815 |
jsr166 |
1.32 |
private static class CheckedEntry<K,V,T> implements Map.Entry<K,V> { |
2816 |
|
|
private final Map.Entry<K, V> e; |
2817 |
|
|
private final Class<T> valueType; |
2818 |
dl |
1.1 |
|
2819 |
jsr166 |
1.32 |
CheckedEntry(Map.Entry<K, V> e, Class<T> valueType) { |
2820 |
dl |
1.1 |
this.e = e; |
2821 |
|
|
this.valueType = valueType; |
2822 |
|
|
} |
2823 |
|
|
|
2824 |
|
|
public K getKey() { return e.getKey(); } |
2825 |
|
|
public V getValue() { return e.getValue(); } |
2826 |
|
|
public int hashCode() { return e.hashCode(); } |
2827 |
|
|
public String toString() { return e.toString(); } |
2828 |
|
|
|
2829 |
|
|
public V setValue(V value) { |
2830 |
jsr166 |
1.32 |
if (value != null && !valueType.isInstance(value)) |
2831 |
|
|
throw new ClassCastException(badValueMsg(value)); |
2832 |
dl |
1.1 |
return e.setValue(value); |
2833 |
|
|
} |
2834 |
|
|
|
2835 |
jsr166 |
1.33 |
private String badValueMsg(Object value) { |
2836 |
|
|
return "Attempt to insert " + value.getClass() + |
2837 |
|
|
" value into map with value type " + valueType; |
2838 |
|
|
} |
2839 |
jsr166 |
1.32 |
|
2840 |
dl |
1.1 |
public boolean equals(Object o) { |
2841 |
jsr166 |
1.33 |
if (o == this) |
2842 |
|
|
return true; |
2843 |
dl |
1.1 |
if (!(o instanceof Map.Entry)) |
2844 |
|
|
return false; |
2845 |
jsr166 |
1.32 |
return e.equals(new AbstractMap.SimpleImmutableEntry |
2846 |
jsr166 |
1.33 |
<Object, Object>((Map.Entry<?,?>)o)); |
2847 |
dl |
1.1 |
} |
2848 |
|
|
} |
2849 |
|
|
} |
2850 |
|
|
} |
2851 |
|
|
|
2852 |
|
|
/** |
2853 |
jsr166 |
1.32 |
* Returns a dynamically typesafe view of the specified sorted map. |
2854 |
|
|
* Any attempt to insert a mapping whose key or value have the wrong |
2855 |
|
|
* type will result in an immediate {@link ClassCastException}. |
2856 |
|
|
* Similarly, any attempt to modify the value currently associated with |
2857 |
|
|
* a key will result in an immediate {@link ClassCastException}, |
2858 |
|
|
* whether the modification is attempted directly through the map |
2859 |
|
|
* itself, or through a {@link Map.Entry} instance obtained from the |
2860 |
|
|
* map's {@link Map#entrySet() entry set} view. |
2861 |
dl |
1.1 |
* |
2862 |
|
|
* <p>Assuming a map contains no incorrectly typed keys or values |
2863 |
|
|
* prior to the time a dynamically typesafe view is generated, and |
2864 |
|
|
* that all subsequent access to the map takes place through the view |
2865 |
|
|
* (or one of its collection views), it is <i>guaranteed</i> that the |
2866 |
|
|
* map cannot contain an incorrectly typed key or value. |
2867 |
|
|
* |
2868 |
|
|
* <p>A discussion of the use of dynamically typesafe views may be |
2869 |
jsr166 |
1.32 |
* found in the documentation for the {@link #checkedCollection |
2870 |
|
|
* checkedCollection} method. |
2871 |
dl |
1.1 |
* |
2872 |
|
|
* <p>The returned map will be serializable if the specified map is |
2873 |
|
|
* serializable. |
2874 |
|
|
* |
2875 |
jsr166 |
1.32 |
* <p>Since {@code null} is considered to be a value of any reference |
2876 |
|
|
* type, the returned map permits insertion of null keys or values |
2877 |
|
|
* whenever the backing map does. |
2878 |
|
|
* |
2879 |
dl |
1.1 |
* @param m the map for which a dynamically typesafe view is to be |
2880 |
jsr166 |
1.32 |
* returned |
2881 |
|
|
* @param keyType the type of key that {@code m} is permitted to hold |
2882 |
|
|
* @param valueType the type of value that {@code m} is permitted to hold |
2883 |
dl |
1.1 |
* @return a dynamically typesafe view of the specified map |
2884 |
|
|
* @since 1.5 |
2885 |
|
|
*/ |
2886 |
|
|
public static <K,V> SortedMap<K,V> checkedSortedMap(SortedMap<K, V> m, |
2887 |
|
|
Class<K> keyType, |
2888 |
|
|
Class<V> valueType) { |
2889 |
|
|
return new CheckedSortedMap<K,V>(m, keyType, valueType); |
2890 |
|
|
} |
2891 |
|
|
|
2892 |
|
|
/** |
2893 |
|
|
* @serial include |
2894 |
|
|
*/ |
2895 |
|
|
static class CheckedSortedMap<K,V> extends CheckedMap<K,V> |
2896 |
|
|
implements SortedMap<K,V>, Serializable |
2897 |
|
|
{ |
2898 |
|
|
private static final long serialVersionUID = 1599671320688067438L; |
2899 |
|
|
|
2900 |
|
|
private final SortedMap<K, V> sm; |
2901 |
|
|
|
2902 |
|
|
CheckedSortedMap(SortedMap<K, V> m, |
2903 |
|
|
Class<K> keyType, Class<V> valueType) { |
2904 |
|
|
super(m, keyType, valueType); |
2905 |
|
|
sm = m; |
2906 |
|
|
} |
2907 |
|
|
|
2908 |
|
|
public Comparator<? super K> comparator() { return sm.comparator(); } |
2909 |
|
|
public K firstKey() { return sm.firstKey(); } |
2910 |
|
|
public K lastKey() { return sm.lastKey(); } |
2911 |
|
|
|
2912 |
|
|
public SortedMap<K,V> subMap(K fromKey, K toKey) { |
2913 |
jsr166 |
1.32 |
return checkedSortedMap(sm.subMap(fromKey, toKey), |
2914 |
jsr166 |
1.33 |
keyType, valueType); |
2915 |
dl |
1.1 |
} |
2916 |
|
|
public SortedMap<K,V> headMap(K toKey) { |
2917 |
jsr166 |
1.32 |
return checkedSortedMap(sm.headMap(toKey), keyType, valueType); |
2918 |
dl |
1.1 |
} |
2919 |
|
|
public SortedMap<K,V> tailMap(K fromKey) { |
2920 |
jsr166 |
1.32 |
return checkedSortedMap(sm.tailMap(fromKey), keyType, valueType); |
2921 |
dl |
1.1 |
} |
2922 |
|
|
} |
2923 |
|
|
|
2924 |
jsr166 |
1.32 |
// Empty collections |
2925 |
|
|
|
2926 |
|
|
/** |
2927 |
|
|
* Returns an iterator that has no elements. More precisely, |
2928 |
|
|
* |
2929 |
|
|
* <ul compact> |
2930 |
|
|
* |
2931 |
|
|
* <li>{@link Iterator#hasNext hasNext} always returns {@code |
2932 |
|
|
* false}. |
2933 |
|
|
* |
2934 |
|
|
* <li>{@link Iterator#next next} always throws {@link |
2935 |
|
|
* NoSuchElementException}. |
2936 |
|
|
* |
2937 |
|
|
* <li>{@link Iterator#remove remove} always throws {@link |
2938 |
|
|
* IllegalStateException}. |
2939 |
|
|
* |
2940 |
|
|
* </ul> |
2941 |
|
|
* |
2942 |
|
|
* <p>Implementations of this method are permitted, but not |
2943 |
|
|
* required, to return the same object from multiple invocations. |
2944 |
|
|
* |
2945 |
|
|
* @return an empty iterator |
2946 |
|
|
* @since 1.7 |
2947 |
|
|
*/ |
2948 |
|
|
@SuppressWarnings("unchecked") |
2949 |
|
|
public static <T> Iterator<T> emptyIterator() { |
2950 |
jsr166 |
1.33 |
return (Iterator<T>) EmptyIterator.EMPTY_ITERATOR; |
2951 |
jsr166 |
1.32 |
} |
2952 |
|
|
|
2953 |
|
|
private static class EmptyIterator<E> implements Iterator<E> { |
2954 |
jsr166 |
1.33 |
static final EmptyIterator<Object> EMPTY_ITERATOR |
2955 |
|
|
= new EmptyIterator<Object>(); |
2956 |
jsr166 |
1.32 |
|
2957 |
jsr166 |
1.33 |
public boolean hasNext() { return false; } |
2958 |
|
|
public E next() { throw new NoSuchElementException(); } |
2959 |
|
|
public void remove() { throw new IllegalStateException(); } |
2960 |
jsr166 |
1.32 |
} |
2961 |
|
|
|
2962 |
|
|
/** |
2963 |
|
|
* Returns a list iterator that has no elements. More precisely, |
2964 |
|
|
* |
2965 |
|
|
* <ul compact> |
2966 |
|
|
* |
2967 |
|
|
* <li>{@link Iterator#hasNext hasNext} and {@link |
2968 |
|
|
* ListIterator#hasPrevious hasPrevious} always return {@code |
2969 |
|
|
* false}. |
2970 |
|
|
* |
2971 |
|
|
* <li>{@link Iterator#next next} and {@link ListIterator#previous |
2972 |
|
|
* previous} always throw {@link NoSuchElementException}. |
2973 |
|
|
* |
2974 |
|
|
* <li>{@link Iterator#remove remove} and {@link ListIterator#set |
2975 |
|
|
* set} always throw {@link IllegalStateException}. |
2976 |
|
|
* |
2977 |
|
|
* <li>{@link ListIterator#add add} always throws {@link |
2978 |
|
|
* UnsupportedOperationException}. |
2979 |
|
|
* |
2980 |
|
|
* <li>{@link ListIterator#nextIndex nextIndex} always returns |
2981 |
|
|
* {@code 0} . |
2982 |
|
|
* |
2983 |
|
|
* <li>{@link ListIterator#previousIndex previousIndex} always |
2984 |
|
|
* returns {@code -1}. |
2985 |
|
|
* |
2986 |
|
|
* </ul> |
2987 |
|
|
* |
2988 |
|
|
* <p>Implementations of this method are permitted, but not |
2989 |
|
|
* required, to return the same object from multiple invocations. |
2990 |
|
|
* |
2991 |
|
|
* @return an empty list iterator |
2992 |
|
|
* @since 1.7 |
2993 |
|
|
*/ |
2994 |
|
|
@SuppressWarnings("unchecked") |
2995 |
|
|
public static <T> ListIterator<T> emptyListIterator() { |
2996 |
jsr166 |
1.33 |
return (ListIterator<T>) EmptyListIterator.EMPTY_ITERATOR; |
2997 |
jsr166 |
1.32 |
} |
2998 |
|
|
|
2999 |
|
|
private static class EmptyListIterator<E> |
3000 |
jsr166 |
1.33 |
extends EmptyIterator<E> |
3001 |
|
|
implements ListIterator<E> |
3002 |
jsr166 |
1.32 |
{ |
3003 |
jsr166 |
1.33 |
static final EmptyListIterator<Object> EMPTY_ITERATOR |
3004 |
|
|
= new EmptyListIterator<Object>(); |
3005 |
jsr166 |
1.32 |
|
3006 |
jsr166 |
1.33 |
public boolean hasPrevious() { return false; } |
3007 |
|
|
public E previous() { throw new NoSuchElementException(); } |
3008 |
|
|
public int nextIndex() { return 0; } |
3009 |
|
|
public int previousIndex() { return -1; } |
3010 |
|
|
public void set(E e) { throw new IllegalStateException(); } |
3011 |
|
|
public void add(E e) { throw new UnsupportedOperationException(); } |
3012 |
jsr166 |
1.32 |
} |
3013 |
|
|
|
3014 |
|
|
/** |
3015 |
|
|
* Returns an enumeration that has no elements. More precisely, |
3016 |
|
|
* |
3017 |
|
|
* <ul compact> |
3018 |
|
|
* |
3019 |
|
|
* <li>{@link Enumeration#hasMoreElements hasMoreElements} always |
3020 |
|
|
* returns {@code false}. |
3021 |
|
|
* |
3022 |
|
|
* <li> {@link Enumeration#nextElement nextElement} always throws |
3023 |
|
|
* {@link NoSuchElementException}. |
3024 |
|
|
* |
3025 |
|
|
* </ul> |
3026 |
|
|
* |
3027 |
|
|
* <p>Implementations of this method are permitted, but not |
3028 |
|
|
* required, to return the same object from multiple invocations. |
3029 |
|
|
* |
3030 |
|
|
* @return an empty enumeration |
3031 |
|
|
* @since 1.7 |
3032 |
|
|
*/ |
3033 |
|
|
@SuppressWarnings("unchecked") |
3034 |
|
|
public static <T> Enumeration<T> emptyEnumeration() { |
3035 |
jsr166 |
1.33 |
return (Enumeration<T>) EmptyEnumeration.EMPTY_ENUMERATION; |
3036 |
jsr166 |
1.32 |
} |
3037 |
|
|
|
3038 |
|
|
private static class EmptyEnumeration<E> implements Enumeration<E> { |
3039 |
jsr166 |
1.33 |
static final EmptyEnumeration<Object> EMPTY_ENUMERATION |
3040 |
|
|
= new EmptyEnumeration<Object>(); |
3041 |
jsr166 |
1.32 |
|
3042 |
jsr166 |
1.33 |
public boolean hasMoreElements() { return false; } |
3043 |
|
|
public E nextElement() { throw new NoSuchElementException(); } |
3044 |
jsr166 |
1.32 |
} |
3045 |
dl |
1.1 |
|
3046 |
|
|
/** |
3047 |
|
|
* The empty set (immutable). This set is serializable. |
3048 |
|
|
* |
3049 |
|
|
* @see #emptySet() |
3050 |
|
|
*/ |
3051 |
jsr166 |
1.32 |
@SuppressWarnings("unchecked") |
3052 |
|
|
public static final Set EMPTY_SET = new EmptySet<Object>(); |
3053 |
dl |
1.1 |
|
3054 |
|
|
/** |
3055 |
|
|
* Returns the empty set (immutable). This set is serializable. |
3056 |
|
|
* Unlike the like-named field, this method is parameterized. |
3057 |
|
|
* |
3058 |
|
|
* <p>This example illustrates the type-safe way to obtain an empty set: |
3059 |
|
|
* <pre> |
3060 |
|
|
* Set<String> s = Collections.emptySet(); |
3061 |
|
|
* </pre> |
3062 |
|
|
* Implementation note: Implementations of this method need not |
3063 |
|
|
* create a separate <tt>Set</tt> object for each call. Using this |
3064 |
|
|
* method is likely to have comparable cost to using the like-named |
3065 |
|
|
* field. (Unlike this method, the field does not provide type safety.) |
3066 |
|
|
* |
3067 |
|
|
* @see #EMPTY_SET |
3068 |
|
|
* @since 1.5 |
3069 |
|
|
*/ |
3070 |
jsr166 |
1.32 |
@SuppressWarnings("unchecked") |
3071 |
dl |
1.1 |
public static final <T> Set<T> emptySet() { |
3072 |
jsr166 |
1.33 |
return (Set<T>) EMPTY_SET; |
3073 |
dl |
1.1 |
} |
3074 |
|
|
|
3075 |
|
|
/** |
3076 |
|
|
* @serial include |
3077 |
|
|
*/ |
3078 |
jsr166 |
1.32 |
private static class EmptySet<E> |
3079 |
jsr166 |
1.33 |
extends AbstractSet<E> |
3080 |
|
|
implements Serializable |
3081 |
jsr166 |
1.32 |
{ |
3082 |
jsr166 |
1.33 |
private static final long serialVersionUID = 1582296315990362920L; |
3083 |
dl |
1.1 |
|
3084 |
jsr166 |
1.33 |
public Iterator<E> iterator() { return emptyIterator(); } |
3085 |
dl |
1.1 |
|
3086 |
|
|
public int size() {return 0;} |
3087 |
jsr166 |
1.33 |
public boolean isEmpty() {return true;} |
3088 |
dl |
1.1 |
|
3089 |
|
|
public boolean contains(Object obj) {return false;} |
3090 |
jsr166 |
1.32 |
public boolean containsAll(Collection<?> c) { return c.isEmpty(); } |
3091 |
dl |
1.1 |
|
3092 |
jsr166 |
1.32 |
public Object[] toArray() { return new Object[0]; } |
3093 |
|
|
|
3094 |
|
|
public <T> T[] toArray(T[] a) { |
3095 |
|
|
if (a.length > 0) |
3096 |
|
|
a[0] = null; |
3097 |
|
|
return a; |
3098 |
|
|
} |
3099 |
|
|
|
3100 |
jsr166 |
1.33 |
// Preserves singleton property |
3101 |
dl |
1.1 |
private Object readResolve() { |
3102 |
|
|
return EMPTY_SET; |
3103 |
|
|
} |
3104 |
|
|
} |
3105 |
|
|
|
3106 |
|
|
/** |
3107 |
|
|
* The empty list (immutable). This list is serializable. |
3108 |
|
|
* |
3109 |
|
|
* @see #emptyList() |
3110 |
|
|
*/ |
3111 |
jsr166 |
1.32 |
@SuppressWarnings("unchecked") |
3112 |
|
|
public static final List EMPTY_LIST = new EmptyList<Object>(); |
3113 |
dl |
1.1 |
|
3114 |
|
|
/** |
3115 |
|
|
* Returns the empty list (immutable). This list is serializable. |
3116 |
|
|
* |
3117 |
|
|
* <p>This example illustrates the type-safe way to obtain an empty list: |
3118 |
|
|
* <pre> |
3119 |
|
|
* List<String> s = Collections.emptyList(); |
3120 |
|
|
* </pre> |
3121 |
|
|
* Implementation note: Implementations of this method need not |
3122 |
|
|
* create a separate <tt>List</tt> object for each call. Using this |
3123 |
|
|
* method is likely to have comparable cost to using the like-named |
3124 |
|
|
* field. (Unlike this method, the field does not provide type safety.) |
3125 |
|
|
* |
3126 |
|
|
* @see #EMPTY_LIST |
3127 |
|
|
* @since 1.5 |
3128 |
|
|
*/ |
3129 |
jsr166 |
1.32 |
@SuppressWarnings("unchecked") |
3130 |
dl |
1.1 |
public static final <T> List<T> emptyList() { |
3131 |
jsr166 |
1.33 |
return (List<T>) EMPTY_LIST; |
3132 |
dl |
1.1 |
} |
3133 |
|
|
|
3134 |
|
|
/** |
3135 |
|
|
* @serial include |
3136 |
|
|
*/ |
3137 |
jsr166 |
1.32 |
private static class EmptyList<E> |
3138 |
jsr166 |
1.33 |
extends AbstractList<E> |
3139 |
|
|
implements RandomAccess, Serializable { |
3140 |
|
|
private static final long serialVersionUID = 8842843931221139166L; |
3141 |
|
|
|
3142 |
|
|
public Iterator<E> iterator() { |
3143 |
|
|
return emptyIterator(); |
3144 |
|
|
} |
3145 |
|
|
public ListIterator<E> listIterator() { |
3146 |
|
|
return emptyListIterator(); |
3147 |
|
|
} |
3148 |
jsr166 |
1.32 |
|
3149 |
jsr166 |
1.33 |
public int size() {return 0;} |
3150 |
|
|
public boolean isEmpty() {return true;} |
3151 |
dl |
1.1 |
|
3152 |
|
|
public boolean contains(Object obj) {return false;} |
3153 |
jsr166 |
1.32 |
public boolean containsAll(Collection<?> c) { return c.isEmpty(); } |
3154 |
dl |
1.1 |
|
3155 |
jsr166 |
1.32 |
public Object[] toArray() { return new Object[0]; } |
3156 |
|
|
|
3157 |
|
|
public <T> T[] toArray(T[] a) { |
3158 |
|
|
if (a.length > 0) |
3159 |
|
|
a[0] = null; |
3160 |
|
|
return a; |
3161 |
|
|
} |
3162 |
|
|
|
3163 |
|
|
public E get(int index) { |
3164 |
dl |
1.1 |
throw new IndexOutOfBoundsException("Index: "+index); |
3165 |
|
|
} |
3166 |
|
|
|
3167 |
jsr166 |
1.32 |
public boolean equals(Object o) { |
3168 |
|
|
return (o instanceof List) && ((List<?>)o).isEmpty(); |
3169 |
|
|
} |
3170 |
|
|
|
3171 |
|
|
public int hashCode() { return 1; } |
3172 |
|
|
|
3173 |
dl |
1.1 |
// Preserves singleton property |
3174 |
|
|
private Object readResolve() { |
3175 |
|
|
return EMPTY_LIST; |
3176 |
|
|
} |
3177 |
|
|
} |
3178 |
|
|
|
3179 |
|
|
/** |
3180 |
|
|
* The empty map (immutable). This map is serializable. |
3181 |
|
|
* |
3182 |
|
|
* @see #emptyMap() |
3183 |
|
|
* @since 1.3 |
3184 |
|
|
*/ |
3185 |
jsr166 |
1.32 |
@SuppressWarnings("unchecked") |
3186 |
|
|
public static final Map EMPTY_MAP = new EmptyMap<Object,Object>(); |
3187 |
dl |
1.1 |
|
3188 |
|
|
/** |
3189 |
|
|
* Returns the empty map (immutable). This map is serializable. |
3190 |
|
|
* |
3191 |
|
|
* <p>This example illustrates the type-safe way to obtain an empty set: |
3192 |
|
|
* <pre> |
3193 |
|
|
* Map<String, Date> s = Collections.emptyMap(); |
3194 |
|
|
* </pre> |
3195 |
|
|
* Implementation note: Implementations of this method need not |
3196 |
|
|
* create a separate <tt>Map</tt> object for each call. Using this |
3197 |
|
|
* method is likely to have comparable cost to using the like-named |
3198 |
|
|
* field. (Unlike this method, the field does not provide type safety.) |
3199 |
|
|
* |
3200 |
|
|
* @see #EMPTY_MAP |
3201 |
|
|
* @since 1.5 |
3202 |
|
|
*/ |
3203 |
jsr166 |
1.32 |
@SuppressWarnings("unchecked") |
3204 |
dl |
1.1 |
public static final <K,V> Map<K,V> emptyMap() { |
3205 |
jsr166 |
1.33 |
return (Map<K,V>) EMPTY_MAP; |
3206 |
dl |
1.1 |
} |
3207 |
|
|
|
3208 |
jsr166 |
1.32 |
/** |
3209 |
|
|
* @serial include |
3210 |
|
|
*/ |
3211 |
|
|
private static class EmptyMap<K,V> |
3212 |
jsr166 |
1.33 |
extends AbstractMap<K,V> |
3213 |
|
|
implements Serializable |
3214 |
jsr166 |
1.32 |
{ |
3215 |
dl |
1.1 |
private static final long serialVersionUID = 6428348081105594320L; |
3216 |
|
|
|
3217 |
|
|
public int size() {return 0;} |
3218 |
|
|
public boolean isEmpty() {return true;} |
3219 |
|
|
public boolean containsKey(Object key) {return false;} |
3220 |
|
|
public boolean containsValue(Object value) {return false;} |
3221 |
jsr166 |
1.33 |
public V get(Object key) {return null;} |
3222 |
jsr166 |
1.32 |
public Set<K> keySet() {return emptySet();} |
3223 |
|
|
public Collection<V> values() {return emptySet();} |
3224 |
|
|
public Set<Map.Entry<K,V>> entrySet() {return emptySet();} |
3225 |
dl |
1.1 |
|
3226 |
|
|
public boolean equals(Object o) { |
3227 |
jsr166 |
1.32 |
return (o instanceof Map) && ((Map<?,?>)o).isEmpty(); |
3228 |
dl |
1.1 |
} |
3229 |
|
|
|
3230 |
|
|
public int hashCode() {return 0;} |
3231 |
|
|
|
3232 |
|
|
// Preserves singleton property |
3233 |
|
|
private Object readResolve() { |
3234 |
|
|
return EMPTY_MAP; |
3235 |
|
|
} |
3236 |
|
|
} |
3237 |
|
|
|
3238 |
jsr166 |
1.32 |
// Singleton collections |
3239 |
|
|
|
3240 |
dl |
1.1 |
/** |
3241 |
|
|
* Returns an immutable set containing only the specified object. |
3242 |
|
|
* The returned set is serializable. |
3243 |
|
|
* |
3244 |
|
|
* @param o the sole object to be stored in the returned set. |
3245 |
|
|
* @return an immutable set containing only the specified object. |
3246 |
|
|
*/ |
3247 |
|
|
public static <T> Set<T> singleton(T o) { |
3248 |
jsr166 |
1.33 |
return new SingletonSet<T>(o); |
3249 |
dl |
1.1 |
} |
3250 |
|
|
|
3251 |
jsr166 |
1.32 |
static <E> Iterator<E> singletonIterator(final E e) { |
3252 |
jsr166 |
1.33 |
return new Iterator<E>() { |
3253 |
|
|
private boolean hasNext = true; |
3254 |
|
|
public boolean hasNext() { |
3255 |
|
|
return hasNext; |
3256 |
|
|
} |
3257 |
|
|
public E next() { |
3258 |
|
|
if (hasNext) { |
3259 |
|
|
hasNext = false; |
3260 |
|
|
return e; |
3261 |
|
|
} |
3262 |
|
|
throw new NoSuchElementException(); |
3263 |
|
|
} |
3264 |
|
|
public void remove() { |
3265 |
|
|
throw new UnsupportedOperationException(); |
3266 |
|
|
} |
3267 |
|
|
}; |
3268 |
jsr166 |
1.32 |
} |
3269 |
|
|
|
3270 |
dl |
1.1 |
/** |
3271 |
|
|
* @serial include |
3272 |
|
|
*/ |
3273 |
|
|
private static class SingletonSet<E> |
3274 |
jsr166 |
1.33 |
extends AbstractSet<E> |
3275 |
|
|
implements Serializable |
3276 |
dl |
1.1 |
{ |
3277 |
jsr166 |
1.33 |
private static final long serialVersionUID = 3193687207550431679L; |
3278 |
dl |
1.1 |
|
3279 |
|
|
final private E element; |
3280 |
|
|
|
3281 |
jsr166 |
1.5 |
SingletonSet(E e) {element = e;} |
3282 |
dl |
1.1 |
|
3283 |
|
|
public Iterator<E> iterator() { |
3284 |
jsr166 |
1.33 |
return singletonIterator(element); |
3285 |
dl |
1.1 |
} |
3286 |
|
|
|
3287 |
|
|
public int size() {return 1;} |
3288 |
|
|
|
3289 |
|
|
public boolean contains(Object o) {return eq(o, element);} |
3290 |
|
|
} |
3291 |
|
|
|
3292 |
|
|
/** |
3293 |
|
|
* Returns an immutable list containing only the specified object. |
3294 |
|
|
* The returned list is serializable. |
3295 |
|
|
* |
3296 |
|
|
* @param o the sole object to be stored in the returned list. |
3297 |
|
|
* @return an immutable list containing only the specified object. |
3298 |
|
|
* @since 1.3 |
3299 |
|
|
*/ |
3300 |
|
|
public static <T> List<T> singletonList(T o) { |
3301 |
jsr166 |
1.33 |
return new SingletonList<T>(o); |
3302 |
dl |
1.1 |
} |
3303 |
|
|
|
3304 |
jsr166 |
1.32 |
/** |
3305 |
|
|
* @serial include |
3306 |
|
|
*/ |
3307 |
dl |
1.1 |
private static class SingletonList<E> |
3308 |
jsr166 |
1.33 |
extends AbstractList<E> |
3309 |
|
|
implements RandomAccess, Serializable { |
3310 |
dl |
1.1 |
|
3311 |
jsr166 |
1.32 |
private static final long serialVersionUID = 3093736618740652951L; |
3312 |
dl |
1.1 |
|
3313 |
|
|
private final E element; |
3314 |
|
|
|
3315 |
|
|
SingletonList(E obj) {element = obj;} |
3316 |
|
|
|
3317 |
jsr166 |
1.32 |
public Iterator<E> iterator() { |
3318 |
jsr166 |
1.33 |
return singletonIterator(element); |
3319 |
jsr166 |
1.32 |
} |
3320 |
|
|
|
3321 |
dl |
1.1 |
public int size() {return 1;} |
3322 |
|
|
|
3323 |
|
|
public boolean contains(Object obj) {return eq(obj, element);} |
3324 |
|
|
|
3325 |
|
|
public E get(int index) { |
3326 |
|
|
if (index != 0) |
3327 |
|
|
throw new IndexOutOfBoundsException("Index: "+index+", Size: 1"); |
3328 |
|
|
return element; |
3329 |
|
|
} |
3330 |
|
|
} |
3331 |
|
|
|
3332 |
|
|
/** |
3333 |
|
|
* Returns an immutable map, mapping only the specified key to the |
3334 |
|
|
* specified value. The returned map is serializable. |
3335 |
|
|
* |
3336 |
|
|
* @param key the sole key to be stored in the returned map. |
3337 |
|
|
* @param value the value to which the returned map maps <tt>key</tt>. |
3338 |
|
|
* @return an immutable map containing only the specified key-value |
3339 |
|
|
* mapping. |
3340 |
|
|
* @since 1.3 |
3341 |
|
|
*/ |
3342 |
|
|
public static <K,V> Map<K,V> singletonMap(K key, V value) { |
3343 |
jsr166 |
1.33 |
return new SingletonMap<K,V>(key, value); |
3344 |
dl |
1.1 |
} |
3345 |
|
|
|
3346 |
jsr166 |
1.32 |
/** |
3347 |
|
|
* @serial include |
3348 |
|
|
*/ |
3349 |
dl |
1.1 |
private static class SingletonMap<K,V> |
3350 |
jsr166 |
1.33 |
extends AbstractMap<K,V> |
3351 |
|
|
implements Serializable { |
3352 |
|
|
private static final long serialVersionUID = -6979724477215052911L; |
3353 |
dl |
1.1 |
|
3354 |
|
|
private final K k; |
3355 |
jsr166 |
1.33 |
private final V v; |
3356 |
dl |
1.1 |
|
3357 |
|
|
SingletonMap(K key, V value) { |
3358 |
|
|
k = key; |
3359 |
|
|
v = value; |
3360 |
|
|
} |
3361 |
|
|
|
3362 |
|
|
public int size() {return 1;} |
3363 |
|
|
|
3364 |
|
|
public boolean isEmpty() {return false;} |
3365 |
|
|
|
3366 |
|
|
public boolean containsKey(Object key) {return eq(key, k);} |
3367 |
|
|
|
3368 |
|
|
public boolean containsValue(Object value) {return eq(value, v);} |
3369 |
|
|
|
3370 |
|
|
public V get(Object key) {return (eq(key, k) ? v : null);} |
3371 |
|
|
|
3372 |
|
|
private transient Set<K> keySet = null; |
3373 |
|
|
private transient Set<Map.Entry<K,V>> entrySet = null; |
3374 |
|
|
private transient Collection<V> values = null; |
3375 |
|
|
|
3376 |
jsr166 |
1.33 |
public Set<K> keySet() { |
3377 |
|
|
if (keySet==null) |
3378 |
|
|
keySet = singleton(k); |
3379 |
|
|
return keySet; |
3380 |
|
|
} |
3381 |
|
|
|
3382 |
|
|
public Set<Map.Entry<K,V>> entrySet() { |
3383 |
|
|
if (entrySet==null) |
3384 |
|
|
entrySet = Collections.<Map.Entry<K,V>>singleton( |
3385 |
|
|
new SimpleImmutableEntry<K,V>(k, v)); |
3386 |
|
|
return entrySet; |
3387 |
|
|
} |
3388 |
|
|
|
3389 |
|
|
public Collection<V> values() { |
3390 |
|
|
if (values==null) |
3391 |
|
|
values = singleton(v); |
3392 |
|
|
return values; |
3393 |
|
|
} |
3394 |
dl |
1.1 |
|
3395 |
|
|
} |
3396 |
|
|
|
3397 |
jsr166 |
1.32 |
// Miscellaneous |
3398 |
|
|
|
3399 |
dl |
1.1 |
/** |
3400 |
|
|
* Returns an immutable list consisting of <tt>n</tt> copies of the |
3401 |
|
|
* specified object. The newly allocated data object is tiny (it contains |
3402 |
|
|
* a single reference to the data object). This method is useful in |
3403 |
|
|
* combination with the <tt>List.addAll</tt> method to grow lists. |
3404 |
|
|
* The returned list is serializable. |
3405 |
|
|
* |
3406 |
|
|
* @param n the number of elements in the returned list. |
3407 |
|
|
* @param o the element to appear repeatedly in the returned list. |
3408 |
|
|
* @return an immutable list consisting of <tt>n</tt> copies of the |
3409 |
jsr166 |
1.33 |
* specified object. |
3410 |
dl |
1.1 |
* @throws IllegalArgumentException if n < 0. |
3411 |
|
|
* @see List#addAll(Collection) |
3412 |
|
|
* @see List#addAll(int, Collection) |
3413 |
|
|
*/ |
3414 |
|
|
public static <T> List<T> nCopies(int n, T o) { |
3415 |
jsr166 |
1.33 |
if (n < 0) |
3416 |
|
|
throw new IllegalArgumentException("List length = " + n); |
3417 |
dl |
1.1 |
return new CopiesList<T>(n, o); |
3418 |
|
|
} |
3419 |
|
|
|
3420 |
|
|
/** |
3421 |
|
|
* @serial include |
3422 |
|
|
*/ |
3423 |
|
|
private static class CopiesList<E> |
3424 |
jsr166 |
1.33 |
extends AbstractList<E> |
3425 |
|
|
implements RandomAccess, Serializable |
3426 |
dl |
1.1 |
{ |
3427 |
jsr166 |
1.32 |
private static final long serialVersionUID = 2739099268398711800L; |
3428 |
dl |
1.1 |
|
3429 |
jsr166 |
1.14 |
final int n; |
3430 |
|
|
final E element; |
3431 |
dl |
1.1 |
|
3432 |
jsr166 |
1.5 |
CopiesList(int n, E e) { |
3433 |
jsr166 |
1.33 |
assert n >= 0; |
3434 |
dl |
1.1 |
this.n = n; |
3435 |
jsr166 |
1.5 |
element = e; |
3436 |
dl |
1.1 |
} |
3437 |
|
|
|
3438 |
|
|
public int size() { |
3439 |
|
|
return n; |
3440 |
|
|
} |
3441 |
|
|
|
3442 |
|
|
public boolean contains(Object obj) { |
3443 |
|
|
return n != 0 && eq(obj, element); |
3444 |
|
|
} |
3445 |
|
|
|
3446 |
jsr166 |
1.33 |
public int indexOf(Object o) { |
3447 |
|
|
return contains(o) ? 0 : -1; |
3448 |
|
|
} |
3449 |
|
|
|
3450 |
|
|
public int lastIndexOf(Object o) { |
3451 |
|
|
return contains(o) ? n - 1 : -1; |
3452 |
|
|
} |
3453 |
jsr166 |
1.14 |
|
3454 |
dl |
1.1 |
public E get(int index) { |
3455 |
jsr166 |
1.14 |
if (index < 0 || index >= n) |
3456 |
dl |
1.1 |
throw new IndexOutOfBoundsException("Index: "+index+ |
3457 |
|
|
", Size: "+n); |
3458 |
|
|
return element; |
3459 |
|
|
} |
3460 |
jsr166 |
1.14 |
|
3461 |
jsr166 |
1.33 |
public Object[] toArray() { |
3462 |
|
|
final Object[] a = new Object[n]; |
3463 |
|
|
if (element != null) |
3464 |
|
|
Arrays.fill(a, 0, n, element); |
3465 |
|
|
return a; |
3466 |
|
|
} |
3467 |
|
|
|
3468 |
|
|
public <T> T[] toArray(T[] a) { |
3469 |
|
|
final int n = this.n; |
3470 |
|
|
if (a.length < n) { |
3471 |
|
|
a = (T[])java.lang.reflect.Array |
3472 |
|
|
.newInstance(a.getClass().getComponentType(), n); |
3473 |
|
|
if (element != null) |
3474 |
|
|
Arrays.fill(a, 0, n, element); |
3475 |
|
|
} else { |
3476 |
|
|
Arrays.fill(a, 0, n, element); |
3477 |
|
|
if (a.length > n) |
3478 |
|
|
a[n] = null; |
3479 |
|
|
} |
3480 |
|
|
return a; |
3481 |
|
|
} |
3482 |
|
|
|
3483 |
|
|
public List<E> subList(int fromIndex, int toIndex) { |
3484 |
|
|
if (fromIndex < 0) |
3485 |
|
|
throw new IndexOutOfBoundsException("fromIndex = " + fromIndex); |
3486 |
|
|
if (toIndex > n) |
3487 |
|
|
throw new IndexOutOfBoundsException("toIndex = " + toIndex); |
3488 |
|
|
if (fromIndex > toIndex) |
3489 |
|
|
throw new IllegalArgumentException("fromIndex(" + fromIndex + |
3490 |
|
|
") > toIndex(" + toIndex + ")"); |
3491 |
|
|
return new CopiesList<E>(toIndex - fromIndex, element); |
3492 |
|
|
} |
3493 |
dl |
1.1 |
} |
3494 |
|
|
|
3495 |
|
|
/** |
3496 |
|
|
* Returns a comparator that imposes the reverse of the <i>natural |
3497 |
|
|
* ordering</i> on a collection of objects that implement the |
3498 |
|
|
* <tt>Comparable</tt> interface. (The natural ordering is the ordering |
3499 |
|
|
* imposed by the objects' own <tt>compareTo</tt> method.) This enables a |
3500 |
|
|
* simple idiom for sorting (or maintaining) collections (or arrays) of |
3501 |
|
|
* objects that implement the <tt>Comparable</tt> interface in |
3502 |
|
|
* reverse-natural-order. For example, suppose a is an array of |
3503 |
|
|
* strings. Then: <pre> |
3504 |
jsr166 |
1.33 |
* Arrays.sort(a, Collections.reverseOrder()); |
3505 |
dl |
1.1 |
* </pre> sorts the array in reverse-lexicographic (alphabetical) order.<p> |
3506 |
|
|
* |
3507 |
|
|
* The returned comparator is serializable. |
3508 |
|
|
* |
3509 |
|
|
* @return a comparator that imposes the reverse of the <i>natural |
3510 |
jsr166 |
1.33 |
* ordering</i> on a collection of objects that implement |
3511 |
|
|
* the <tt>Comparable</tt> interface. |
3512 |
dl |
1.1 |
* @see Comparable |
3513 |
|
|
*/ |
3514 |
|
|
public static <T> Comparator<T> reverseOrder() { |
3515 |
jsr166 |
1.30 |
return (Comparator<T>) ReverseComparator.REVERSE_ORDER; |
3516 |
dl |
1.1 |
} |
3517 |
|
|
|
3518 |
|
|
/** |
3519 |
|
|
* @serial include |
3520 |
|
|
*/ |
3521 |
jsr166 |
1.30 |
private static class ReverseComparator |
3522 |
jsr166 |
1.33 |
implements Comparator<Comparable<Object>>, Serializable { |
3523 |
dl |
1.1 |
|
3524 |
jsr166 |
1.33 |
private static final long serialVersionUID = 7207038068494060240L; |
3525 |
dl |
1.1 |
|
3526 |
jsr166 |
1.33 |
static final ReverseComparator REVERSE_ORDER |
3527 |
|
|
= new ReverseComparator(); |
3528 |
jsr166 |
1.30 |
|
3529 |
dl |
1.1 |
public int compare(Comparable<Object> c1, Comparable<Object> c2) { |
3530 |
|
|
return c2.compareTo(c1); |
3531 |
|
|
} |
3532 |
jsr166 |
1.22 |
|
3533 |
|
|
private Object readResolve() { return reverseOrder(); } |
3534 |
dl |
1.1 |
} |
3535 |
|
|
|
3536 |
|
|
/** |
3537 |
|
|
* Returns a comparator that imposes the reverse ordering of the specified |
3538 |
|
|
* comparator. If the specified comparator is null, this method is |
3539 |
|
|
* equivalent to {@link #reverseOrder()} (in other words, it returns a |
3540 |
|
|
* comparator that imposes the reverse of the <i>natural ordering</i> on a |
3541 |
|
|
* collection of objects that implement the Comparable interface). |
3542 |
|
|
* |
3543 |
|
|
* <p>The returned comparator is serializable (assuming the specified |
3544 |
|
|
* comparator is also serializable or null). |
3545 |
|
|
* |
3546 |
|
|
* @return a comparator that imposes the reverse ordering of the |
3547 |
jsr166 |
1.30 |
* specified comparator |
3548 |
dl |
1.1 |
* @since 1.5 |
3549 |
|
|
*/ |
3550 |
|
|
public static <T> Comparator<T> reverseOrder(Comparator<T> cmp) { |
3551 |
|
|
if (cmp == null) |
3552 |
jsr166 |
1.22 |
return reverseOrder(); |
3553 |
jsr166 |
1.4 |
|
3554 |
jsr166 |
1.33 |
if (cmp instanceof ReverseComparator2) |
3555 |
|
|
return ((ReverseComparator2<T>)cmp).cmp; |
3556 |
jsr166 |
1.30 |
|
3557 |
dl |
1.1 |
return new ReverseComparator2<T>(cmp); |
3558 |
|
|
} |
3559 |
jsr166 |
1.4 |
|
3560 |
dl |
1.1 |
/** |
3561 |
|
|
* @serial include |
3562 |
|
|
*/ |
3563 |
|
|
private static class ReverseComparator2<T> implements Comparator<T>, |
3564 |
|
|
Serializable |
3565 |
|
|
{ |
3566 |
|
|
private static final long serialVersionUID = 4374092139857L; |
3567 |
jsr166 |
1.4 |
|
3568 |
dl |
1.1 |
/** |
3569 |
|
|
* The comparator specified in the static factory. This will never |
3570 |
|
|
* be null, as the static factory returns a ReverseComparator |
3571 |
|
|
* instance if its argument is null. |
3572 |
|
|
* |
3573 |
|
|
* @serial |
3574 |
|
|
*/ |
3575 |
jsr166 |
1.32 |
final Comparator<T> cmp; |
3576 |
jsr166 |
1.4 |
|
3577 |
dl |
1.1 |
ReverseComparator2(Comparator<T> cmp) { |
3578 |
|
|
assert cmp != null; |
3579 |
|
|
this.cmp = cmp; |
3580 |
|
|
} |
3581 |
jsr166 |
1.4 |
|
3582 |
dl |
1.1 |
public int compare(T t1, T t2) { |
3583 |
|
|
return cmp.compare(t2, t1); |
3584 |
|
|
} |
3585 |
jsr166 |
1.30 |
|
3586 |
jsr166 |
1.33 |
public boolean equals(Object o) { |
3587 |
|
|
return (o == this) || |
3588 |
|
|
(o instanceof ReverseComparator2 && |
3589 |
|
|
cmp.equals(((ReverseComparator2)o).cmp)); |
3590 |
|
|
} |
3591 |
|
|
|
3592 |
|
|
public int hashCode() { |
3593 |
|
|
return cmp.hashCode() ^ Integer.MIN_VALUE; |
3594 |
|
|
} |
3595 |
dl |
1.1 |
} |
3596 |
|
|
|
3597 |
|
|
/** |
3598 |
|
|
* Returns an enumeration over the specified collection. This provides |
3599 |
|
|
* interoperability with legacy APIs that require an enumeration |
3600 |
|
|
* as input. |
3601 |
|
|
* |
3602 |
|
|
* @param c the collection for which an enumeration is to be returned. |
3603 |
|
|
* @return an enumeration over the specified collection. |
3604 |
|
|
* @see Enumeration |
3605 |
|
|
*/ |
3606 |
|
|
public static <T> Enumeration<T> enumeration(final Collection<T> c) { |
3607 |
jsr166 |
1.33 |
return new Enumeration<T>() { |
3608 |
|
|
private final Iterator<T> i = c.iterator(); |
3609 |
dl |
1.1 |
|
3610 |
jsr166 |
1.33 |
public boolean hasMoreElements() { |
3611 |
|
|
return i.hasNext(); |
3612 |
|
|
} |
3613 |
|
|
|
3614 |
|
|
public T nextElement() { |
3615 |
|
|
return i.next(); |
3616 |
|
|
} |
3617 |
dl |
1.1 |
}; |
3618 |
|
|
} |
3619 |
|
|
|
3620 |
|
|
/** |
3621 |
|
|
* Returns an array list containing the elements returned by the |
3622 |
|
|
* specified enumeration in the order they are returned by the |
3623 |
|
|
* enumeration. This method provides interoperability between |
3624 |
|
|
* legacy APIs that return enumerations and new APIs that require |
3625 |
|
|
* collections. |
3626 |
|
|
* |
3627 |
|
|
* @param e enumeration providing elements for the returned |
3628 |
|
|
* array list |
3629 |
|
|
* @return an array list containing the elements returned |
3630 |
|
|
* by the specified enumeration. |
3631 |
|
|
* @since 1.4 |
3632 |
|
|
* @see Enumeration |
3633 |
|
|
* @see ArrayList |
3634 |
|
|
*/ |
3635 |
|
|
public static <T> ArrayList<T> list(Enumeration<T> e) { |
3636 |
|
|
ArrayList<T> l = new ArrayList<T>(); |
3637 |
|
|
while (e.hasMoreElements()) |
3638 |
|
|
l.add(e.nextElement()); |
3639 |
|
|
return l; |
3640 |
|
|
} |
3641 |
|
|
|
3642 |
|
|
/** |
3643 |
|
|
* Returns true if the specified arguments are equal, or both null. |
3644 |
|
|
*/ |
3645 |
jsr166 |
1.32 |
static boolean eq(Object o1, Object o2) { |
3646 |
|
|
return o1==null ? o2==null : o1.equals(o2); |
3647 |
dl |
1.1 |
} |
3648 |
|
|
|
3649 |
|
|
/** |
3650 |
|
|
* Returns the number of elements in the specified collection equal to the |
3651 |
|
|
* specified object. More formally, returns the number of elements |
3652 |
|
|
* <tt>e</tt> in the collection such that |
3653 |
|
|
* <tt>(o == null ? e == null : o.equals(e))</tt>. |
3654 |
|
|
* |
3655 |
|
|
* @param c the collection in which to determine the frequency |
3656 |
|
|
* of <tt>o</tt> |
3657 |
|
|
* @param o the object whose frequency is to be determined |
3658 |
|
|
* @throws NullPointerException if <tt>c</tt> is null |
3659 |
|
|
* @since 1.5 |
3660 |
|
|
*/ |
3661 |
|
|
public static int frequency(Collection<?> c, Object o) { |
3662 |
|
|
int result = 0; |
3663 |
|
|
if (o == null) { |
3664 |
|
|
for (Object e : c) |
3665 |
|
|
if (e == null) |
3666 |
|
|
result++; |
3667 |
|
|
} else { |
3668 |
|
|
for (Object e : c) |
3669 |
|
|
if (o.equals(e)) |
3670 |
|
|
result++; |
3671 |
|
|
} |
3672 |
|
|
return result; |
3673 |
|
|
} |
3674 |
|
|
|
3675 |
|
|
/** |
3676 |
|
|
* Returns <tt>true</tt> if the two specified collections have no |
3677 |
|
|
* elements in common. |
3678 |
|
|
* |
3679 |
|
|
* <p>Care must be exercised if this method is used on collections that |
3680 |
|
|
* do not comply with the general contract for <tt>Collection</tt>. |
3681 |
|
|
* Implementations may elect to iterate over either collection and test |
3682 |
|
|
* for containment in the other collection (or to perform any equivalent |
3683 |
|
|
* computation). If either collection uses a nonstandard equality test |
3684 |
|
|
* (as does a {@link SortedSet} whose ordering is not <i>compatible with |
3685 |
|
|
* equals</i>, or the key set of an {@link IdentityHashMap}), both |
3686 |
|
|
* collections must use the same nonstandard equality test, or the |
3687 |
|
|
* result of this method is undefined. |
3688 |
|
|
* |
3689 |
|
|
* <p>Note that it is permissible to pass the same collection in both |
3690 |
|
|
* parameters, in which case the method will return true if and only if |
3691 |
|
|
* the collection is empty. |
3692 |
|
|
* |
3693 |
|
|
* @param c1 a collection |
3694 |
|
|
* @param c2 a collection |
3695 |
|
|
* @throws NullPointerException if either collection is null |
3696 |
|
|
* @since 1.5 |
3697 |
|
|
*/ |
3698 |
|
|
public static boolean disjoint(Collection<?> c1, Collection<?> c2) { |
3699 |
|
|
/* |
3700 |
|
|
* We're going to iterate through c1 and test for inclusion in c2. |
3701 |
|
|
* If c1 is a Set and c2 isn't, swap the collections. Otherwise, |
3702 |
|
|
* place the shorter collection in c1. Hopefully this heuristic |
3703 |
|
|
* will minimize the cost of the operation. |
3704 |
|
|
*/ |
3705 |
|
|
if ((c1 instanceof Set) && !(c2 instanceof Set) || |
3706 |
|
|
(c1.size() > c2.size())) { |
3707 |
|
|
Collection<?> tmp = c1; |
3708 |
|
|
c1 = c2; |
3709 |
|
|
c2 = tmp; |
3710 |
|
|
} |
3711 |
jsr166 |
1.4 |
|
3712 |
dl |
1.1 |
for (Object e : c1) |
3713 |
|
|
if (c2.contains(e)) |
3714 |
|
|
return false; |
3715 |
|
|
return true; |
3716 |
|
|
} |
3717 |
|
|
|
3718 |
|
|
/** |
3719 |
|
|
* Adds all of the specified elements to the specified collection. |
3720 |
|
|
* Elements to be added may be specified individually or as an array. |
3721 |
|
|
* The behavior of this convenience method is identical to that of |
3722 |
|
|
* <tt>c.addAll(Arrays.asList(elements))</tt>, but this method is likely |
3723 |
|
|
* to run significantly faster under most implementations. |
3724 |
|
|
* |
3725 |
|
|
* <p>When elements are specified individually, this method provides a |
3726 |
|
|
* convenient way to add a few elements to an existing collection: |
3727 |
|
|
* <pre> |
3728 |
|
|
* Collections.addAll(flavors, "Peaches 'n Plutonium", "Rocky Racoon"); |
3729 |
|
|
* </pre> |
3730 |
|
|
* |
3731 |
|
|
* @param c the collection into which <tt>elements</tt> are to be inserted |
3732 |
jsr166 |
1.19 |
* @param elements the elements to insert into <tt>c</tt> |
3733 |
dl |
1.1 |
* @return <tt>true</tt> if the collection changed as a result of the call |
3734 |
|
|
* @throws UnsupportedOperationException if <tt>c</tt> does not support |
3735 |
jsr166 |
1.19 |
* the <tt>add</tt> operation |
3736 |
dl |
1.1 |
* @throws NullPointerException if <tt>elements</tt> contains one or more |
3737 |
jsr166 |
1.6 |
* null values and <tt>c</tt> does not permit null elements, or |
3738 |
dl |
1.1 |
* if <tt>c</tt> or <tt>elements</tt> are <tt>null</tt> |
3739 |
jsr166 |
1.6 |
* @throws IllegalArgumentException if some property of a value in |
3740 |
dl |
1.1 |
* <tt>elements</tt> prevents it from being added to <tt>c</tt> |
3741 |
|
|
* @see Collection#addAll(Collection) |
3742 |
|
|
* @since 1.5 |
3743 |
|
|
*/ |
3744 |
jsr166 |
1.19 |
public static <T> boolean addAll(Collection<? super T> c, T... elements) { |
3745 |
dl |
1.1 |
boolean result = false; |
3746 |
jsr166 |
1.19 |
for (T element : elements) |
3747 |
|
|
result |= c.add(element); |
3748 |
dl |
1.1 |
return result; |
3749 |
|
|
} |
3750 |
|
|
|
3751 |
|
|
/** |
3752 |
|
|
* Returns a set backed by the specified map. The resulting set displays |
3753 |
|
|
* the same ordering, concurrency, and performance characteristics as the |
3754 |
|
|
* backing map. In essence, this factory method provides a {@link Set} |
3755 |
|
|
* implementation corresponding to any {@link Map} implementation. There |
3756 |
|
|
* is no need to use this method on a {@link Map} implementation that |
3757 |
|
|
* already has a corresponding {@link Set} implementation (such as {@link |
3758 |
|
|
* HashMap} or {@link TreeMap}). |
3759 |
|
|
* |
3760 |
|
|
* <p>Each method invocation on the set returned by this method results in |
3761 |
|
|
* exactly one method invocation on the backing map or its <tt>keySet</tt> |
3762 |
|
|
* view, with one exception. The <tt>addAll</tt> method is implemented |
3763 |
|
|
* as a sequence of <tt>put</tt> invocations on the backing map. |
3764 |
|
|
* |
3765 |
|
|
* <p>The specified map must be empty at the time this method is invoked, |
3766 |
|
|
* and should not be accessed directly after this method returns. These |
3767 |
|
|
* conditions are ensured if the map is created empty, passed directly |
3768 |
|
|
* to this method, and no reference to the map is retained, as illustrated |
3769 |
|
|
* in the following code fragment: |
3770 |
|
|
* <pre> |
3771 |
jsr166 |
1.15 |
* Set<Object> weakHashSet = Collections.newSetFromMap( |
3772 |
dl |
1.1 |
* new WeakHashMap<Object, Boolean>()); |
3773 |
|
|
* </pre> |
3774 |
|
|
* |
3775 |
|
|
* @param map the backing map |
3776 |
|
|
* @return the set backed by the map |
3777 |
|
|
* @throws IllegalArgumentException if <tt>map</tt> is not empty |
3778 |
jsr166 |
1.12 |
* @since 1.6 |
3779 |
dl |
1.1 |
*/ |
3780 |
jsr166 |
1.14 |
public static <E> Set<E> newSetFromMap(Map<E, Boolean> map) { |
3781 |
|
|
return new SetFromMap<E>(map); |
3782 |
dl |
1.1 |
} |
3783 |
|
|
|
3784 |
jsr166 |
1.32 |
/** |
3785 |
|
|
* @serial include |
3786 |
|
|
*/ |
3787 |
jsr166 |
1.14 |
private static class SetFromMap<E> extends AbstractSet<E> |
3788 |
dl |
1.1 |
implements Set<E>, Serializable |
3789 |
|
|
{ |
3790 |
|
|
private final Map<E, Boolean> m; // The backing map |
3791 |
jsr166 |
1.23 |
private transient Set<E> s; // Its keySet |
3792 |
dl |
1.1 |
|
3793 |
jsr166 |
1.14 |
SetFromMap(Map<E, Boolean> map) { |
3794 |
dl |
1.1 |
if (!map.isEmpty()) |
3795 |
|
|
throw new IllegalArgumentException("Map is non-empty"); |
3796 |
|
|
m = map; |
3797 |
jsr166 |
1.23 |
s = map.keySet(); |
3798 |
dl |
1.1 |
} |
3799 |
|
|
|
3800 |
jsr166 |
1.23 |
public void clear() { m.clear(); } |
3801 |
dl |
1.1 |
public int size() { return m.size(); } |
3802 |
|
|
public boolean isEmpty() { return m.isEmpty(); } |
3803 |
|
|
public boolean contains(Object o) { return m.containsKey(o); } |
3804 |
|
|
public boolean remove(Object o) { return m.remove(o) != null; } |
3805 |
jsr166 |
1.23 |
public boolean add(E e) { return m.put(e, Boolean.TRUE) == null; } |
3806 |
|
|
public Iterator<E> iterator() { return s.iterator(); } |
3807 |
|
|
public Object[] toArray() { return s.toArray(); } |
3808 |
|
|
public <T> T[] toArray(T[] a) { return s.toArray(a); } |
3809 |
|
|
public String toString() { return s.toString(); } |
3810 |
|
|
public int hashCode() { return s.hashCode(); } |
3811 |
|
|
public boolean equals(Object o) { return o == this || s.equals(o); } |
3812 |
|
|
public boolean containsAll(Collection<?> c) {return s.containsAll(c);} |
3813 |
|
|
public boolean removeAll(Collection<?> c) {return s.removeAll(c);} |
3814 |
|
|
public boolean retainAll(Collection<?> c) {return s.retainAll(c);} |
3815 |
jsr166 |
1.33 |
// addAll is the only inherited implementation |
3816 |
dl |
1.1 |
|
3817 |
|
|
private static final long serialVersionUID = 2454657854757543876L; |
3818 |
|
|
|
3819 |
jsr166 |
1.23 |
private void readObject(java.io.ObjectInputStream stream) |
3820 |
dl |
1.1 |
throws IOException, ClassNotFoundException |
3821 |
|
|
{ |
3822 |
jsr166 |
1.23 |
stream.defaultReadObject(); |
3823 |
|
|
s = m.keySet(); |
3824 |
dl |
1.1 |
} |
3825 |
|
|
} |
3826 |
|
|
|
3827 |
|
|
/** |
3828 |
|
|
* Returns a view of a {@link Deque} as a Last-in-first-out (Lifo) |
3829 |
|
|
* {@link Queue}. Method <tt>add</tt> is mapped to <tt>push</tt>, |
3830 |
|
|
* <tt>remove</tt> is mapped to <tt>pop</tt> and so on. This |
3831 |
|
|
* view can be useful when you would like to use a method |
3832 |
|
|
* requiring a <tt>Queue</tt> but you need Lifo ordering. |
3833 |
jsr166 |
1.17 |
* |
3834 |
jsr166 |
1.24 |
* <p>Each method invocation on the queue returned by this method |
3835 |
|
|
* results in exactly one method invocation on the backing deque, with |
3836 |
|
|
* one exception. The {@link Queue#addAll addAll} method is |
3837 |
|
|
* implemented as a sequence of {@link Deque#addFirst addFirst} |
3838 |
|
|
* invocations on the backing deque. |
3839 |
|
|
* |
3840 |
jsr166 |
1.13 |
* @param deque the deque |
3841 |
dl |
1.1 |
* @return the queue |
3842 |
|
|
* @since 1.6 |
3843 |
|
|
*/ |
3844 |
|
|
public static <T> Queue<T> asLifoQueue(Deque<T> deque) { |
3845 |
|
|
return new AsLIFOQueue<T>(deque); |
3846 |
|
|
} |
3847 |
|
|
|
3848 |
jsr166 |
1.32 |
/** |
3849 |
|
|
* @serial include |
3850 |
|
|
*/ |
3851 |
jsr166 |
1.4 |
static class AsLIFOQueue<E> extends AbstractQueue<E> |
3852 |
dl |
1.1 |
implements Queue<E>, Serializable { |
3853 |
jsr166 |
1.33 |
private static final long serialVersionUID = 1802017725587941708L; |
3854 |
dl |
1.1 |
private final Deque<E> q; |
3855 |
jsr166 |
1.23 |
AsLIFOQueue(Deque<E> q) { this.q = q; } |
3856 |
|
|
public boolean add(E e) { q.addFirst(e); return true; } |
3857 |
|
|
public boolean offer(E e) { return q.offerFirst(e); } |
3858 |
|
|
public E poll() { return q.pollFirst(); } |
3859 |
|
|
public E remove() { return q.removeFirst(); } |
3860 |
|
|
public E peek() { return q.peekFirst(); } |
3861 |
|
|
public E element() { return q.getFirst(); } |
3862 |
|
|
public void clear() { q.clear(); } |
3863 |
|
|
public int size() { return q.size(); } |
3864 |
|
|
public boolean isEmpty() { return q.isEmpty(); } |
3865 |
|
|
public boolean contains(Object o) { return q.contains(o); } |
3866 |
|
|
public boolean remove(Object o) { return q.remove(o); } |
3867 |
|
|
public Iterator<E> iterator() { return q.iterator(); } |
3868 |
|
|
public Object[] toArray() { return q.toArray(); } |
3869 |
|
|
public <T> T[] toArray(T[] a) { return q.toArray(a); } |
3870 |
|
|
public String toString() { return q.toString(); } |
3871 |
jsr166 |
1.33 |
public boolean containsAll(Collection<?> c) {return q.containsAll(c);} |
3872 |
|
|
public boolean removeAll(Collection<?> c) {return q.removeAll(c);} |
3873 |
|
|
public boolean retainAll(Collection<?> c) {return q.retainAll(c);} |
3874 |
|
|
// We use inherited addAll; forwarding addAll would be wrong |
3875 |
dl |
1.1 |
} |
3876 |
|
|
} |