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dl |
1.1 |
/* |
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* %W% %E% |
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* |
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jsr166 |
1.18 |
* Copyright 2006 Sun Microsystems, Inc. All rights reserved. |
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1.1 |
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. |
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*/ |
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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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dl |
1.1 |
* <a href="{@docRoot}/../guide/collections/index.html"> |
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* 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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* @version %I%, %G% |
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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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* @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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jsr166 |
1.7 |
* tuning parameters below determine the cutoff point for what constitutes |
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* 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 |
1.4 |
* 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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* <i>mutually comparable</i> (for example, strings and integers). |
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* @throws UnsupportedOperationException if the specified list's |
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* list-iterator does not support the <tt>set</tt> operation. |
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* @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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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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} |
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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> |
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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 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 |
1.4 |
* n log(n) performance. |
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dl |
1.1 |
* |
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* The specified list must be modifiable, but need not be resizable. |
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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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* @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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* <i>mutually comparable</i> using the specified comparator. |
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* @throws UnsupportedOperationException if the specified list's |
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* list-iterator does not support the <tt>set</tt> operation. |
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* @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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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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} |
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} |
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/** |
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* Searches the specified list for the specified object using the binary |
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* search algorithm. The list must be sorted into ascending order |
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jsr166 |
1.25 |
* according to the {@linkplain Comparable natural ordering} of its |
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* elements (as by the {@link #sort(List)} method) prior to making this |
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* call. If it is not sorted, the results are undefined. If the list |
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* contains multiple elements equal to the specified object, there is no |
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* guarantee which one will be found. |
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dl |
1.1 |
* |
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jsr166 |
1.25 |
* <p>This method runs in log(n) time for a "random access" list (which |
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dl |
1.1 |
* provides near-constant-time positional access). If the specified list |
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* does not implement the {@link RandomAccess} interface and is large, |
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* this method will do an iterator-based binary search that performs |
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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. |
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dl |
1.2 |
* @return the index of the search key, if it is contained in the list; |
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dl |
1.1 |
* 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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jsr166 |
1.25 |
* element greater than the key, or <tt>list.size()</tt> if all |
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dl |
1.1 |
* 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. |
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* @throws ClassCastException if the list contains elements that are not |
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* <i>mutually comparable</i> (for example, strings and |
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jsr166 |
1.25 |
* integers), or the search key is not mutually comparable |
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dl |
1.1 |
* with the elements of the list. |
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*/ |
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public static <T> |
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int binarySearch(List<? extends Comparable<? super T>> list, T key) { |
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if (list instanceof RandomAccess || list.size()<BINARYSEARCH_THRESHOLD) |
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return Collections.indexedBinarySearch(list, key); |
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else |
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return Collections.iteratorBinarySearch(list, key); |
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} |
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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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{ |
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int low = 0; |
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int high = list.size()-1; |
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while (low <= high) { |
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jsr166 |
1.25 |
int mid = (low + high) >>> 1; |
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dl |
1.1 |
Comparable<? super T> midVal = list.get(mid); |
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int cmp = midVal.compareTo(key); |
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if (cmp < 0) |
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low = mid + 1; |
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else if (cmp > 0) |
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high = mid - 1; |
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else |
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return mid; // key found |
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} |
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return -(low + 1); // key not found |
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} |
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private static <T> |
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int iteratorBinarySearch(List<? extends Comparable<? super T>> list, T key) |
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{ |
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int low = 0; |
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int high = list.size()-1; |
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ListIterator<? extends Comparable<? super T>> i = list.listIterator(); |
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while (low <= high) { |
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jsr166 |
1.25 |
int mid = (low + high) >>> 1; |
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dl |
1.1 |
Comparable<? super T> midVal = get(i, mid); |
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int cmp = midVal.compareTo(key); |
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if (cmp < 0) |
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low = mid + 1; |
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else if (cmp > 0) |
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high = mid - 1; |
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else |
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return mid; // key found |
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} |
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return -(low + 1); // key not found |
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} |
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/** |
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* Gets the ith element from the given list by repositioning the specified |
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* list listIterator. |
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*/ |
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private static <T> T get(ListIterator<? extends T> i, int index) { |
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T obj = null; |
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int pos = i.nextIndex(); |
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if (pos <= index) { |
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do { |
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obj = i.next(); |
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} while (pos++ < index); |
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} else { |
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do { |
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obj = i.previous(); |
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} while (--pos > index); |
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} |
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return obj; |
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} |
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/** |
269 |
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* Searches the specified list for the specified object using the binary |
270 |
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* search algorithm. The list must be sorted into ascending order |
271 |
jsr166 |
1.25 |
* according to the specified comparator (as by the |
272 |
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* {@link #sort(List, Comparator) sort(List, Comparator)} |
273 |
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* method), prior to making this call. If it is |
274 |
dl |
1.1 |
* not sorted, the results are undefined. If the list contains multiple |
275 |
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* elements equal to the specified object, there is no guarantee which one |
276 |
jsr166 |
1.25 |
* will be found. |
277 |
dl |
1.1 |
* |
278 |
jsr166 |
1.25 |
* <p>This method runs in log(n) time for a "random access" list (which |
279 |
dl |
1.1 |
* provides near-constant-time positional access). If the specified list |
280 |
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* does not implement the {@link RandomAccess} interface and is large, |
281 |
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* this method will do an iterator-based binary search that performs |
282 |
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* O(n) link traversals and O(log n) element comparisons. |
283 |
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* |
284 |
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* @param list the list to be searched. |
285 |
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* @param key the key to be searched for. |
286 |
jsr166 |
1.25 |
* @param c the comparator by which the list is ordered. |
287 |
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* A <tt>null</tt> value indicates that the elements' |
288 |
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* {@linkplain Comparable natural ordering} should be used. |
289 |
dl |
1.2 |
* @return the index of the search key, if it is contained in the list; |
290 |
dl |
1.1 |
* 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 |
292 |
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* key would be inserted into the list: the index of the first |
293 |
jsr166 |
1.25 |
* element greater than the key, or <tt>list.size()</tt> if all |
294 |
dl |
1.1 |
* elements in the list are less than the specified key. Note |
295 |
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* that this guarantees that the return value will be >= 0 if |
296 |
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* and only if the key is found. |
297 |
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* @throws ClassCastException if the list contains elements that are not |
298 |
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* <i>mutually comparable</i> using the specified comparator, |
299 |
jsr166 |
1.25 |
* or the search key is not mutually comparable with the |
300 |
dl |
1.1 |
* elements of the list using this comparator. |
301 |
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*/ |
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public static <T> int binarySearch(List<? extends T> list, T key, Comparator<? super T> c) { |
303 |
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if (c==null) |
304 |
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return binarySearch((List) list, key); |
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if (list instanceof RandomAccess || list.size()<BINARYSEARCH_THRESHOLD) |
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return Collections.indexedBinarySearch(list, key, c); |
308 |
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else |
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return Collections.iteratorBinarySearch(list, key, c); |
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} |
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private static <T> int indexedBinarySearch(List<? extends T> l, T key, Comparator<? super T> c) { |
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int low = 0; |
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int high = l.size()-1; |
315 |
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while (low <= high) { |
317 |
jsr166 |
1.25 |
int mid = (low + high) >>> 1; |
318 |
dl |
1.1 |
T midVal = l.get(mid); |
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int cmp = c.compare(midVal, key); |
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if (cmp < 0) |
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low = mid + 1; |
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else if (cmp > 0) |
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high = mid - 1; |
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else |
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return mid; // key found |
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} |
328 |
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return -(low + 1); // key not found |
329 |
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} |
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private static <T> int iteratorBinarySearch(List<? extends T> l, T key, Comparator<? super T> c) { |
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int low = 0; |
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int high = l.size()-1; |
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ListIterator<? extends T> i = l.listIterator(); |
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336 |
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while (low <= high) { |
337 |
jsr166 |
1.25 |
int mid = (low + high) >>> 1; |
338 |
dl |
1.1 |
T midVal = get(i, mid); |
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int cmp = c.compare(midVal, key); |
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if (cmp < 0) |
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low = mid + 1; |
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else if (cmp > 0) |
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high = mid - 1; |
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else |
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return mid; // key found |
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} |
348 |
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return -(low + 1); // key not found |
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} |
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private interface SelfComparable extends Comparable<SelfComparable> {} |
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/** |
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|
|
* Reverses the order of the elements in the specified list.<p> |
356 |
|
|
* |
357 |
|
|
* This method runs in linear time. |
358 |
|
|
* |
359 |
|
|
* @param list the list whose elements are to be reversed. |
360 |
|
|
* @throws UnsupportedOperationException if the specified list or |
361 |
jsr166 |
1.4 |
* its list-iterator does not support the <tt>set</tt> operation. |
362 |
dl |
1.1 |
*/ |
363 |
|
|
public static void reverse(List<?> list) { |
364 |
|
|
int size = list.size(); |
365 |
|
|
if (size < REVERSE_THRESHOLD || list instanceof RandomAccess) { |
366 |
|
|
for (int i=0, mid=size>>1, j=size-1; i<mid; i++, j--) |
367 |
|
|
swap(list, i, j); |
368 |
|
|
} else { |
369 |
|
|
ListIterator fwd = list.listIterator(); |
370 |
|
|
ListIterator rev = list.listIterator(size); |
371 |
|
|
for (int i=0, mid=list.size()>>1; i<mid; i++) { |
372 |
|
|
Object tmp = fwd.next(); |
373 |
|
|
fwd.set(rev.previous()); |
374 |
|
|
rev.set(tmp); |
375 |
|
|
} |
376 |
|
|
} |
377 |
|
|
} |
378 |
|
|
|
379 |
|
|
/** |
380 |
|
|
* Randomly permutes the specified list using a default source of |
381 |
|
|
* randomness. All permutations occur with approximately equal |
382 |
|
|
* likelihood.<p> |
383 |
|
|
* |
384 |
|
|
* The hedge "approximately" is used in the foregoing description because |
385 |
|
|
* default source of randomness is only approximately an unbiased source |
386 |
|
|
* of independently chosen bits. If it were a perfect source of randomly |
387 |
|
|
* chosen bits, then the algorithm would choose permutations with perfect |
388 |
|
|
* uniformity.<p> |
389 |
|
|
* |
390 |
|
|
* This implementation traverses the list backwards, from the last element |
391 |
|
|
* up to the second, repeatedly swapping a randomly selected element into |
392 |
|
|
* the "current position". Elements are randomly selected from the |
393 |
|
|
* portion of the list that runs from the first element to the current |
394 |
|
|
* position, inclusive.<p> |
395 |
|
|
* |
396 |
|
|
* This method runs in linear time. If the specified list does not |
397 |
|
|
* implement the {@link RandomAccess} interface and is large, this |
398 |
|
|
* implementation dumps the specified list into an array before shuffling |
399 |
|
|
* it, and dumps the shuffled array back into the list. This avoids the |
400 |
|
|
* quadratic behavior that would result from shuffling a "sequential |
401 |
|
|
* access" list in place. |
402 |
|
|
* |
403 |
|
|
* @param list the list to be shuffled. |
404 |
|
|
* @throws UnsupportedOperationException if the specified list or |
405 |
jsr166 |
1.4 |
* its list-iterator does not support the <tt>set</tt> operation. |
406 |
dl |
1.1 |
*/ |
407 |
|
|
public static void shuffle(List<?> list) { |
408 |
jsr166 |
1.9 |
if (r == null) { |
409 |
|
|
r = new Random(); |
410 |
|
|
} |
411 |
dl |
1.1 |
shuffle(list, r); |
412 |
|
|
} |
413 |
jsr166 |
1.9 |
private static Random r; |
414 |
dl |
1.1 |
|
415 |
|
|
/** |
416 |
|
|
* Randomly permute the specified list using the specified source of |
417 |
|
|
* randomness. All permutations occur with equal likelihood |
418 |
|
|
* assuming that the source of randomness is fair.<p> |
419 |
|
|
* |
420 |
|
|
* This implementation traverses the list backwards, from the last element |
421 |
|
|
* up to the second, repeatedly swapping a randomly selected element into |
422 |
|
|
* the "current position". Elements are randomly selected from the |
423 |
|
|
* portion of the list that runs from the first element to the current |
424 |
|
|
* position, inclusive.<p> |
425 |
|
|
* |
426 |
|
|
* This method runs in linear time. If the specified list does not |
427 |
|
|
* implement the {@link RandomAccess} interface and is large, this |
428 |
|
|
* implementation dumps the specified list into an array before shuffling |
429 |
|
|
* it, and dumps the shuffled array back into the list. This avoids the |
430 |
|
|
* quadratic behavior that would result from shuffling a "sequential |
431 |
|
|
* access" list in place. |
432 |
|
|
* |
433 |
|
|
* @param list the list to be shuffled. |
434 |
|
|
* @param rnd the source of randomness to use to shuffle the list. |
435 |
|
|
* @throws UnsupportedOperationException if the specified list or its |
436 |
|
|
* list-iterator does not support the <tt>set</tt> operation. |
437 |
|
|
*/ |
438 |
|
|
public static void shuffle(List<?> list, Random rnd) { |
439 |
|
|
int size = list.size(); |
440 |
|
|
if (size < SHUFFLE_THRESHOLD || list instanceof RandomAccess) { |
441 |
|
|
for (int i=size; i>1; i--) |
442 |
|
|
swap(list, i-1, rnd.nextInt(i)); |
443 |
|
|
} else { |
444 |
|
|
Object arr[] = list.toArray(); |
445 |
|
|
|
446 |
|
|
// Shuffle array |
447 |
|
|
for (int i=size; i>1; i--) |
448 |
|
|
swap(arr, i-1, rnd.nextInt(i)); |
449 |
|
|
|
450 |
|
|
// Dump array back into list |
451 |
|
|
ListIterator it = list.listIterator(); |
452 |
|
|
for (int i=0; i<arr.length; i++) { |
453 |
|
|
it.next(); |
454 |
|
|
it.set(arr[i]); |
455 |
|
|
} |
456 |
|
|
} |
457 |
|
|
} |
458 |
|
|
|
459 |
|
|
/** |
460 |
|
|
* Swaps the elements at the specified positions in the specified list. |
461 |
|
|
* (If the specified positions are equal, invoking this method leaves |
462 |
|
|
* the list unchanged.) |
463 |
|
|
* |
464 |
|
|
* @param list The list in which to swap elements. |
465 |
|
|
* @param i the index of one element to be swapped. |
466 |
|
|
* @param j the index of the other element to be swapped. |
467 |
|
|
* @throws IndexOutOfBoundsException if either <tt>i</tt> or <tt>j</tt> |
468 |
|
|
* is out of range (i < 0 || i >= list.size() |
469 |
|
|
* || j < 0 || j >= list.size()). |
470 |
|
|
* @since 1.4 |
471 |
|
|
*/ |
472 |
|
|
public static void swap(List<?> list, int i, int j) { |
473 |
|
|
final List l = list; |
474 |
|
|
l.set(i, l.set(j, l.get(i))); |
475 |
|
|
} |
476 |
|
|
|
477 |
|
|
/** |
478 |
|
|
* Swaps the two specified elements in the specified array. |
479 |
|
|
*/ |
480 |
|
|
private static void swap(Object[] arr, int i, int j) { |
481 |
|
|
Object tmp = arr[i]; |
482 |
|
|
arr[i] = arr[j]; |
483 |
|
|
arr[j] = tmp; |
484 |
|
|
} |
485 |
|
|
|
486 |
|
|
/** |
487 |
|
|
* Replaces all of the elements of the specified list with the specified |
488 |
|
|
* element. <p> |
489 |
|
|
* |
490 |
|
|
* This method runs in linear time. |
491 |
|
|
* |
492 |
|
|
* @param list the list to be filled with the specified element. |
493 |
|
|
* @param obj The element with which to fill the specified list. |
494 |
|
|
* @throws UnsupportedOperationException if the specified list or its |
495 |
|
|
* list-iterator does not support the <tt>set</tt> operation. |
496 |
|
|
*/ |
497 |
|
|
public static <T> void fill(List<? super T> list, T obj) { |
498 |
|
|
int size = list.size(); |
499 |
|
|
|
500 |
|
|
if (size < FILL_THRESHOLD || list instanceof RandomAccess) { |
501 |
|
|
for (int i=0; i<size; i++) |
502 |
|
|
list.set(i, obj); |
503 |
|
|
} else { |
504 |
|
|
ListIterator<? super T> itr = list.listIterator(); |
505 |
|
|
for (int i=0; i<size; i++) { |
506 |
|
|
itr.next(); |
507 |
|
|
itr.set(obj); |
508 |
|
|
} |
509 |
|
|
} |
510 |
|
|
} |
511 |
|
|
|
512 |
|
|
/** |
513 |
|
|
* Copies all of the elements from one list into another. After the |
514 |
|
|
* operation, the index of each copied element in the destination list |
515 |
|
|
* will be identical to its index in the source list. The destination |
516 |
|
|
* list must be at least as long as the source list. If it is longer, the |
517 |
|
|
* remaining elements in the destination list are unaffected. <p> |
518 |
|
|
* |
519 |
|
|
* This method runs in linear time. |
520 |
|
|
* |
521 |
|
|
* @param dest The destination list. |
522 |
|
|
* @param src The source list. |
523 |
|
|
* @throws IndexOutOfBoundsException if the destination list is too small |
524 |
|
|
* to contain the entire source List. |
525 |
|
|
* @throws UnsupportedOperationException if the destination list's |
526 |
|
|
* list-iterator does not support the <tt>set</tt> operation. |
527 |
|
|
*/ |
528 |
|
|
public static <T> void copy(List<? super T> dest, List<? extends T> src) { |
529 |
|
|
int srcSize = src.size(); |
530 |
|
|
if (srcSize > dest.size()) |
531 |
|
|
throw new IndexOutOfBoundsException("Source does not fit in dest"); |
532 |
|
|
|
533 |
|
|
if (srcSize < COPY_THRESHOLD || |
534 |
|
|
(src instanceof RandomAccess && dest instanceof RandomAccess)) { |
535 |
|
|
for (int i=0; i<srcSize; i++) |
536 |
|
|
dest.set(i, src.get(i)); |
537 |
|
|
} else { |
538 |
|
|
ListIterator<? super T> di=dest.listIterator(); |
539 |
|
|
ListIterator<? extends T> si=src.listIterator(); |
540 |
|
|
for (int i=0; i<srcSize; i++) { |
541 |
|
|
di.next(); |
542 |
|
|
di.set(si.next()); |
543 |
|
|
} |
544 |
|
|
} |
545 |
|
|
} |
546 |
|
|
|
547 |
|
|
/** |
548 |
|
|
* Returns the minimum element of the given collection, according to the |
549 |
|
|
* <i>natural ordering</i> of its elements. All elements in the |
550 |
|
|
* collection must implement the <tt>Comparable</tt> interface. |
551 |
|
|
* Furthermore, all elements in the collection must be <i>mutually |
552 |
|
|
* comparable</i> (that is, <tt>e1.compareTo(e2)</tt> must not throw a |
553 |
|
|
* <tt>ClassCastException</tt> for any elements <tt>e1</tt> and |
554 |
|
|
* <tt>e2</tt> in the collection).<p> |
555 |
|
|
* |
556 |
|
|
* This method iterates over the entire collection, hence it requires |
557 |
|
|
* time proportional to the size of the collection. |
558 |
|
|
* |
559 |
|
|
* @param coll the collection whose minimum element is to be determined. |
560 |
|
|
* @return the minimum element of the given collection, according |
561 |
|
|
* to the <i>natural ordering</i> of its elements. |
562 |
|
|
* @throws ClassCastException if the collection contains elements that are |
563 |
|
|
* not <i>mutually comparable</i> (for example, strings and |
564 |
|
|
* integers). |
565 |
|
|
* @throws NoSuchElementException if the collection is empty. |
566 |
|
|
* @see Comparable |
567 |
|
|
*/ |
568 |
|
|
public static <T extends Object & Comparable<? super T>> T min(Collection<? extends T> coll) { |
569 |
|
|
Iterator<? extends T> i = coll.iterator(); |
570 |
|
|
T candidate = i.next(); |
571 |
|
|
|
572 |
jsr166 |
1.6 |
while (i.hasNext()) { |
573 |
dl |
1.1 |
T next = i.next(); |
574 |
|
|
if (next.compareTo(candidate) < 0) |
575 |
|
|
candidate = next; |
576 |
|
|
} |
577 |
|
|
return candidate; |
578 |
|
|
} |
579 |
|
|
|
580 |
|
|
/** |
581 |
|
|
* Returns the minimum element of the given collection, according to the |
582 |
|
|
* order induced by the specified comparator. All elements in the |
583 |
|
|
* collection must be <i>mutually comparable</i> by the specified |
584 |
|
|
* comparator (that is, <tt>comp.compare(e1, e2)</tt> must not throw a |
585 |
|
|
* <tt>ClassCastException</tt> for any elements <tt>e1</tt> and |
586 |
|
|
* <tt>e2</tt> in the collection).<p> |
587 |
|
|
* |
588 |
|
|
* This method iterates over the entire collection, hence it requires |
589 |
|
|
* time proportional to the size of the collection. |
590 |
|
|
* |
591 |
|
|
* @param coll the collection whose minimum element is to be determined. |
592 |
|
|
* @param comp the comparator with which to determine the minimum element. |
593 |
|
|
* A <tt>null</tt> value indicates that the elements' <i>natural |
594 |
|
|
* ordering</i> should be used. |
595 |
|
|
* @return the minimum element of the given collection, according |
596 |
|
|
* to the specified comparator. |
597 |
|
|
* @throws ClassCastException if the collection contains elements that are |
598 |
|
|
* not <i>mutually comparable</i> using the specified comparator. |
599 |
|
|
* @throws NoSuchElementException if the collection is empty. |
600 |
|
|
* @see Comparable |
601 |
|
|
*/ |
602 |
|
|
public static <T> T min(Collection<? extends T> coll, Comparator<? super T> comp) { |
603 |
|
|
if (comp==null) |
604 |
|
|
return (T)min((Collection<SelfComparable>) (Collection) coll); |
605 |
|
|
|
606 |
|
|
Iterator<? extends T> i = coll.iterator(); |
607 |
|
|
T candidate = i.next(); |
608 |
|
|
|
609 |
jsr166 |
1.6 |
while (i.hasNext()) { |
610 |
dl |
1.1 |
T next = i.next(); |
611 |
|
|
if (comp.compare(next, candidate) < 0) |
612 |
|
|
candidate = next; |
613 |
|
|
} |
614 |
|
|
return candidate; |
615 |
|
|
} |
616 |
|
|
|
617 |
|
|
/** |
618 |
|
|
* Returns the maximum element of the given collection, according to the |
619 |
|
|
* <i>natural ordering</i> of its elements. All elements in the |
620 |
|
|
* collection must implement the <tt>Comparable</tt> interface. |
621 |
|
|
* Furthermore, all elements in the collection must be <i>mutually |
622 |
|
|
* comparable</i> (that is, <tt>e1.compareTo(e2)</tt> must not throw a |
623 |
|
|
* <tt>ClassCastException</tt> for any elements <tt>e1</tt> and |
624 |
|
|
* <tt>e2</tt> in the collection).<p> |
625 |
|
|
* |
626 |
|
|
* This method iterates over the entire collection, hence it requires |
627 |
|
|
* time proportional to the size of the collection. |
628 |
|
|
* |
629 |
|
|
* @param coll the collection whose maximum element is to be determined. |
630 |
|
|
* @return the maximum element of the given collection, according |
631 |
|
|
* to the <i>natural ordering</i> of its elements. |
632 |
|
|
* @throws ClassCastException if the collection contains elements that are |
633 |
|
|
* not <i>mutually comparable</i> (for example, strings and |
634 |
|
|
* integers). |
635 |
|
|
* @throws NoSuchElementException if the collection is empty. |
636 |
|
|
* @see Comparable |
637 |
|
|
*/ |
638 |
|
|
public static <T extends Object & Comparable<? super T>> T max(Collection<? extends T> coll) { |
639 |
|
|
Iterator<? extends T> i = coll.iterator(); |
640 |
|
|
T candidate = i.next(); |
641 |
|
|
|
642 |
jsr166 |
1.6 |
while (i.hasNext()) { |
643 |
dl |
1.1 |
T next = i.next(); |
644 |
|
|
if (next.compareTo(candidate) > 0) |
645 |
|
|
candidate = next; |
646 |
|
|
} |
647 |
|
|
return candidate; |
648 |
|
|
} |
649 |
|
|
|
650 |
|
|
/** |
651 |
|
|
* Returns the maximum element of the given collection, according to the |
652 |
|
|
* order induced by the specified comparator. All elements in the |
653 |
|
|
* collection must be <i>mutually comparable</i> by the specified |
654 |
|
|
* comparator (that is, <tt>comp.compare(e1, e2)</tt> must not throw a |
655 |
|
|
* <tt>ClassCastException</tt> for any elements <tt>e1</tt> and |
656 |
|
|
* <tt>e2</tt> in the collection).<p> |
657 |
|
|
* |
658 |
|
|
* This method iterates over the entire collection, hence it requires |
659 |
|
|
* time proportional to the size of the collection. |
660 |
|
|
* |
661 |
|
|
* @param coll the collection whose maximum element is to be determined. |
662 |
|
|
* @param comp the comparator with which to determine the maximum element. |
663 |
|
|
* A <tt>null</tt> value indicates that the elements' <i>natural |
664 |
|
|
* ordering</i> should be used. |
665 |
|
|
* @return the maximum element of the given collection, according |
666 |
|
|
* to the specified comparator. |
667 |
|
|
* @throws ClassCastException if the collection contains elements that are |
668 |
|
|
* not <i>mutually comparable</i> using the specified comparator. |
669 |
|
|
* @throws NoSuchElementException if the collection is empty. |
670 |
|
|
* @see Comparable |
671 |
|
|
*/ |
672 |
|
|
public static <T> T max(Collection<? extends T> coll, Comparator<? super T> comp) { |
673 |
|
|
if (comp==null) |
674 |
|
|
return (T)max((Collection<SelfComparable>) (Collection) coll); |
675 |
|
|
|
676 |
|
|
Iterator<? extends T> i = coll.iterator(); |
677 |
|
|
T candidate = i.next(); |
678 |
|
|
|
679 |
jsr166 |
1.6 |
while (i.hasNext()) { |
680 |
dl |
1.1 |
T next = i.next(); |
681 |
|
|
if (comp.compare(next, candidate) > 0) |
682 |
|
|
candidate = next; |
683 |
|
|
} |
684 |
|
|
return candidate; |
685 |
|
|
} |
686 |
|
|
|
687 |
|
|
/** |
688 |
|
|
* Rotates the elements in the specified list by the specified distance. |
689 |
|
|
* After calling this method, the element at index <tt>i</tt> will be |
690 |
|
|
* the element previously at index <tt>(i - distance)</tt> mod |
691 |
|
|
* <tt>list.size()</tt>, for all values of <tt>i</tt> between <tt>0</tt> |
692 |
|
|
* and <tt>list.size()-1</tt>, inclusive. (This method has no effect on |
693 |
|
|
* the size of the list.) |
694 |
|
|
* |
695 |
|
|
* <p>For example, suppose <tt>list</tt> comprises<tt> [t, a, n, k, s]</tt>. |
696 |
|
|
* After invoking <tt>Collections.rotate(list, 1)</tt> (or |
697 |
|
|
* <tt>Collections.rotate(list, -4)</tt>), <tt>list</tt> will comprise |
698 |
|
|
* <tt>[s, t, a, n, k]</tt>. |
699 |
|
|
* |
700 |
|
|
* <p>Note that this method can usefully be applied to sublists to |
701 |
|
|
* move one or more elements within a list while preserving the |
702 |
|
|
* order of the remaining elements. For example, the following idiom |
703 |
|
|
* moves the element at index <tt>j</tt> forward to position |
704 |
|
|
* <tt>k</tt> (which must be greater than or equal to <tt>j</tt>): |
705 |
|
|
* <pre> |
706 |
|
|
* Collections.rotate(list.subList(j, k+1), -1); |
707 |
|
|
* </pre> |
708 |
|
|
* To make this concrete, suppose <tt>list</tt> comprises |
709 |
|
|
* <tt>[a, b, c, d, e]</tt>. To move the element at index <tt>1</tt> |
710 |
|
|
* (<tt>b</tt>) forward two positions, perform the following invocation: |
711 |
|
|
* <pre> |
712 |
|
|
* Collections.rotate(l.subList(1, 4), -1); |
713 |
|
|
* </pre> |
714 |
|
|
* The resulting list is <tt>[a, c, d, b, e]</tt>. |
715 |
jsr166 |
1.4 |
* |
716 |
dl |
1.1 |
* <p>To move more than one element forward, increase the absolute value |
717 |
|
|
* of the rotation distance. To move elements backward, use a positive |
718 |
|
|
* shift distance. |
719 |
|
|
* |
720 |
|
|
* <p>If the specified list is small or implements the {@link |
721 |
|
|
* RandomAccess} interface, this implementation exchanges the first |
722 |
|
|
* element into the location it should go, and then repeatedly exchanges |
723 |
|
|
* the displaced element into the location it should go until a displaced |
724 |
|
|
* element is swapped into the first element. If necessary, the process |
725 |
|
|
* is repeated on the second and successive elements, until the rotation |
726 |
|
|
* is complete. If the specified list is large and doesn't implement the |
727 |
|
|
* <tt>RandomAccess</tt> interface, this implementation breaks the |
728 |
|
|
* list into two sublist views around index <tt>-distance mod size</tt>. |
729 |
|
|
* Then the {@link #reverse(List)} method is invoked on each sublist view, |
730 |
|
|
* and finally it is invoked on the entire list. For a more complete |
731 |
|
|
* description of both algorithms, see Section 2.3 of Jon Bentley's |
732 |
|
|
* <i>Programming Pearls</i> (Addison-Wesley, 1986). |
733 |
|
|
* |
734 |
|
|
* @param list the list to be rotated. |
735 |
|
|
* @param distance the distance to rotate the list. There are no |
736 |
|
|
* constraints on this value; it may be zero, negative, or |
737 |
|
|
* greater than <tt>list.size()</tt>. |
738 |
|
|
* @throws UnsupportedOperationException if the specified list or |
739 |
jsr166 |
1.4 |
* its list-iterator does not support the <tt>set</tt> operation. |
740 |
dl |
1.1 |
* @since 1.4 |
741 |
|
|
*/ |
742 |
|
|
public static void rotate(List<?> list, int distance) { |
743 |
|
|
if (list instanceof RandomAccess || list.size() < ROTATE_THRESHOLD) |
744 |
|
|
rotate1((List)list, distance); |
745 |
|
|
else |
746 |
|
|
rotate2((List)list, distance); |
747 |
|
|
} |
748 |
|
|
|
749 |
|
|
private static <T> void rotate1(List<T> list, int distance) { |
750 |
|
|
int size = list.size(); |
751 |
|
|
if (size == 0) |
752 |
|
|
return; |
753 |
|
|
distance = distance % size; |
754 |
|
|
if (distance < 0) |
755 |
|
|
distance += size; |
756 |
|
|
if (distance == 0) |
757 |
|
|
return; |
758 |
|
|
|
759 |
|
|
for (int cycleStart = 0, nMoved = 0; nMoved != size; cycleStart++) { |
760 |
|
|
T displaced = list.get(cycleStart); |
761 |
|
|
int i = cycleStart; |
762 |
|
|
do { |
763 |
|
|
i += distance; |
764 |
|
|
if (i >= size) |
765 |
|
|
i -= size; |
766 |
|
|
displaced = list.set(i, displaced); |
767 |
|
|
nMoved ++; |
768 |
|
|
} while(i != cycleStart); |
769 |
|
|
} |
770 |
|
|
} |
771 |
|
|
|
772 |
|
|
private static void rotate2(List<?> list, int distance) { |
773 |
|
|
int size = list.size(); |
774 |
|
|
if (size == 0) |
775 |
jsr166 |
1.4 |
return; |
776 |
dl |
1.1 |
int mid = -distance % size; |
777 |
|
|
if (mid < 0) |
778 |
|
|
mid += size; |
779 |
|
|
if (mid == 0) |
780 |
|
|
return; |
781 |
|
|
|
782 |
|
|
reverse(list.subList(0, mid)); |
783 |
|
|
reverse(list.subList(mid, size)); |
784 |
|
|
reverse(list); |
785 |
|
|
} |
786 |
|
|
|
787 |
|
|
/** |
788 |
|
|
* Replaces all occurrences of one specified value in a list with another. |
789 |
|
|
* More formally, replaces with <tt>newVal</tt> each element <tt>e</tt> |
790 |
|
|
* in <tt>list</tt> such that |
791 |
|
|
* <tt>(oldVal==null ? e==null : oldVal.equals(e))</tt>. |
792 |
|
|
* (This method has no effect on the size of the list.) |
793 |
|
|
* |
794 |
|
|
* @param list the list in which replacement is to occur. |
795 |
|
|
* @param oldVal the old value to be replaced. |
796 |
|
|
* @param newVal the new value with which <tt>oldVal</tt> is to be |
797 |
|
|
* replaced. |
798 |
|
|
* @return <tt>true</tt> if <tt>list</tt> contained one or more elements |
799 |
|
|
* <tt>e</tt> such that |
800 |
|
|
* <tt>(oldVal==null ? e==null : oldVal.equals(e))</tt>. |
801 |
|
|
* @throws UnsupportedOperationException if the specified list or |
802 |
jsr166 |
1.4 |
* its list-iterator does not support the <tt>set</tt> operation. |
803 |
dl |
1.1 |
* @since 1.4 |
804 |
|
|
*/ |
805 |
|
|
public static <T> boolean replaceAll(List<T> list, T oldVal, T newVal) { |
806 |
|
|
boolean result = false; |
807 |
|
|
int size = list.size(); |
808 |
|
|
if (size < REPLACEALL_THRESHOLD || list instanceof RandomAccess) { |
809 |
|
|
if (oldVal==null) { |
810 |
|
|
for (int i=0; i<size; i++) { |
811 |
|
|
if (list.get(i)==null) { |
812 |
|
|
list.set(i, newVal); |
813 |
|
|
result = true; |
814 |
|
|
} |
815 |
|
|
} |
816 |
|
|
} else { |
817 |
|
|
for (int i=0; i<size; i++) { |
818 |
|
|
if (oldVal.equals(list.get(i))) { |
819 |
|
|
list.set(i, newVal); |
820 |
|
|
result = true; |
821 |
|
|
} |
822 |
|
|
} |
823 |
|
|
} |
824 |
|
|
} else { |
825 |
|
|
ListIterator<T> itr=list.listIterator(); |
826 |
|
|
if (oldVal==null) { |
827 |
|
|
for (int i=0; i<size; i++) { |
828 |
|
|
if (itr.next()==null) { |
829 |
|
|
itr.set(newVal); |
830 |
|
|
result = true; |
831 |
|
|
} |
832 |
|
|
} |
833 |
|
|
} else { |
834 |
|
|
for (int i=0; i<size; i++) { |
835 |
|
|
if (oldVal.equals(itr.next())) { |
836 |
|
|
itr.set(newVal); |
837 |
|
|
result = true; |
838 |
|
|
} |
839 |
|
|
} |
840 |
|
|
} |
841 |
|
|
} |
842 |
|
|
return result; |
843 |
|
|
} |
844 |
|
|
|
845 |
|
|
/** |
846 |
|
|
* Returns the starting position of the first occurrence of the specified |
847 |
|
|
* target list within the specified source list, or -1 if there is no |
848 |
|
|
* such occurrence. More formally, returns the lowest index <tt>i</tt> |
849 |
|
|
* such that <tt>source.subList(i, i+target.size()).equals(target)</tt>, |
850 |
|
|
* or -1 if there is no such index. (Returns -1 if |
851 |
|
|
* <tt>target.size() > source.size()</tt>.) |
852 |
|
|
* |
853 |
|
|
* <p>This implementation uses the "brute force" technique of scanning |
854 |
|
|
* over the source list, looking for a match with the target at each |
855 |
|
|
* location in turn. |
856 |
|
|
* |
857 |
|
|
* @param source the list in which to search for the first occurrence |
858 |
|
|
* of <tt>target</tt>. |
859 |
|
|
* @param target the list to search for as a subList of <tt>source</tt>. |
860 |
|
|
* @return the starting position of the first occurrence of the specified |
861 |
|
|
* target list within the specified source list, or -1 if there |
862 |
|
|
* is no such occurrence. |
863 |
|
|
* @since 1.4 |
864 |
|
|
*/ |
865 |
|
|
public static int indexOfSubList(List<?> source, List<?> target) { |
866 |
|
|
int sourceSize = source.size(); |
867 |
|
|
int targetSize = target.size(); |
868 |
|
|
int maxCandidate = sourceSize - targetSize; |
869 |
|
|
|
870 |
|
|
if (sourceSize < INDEXOFSUBLIST_THRESHOLD || |
871 |
|
|
(source instanceof RandomAccess&&target instanceof RandomAccess)) { |
872 |
|
|
nextCand: |
873 |
|
|
for (int candidate = 0; candidate <= maxCandidate; candidate++) { |
874 |
|
|
for (int i=0, j=candidate; i<targetSize; i++, j++) |
875 |
|
|
if (!eq(target.get(i), source.get(j))) |
876 |
|
|
continue nextCand; // Element mismatch, try next cand |
877 |
|
|
return candidate; // All elements of candidate matched target |
878 |
|
|
} |
879 |
|
|
} else { // Iterator version of above algorithm |
880 |
|
|
ListIterator<?> si = source.listIterator(); |
881 |
|
|
nextCand: |
882 |
|
|
for (int candidate = 0; candidate <= maxCandidate; candidate++) { |
883 |
|
|
ListIterator<?> ti = target.listIterator(); |
884 |
|
|
for (int i=0; i<targetSize; i++) { |
885 |
|
|
if (!eq(ti.next(), si.next())) { |
886 |
|
|
// Back up source iterator to next candidate |
887 |
|
|
for (int j=0; j<i; j++) |
888 |
|
|
si.previous(); |
889 |
|
|
continue nextCand; |
890 |
|
|
} |
891 |
|
|
} |
892 |
|
|
return candidate; |
893 |
|
|
} |
894 |
|
|
} |
895 |
|
|
return -1; // No candidate matched the target |
896 |
|
|
} |
897 |
|
|
|
898 |
|
|
/** |
899 |
|
|
* Returns the starting position of the last occurrence of the specified |
900 |
|
|
* target list within the specified source list, or -1 if there is no such |
901 |
|
|
* occurrence. More formally, returns the highest index <tt>i</tt> |
902 |
|
|
* such that <tt>source.subList(i, i+target.size()).equals(target)</tt>, |
903 |
|
|
* or -1 if there is no such index. (Returns -1 if |
904 |
|
|
* <tt>target.size() > source.size()</tt>.) |
905 |
|
|
* |
906 |
|
|
* <p>This implementation uses the "brute force" technique of iterating |
907 |
|
|
* over the source list, looking for a match with the target at each |
908 |
|
|
* location in turn. |
909 |
|
|
* |
910 |
|
|
* @param source the list in which to search for the last occurrence |
911 |
|
|
* of <tt>target</tt>. |
912 |
|
|
* @param target the list to search for as a subList of <tt>source</tt>. |
913 |
|
|
* @return the starting position of the last occurrence of the specified |
914 |
|
|
* target list within the specified source list, or -1 if there |
915 |
|
|
* is no such occurrence. |
916 |
|
|
* @since 1.4 |
917 |
|
|
*/ |
918 |
|
|
public static int lastIndexOfSubList(List<?> source, List<?> target) { |
919 |
|
|
int sourceSize = source.size(); |
920 |
|
|
int targetSize = target.size(); |
921 |
|
|
int maxCandidate = sourceSize - targetSize; |
922 |
|
|
|
923 |
|
|
if (sourceSize < INDEXOFSUBLIST_THRESHOLD || |
924 |
|
|
source instanceof RandomAccess) { // Index access version |
925 |
|
|
nextCand: |
926 |
|
|
for (int candidate = maxCandidate; candidate >= 0; candidate--) { |
927 |
|
|
for (int i=0, j=candidate; i<targetSize; i++, j++) |
928 |
|
|
if (!eq(target.get(i), source.get(j))) |
929 |
|
|
continue nextCand; // Element mismatch, try next cand |
930 |
|
|
return candidate; // All elements of candidate matched target |
931 |
|
|
} |
932 |
|
|
} else { // Iterator version of above algorithm |
933 |
|
|
if (maxCandidate < 0) |
934 |
|
|
return -1; |
935 |
|
|
ListIterator<?> si = source.listIterator(maxCandidate); |
936 |
|
|
nextCand: |
937 |
|
|
for (int candidate = maxCandidate; candidate >= 0; candidate--) { |
938 |
|
|
ListIterator<?> ti = target.listIterator(); |
939 |
|
|
for (int i=0; i<targetSize; i++) { |
940 |
|
|
if (!eq(ti.next(), si.next())) { |
941 |
|
|
if (candidate != 0) { |
942 |
|
|
// Back up source iterator to next candidate |
943 |
|
|
for (int j=0; j<=i+1; j++) |
944 |
|
|
si.previous(); |
945 |
|
|
} |
946 |
|
|
continue nextCand; |
947 |
|
|
} |
948 |
|
|
} |
949 |
|
|
return candidate; |
950 |
|
|
} |
951 |
|
|
} |
952 |
|
|
return -1; // No candidate matched the target |
953 |
|
|
} |
954 |
|
|
|
955 |
|
|
|
956 |
|
|
// Unmodifiable Wrappers |
957 |
|
|
|
958 |
|
|
/** |
959 |
|
|
* Returns an unmodifiable view of the specified collection. This method |
960 |
|
|
* allows modules to provide users with "read-only" access to internal |
961 |
|
|
* collections. Query operations on the returned collection "read through" |
962 |
|
|
* to the specified collection, and attempts to modify the returned |
963 |
|
|
* collection, whether direct or via its iterator, result in an |
964 |
|
|
* <tt>UnsupportedOperationException</tt>.<p> |
965 |
|
|
* |
966 |
|
|
* The returned collection does <i>not</i> pass the hashCode and equals |
967 |
|
|
* operations through to the backing collection, but relies on |
968 |
|
|
* <tt>Object</tt>'s <tt>equals</tt> and <tt>hashCode</tt> methods. This |
969 |
|
|
* is necessary to preserve the contracts of these operations in the case |
970 |
|
|
* that the backing collection is a set or a list.<p> |
971 |
|
|
* |
972 |
|
|
* The returned collection will be serializable if the specified collection |
973 |
jsr166 |
1.4 |
* is serializable. |
974 |
dl |
1.1 |
* |
975 |
|
|
* @param c the collection for which an unmodifiable view is to be |
976 |
|
|
* returned. |
977 |
|
|
* @return an unmodifiable view of the specified collection. |
978 |
|
|
*/ |
979 |
|
|
public static <T> Collection<T> unmodifiableCollection(Collection<? extends T> c) { |
980 |
|
|
return new UnmodifiableCollection<T>(c); |
981 |
|
|
} |
982 |
|
|
|
983 |
|
|
/** |
984 |
|
|
* @serial include |
985 |
|
|
*/ |
986 |
|
|
static class UnmodifiableCollection<E> implements Collection<E>, Serializable { |
987 |
|
|
// use serialVersionUID from JDK 1.2.2 for interoperability |
988 |
|
|
private static final long serialVersionUID = 1820017752578914078L; |
989 |
|
|
|
990 |
|
|
final Collection<? extends E> c; |
991 |
|
|
|
992 |
|
|
UnmodifiableCollection(Collection<? extends E> c) { |
993 |
|
|
if (c==null) |
994 |
|
|
throw new NullPointerException(); |
995 |
|
|
this.c = c; |
996 |
|
|
} |
997 |
|
|
|
998 |
|
|
public int size() {return c.size();} |
999 |
|
|
public boolean isEmpty() {return c.isEmpty();} |
1000 |
|
|
public boolean contains(Object o) {return c.contains(o);} |
1001 |
|
|
public Object[] toArray() {return c.toArray();} |
1002 |
|
|
public <T> T[] toArray(T[] a) {return c.toArray(a);} |
1003 |
|
|
public String toString() {return c.toString();} |
1004 |
|
|
|
1005 |
|
|
public Iterator<E> iterator() { |
1006 |
|
|
return new Iterator<E>() { |
1007 |
|
|
Iterator<? extends E> i = c.iterator(); |
1008 |
|
|
|
1009 |
|
|
public boolean hasNext() {return i.hasNext();} |
1010 |
|
|
public E next() {return i.next();} |
1011 |
|
|
public void remove() { |
1012 |
|
|
throw new UnsupportedOperationException(); |
1013 |
|
|
} |
1014 |
|
|
}; |
1015 |
|
|
} |
1016 |
|
|
|
1017 |
jsr166 |
1.5 |
public boolean add(E e){ |
1018 |
dl |
1.1 |
throw new UnsupportedOperationException(); |
1019 |
|
|
} |
1020 |
|
|
public boolean remove(Object o) { |
1021 |
|
|
throw new UnsupportedOperationException(); |
1022 |
|
|
} |
1023 |
|
|
|
1024 |
|
|
public boolean containsAll(Collection<?> coll) { |
1025 |
|
|
return c.containsAll(coll); |
1026 |
|
|
} |
1027 |
|
|
public boolean addAll(Collection<? extends E> coll) { |
1028 |
|
|
throw new UnsupportedOperationException(); |
1029 |
|
|
} |
1030 |
|
|
public boolean removeAll(Collection<?> coll) { |
1031 |
|
|
throw new UnsupportedOperationException(); |
1032 |
|
|
} |
1033 |
|
|
public boolean retainAll(Collection<?> coll) { |
1034 |
|
|
throw new UnsupportedOperationException(); |
1035 |
|
|
} |
1036 |
|
|
public void clear() { |
1037 |
|
|
throw new UnsupportedOperationException(); |
1038 |
|
|
} |
1039 |
|
|
} |
1040 |
|
|
|
1041 |
|
|
/** |
1042 |
|
|
* Returns an unmodifiable view of the specified set. This method allows |
1043 |
|
|
* modules to provide users with "read-only" access to internal sets. |
1044 |
|
|
* Query operations on the returned set "read through" to the specified |
1045 |
|
|
* set, and attempts to modify the returned set, whether direct or via its |
1046 |
|
|
* iterator, result in an <tt>UnsupportedOperationException</tt>.<p> |
1047 |
|
|
* |
1048 |
|
|
* The returned set will be serializable if the specified set |
1049 |
jsr166 |
1.4 |
* is serializable. |
1050 |
dl |
1.1 |
* |
1051 |
|
|
* @param s the set for which an unmodifiable view is to be returned. |
1052 |
|
|
* @return an unmodifiable view of the specified set. |
1053 |
|
|
*/ |
1054 |
|
|
public static <T> Set<T> unmodifiableSet(Set<? extends T> s) { |
1055 |
|
|
return new UnmodifiableSet<T>(s); |
1056 |
|
|
} |
1057 |
|
|
|
1058 |
|
|
/** |
1059 |
|
|
* @serial include |
1060 |
|
|
*/ |
1061 |
|
|
static class UnmodifiableSet<E> extends UnmodifiableCollection<E> |
1062 |
|
|
implements Set<E>, Serializable { |
1063 |
|
|
private static final long serialVersionUID = -9215047833775013803L; |
1064 |
|
|
|
1065 |
|
|
UnmodifiableSet(Set<? extends E> s) {super(s);} |
1066 |
jsr166 |
1.23 |
public boolean equals(Object o) {return o == this || c.equals(o);} |
1067 |
dl |
1.1 |
public int hashCode() {return c.hashCode();} |
1068 |
|
|
} |
1069 |
|
|
|
1070 |
|
|
/** |
1071 |
|
|
* Returns an unmodifiable view of the specified sorted set. This method |
1072 |
|
|
* allows modules to provide users with "read-only" access to internal |
1073 |
|
|
* sorted sets. Query operations on the returned sorted set "read |
1074 |
|
|
* through" to the specified sorted set. Attempts to modify the returned |
1075 |
|
|
* sorted set, whether direct, via its iterator, or via its |
1076 |
|
|
* <tt>subSet</tt>, <tt>headSet</tt>, or <tt>tailSet</tt> views, result in |
1077 |
|
|
* an <tt>UnsupportedOperationException</tt>.<p> |
1078 |
|
|
* |
1079 |
|
|
* The returned sorted set will be serializable if the specified sorted set |
1080 |
jsr166 |
1.4 |
* is serializable. |
1081 |
dl |
1.1 |
* |
1082 |
|
|
* @param s the sorted set for which an unmodifiable view is to be |
1083 |
jsr166 |
1.4 |
* returned. |
1084 |
dl |
1.1 |
* @return an unmodifiable view of the specified sorted set. |
1085 |
|
|
*/ |
1086 |
|
|
public static <T> SortedSet<T> unmodifiableSortedSet(SortedSet<T> s) { |
1087 |
|
|
return new UnmodifiableSortedSet<T>(s); |
1088 |
|
|
} |
1089 |
|
|
|
1090 |
|
|
/** |
1091 |
|
|
* @serial include |
1092 |
|
|
*/ |
1093 |
|
|
static class UnmodifiableSortedSet<E> |
1094 |
|
|
extends UnmodifiableSet<E> |
1095 |
|
|
implements SortedSet<E>, Serializable { |
1096 |
|
|
private static final long serialVersionUID = -4929149591599911165L; |
1097 |
|
|
private final SortedSet<E> ss; |
1098 |
|
|
|
1099 |
|
|
UnmodifiableSortedSet(SortedSet<E> s) {super(s); ss = s;} |
1100 |
|
|
|
1101 |
|
|
public Comparator<? super E> comparator() {return ss.comparator();} |
1102 |
|
|
|
1103 |
|
|
public SortedSet<E> subSet(E fromElement, E toElement) { |
1104 |
|
|
return new UnmodifiableSortedSet<E>(ss.subSet(fromElement,toElement)); |
1105 |
|
|
} |
1106 |
|
|
public SortedSet<E> headSet(E toElement) { |
1107 |
|
|
return new UnmodifiableSortedSet<E>(ss.headSet(toElement)); |
1108 |
|
|
} |
1109 |
|
|
public SortedSet<E> tailSet(E fromElement) { |
1110 |
|
|
return new UnmodifiableSortedSet<E>(ss.tailSet(fromElement)); |
1111 |
|
|
} |
1112 |
|
|
|
1113 |
|
|
public E first() {return ss.first();} |
1114 |
|
|
public E last() {return ss.last();} |
1115 |
|
|
} |
1116 |
|
|
|
1117 |
|
|
/** |
1118 |
|
|
* Returns an unmodifiable view of the specified list. This method allows |
1119 |
|
|
* modules to provide users with "read-only" access to internal |
1120 |
|
|
* lists. Query operations on the returned list "read through" to the |
1121 |
|
|
* specified list, and attempts to modify the returned list, whether |
1122 |
|
|
* direct or via its iterator, result in an |
1123 |
|
|
* <tt>UnsupportedOperationException</tt>.<p> |
1124 |
|
|
* |
1125 |
|
|
* The returned list will be serializable if the specified list |
1126 |
|
|
* is serializable. Similarly, the returned list will implement |
1127 |
|
|
* {@link RandomAccess} if the specified list does. |
1128 |
|
|
* |
1129 |
|
|
* @param list the list for which an unmodifiable view is to be returned. |
1130 |
|
|
* @return an unmodifiable view of the specified list. |
1131 |
|
|
*/ |
1132 |
|
|
public static <T> List<T> unmodifiableList(List<? extends T> list) { |
1133 |
|
|
return (list instanceof RandomAccess ? |
1134 |
|
|
new UnmodifiableRandomAccessList<T>(list) : |
1135 |
|
|
new UnmodifiableList<T>(list)); |
1136 |
|
|
} |
1137 |
|
|
|
1138 |
|
|
/** |
1139 |
|
|
* @serial include |
1140 |
|
|
*/ |
1141 |
|
|
static class UnmodifiableList<E> extends UnmodifiableCollection<E> |
1142 |
|
|
implements List<E> { |
1143 |
|
|
static final long serialVersionUID = -283967356065247728L; |
1144 |
|
|
final List<? extends E> list; |
1145 |
|
|
|
1146 |
|
|
UnmodifiableList(List<? extends E> list) { |
1147 |
|
|
super(list); |
1148 |
|
|
this.list = list; |
1149 |
|
|
} |
1150 |
|
|
|
1151 |
jsr166 |
1.23 |
public boolean equals(Object o) {return o == this || list.equals(o);} |
1152 |
dl |
1.1 |
public int hashCode() {return list.hashCode();} |
1153 |
|
|
|
1154 |
|
|
public E get(int index) {return list.get(index);} |
1155 |
|
|
public E set(int index, E element) { |
1156 |
|
|
throw new UnsupportedOperationException(); |
1157 |
|
|
} |
1158 |
|
|
public void add(int index, E element) { |
1159 |
|
|
throw new UnsupportedOperationException(); |
1160 |
|
|
} |
1161 |
|
|
public E remove(int index) { |
1162 |
|
|
throw new UnsupportedOperationException(); |
1163 |
|
|
} |
1164 |
|
|
public int indexOf(Object o) {return list.indexOf(o);} |
1165 |
|
|
public int lastIndexOf(Object o) {return list.lastIndexOf(o);} |
1166 |
|
|
public boolean addAll(int index, Collection<? extends E> c) { |
1167 |
|
|
throw new UnsupportedOperationException(); |
1168 |
|
|
} |
1169 |
|
|
public ListIterator<E> listIterator() {return listIterator(0);} |
1170 |
|
|
|
1171 |
|
|
public ListIterator<E> listIterator(final int index) { |
1172 |
|
|
return new ListIterator<E>() { |
1173 |
|
|
ListIterator<? extends E> i = list.listIterator(index); |
1174 |
|
|
|
1175 |
|
|
public boolean hasNext() {return i.hasNext();} |
1176 |
|
|
public E next() {return i.next();} |
1177 |
|
|
public boolean hasPrevious() {return i.hasPrevious();} |
1178 |
|
|
public E previous() {return i.previous();} |
1179 |
|
|
public int nextIndex() {return i.nextIndex();} |
1180 |
|
|
public int previousIndex() {return i.previousIndex();} |
1181 |
|
|
|
1182 |
|
|
public void remove() { |
1183 |
|
|
throw new UnsupportedOperationException(); |
1184 |
|
|
} |
1185 |
jsr166 |
1.5 |
public void set(E e) { |
1186 |
dl |
1.1 |
throw new UnsupportedOperationException(); |
1187 |
|
|
} |
1188 |
jsr166 |
1.5 |
public void add(E e) { |
1189 |
dl |
1.1 |
throw new UnsupportedOperationException(); |
1190 |
|
|
} |
1191 |
|
|
}; |
1192 |
|
|
} |
1193 |
|
|
|
1194 |
|
|
public List<E> subList(int fromIndex, int toIndex) { |
1195 |
|
|
return new UnmodifiableList<E>(list.subList(fromIndex, toIndex)); |
1196 |
|
|
} |
1197 |
|
|
|
1198 |
|
|
/** |
1199 |
|
|
* UnmodifiableRandomAccessList instances are serialized as |
1200 |
|
|
* UnmodifiableList instances to allow them to be deserialized |
1201 |
|
|
* in pre-1.4 JREs (which do not have UnmodifiableRandomAccessList). |
1202 |
|
|
* This method inverts the transformation. As a beneficial |
1203 |
|
|
* side-effect, it also grafts the RandomAccess marker onto |
1204 |
|
|
* UnmodifiableList instances that were serialized in pre-1.4 JREs. |
1205 |
|
|
* |
1206 |
|
|
* Note: Unfortunately, UnmodifiableRandomAccessList instances |
1207 |
|
|
* serialized in 1.4.1 and deserialized in 1.4 will become |
1208 |
|
|
* UnmodifiableList instances, as this method was missing in 1.4. |
1209 |
|
|
*/ |
1210 |
|
|
private Object readResolve() { |
1211 |
|
|
return (list instanceof RandomAccess |
1212 |
|
|
? new UnmodifiableRandomAccessList<E>(list) |
1213 |
|
|
: this); |
1214 |
|
|
} |
1215 |
|
|
} |
1216 |
|
|
|
1217 |
|
|
/** |
1218 |
|
|
* @serial include |
1219 |
|
|
*/ |
1220 |
|
|
static class UnmodifiableRandomAccessList<E> extends UnmodifiableList<E> |
1221 |
|
|
implements RandomAccess |
1222 |
|
|
{ |
1223 |
|
|
UnmodifiableRandomAccessList(List<? extends E> list) { |
1224 |
|
|
super(list); |
1225 |
|
|
} |
1226 |
|
|
|
1227 |
|
|
public List<E> subList(int fromIndex, int toIndex) { |
1228 |
|
|
return new UnmodifiableRandomAccessList<E>( |
1229 |
|
|
list.subList(fromIndex, toIndex)); |
1230 |
|
|
} |
1231 |
|
|
|
1232 |
|
|
private static final long serialVersionUID = -2542308836966382001L; |
1233 |
|
|
|
1234 |
|
|
/** |
1235 |
|
|
* Allows instances to be deserialized in pre-1.4 JREs (which do |
1236 |
|
|
* not have UnmodifiableRandomAccessList). UnmodifiableList has |
1237 |
|
|
* a readResolve method that inverts this transformation upon |
1238 |
|
|
* deserialization. |
1239 |
|
|
*/ |
1240 |
|
|
private Object writeReplace() { |
1241 |
|
|
return new UnmodifiableList<E>(list); |
1242 |
|
|
} |
1243 |
|
|
} |
1244 |
|
|
|
1245 |
|
|
/** |
1246 |
|
|
* Returns an unmodifiable view of the specified map. This method |
1247 |
|
|
* allows modules to provide users with "read-only" access to internal |
1248 |
|
|
* maps. Query operations on the returned map "read through" |
1249 |
|
|
* to the specified map, and attempts to modify the returned |
1250 |
|
|
* map, whether direct or via its collection views, result in an |
1251 |
|
|
* <tt>UnsupportedOperationException</tt>.<p> |
1252 |
|
|
* |
1253 |
|
|
* The returned map will be serializable if the specified map |
1254 |
jsr166 |
1.4 |
* is serializable. |
1255 |
dl |
1.1 |
* |
1256 |
|
|
* @param m the map for which an unmodifiable view is to be returned. |
1257 |
|
|
* @return an unmodifiable view of the specified map. |
1258 |
|
|
*/ |
1259 |
|
|
public static <K,V> Map<K,V> unmodifiableMap(Map<? extends K, ? extends V> m) { |
1260 |
|
|
return new UnmodifiableMap<K,V>(m); |
1261 |
|
|
} |
1262 |
|
|
|
1263 |
|
|
/** |
1264 |
|
|
* @serial include |
1265 |
|
|
*/ |
1266 |
|
|
private static class UnmodifiableMap<K,V> implements Map<K,V>, Serializable { |
1267 |
|
|
// use serialVersionUID from JDK 1.2.2 for interoperability |
1268 |
|
|
private static final long serialVersionUID = -1034234728574286014L; |
1269 |
|
|
|
1270 |
|
|
private final Map<? extends K, ? extends V> m; |
1271 |
|
|
|
1272 |
|
|
UnmodifiableMap(Map<? extends K, ? extends V> m) { |
1273 |
|
|
if (m==null) |
1274 |
|
|
throw new NullPointerException(); |
1275 |
|
|
this.m = m; |
1276 |
|
|
} |
1277 |
|
|
|
1278 |
|
|
public int size() {return m.size();} |
1279 |
|
|
public boolean isEmpty() {return m.isEmpty();} |
1280 |
|
|
public boolean containsKey(Object key) {return m.containsKey(key);} |
1281 |
|
|
public boolean containsValue(Object val) {return m.containsValue(val);} |
1282 |
|
|
public V get(Object key) {return m.get(key);} |
1283 |
|
|
|
1284 |
|
|
public V put(K key, V value) { |
1285 |
|
|
throw new UnsupportedOperationException(); |
1286 |
|
|
} |
1287 |
|
|
public V remove(Object key) { |
1288 |
|
|
throw new UnsupportedOperationException(); |
1289 |
|
|
} |
1290 |
jsr166 |
1.11 |
public void putAll(Map<? extends K, ? extends V> m) { |
1291 |
dl |
1.1 |
throw new UnsupportedOperationException(); |
1292 |
|
|
} |
1293 |
|
|
public void clear() { |
1294 |
|
|
throw new UnsupportedOperationException(); |
1295 |
|
|
} |
1296 |
|
|
|
1297 |
|
|
private transient Set<K> keySet = null; |
1298 |
|
|
private transient Set<Map.Entry<K,V>> entrySet = null; |
1299 |
|
|
private transient Collection<V> values = null; |
1300 |
|
|
|
1301 |
|
|
public Set<K> keySet() { |
1302 |
|
|
if (keySet==null) |
1303 |
|
|
keySet = unmodifiableSet(m.keySet()); |
1304 |
|
|
return keySet; |
1305 |
|
|
} |
1306 |
|
|
|
1307 |
|
|
public Set<Map.Entry<K,V>> entrySet() { |
1308 |
|
|
if (entrySet==null) |
1309 |
|
|
entrySet = new UnmodifiableEntrySet<K,V>(m.entrySet()); |
1310 |
|
|
return entrySet; |
1311 |
|
|
} |
1312 |
|
|
|
1313 |
|
|
public Collection<V> values() { |
1314 |
|
|
if (values==null) |
1315 |
|
|
values = unmodifiableCollection(m.values()); |
1316 |
|
|
return values; |
1317 |
|
|
} |
1318 |
|
|
|
1319 |
jsr166 |
1.23 |
public boolean equals(Object o) {return o == this || m.equals(o);} |
1320 |
dl |
1.1 |
public int hashCode() {return m.hashCode();} |
1321 |
|
|
public String toString() {return m.toString();} |
1322 |
|
|
|
1323 |
|
|
/** |
1324 |
|
|
* We need this class in addition to UnmodifiableSet as |
1325 |
|
|
* Map.Entries themselves permit modification of the backing Map |
1326 |
|
|
* via their setValue operation. This class is subtle: there are |
1327 |
|
|
* many possible attacks that must be thwarted. |
1328 |
|
|
* |
1329 |
|
|
* @serial include |
1330 |
|
|
*/ |
1331 |
|
|
static class UnmodifiableEntrySet<K,V> |
1332 |
|
|
extends UnmodifiableSet<Map.Entry<K,V>> { |
1333 |
|
|
private static final long serialVersionUID = 7854390611657943733L; |
1334 |
|
|
|
1335 |
|
|
UnmodifiableEntrySet(Set<? extends Map.Entry<? extends K, ? extends V>> s) { |
1336 |
jsr166 |
1.4 |
super((Set)s); |
1337 |
dl |
1.1 |
} |
1338 |
|
|
public Iterator<Map.Entry<K,V>> iterator() { |
1339 |
|
|
return new Iterator<Map.Entry<K,V>>() { |
1340 |
|
|
Iterator<? extends Map.Entry<? extends K, ? extends V>> i = c.iterator(); |
1341 |
|
|
|
1342 |
|
|
public boolean hasNext() { |
1343 |
|
|
return i.hasNext(); |
1344 |
|
|
} |
1345 |
|
|
public Map.Entry<K,V> next() { |
1346 |
|
|
return new UnmodifiableEntry<K,V>(i.next()); |
1347 |
|
|
} |
1348 |
|
|
public void remove() { |
1349 |
|
|
throw new UnsupportedOperationException(); |
1350 |
|
|
} |
1351 |
|
|
}; |
1352 |
|
|
} |
1353 |
|
|
|
1354 |
|
|
public Object[] toArray() { |
1355 |
|
|
Object[] a = c.toArray(); |
1356 |
|
|
for (int i=0; i<a.length; i++) |
1357 |
|
|
a[i] = new UnmodifiableEntry<K,V>((Map.Entry<K,V>)a[i]); |
1358 |
|
|
return a; |
1359 |
|
|
} |
1360 |
|
|
|
1361 |
|
|
public <T> T[] toArray(T[] a) { |
1362 |
|
|
// We don't pass a to c.toArray, to avoid window of |
1363 |
|
|
// vulnerability wherein an unscrupulous multithreaded client |
1364 |
|
|
// could get his hands on raw (unwrapped) Entries from c. |
1365 |
jsr166 |
1.10 |
Object[] arr = c.toArray(a.length==0 ? a : Arrays.copyOf(a, 0)); |
1366 |
dl |
1.1 |
|
1367 |
|
|
for (int i=0; i<arr.length; i++) |
1368 |
|
|
arr[i] = new UnmodifiableEntry<K,V>((Map.Entry<K,V>)arr[i]); |
1369 |
|
|
|
1370 |
|
|
if (arr.length > a.length) |
1371 |
|
|
return (T[])arr; |
1372 |
|
|
|
1373 |
|
|
System.arraycopy(arr, 0, a, 0, arr.length); |
1374 |
|
|
if (a.length > arr.length) |
1375 |
|
|
a[arr.length] = null; |
1376 |
|
|
return a; |
1377 |
|
|
} |
1378 |
|
|
|
1379 |
|
|
/** |
1380 |
|
|
* This method is overridden to protect the backing set against |
1381 |
|
|
* an object with a nefarious equals function that senses |
1382 |
|
|
* that the equality-candidate is Map.Entry and calls its |
1383 |
|
|
* setValue method. |
1384 |
|
|
*/ |
1385 |
|
|
public boolean contains(Object o) { |
1386 |
|
|
if (!(o instanceof Map.Entry)) |
1387 |
|
|
return false; |
1388 |
|
|
return c.contains(new UnmodifiableEntry<K,V>((Map.Entry<K,V>) o)); |
1389 |
|
|
} |
1390 |
|
|
|
1391 |
|
|
/** |
1392 |
|
|
* The next two methods are overridden to protect against |
1393 |
|
|
* an unscrupulous List whose contains(Object o) method senses |
1394 |
|
|
* when o is a Map.Entry, and calls o.setValue. |
1395 |
|
|
*/ |
1396 |
|
|
public boolean containsAll(Collection<?> coll) { |
1397 |
|
|
Iterator<?> e = coll.iterator(); |
1398 |
|
|
while (e.hasNext()) |
1399 |
|
|
if (!contains(e.next())) // Invokes safe contains() above |
1400 |
|
|
return false; |
1401 |
|
|
return true; |
1402 |
|
|
} |
1403 |
|
|
public boolean equals(Object o) { |
1404 |
|
|
if (o == this) |
1405 |
|
|
return true; |
1406 |
|
|
|
1407 |
|
|
if (!(o instanceof Set)) |
1408 |
|
|
return false; |
1409 |
|
|
Set s = (Set) o; |
1410 |
|
|
if (s.size() != c.size()) |
1411 |
|
|
return false; |
1412 |
|
|
return containsAll(s); // Invokes safe containsAll() above |
1413 |
|
|
} |
1414 |
|
|
|
1415 |
|
|
/** |
1416 |
|
|
* This "wrapper class" serves two purposes: it prevents |
1417 |
|
|
* the client from modifying the backing Map, by short-circuiting |
1418 |
|
|
* the setValue method, and it protects the backing Map against |
1419 |
|
|
* an ill-behaved Map.Entry that attempts to modify another |
1420 |
|
|
* Map Entry when asked to perform an equality check. |
1421 |
|
|
*/ |
1422 |
|
|
private static class UnmodifiableEntry<K,V> implements Map.Entry<K,V> { |
1423 |
|
|
private Map.Entry<? extends K, ? extends V> e; |
1424 |
|
|
|
1425 |
|
|
UnmodifiableEntry(Map.Entry<? extends K, ? extends V> e) {this.e = e;} |
1426 |
|
|
|
1427 |
|
|
public K getKey() {return e.getKey();} |
1428 |
|
|
public V getValue() {return e.getValue();} |
1429 |
|
|
public V setValue(V value) { |
1430 |
|
|
throw new UnsupportedOperationException(); |
1431 |
|
|
} |
1432 |
|
|
public int hashCode() {return e.hashCode();} |
1433 |
|
|
public boolean equals(Object o) { |
1434 |
|
|
if (!(o instanceof Map.Entry)) |
1435 |
|
|
return false; |
1436 |
|
|
Map.Entry t = (Map.Entry)o; |
1437 |
|
|
return eq(e.getKey(), t.getKey()) && |
1438 |
|
|
eq(e.getValue(), t.getValue()); |
1439 |
|
|
} |
1440 |
|
|
public String toString() {return e.toString();} |
1441 |
|
|
} |
1442 |
|
|
} |
1443 |
|
|
} |
1444 |
|
|
|
1445 |
|
|
/** |
1446 |
|
|
* Returns an unmodifiable view of the specified sorted map. This method |
1447 |
|
|
* allows modules to provide users with "read-only" access to internal |
1448 |
|
|
* sorted maps. Query operations on the returned sorted map "read through" |
1449 |
|
|
* to the specified sorted map. Attempts to modify the returned |
1450 |
|
|
* sorted map, whether direct, via its collection views, or via its |
1451 |
|
|
* <tt>subMap</tt>, <tt>headMap</tt>, or <tt>tailMap</tt> views, result in |
1452 |
|
|
* an <tt>UnsupportedOperationException</tt>.<p> |
1453 |
|
|
* |
1454 |
|
|
* The returned sorted map will be serializable if the specified sorted map |
1455 |
jsr166 |
1.4 |
* is serializable. |
1456 |
dl |
1.1 |
* |
1457 |
|
|
* @param m the sorted map for which an unmodifiable view is to be |
1458 |
jsr166 |
1.4 |
* returned. |
1459 |
dl |
1.1 |
* @return an unmodifiable view of the specified sorted map. |
1460 |
|
|
*/ |
1461 |
|
|
public static <K,V> SortedMap<K,V> unmodifiableSortedMap(SortedMap<K, ? extends V> m) { |
1462 |
|
|
return new UnmodifiableSortedMap<K,V>(m); |
1463 |
|
|
} |
1464 |
|
|
|
1465 |
|
|
/** |
1466 |
|
|
* @serial include |
1467 |
|
|
*/ |
1468 |
|
|
static class UnmodifiableSortedMap<K,V> |
1469 |
|
|
extends UnmodifiableMap<K,V> |
1470 |
|
|
implements SortedMap<K,V>, Serializable { |
1471 |
|
|
private static final long serialVersionUID = -8806743815996713206L; |
1472 |
|
|
|
1473 |
|
|
private final SortedMap<K, ? extends V> sm; |
1474 |
|
|
|
1475 |
|
|
UnmodifiableSortedMap(SortedMap<K, ? extends V> m) {super(m); sm = m;} |
1476 |
|
|
|
1477 |
|
|
public Comparator<? super K> comparator() {return sm.comparator();} |
1478 |
|
|
|
1479 |
|
|
public SortedMap<K,V> subMap(K fromKey, K toKey) { |
1480 |
|
|
return new UnmodifiableSortedMap<K,V>(sm.subMap(fromKey, toKey)); |
1481 |
|
|
} |
1482 |
|
|
public SortedMap<K,V> headMap(K toKey) { |
1483 |
|
|
return new UnmodifiableSortedMap<K,V>(sm.headMap(toKey)); |
1484 |
|
|
} |
1485 |
|
|
public SortedMap<K,V> tailMap(K fromKey) { |
1486 |
|
|
return new UnmodifiableSortedMap<K,V>(sm.tailMap(fromKey)); |
1487 |
|
|
} |
1488 |
|
|
|
1489 |
|
|
public K firstKey() {return sm.firstKey();} |
1490 |
|
|
public K lastKey() {return sm.lastKey();} |
1491 |
|
|
} |
1492 |
|
|
|
1493 |
|
|
|
1494 |
|
|
// Synch Wrappers |
1495 |
|
|
|
1496 |
|
|
/** |
1497 |
|
|
* Returns a synchronized (thread-safe) collection backed by the specified |
1498 |
|
|
* collection. In order to guarantee serial access, it is critical that |
1499 |
|
|
* <strong>all</strong> access to the backing collection is accomplished |
1500 |
|
|
* through the returned collection.<p> |
1501 |
|
|
* |
1502 |
|
|
* It is imperative that the user manually synchronize on the returned |
1503 |
|
|
* collection when iterating over it: |
1504 |
|
|
* <pre> |
1505 |
|
|
* Collection c = Collections.synchronizedCollection(myCollection); |
1506 |
|
|
* ... |
1507 |
|
|
* synchronized(c) { |
1508 |
|
|
* Iterator i = c.iterator(); // Must be in the synchronized block |
1509 |
|
|
* while (i.hasNext()) |
1510 |
|
|
* foo(i.next()); |
1511 |
|
|
* } |
1512 |
|
|
* </pre> |
1513 |
|
|
* Failure to follow this advice may result in non-deterministic behavior. |
1514 |
|
|
* |
1515 |
|
|
* <p>The returned collection does <i>not</i> pass the <tt>hashCode</tt> |
1516 |
|
|
* and <tt>equals</tt> operations through to the backing collection, but |
1517 |
|
|
* relies on <tt>Object</tt>'s equals and hashCode methods. This is |
1518 |
|
|
* necessary to preserve the contracts of these operations in the case |
1519 |
|
|
* that the backing collection is a set or a list.<p> |
1520 |
|
|
* |
1521 |
|
|
* The returned collection will be serializable if the specified collection |
1522 |
jsr166 |
1.4 |
* is serializable. |
1523 |
dl |
1.1 |
* |
1524 |
|
|
* @param c the collection to be "wrapped" in a synchronized collection. |
1525 |
|
|
* @return a synchronized view of the specified collection. |
1526 |
|
|
*/ |
1527 |
|
|
public static <T> Collection<T> synchronizedCollection(Collection<T> c) { |
1528 |
|
|
return new SynchronizedCollection<T>(c); |
1529 |
|
|
} |
1530 |
|
|
|
1531 |
|
|
static <T> Collection<T> synchronizedCollection(Collection<T> c, Object mutex) { |
1532 |
|
|
return new SynchronizedCollection<T>(c, mutex); |
1533 |
|
|
} |
1534 |
|
|
|
1535 |
|
|
/** |
1536 |
|
|
* @serial include |
1537 |
|
|
*/ |
1538 |
|
|
static class SynchronizedCollection<E> implements Collection<E>, Serializable { |
1539 |
|
|
// use serialVersionUID from JDK 1.2.2 for interoperability |
1540 |
|
|
private static final long serialVersionUID = 3053995032091335093L; |
1541 |
|
|
|
1542 |
jsr166 |
1.23 |
final Collection<E> c; // Backing Collection |
1543 |
|
|
final Object mutex; // Object on which to synchronize |
1544 |
dl |
1.1 |
|
1545 |
|
|
SynchronizedCollection(Collection<E> c) { |
1546 |
|
|
if (c==null) |
1547 |
|
|
throw new NullPointerException(); |
1548 |
|
|
this.c = c; |
1549 |
|
|
mutex = this; |
1550 |
|
|
} |
1551 |
|
|
SynchronizedCollection(Collection<E> c, Object mutex) { |
1552 |
|
|
this.c = c; |
1553 |
|
|
this.mutex = mutex; |
1554 |
|
|
} |
1555 |
|
|
|
1556 |
|
|
public int size() { |
1557 |
|
|
synchronized(mutex) {return c.size();} |
1558 |
|
|
} |
1559 |
|
|
public boolean isEmpty() { |
1560 |
|
|
synchronized(mutex) {return c.isEmpty();} |
1561 |
|
|
} |
1562 |
|
|
public boolean contains(Object o) { |
1563 |
|
|
synchronized(mutex) {return c.contains(o);} |
1564 |
|
|
} |
1565 |
|
|
public Object[] toArray() { |
1566 |
|
|
synchronized(mutex) {return c.toArray();} |
1567 |
|
|
} |
1568 |
|
|
public <T> T[] toArray(T[] a) { |
1569 |
|
|
synchronized(mutex) {return c.toArray(a);} |
1570 |
|
|
} |
1571 |
|
|
|
1572 |
|
|
public Iterator<E> iterator() { |
1573 |
|
|
return c.iterator(); // Must be manually synched by user! |
1574 |
|
|
} |
1575 |
|
|
|
1576 |
jsr166 |
1.5 |
public boolean add(E e) { |
1577 |
|
|
synchronized(mutex) {return c.add(e);} |
1578 |
dl |
1.1 |
} |
1579 |
|
|
public boolean remove(Object o) { |
1580 |
|
|
synchronized(mutex) {return c.remove(o);} |
1581 |
|
|
} |
1582 |
|
|
|
1583 |
|
|
public boolean containsAll(Collection<?> coll) { |
1584 |
|
|
synchronized(mutex) {return c.containsAll(coll);} |
1585 |
|
|
} |
1586 |
|
|
public boolean addAll(Collection<? extends E> coll) { |
1587 |
|
|
synchronized(mutex) {return c.addAll(coll);} |
1588 |
|
|
} |
1589 |
|
|
public boolean removeAll(Collection<?> coll) { |
1590 |
|
|
synchronized(mutex) {return c.removeAll(coll);} |
1591 |
|
|
} |
1592 |
|
|
public boolean retainAll(Collection<?> coll) { |
1593 |
|
|
synchronized(mutex) {return c.retainAll(coll);} |
1594 |
|
|
} |
1595 |
|
|
public void clear() { |
1596 |
|
|
synchronized(mutex) {c.clear();} |
1597 |
|
|
} |
1598 |
|
|
public String toString() { |
1599 |
|
|
synchronized(mutex) {return c.toString();} |
1600 |
|
|
} |
1601 |
|
|
private void writeObject(ObjectOutputStream s) throws IOException { |
1602 |
|
|
synchronized(mutex) {s.defaultWriteObject();} |
1603 |
|
|
} |
1604 |
|
|
} |
1605 |
|
|
|
1606 |
|
|
/** |
1607 |
|
|
* Returns a synchronized (thread-safe) set backed by the specified |
1608 |
|
|
* set. In order to guarantee serial access, it is critical that |
1609 |
|
|
* <strong>all</strong> access to the backing set is accomplished |
1610 |
|
|
* through the returned set.<p> |
1611 |
|
|
* |
1612 |
|
|
* It is imperative that the user manually synchronize on the returned |
1613 |
|
|
* set when iterating over it: |
1614 |
|
|
* <pre> |
1615 |
|
|
* Set s = Collections.synchronizedSet(new HashSet()); |
1616 |
|
|
* ... |
1617 |
|
|
* synchronized(s) { |
1618 |
|
|
* Iterator i = s.iterator(); // Must be in the synchronized block |
1619 |
|
|
* while (i.hasNext()) |
1620 |
|
|
* foo(i.next()); |
1621 |
|
|
* } |
1622 |
|
|
* </pre> |
1623 |
|
|
* Failure to follow this advice may result in non-deterministic behavior. |
1624 |
|
|
* |
1625 |
|
|
* <p>The returned set will be serializable if the specified set is |
1626 |
|
|
* serializable. |
1627 |
|
|
* |
1628 |
|
|
* @param s the set to be "wrapped" in a synchronized set. |
1629 |
|
|
* @return a synchronized view of the specified set. |
1630 |
|
|
*/ |
1631 |
|
|
public static <T> Set<T> synchronizedSet(Set<T> s) { |
1632 |
|
|
return new SynchronizedSet<T>(s); |
1633 |
|
|
} |
1634 |
|
|
|
1635 |
|
|
static <T> Set<T> synchronizedSet(Set<T> s, Object mutex) { |
1636 |
|
|
return new SynchronizedSet<T>(s, mutex); |
1637 |
|
|
} |
1638 |
|
|
|
1639 |
|
|
/** |
1640 |
|
|
* @serial include |
1641 |
|
|
*/ |
1642 |
|
|
static class SynchronizedSet<E> |
1643 |
|
|
extends SynchronizedCollection<E> |
1644 |
|
|
implements Set<E> { |
1645 |
|
|
private static final long serialVersionUID = 487447009682186044L; |
1646 |
|
|
|
1647 |
|
|
SynchronizedSet(Set<E> s) { |
1648 |
|
|
super(s); |
1649 |
|
|
} |
1650 |
|
|
SynchronizedSet(Set<E> s, Object mutex) { |
1651 |
|
|
super(s, mutex); |
1652 |
|
|
} |
1653 |
|
|
|
1654 |
|
|
public boolean equals(Object o) { |
1655 |
|
|
synchronized(mutex) {return c.equals(o);} |
1656 |
|
|
} |
1657 |
|
|
public int hashCode() { |
1658 |
|
|
synchronized(mutex) {return c.hashCode();} |
1659 |
|
|
} |
1660 |
|
|
} |
1661 |
|
|
|
1662 |
|
|
/** |
1663 |
|
|
* Returns a synchronized (thread-safe) sorted set backed by the specified |
1664 |
|
|
* sorted set. In order to guarantee serial access, it is critical that |
1665 |
|
|
* <strong>all</strong> access to the backing sorted set is accomplished |
1666 |
|
|
* through the returned sorted set (or its views).<p> |
1667 |
|
|
* |
1668 |
|
|
* It is imperative that the user manually synchronize on the returned |
1669 |
|
|
* sorted set when iterating over it or any of its <tt>subSet</tt>, |
1670 |
|
|
* <tt>headSet</tt>, or <tt>tailSet</tt> views. |
1671 |
|
|
* <pre> |
1672 |
jsr166 |
1.4 |
* SortedSet s = Collections.synchronizedSortedSet(new TreeSet()); |
1673 |
dl |
1.1 |
* ... |
1674 |
|
|
* synchronized(s) { |
1675 |
|
|
* Iterator i = s.iterator(); // Must be in the synchronized block |
1676 |
|
|
* while (i.hasNext()) |
1677 |
|
|
* foo(i.next()); |
1678 |
|
|
* } |
1679 |
|
|
* </pre> |
1680 |
|
|
* or: |
1681 |
|
|
* <pre> |
1682 |
jsr166 |
1.4 |
* SortedSet s = Collections.synchronizedSortedSet(new TreeSet()); |
1683 |
dl |
1.1 |
* SortedSet s2 = s.headSet(foo); |
1684 |
|
|
* ... |
1685 |
|
|
* synchronized(s) { // Note: s, not s2!!! |
1686 |
|
|
* Iterator i = s2.iterator(); // Must be in the synchronized block |
1687 |
|
|
* while (i.hasNext()) |
1688 |
|
|
* foo(i.next()); |
1689 |
|
|
* } |
1690 |
|
|
* </pre> |
1691 |
|
|
* Failure to follow this advice may result in non-deterministic behavior. |
1692 |
|
|
* |
1693 |
|
|
* <p>The returned sorted set will be serializable if the specified |
1694 |
|
|
* sorted set is serializable. |
1695 |
|
|
* |
1696 |
|
|
* @param s the sorted set to be "wrapped" in a synchronized sorted set. |
1697 |
|
|
* @return a synchronized view of the specified sorted set. |
1698 |
|
|
*/ |
1699 |
|
|
public static <T> SortedSet<T> synchronizedSortedSet(SortedSet<T> s) { |
1700 |
|
|
return new SynchronizedSortedSet<T>(s); |
1701 |
|
|
} |
1702 |
|
|
|
1703 |
|
|
/** |
1704 |
|
|
* @serial include |
1705 |
|
|
*/ |
1706 |
|
|
static class SynchronizedSortedSet<E> |
1707 |
|
|
extends SynchronizedSet<E> |
1708 |
|
|
implements SortedSet<E> |
1709 |
|
|
{ |
1710 |
|
|
private static final long serialVersionUID = 8695801310862127406L; |
1711 |
|
|
|
1712 |
|
|
final private SortedSet<E> ss; |
1713 |
|
|
|
1714 |
|
|
SynchronizedSortedSet(SortedSet<E> s) { |
1715 |
|
|
super(s); |
1716 |
|
|
ss = s; |
1717 |
|
|
} |
1718 |
|
|
SynchronizedSortedSet(SortedSet<E> s, Object mutex) { |
1719 |
|
|
super(s, mutex); |
1720 |
|
|
ss = s; |
1721 |
|
|
} |
1722 |
|
|
|
1723 |
|
|
public Comparator<? super E> comparator() { |
1724 |
|
|
synchronized(mutex) {return ss.comparator();} |
1725 |
|
|
} |
1726 |
|
|
|
1727 |
|
|
public SortedSet<E> subSet(E fromElement, E toElement) { |
1728 |
|
|
synchronized(mutex) { |
1729 |
|
|
return new SynchronizedSortedSet<E>( |
1730 |
|
|
ss.subSet(fromElement, toElement), mutex); |
1731 |
|
|
} |
1732 |
|
|
} |
1733 |
|
|
public SortedSet<E> headSet(E toElement) { |
1734 |
|
|
synchronized(mutex) { |
1735 |
|
|
return new SynchronizedSortedSet<E>(ss.headSet(toElement), mutex); |
1736 |
|
|
} |
1737 |
|
|
} |
1738 |
|
|
public SortedSet<E> tailSet(E fromElement) { |
1739 |
|
|
synchronized(mutex) { |
1740 |
|
|
return new SynchronizedSortedSet<E>(ss.tailSet(fromElement),mutex); |
1741 |
|
|
} |
1742 |
|
|
} |
1743 |
|
|
|
1744 |
|
|
public E first() { |
1745 |
|
|
synchronized(mutex) {return ss.first();} |
1746 |
|
|
} |
1747 |
|
|
public E last() { |
1748 |
|
|
synchronized(mutex) {return ss.last();} |
1749 |
|
|
} |
1750 |
|
|
} |
1751 |
|
|
|
1752 |
|
|
/** |
1753 |
|
|
* Returns a synchronized (thread-safe) list backed by the specified |
1754 |
|
|
* list. In order to guarantee serial access, it is critical that |
1755 |
|
|
* <strong>all</strong> access to the backing list is accomplished |
1756 |
|
|
* through the returned list.<p> |
1757 |
|
|
* |
1758 |
|
|
* It is imperative that the user manually synchronize on the returned |
1759 |
|
|
* list when iterating over it: |
1760 |
|
|
* <pre> |
1761 |
|
|
* List list = Collections.synchronizedList(new ArrayList()); |
1762 |
|
|
* ... |
1763 |
|
|
* synchronized(list) { |
1764 |
|
|
* Iterator i = list.iterator(); // Must be in synchronized block |
1765 |
|
|
* while (i.hasNext()) |
1766 |
|
|
* foo(i.next()); |
1767 |
|
|
* } |
1768 |
|
|
* </pre> |
1769 |
|
|
* Failure to follow this advice may result in non-deterministic behavior. |
1770 |
|
|
* |
1771 |
|
|
* <p>The returned list will be serializable if the specified list is |
1772 |
|
|
* serializable. |
1773 |
|
|
* |
1774 |
|
|
* @param list the list to be "wrapped" in a synchronized list. |
1775 |
|
|
* @return a synchronized view of the specified list. |
1776 |
|
|
*/ |
1777 |
|
|
public static <T> List<T> synchronizedList(List<T> list) { |
1778 |
|
|
return (list instanceof RandomAccess ? |
1779 |
|
|
new SynchronizedRandomAccessList<T>(list) : |
1780 |
|
|
new SynchronizedList<T>(list)); |
1781 |
|
|
} |
1782 |
|
|
|
1783 |
|
|
static <T> List<T> synchronizedList(List<T> list, Object mutex) { |
1784 |
|
|
return (list instanceof RandomAccess ? |
1785 |
|
|
new SynchronizedRandomAccessList<T>(list, mutex) : |
1786 |
|
|
new SynchronizedList<T>(list, mutex)); |
1787 |
|
|
} |
1788 |
|
|
|
1789 |
|
|
/** |
1790 |
|
|
* @serial include |
1791 |
|
|
*/ |
1792 |
|
|
static class SynchronizedList<E> |
1793 |
|
|
extends SynchronizedCollection<E> |
1794 |
|
|
implements List<E> { |
1795 |
|
|
static final long serialVersionUID = -7754090372962971524L; |
1796 |
|
|
|
1797 |
|
|
final List<E> list; |
1798 |
|
|
|
1799 |
|
|
SynchronizedList(List<E> list) { |
1800 |
|
|
super(list); |
1801 |
|
|
this.list = list; |
1802 |
|
|
} |
1803 |
|
|
SynchronizedList(List<E> list, Object mutex) { |
1804 |
|
|
super(list, mutex); |
1805 |
|
|
this.list = list; |
1806 |
|
|
} |
1807 |
|
|
|
1808 |
|
|
public boolean equals(Object o) { |
1809 |
|
|
synchronized(mutex) {return list.equals(o);} |
1810 |
|
|
} |
1811 |
|
|
public int hashCode() { |
1812 |
|
|
synchronized(mutex) {return list.hashCode();} |
1813 |
|
|
} |
1814 |
|
|
|
1815 |
|
|
public E get(int index) { |
1816 |
|
|
synchronized(mutex) {return list.get(index);} |
1817 |
|
|
} |
1818 |
|
|
public E set(int index, E element) { |
1819 |
|
|
synchronized(mutex) {return list.set(index, element);} |
1820 |
|
|
} |
1821 |
|
|
public void add(int index, E element) { |
1822 |
|
|
synchronized(mutex) {list.add(index, element);} |
1823 |
|
|
} |
1824 |
|
|
public E remove(int index) { |
1825 |
|
|
synchronized(mutex) {return list.remove(index);} |
1826 |
|
|
} |
1827 |
|
|
|
1828 |
|
|
public int indexOf(Object o) { |
1829 |
|
|
synchronized(mutex) {return list.indexOf(o);} |
1830 |
|
|
} |
1831 |
|
|
public int lastIndexOf(Object o) { |
1832 |
|
|
synchronized(mutex) {return list.lastIndexOf(o);} |
1833 |
|
|
} |
1834 |
|
|
|
1835 |
|
|
public boolean addAll(int index, Collection<? extends E> c) { |
1836 |
|
|
synchronized(mutex) {return list.addAll(index, c);} |
1837 |
|
|
} |
1838 |
|
|
|
1839 |
|
|
public ListIterator<E> listIterator() { |
1840 |
|
|
return list.listIterator(); // Must be manually synched by user |
1841 |
|
|
} |
1842 |
|
|
|
1843 |
|
|
public ListIterator<E> listIterator(int index) { |
1844 |
|
|
return list.listIterator(index); // Must be manually synched by user |
1845 |
|
|
} |
1846 |
|
|
|
1847 |
|
|
public List<E> subList(int fromIndex, int toIndex) { |
1848 |
|
|
synchronized(mutex) { |
1849 |
|
|
return new SynchronizedList<E>(list.subList(fromIndex, toIndex), |
1850 |
|
|
mutex); |
1851 |
|
|
} |
1852 |
|
|
} |
1853 |
|
|
|
1854 |
|
|
/** |
1855 |
|
|
* SynchronizedRandomAccessList instances are serialized as |
1856 |
|
|
* SynchronizedList instances to allow them to be deserialized |
1857 |
|
|
* in pre-1.4 JREs (which do not have SynchronizedRandomAccessList). |
1858 |
|
|
* This method inverts the transformation. As a beneficial |
1859 |
|
|
* side-effect, it also grafts the RandomAccess marker onto |
1860 |
|
|
* SynchronizedList instances that were serialized in pre-1.4 JREs. |
1861 |
|
|
* |
1862 |
|
|
* Note: Unfortunately, SynchronizedRandomAccessList instances |
1863 |
|
|
* serialized in 1.4.1 and deserialized in 1.4 will become |
1864 |
|
|
* SynchronizedList instances, as this method was missing in 1.4. |
1865 |
|
|
*/ |
1866 |
|
|
private Object readResolve() { |
1867 |
|
|
return (list instanceof RandomAccess |
1868 |
|
|
? new SynchronizedRandomAccessList<E>(list) |
1869 |
|
|
: this); |
1870 |
|
|
} |
1871 |
|
|
} |
1872 |
|
|
|
1873 |
|
|
/** |
1874 |
|
|
* @serial include |
1875 |
|
|
*/ |
1876 |
|
|
static class SynchronizedRandomAccessList<E> |
1877 |
|
|
extends SynchronizedList<E> |
1878 |
|
|
implements RandomAccess { |
1879 |
|
|
|
1880 |
|
|
SynchronizedRandomAccessList(List<E> list) { |
1881 |
|
|
super(list); |
1882 |
|
|
} |
1883 |
|
|
|
1884 |
|
|
SynchronizedRandomAccessList(List<E> list, Object mutex) { |
1885 |
|
|
super(list, mutex); |
1886 |
|
|
} |
1887 |
|
|
|
1888 |
|
|
public List<E> subList(int fromIndex, int toIndex) { |
1889 |
|
|
synchronized(mutex) { |
1890 |
|
|
return new SynchronizedRandomAccessList<E>( |
1891 |
|
|
list.subList(fromIndex, toIndex), mutex); |
1892 |
|
|
} |
1893 |
|
|
} |
1894 |
|
|
|
1895 |
|
|
static final long serialVersionUID = 1530674583602358482L; |
1896 |
|
|
|
1897 |
|
|
/** |
1898 |
|
|
* Allows instances to be deserialized in pre-1.4 JREs (which do |
1899 |
|
|
* not have SynchronizedRandomAccessList). SynchronizedList has |
1900 |
|
|
* a readResolve method that inverts this transformation upon |
1901 |
|
|
* deserialization. |
1902 |
|
|
*/ |
1903 |
|
|
private Object writeReplace() { |
1904 |
|
|
return new SynchronizedList<E>(list); |
1905 |
|
|
} |
1906 |
|
|
} |
1907 |
|
|
|
1908 |
|
|
/** |
1909 |
|
|
* Returns a synchronized (thread-safe) map backed by the specified |
1910 |
|
|
* map. In order to guarantee serial access, it is critical that |
1911 |
|
|
* <strong>all</strong> access to the backing map is accomplished |
1912 |
|
|
* through the returned map.<p> |
1913 |
|
|
* |
1914 |
|
|
* It is imperative that the user manually synchronize on the returned |
1915 |
|
|
* map when iterating over any of its collection views: |
1916 |
|
|
* <pre> |
1917 |
|
|
* Map m = Collections.synchronizedMap(new HashMap()); |
1918 |
|
|
* ... |
1919 |
|
|
* Set s = m.keySet(); // Needn't be in synchronized block |
1920 |
|
|
* ... |
1921 |
|
|
* synchronized(m) { // Synchronizing on m, not s! |
1922 |
|
|
* Iterator i = s.iterator(); // Must be in synchronized block |
1923 |
|
|
* while (i.hasNext()) |
1924 |
|
|
* foo(i.next()); |
1925 |
|
|
* } |
1926 |
|
|
* </pre> |
1927 |
|
|
* Failure to follow this advice may result in non-deterministic behavior. |
1928 |
|
|
* |
1929 |
|
|
* <p>The returned map will be serializable if the specified map is |
1930 |
|
|
* serializable. |
1931 |
|
|
* |
1932 |
|
|
* @param m the map to be "wrapped" in a synchronized map. |
1933 |
|
|
* @return a synchronized view of the specified map. |
1934 |
|
|
*/ |
1935 |
|
|
public static <K,V> Map<K,V> synchronizedMap(Map<K,V> m) { |
1936 |
|
|
return new SynchronizedMap<K,V>(m); |
1937 |
|
|
} |
1938 |
|
|
|
1939 |
|
|
/** |
1940 |
|
|
* @serial include |
1941 |
|
|
*/ |
1942 |
|
|
private static class SynchronizedMap<K,V> |
1943 |
|
|
implements Map<K,V>, Serializable { |
1944 |
|
|
// use serialVersionUID from JDK 1.2.2 for interoperability |
1945 |
|
|
private static final long serialVersionUID = 1978198479659022715L; |
1946 |
|
|
|
1947 |
|
|
private final Map<K,V> m; // Backing Map |
1948 |
|
|
final Object mutex; // Object on which to synchronize |
1949 |
|
|
|
1950 |
|
|
SynchronizedMap(Map<K,V> m) { |
1951 |
|
|
if (m==null) |
1952 |
|
|
throw new NullPointerException(); |
1953 |
|
|
this.m = m; |
1954 |
|
|
mutex = this; |
1955 |
|
|
} |
1956 |
|
|
|
1957 |
|
|
SynchronizedMap(Map<K,V> m, Object mutex) { |
1958 |
|
|
this.m = m; |
1959 |
|
|
this.mutex = mutex; |
1960 |
|
|
} |
1961 |
|
|
|
1962 |
|
|
public int size() { |
1963 |
|
|
synchronized(mutex) {return m.size();} |
1964 |
|
|
} |
1965 |
|
|
public boolean isEmpty(){ |
1966 |
|
|
synchronized(mutex) {return m.isEmpty();} |
1967 |
|
|
} |
1968 |
|
|
public boolean containsKey(Object key) { |
1969 |
|
|
synchronized(mutex) {return m.containsKey(key);} |
1970 |
|
|
} |
1971 |
|
|
public boolean containsValue(Object value){ |
1972 |
|
|
synchronized(mutex) {return m.containsValue(value);} |
1973 |
|
|
} |
1974 |
|
|
public V get(Object key) { |
1975 |
|
|
synchronized(mutex) {return m.get(key);} |
1976 |
|
|
} |
1977 |
|
|
|
1978 |
|
|
public V put(K key, V value) { |
1979 |
|
|
synchronized(mutex) {return m.put(key, value);} |
1980 |
|
|
} |
1981 |
|
|
public V remove(Object key) { |
1982 |
|
|
synchronized(mutex) {return m.remove(key);} |
1983 |
|
|
} |
1984 |
|
|
public void putAll(Map<? extends K, ? extends V> map) { |
1985 |
|
|
synchronized(mutex) {m.putAll(map);} |
1986 |
|
|
} |
1987 |
|
|
public void clear() { |
1988 |
|
|
synchronized(mutex) {m.clear();} |
1989 |
|
|
} |
1990 |
|
|
|
1991 |
|
|
private transient Set<K> keySet = null; |
1992 |
|
|
private transient Set<Map.Entry<K,V>> entrySet = null; |
1993 |
|
|
private transient Collection<V> values = null; |
1994 |
|
|
|
1995 |
|
|
public Set<K> keySet() { |
1996 |
|
|
synchronized(mutex) { |
1997 |
|
|
if (keySet==null) |
1998 |
|
|
keySet = new SynchronizedSet<K>(m.keySet(), mutex); |
1999 |
|
|
return keySet; |
2000 |
|
|
} |
2001 |
|
|
} |
2002 |
|
|
|
2003 |
|
|
public Set<Map.Entry<K,V>> entrySet() { |
2004 |
|
|
synchronized(mutex) { |
2005 |
|
|
if (entrySet==null) |
2006 |
jsr166 |
1.4 |
entrySet = new SynchronizedSet<Map.Entry<K,V>>(m.entrySet(), mutex); |
2007 |
dl |
1.1 |
return entrySet; |
2008 |
|
|
} |
2009 |
|
|
} |
2010 |
|
|
|
2011 |
|
|
public Collection<V> values() { |
2012 |
|
|
synchronized(mutex) { |
2013 |
|
|
if (values==null) |
2014 |
|
|
values = new SynchronizedCollection<V>(m.values(), mutex); |
2015 |
|
|
return values; |
2016 |
|
|
} |
2017 |
|
|
} |
2018 |
|
|
|
2019 |
|
|
public boolean equals(Object o) { |
2020 |
|
|
synchronized(mutex) {return m.equals(o);} |
2021 |
|
|
} |
2022 |
|
|
public int hashCode() { |
2023 |
|
|
synchronized(mutex) {return m.hashCode();} |
2024 |
|
|
} |
2025 |
|
|
public String toString() { |
2026 |
|
|
synchronized(mutex) {return m.toString();} |
2027 |
|
|
} |
2028 |
|
|
private void writeObject(ObjectOutputStream s) throws IOException { |
2029 |
|
|
synchronized(mutex) {s.defaultWriteObject();} |
2030 |
|
|
} |
2031 |
|
|
} |
2032 |
|
|
|
2033 |
|
|
/** |
2034 |
|
|
* Returns a synchronized (thread-safe) sorted map backed by the specified |
2035 |
|
|
* sorted map. In order to guarantee serial access, it is critical that |
2036 |
|
|
* <strong>all</strong> access to the backing sorted map is accomplished |
2037 |
|
|
* through the returned sorted map (or its views).<p> |
2038 |
|
|
* |
2039 |
|
|
* It is imperative that the user manually synchronize on the returned |
2040 |
|
|
* sorted map when iterating over any of its collection views, or the |
2041 |
|
|
* collections views of any of its <tt>subMap</tt>, <tt>headMap</tt> or |
2042 |
|
|
* <tt>tailMap</tt> views. |
2043 |
|
|
* <pre> |
2044 |
jsr166 |
1.4 |
* SortedMap m = Collections.synchronizedSortedMap(new TreeMap()); |
2045 |
dl |
1.1 |
* ... |
2046 |
|
|
* Set s = m.keySet(); // Needn't be in synchronized block |
2047 |
|
|
* ... |
2048 |
|
|
* synchronized(m) { // Synchronizing on m, not s! |
2049 |
|
|
* Iterator i = s.iterator(); // Must be in synchronized block |
2050 |
|
|
* while (i.hasNext()) |
2051 |
|
|
* foo(i.next()); |
2052 |
|
|
* } |
2053 |
|
|
* </pre> |
2054 |
|
|
* or: |
2055 |
|
|
* <pre> |
2056 |
jsr166 |
1.4 |
* SortedMap m = Collections.synchronizedSortedMap(new TreeMap()); |
2057 |
dl |
1.1 |
* SortedMap m2 = m.subMap(foo, bar); |
2058 |
|
|
* ... |
2059 |
|
|
* Set s2 = m2.keySet(); // Needn't be in synchronized block |
2060 |
|
|
* ... |
2061 |
|
|
* synchronized(m) { // Synchronizing on m, not m2 or s2! |
2062 |
|
|
* Iterator i = s.iterator(); // Must be in synchronized block |
2063 |
|
|
* while (i.hasNext()) |
2064 |
|
|
* foo(i.next()); |
2065 |
|
|
* } |
2066 |
|
|
* </pre> |
2067 |
|
|
* Failure to follow this advice may result in non-deterministic behavior. |
2068 |
|
|
* |
2069 |
|
|
* <p>The returned sorted map will be serializable if the specified |
2070 |
|
|
* sorted map is serializable. |
2071 |
|
|
* |
2072 |
|
|
* @param m the sorted map to be "wrapped" in a synchronized sorted map. |
2073 |
|
|
* @return a synchronized view of the specified sorted map. |
2074 |
|
|
*/ |
2075 |
|
|
public static <K,V> SortedMap<K,V> synchronizedSortedMap(SortedMap<K,V> m) { |
2076 |
|
|
return new SynchronizedSortedMap<K,V>(m); |
2077 |
|
|
} |
2078 |
|
|
|
2079 |
|
|
|
2080 |
|
|
/** |
2081 |
|
|
* @serial include |
2082 |
|
|
*/ |
2083 |
|
|
static class SynchronizedSortedMap<K,V> |
2084 |
|
|
extends SynchronizedMap<K,V> |
2085 |
|
|
implements SortedMap<K,V> |
2086 |
|
|
{ |
2087 |
|
|
private static final long serialVersionUID = -8798146769416483793L; |
2088 |
|
|
|
2089 |
|
|
private final SortedMap<K,V> sm; |
2090 |
|
|
|
2091 |
|
|
SynchronizedSortedMap(SortedMap<K,V> m) { |
2092 |
|
|
super(m); |
2093 |
|
|
sm = m; |
2094 |
|
|
} |
2095 |
|
|
SynchronizedSortedMap(SortedMap<K,V> m, Object mutex) { |
2096 |
|
|
super(m, mutex); |
2097 |
|
|
sm = m; |
2098 |
|
|
} |
2099 |
|
|
|
2100 |
|
|
public Comparator<? super K> comparator() { |
2101 |
|
|
synchronized(mutex) {return sm.comparator();} |
2102 |
|
|
} |
2103 |
|
|
|
2104 |
|
|
public SortedMap<K,V> subMap(K fromKey, K toKey) { |
2105 |
|
|
synchronized(mutex) { |
2106 |
|
|
return new SynchronizedSortedMap<K,V>( |
2107 |
|
|
sm.subMap(fromKey, toKey), mutex); |
2108 |
|
|
} |
2109 |
|
|
} |
2110 |
|
|
public SortedMap<K,V> headMap(K toKey) { |
2111 |
|
|
synchronized(mutex) { |
2112 |
|
|
return new SynchronizedSortedMap<K,V>(sm.headMap(toKey), mutex); |
2113 |
|
|
} |
2114 |
|
|
} |
2115 |
|
|
public SortedMap<K,V> tailMap(K fromKey) { |
2116 |
|
|
synchronized(mutex) { |
2117 |
|
|
return new SynchronizedSortedMap<K,V>(sm.tailMap(fromKey),mutex); |
2118 |
|
|
} |
2119 |
|
|
} |
2120 |
|
|
|
2121 |
|
|
public K firstKey() { |
2122 |
|
|
synchronized(mutex) {return sm.firstKey();} |
2123 |
|
|
} |
2124 |
|
|
public K lastKey() { |
2125 |
|
|
synchronized(mutex) {return sm.lastKey();} |
2126 |
|
|
} |
2127 |
|
|
} |
2128 |
|
|
|
2129 |
|
|
// Dynamically typesafe collection wrappers |
2130 |
|
|
|
2131 |
|
|
/** |
2132 |
|
|
* Returns a dynamically typesafe view of the specified collection. Any |
2133 |
|
|
* attempt to insert an element of the wrong type will result in an |
2134 |
|
|
* immediate <tt>ClassCastException</tt>. Assuming a collection contains |
2135 |
|
|
* no incorrectly typed elements prior to the time a dynamically typesafe |
2136 |
|
|
* view is generated, and that all subsequent access to the collection |
2137 |
|
|
* takes place through the view, it is <i>guaranteed</i> that the |
2138 |
|
|
* collection cannot contain an incorrectly typed element. |
2139 |
|
|
* |
2140 |
|
|
* <p>The generics mechanism in the language provides compile-time |
2141 |
|
|
* (static) type checking, but it is possible to defeat this mechanism |
2142 |
|
|
* with unchecked casts. Usually this is not a problem, as the compiler |
2143 |
|
|
* issues warnings on all such unchecked operations. There are, however, |
2144 |
|
|
* times when static type checking alone is not sufficient. For example, |
2145 |
|
|
* suppose a collection is passed to a third-party library and it is |
2146 |
|
|
* imperative that the library code not corrupt the collection by |
2147 |
|
|
* inserting an element of the wrong type. |
2148 |
|
|
* |
2149 |
|
|
* <p>Another use of dynamically typesafe views is debugging. Suppose a |
2150 |
|
|
* program fails with a <tt>ClassCastException</tt>, indicating that an |
2151 |
|
|
* incorrectly typed element was put into a parameterized collection. |
2152 |
|
|
* Unfortunately, the exception can occur at any time after the erroneous |
2153 |
|
|
* element is inserted, so it typically provides little or no information |
2154 |
|
|
* as to the real source of the problem. If the problem is reproducible, |
2155 |
|
|
* one can quickly determine its source by temporarily modifying the |
2156 |
|
|
* program to wrap the collection with a dynamically typesafe view. |
2157 |
|
|
* For example, this declaration: |
2158 |
|
|
* <pre> |
2159 |
|
|
* Collection<String> c = new HashSet<String>(); |
2160 |
|
|
* </pre> |
2161 |
|
|
* may be replaced temporarily by this one: |
2162 |
|
|
* <pre> |
2163 |
|
|
* Collection<String> c = Collections.checkedCollection( |
2164 |
|
|
* new HashSet<String>(), String.class); |
2165 |
|
|
* </pre> |
2166 |
|
|
* Running the program again will cause it to fail at the point where |
2167 |
|
|
* an incorrectly typed element is inserted into the collection, clearly |
2168 |
|
|
* identifying the source of the problem. Once the problem is fixed, the |
2169 |
|
|
* modified declaration may be reverted back to the original. |
2170 |
|
|
* |
2171 |
|
|
* <p>The returned collection does <i>not</i> pass the hashCode and equals |
2172 |
|
|
* operations through to the backing collection, but relies on |
2173 |
|
|
* <tt>Object</tt>'s <tt>equals</tt> and <tt>hashCode</tt> methods. This |
2174 |
|
|
* is necessary to preserve the contracts of these operations in the case |
2175 |
|
|
* that the backing collection is a set or a list. |
2176 |
|
|
* |
2177 |
|
|
* <p>The returned collection will be serializable if the specified |
2178 |
|
|
* collection is serializable. |
2179 |
|
|
* |
2180 |
|
|
* @param c the collection for which a dynamically typesafe view is to be |
2181 |
|
|
* returned |
2182 |
|
|
* @param type the type of element that <tt>c</tt> is permitted to hold |
2183 |
|
|
* @return a dynamically typesafe view of the specified collection |
2184 |
|
|
* @since 1.5 |
2185 |
|
|
*/ |
2186 |
|
|
public static <E> Collection<E> checkedCollection(Collection<E> c, |
2187 |
|
|
Class<E> type) { |
2188 |
|
|
return new CheckedCollection<E>(c, type); |
2189 |
|
|
} |
2190 |
jsr166 |
1.4 |
|
2191 |
dl |
1.1 |
/** |
2192 |
|
|
* @serial include |
2193 |
|
|
*/ |
2194 |
|
|
static class CheckedCollection<E> implements Collection<E>, Serializable { |
2195 |
|
|
private static final long serialVersionUID = 1578914078182001775L; |
2196 |
|
|
|
2197 |
|
|
final Collection<E> c; |
2198 |
|
|
final Class<E> type; |
2199 |
|
|
|
2200 |
|
|
void typeCheck(Object o) { |
2201 |
|
|
if (!type.isInstance(o)) |
2202 |
|
|
throw new ClassCastException("Attempt to insert " + |
2203 |
|
|
o.getClass() + " element into collection with element type " |
2204 |
|
|
+ type); |
2205 |
|
|
} |
2206 |
|
|
|
2207 |
|
|
CheckedCollection(Collection<E> c, Class<E> type) { |
2208 |
|
|
if (c==null || type == null) |
2209 |
|
|
throw new NullPointerException(); |
2210 |
|
|
this.c = c; |
2211 |
|
|
this.type = type; |
2212 |
|
|
} |
2213 |
|
|
|
2214 |
|
|
public int size() { return c.size(); } |
2215 |
|
|
public boolean isEmpty() { return c.isEmpty(); } |
2216 |
|
|
public boolean contains(Object o) { return c.contains(o); } |
2217 |
|
|
public Object[] toArray() { return c.toArray(); } |
2218 |
|
|
public <T> T[] toArray(T[] a) { return c.toArray(a); } |
2219 |
|
|
public String toString() { return c.toString(); } |
2220 |
|
|
public boolean remove(Object o) { return c.remove(o); } |
2221 |
|
|
public boolean containsAll(Collection<?> coll) { |
2222 |
|
|
return c.containsAll(coll); |
2223 |
|
|
} |
2224 |
|
|
public boolean removeAll(Collection<?> coll) { |
2225 |
|
|
return c.removeAll(coll); |
2226 |
|
|
} |
2227 |
|
|
public boolean retainAll(Collection<?> coll) { |
2228 |
|
|
return c.retainAll(coll); |
2229 |
|
|
} |
2230 |
|
|
public void clear() { |
2231 |
|
|
c.clear(); |
2232 |
|
|
} |
2233 |
|
|
|
2234 |
jsr166 |
1.20 |
public Iterator<E> iterator() { |
2235 |
|
|
return new Iterator<E>() { |
2236 |
|
|
private final Iterator<E> it = c.iterator(); |
2237 |
|
|
public boolean hasNext() { return it.hasNext(); } |
2238 |
|
|
public E next() { return it.next(); } |
2239 |
|
|
public void remove() { it.remove(); }}; |
2240 |
|
|
} |
2241 |
|
|
|
2242 |
|
|
public boolean add(E e){ |
2243 |
jsr166 |
1.5 |
typeCheck(e); |
2244 |
|
|
return c.add(e); |
2245 |
dl |
1.1 |
} |
2246 |
|
|
|
2247 |
|
|
public boolean addAll(Collection<? extends E> coll) { |
2248 |
|
|
/* |
2249 |
|
|
* Dump coll into an array of the required type. This serves |
2250 |
|
|
* three purposes: it insulates us from concurrent changes in |
2251 |
|
|
* the contents of coll, it type-checks all of the elements in |
2252 |
jsr166 |
1.6 |
* coll, and it provides all-or-nothing semantics (which we |
2253 |
dl |
1.1 |
* wouldn't get if we type-checked each element as we added it). |
2254 |
|
|
*/ |
2255 |
|
|
E[] a = null; |
2256 |
|
|
try { |
2257 |
|
|
a = coll.toArray(zeroLengthElementArray()); |
2258 |
jsr166 |
1.6 |
} catch (ArrayStoreException e) { |
2259 |
dl |
1.1 |
throw new ClassCastException(); |
2260 |
|
|
} |
2261 |
|
|
|
2262 |
|
|
boolean result = false; |
2263 |
|
|
for (E e : a) |
2264 |
|
|
result |= c.add(e); |
2265 |
|
|
return result; |
2266 |
|
|
} |
2267 |
|
|
|
2268 |
|
|
private E[] zeroLengthElementArray = null; // Lazily initialized |
2269 |
|
|
|
2270 |
|
|
/* |
2271 |
jsr166 |
1.4 |
* We don't need locking or volatile, because it's OK if we create |
2272 |
dl |
1.1 |
* several zeroLengthElementArrays, and they're immutable. |
2273 |
|
|
*/ |
2274 |
|
|
E[] zeroLengthElementArray() { |
2275 |
|
|
if (zeroLengthElementArray == null) |
2276 |
|
|
zeroLengthElementArray = (E[]) Array.newInstance(type, 0); |
2277 |
|
|
return zeroLengthElementArray; |
2278 |
|
|
} |
2279 |
|
|
} |
2280 |
|
|
|
2281 |
|
|
/** |
2282 |
|
|
* Returns a dynamically typesafe view of the specified set. |
2283 |
|
|
* Any attempt to insert an element of the wrong type will result in |
2284 |
|
|
* an immediate <tt>ClassCastException</tt>. Assuming a set contains |
2285 |
|
|
* no incorrectly typed elements prior to the time a dynamically typesafe |
2286 |
|
|
* view is generated, and that all subsequent access to the set |
2287 |
|
|
* takes place through the view, it is <i>guaranteed</i> that the |
2288 |
|
|
* set cannot contain an incorrectly typed element. |
2289 |
|
|
* |
2290 |
|
|
* <p>A discussion of the use of dynamically typesafe views may be |
2291 |
|
|
* found in the documentation for the {@link #checkedCollection checkedCollection} |
2292 |
|
|
* method. |
2293 |
|
|
* |
2294 |
|
|
* <p>The returned set will be serializable if the specified set is |
2295 |
|
|
* serializable. |
2296 |
|
|
* |
2297 |
|
|
* @param s the set for which a dynamically typesafe view is to be |
2298 |
|
|
* returned |
2299 |
|
|
* @param type the type of element that <tt>s</tt> is permitted to hold |
2300 |
|
|
* @return a dynamically typesafe view of the specified set |
2301 |
|
|
* @since 1.5 |
2302 |
|
|
*/ |
2303 |
|
|
public static <E> Set<E> checkedSet(Set<E> s, Class<E> type) { |
2304 |
|
|
return new CheckedSet<E>(s, type); |
2305 |
|
|
} |
2306 |
jsr166 |
1.4 |
|
2307 |
dl |
1.1 |
/** |
2308 |
|
|
* @serial include |
2309 |
|
|
*/ |
2310 |
|
|
static class CheckedSet<E> extends CheckedCollection<E> |
2311 |
|
|
implements Set<E>, Serializable |
2312 |
|
|
{ |
2313 |
|
|
private static final long serialVersionUID = 4694047833775013803L; |
2314 |
|
|
|
2315 |
|
|
CheckedSet(Set<E> s, Class<E> elementType) { super(s, elementType); } |
2316 |
|
|
|
2317 |
jsr166 |
1.23 |
public boolean equals(Object o) { return o == this || c.equals(o); } |
2318 |
dl |
1.1 |
public int hashCode() { return c.hashCode(); } |
2319 |
|
|
} |
2320 |
|
|
|
2321 |
|
|
/** |
2322 |
|
|
* Returns a dynamically typesafe view of the specified sorted set. Any |
2323 |
|
|
* attempt to insert an element of the wrong type will result in an |
2324 |
|
|
* immediate <tt>ClassCastException</tt>. Assuming a sorted set contains |
2325 |
|
|
* no incorrectly typed elements prior to the time a dynamically typesafe |
2326 |
|
|
* view is generated, and that all subsequent access to the sorted set |
2327 |
|
|
* takes place through the view, it is <i>guaranteed</i> that the sorted |
2328 |
|
|
* set cannot contain an incorrectly typed element. |
2329 |
|
|
* |
2330 |
|
|
* <p>A discussion of the use of dynamically typesafe views may be |
2331 |
|
|
* found in the documentation for the {@link #checkedCollection checkedCollection} |
2332 |
|
|
* method. |
2333 |
|
|
* |
2334 |
|
|
* <p>The returned sorted set will be serializable if the specified sorted |
2335 |
|
|
* set is serializable. |
2336 |
|
|
* |
2337 |
|
|
* @param s the sorted set for which a dynamically typesafe view is to be |
2338 |
|
|
* returned |
2339 |
|
|
* @param type the type of element that <tt>s</tt> is permitted to hold |
2340 |
|
|
* @return a dynamically typesafe view of the specified sorted set |
2341 |
|
|
* @since 1.5 |
2342 |
|
|
*/ |
2343 |
|
|
public static <E> SortedSet<E> checkedSortedSet(SortedSet<E> s, |
2344 |
|
|
Class<E> type) { |
2345 |
|
|
return new CheckedSortedSet<E>(s, type); |
2346 |
|
|
} |
2347 |
|
|
|
2348 |
|
|
/** |
2349 |
|
|
* @serial include |
2350 |
|
|
*/ |
2351 |
|
|
static class CheckedSortedSet<E> extends CheckedSet<E> |
2352 |
|
|
implements SortedSet<E>, Serializable |
2353 |
|
|
{ |
2354 |
|
|
private static final long serialVersionUID = 1599911165492914959L; |
2355 |
|
|
private final SortedSet<E> ss; |
2356 |
|
|
|
2357 |
|
|
CheckedSortedSet(SortedSet<E> s, Class<E> type) { |
2358 |
|
|
super(s, type); |
2359 |
|
|
ss = s; |
2360 |
|
|
} |
2361 |
|
|
|
2362 |
|
|
public Comparator<? super E> comparator() { return ss.comparator(); } |
2363 |
|
|
public E first() { return ss.first(); } |
2364 |
|
|
public E last() { return ss.last(); } |
2365 |
|
|
|
2366 |
|
|
public SortedSet<E> subSet(E fromElement, E toElement) { |
2367 |
|
|
return new CheckedSortedSet<E>(ss.subSet(fromElement,toElement), |
2368 |
|
|
type); |
2369 |
|
|
} |
2370 |
|
|
public SortedSet<E> headSet(E toElement) { |
2371 |
|
|
return new CheckedSortedSet<E>(ss.headSet(toElement), type); |
2372 |
|
|
} |
2373 |
|
|
public SortedSet<E> tailSet(E fromElement) { |
2374 |
|
|
return new CheckedSortedSet<E>(ss.tailSet(fromElement), type); |
2375 |
|
|
} |
2376 |
|
|
} |
2377 |
|
|
|
2378 |
|
|
/** |
2379 |
|
|
* Returns a dynamically typesafe view of the specified list. |
2380 |
|
|
* Any attempt to insert an element of the wrong type will result in |
2381 |
|
|
* an immediate <tt>ClassCastException</tt>. Assuming a list contains |
2382 |
|
|
* no incorrectly typed elements prior to the time a dynamically typesafe |
2383 |
|
|
* view is generated, and that all subsequent access to the list |
2384 |
|
|
* takes place through the view, it is <i>guaranteed</i> that the |
2385 |
|
|
* list cannot contain an incorrectly typed element. |
2386 |
|
|
* |
2387 |
|
|
* <p>A discussion of the use of dynamically typesafe views may be |
2388 |
|
|
* found in the documentation for the {@link #checkedCollection checkedCollection} |
2389 |
|
|
* method. |
2390 |
|
|
* |
2391 |
|
|
* <p>The returned list will be serializable if the specified list is |
2392 |
|
|
* serializable. |
2393 |
|
|
* |
2394 |
|
|
* @param list the list for which a dynamically typesafe view is to be |
2395 |
|
|
* returned |
2396 |
|
|
* @param type the type of element that <tt>list</tt> is permitted to hold |
2397 |
|
|
* @return a dynamically typesafe view of the specified list |
2398 |
|
|
* @since 1.5 |
2399 |
|
|
*/ |
2400 |
|
|
public static <E> List<E> checkedList(List<E> list, Class<E> type) { |
2401 |
|
|
return (list instanceof RandomAccess ? |
2402 |
|
|
new CheckedRandomAccessList<E>(list, type) : |
2403 |
|
|
new CheckedList<E>(list, type)); |
2404 |
|
|
} |
2405 |
|
|
|
2406 |
|
|
/** |
2407 |
|
|
* @serial include |
2408 |
|
|
*/ |
2409 |
|
|
static class CheckedList<E> extends CheckedCollection<E> |
2410 |
|
|
implements List<E> |
2411 |
|
|
{ |
2412 |
|
|
static final long serialVersionUID = 65247728283967356L; |
2413 |
|
|
final List<E> list; |
2414 |
|
|
|
2415 |
|
|
CheckedList(List<E> list, Class<E> type) { |
2416 |
|
|
super(list, type); |
2417 |
|
|
this.list = list; |
2418 |
|
|
} |
2419 |
|
|
|
2420 |
jsr166 |
1.23 |
public boolean equals(Object o) { return o == this || list.equals(o); } |
2421 |
dl |
1.1 |
public int hashCode() { return list.hashCode(); } |
2422 |
|
|
public E get(int index) { return list.get(index); } |
2423 |
|
|
public E remove(int index) { return list.remove(index); } |
2424 |
|
|
public int indexOf(Object o) { return list.indexOf(o); } |
2425 |
|
|
public int lastIndexOf(Object o) { return list.lastIndexOf(o); } |
2426 |
|
|
|
2427 |
|
|
public E set(int index, E element) { |
2428 |
|
|
typeCheck(element); |
2429 |
|
|
return list.set(index, element); |
2430 |
|
|
} |
2431 |
|
|
|
2432 |
|
|
public void add(int index, E element) { |
2433 |
|
|
typeCheck(element); |
2434 |
|
|
list.add(index, element); |
2435 |
|
|
} |
2436 |
|
|
|
2437 |
|
|
public boolean addAll(int index, Collection<? extends E> c) { |
2438 |
|
|
// See CheckCollection.addAll, above, for an explanation |
2439 |
|
|
E[] a = null; |
2440 |
|
|
try { |
2441 |
|
|
a = c.toArray(zeroLengthElementArray()); |
2442 |
jsr166 |
1.6 |
} catch (ArrayStoreException e) { |
2443 |
dl |
1.1 |
throw new ClassCastException(); |
2444 |
|
|
} |
2445 |
|
|
|
2446 |
|
|
return list.addAll(index, Arrays.asList(a)); |
2447 |
|
|
} |
2448 |
|
|
public ListIterator<E> listIterator() { return listIterator(0); } |
2449 |
|
|
|
2450 |
|
|
public ListIterator<E> listIterator(final int index) { |
2451 |
|
|
return new ListIterator<E>() { |
2452 |
|
|
ListIterator<E> i = list.listIterator(index); |
2453 |
|
|
|
2454 |
|
|
public boolean hasNext() { return i.hasNext(); } |
2455 |
|
|
public E next() { return i.next(); } |
2456 |
|
|
public boolean hasPrevious() { return i.hasPrevious(); } |
2457 |
|
|
public E previous() { return i.previous(); } |
2458 |
|
|
public int nextIndex() { return i.nextIndex(); } |
2459 |
|
|
public int previousIndex() { return i.previousIndex(); } |
2460 |
|
|
public void remove() { i.remove(); } |
2461 |
|
|
|
2462 |
jsr166 |
1.5 |
public void set(E e) { |
2463 |
|
|
typeCheck(e); |
2464 |
|
|
i.set(e); |
2465 |
dl |
1.1 |
} |
2466 |
|
|
|
2467 |
jsr166 |
1.5 |
public void add(E e) { |
2468 |
|
|
typeCheck(e); |
2469 |
|
|
i.add(e); |
2470 |
dl |
1.1 |
} |
2471 |
|
|
}; |
2472 |
|
|
} |
2473 |
|
|
|
2474 |
|
|
public List<E> subList(int fromIndex, int toIndex) { |
2475 |
|
|
return new CheckedList<E>(list.subList(fromIndex, toIndex), type); |
2476 |
|
|
} |
2477 |
|
|
} |
2478 |
|
|
|
2479 |
|
|
/** |
2480 |
|
|
* @serial include |
2481 |
|
|
*/ |
2482 |
|
|
static class CheckedRandomAccessList<E> extends CheckedList<E> |
2483 |
|
|
implements RandomAccess |
2484 |
|
|
{ |
2485 |
|
|
private static final long serialVersionUID = 1638200125423088369L; |
2486 |
|
|
|
2487 |
|
|
CheckedRandomAccessList(List<E> list, Class<E> type) { |
2488 |
|
|
super(list, type); |
2489 |
|
|
} |
2490 |
|
|
|
2491 |
|
|
public List<E> subList(int fromIndex, int toIndex) { |
2492 |
|
|
return new CheckedRandomAccessList<E>( |
2493 |
|
|
list.subList(fromIndex, toIndex), type); |
2494 |
|
|
} |
2495 |
|
|
} |
2496 |
|
|
|
2497 |
|
|
/** |
2498 |
|
|
* Returns a dynamically typesafe view of the specified map. Any attempt |
2499 |
|
|
* to insert a mapping whose key or value have the wrong type will result |
2500 |
|
|
* in an immediate <tt>ClassCastException</tt>. Similarly, any attempt to |
2501 |
|
|
* modify the value currently associated with a key will result in an |
2502 |
|
|
* immediate <tt>ClassCastException</tt>, whether the modification is |
2503 |
|
|
* attempted directly through the map itself, or through a {@link |
2504 |
|
|
* Map.Entry} instance obtained from the map's {@link Map#entrySet() |
2505 |
|
|
* entry set} view. |
2506 |
|
|
* |
2507 |
|
|
* <p>Assuming a map contains no incorrectly typed keys or values |
2508 |
|
|
* prior to the time a dynamically typesafe view is generated, and |
2509 |
|
|
* that all subsequent access to the map takes place through the view |
2510 |
|
|
* (or one of its collection views), it is <i>guaranteed</i> that the |
2511 |
|
|
* map cannot contain an incorrectly typed key or value. |
2512 |
|
|
* |
2513 |
|
|
* <p>A discussion of the use of dynamically typesafe views may be |
2514 |
|
|
* found in the documentation for the {@link #checkedCollection checkedCollection} |
2515 |
|
|
* method. |
2516 |
|
|
* |
2517 |
|
|
* <p>The returned map will be serializable if the specified map is |
2518 |
|
|
* serializable. |
2519 |
|
|
* |
2520 |
|
|
* @param m the map for which a dynamically typesafe view is to be |
2521 |
|
|
* returned |
2522 |
|
|
* @param keyType the type of key that <tt>m</tt> is permitted to hold |
2523 |
|
|
* @param valueType the type of value that <tt>m</tt> is permitted to hold |
2524 |
|
|
* @return a dynamically typesafe view of the specified map |
2525 |
|
|
* @since 1.5 |
2526 |
|
|
*/ |
2527 |
|
|
public static <K, V> Map<K, V> checkedMap(Map<K, V> m, Class<K> keyType, |
2528 |
|
|
Class<V> valueType) { |
2529 |
|
|
return new CheckedMap<K,V>(m, keyType, valueType); |
2530 |
|
|
} |
2531 |
|
|
|
2532 |
|
|
|
2533 |
|
|
/** |
2534 |
|
|
* @serial include |
2535 |
|
|
*/ |
2536 |
|
|
private static class CheckedMap<K,V> implements Map<K,V>, |
2537 |
|
|
Serializable |
2538 |
|
|
{ |
2539 |
|
|
private static final long serialVersionUID = 5742860141034234728L; |
2540 |
|
|
|
2541 |
|
|
private final Map<K, V> m; |
2542 |
|
|
final Class<K> keyType; |
2543 |
|
|
final Class<V> valueType; |
2544 |
|
|
|
2545 |
|
|
private void typeCheck(Object key, Object value) { |
2546 |
|
|
if (!keyType.isInstance(key)) |
2547 |
|
|
throw new ClassCastException("Attempt to insert " + |
2548 |
|
|
key.getClass() + " key into collection with key type " |
2549 |
|
|
+ keyType); |
2550 |
|
|
|
2551 |
|
|
if (!valueType.isInstance(value)) |
2552 |
|
|
throw new ClassCastException("Attempt to insert " + |
2553 |
|
|
value.getClass() +" value into collection with value type " |
2554 |
|
|
+ valueType); |
2555 |
|
|
} |
2556 |
|
|
|
2557 |
|
|
CheckedMap(Map<K, V> m, Class<K> keyType, Class<V> valueType) { |
2558 |
|
|
if (m == null || keyType == null || valueType == null) |
2559 |
|
|
throw new NullPointerException(); |
2560 |
|
|
this.m = m; |
2561 |
|
|
this.keyType = keyType; |
2562 |
|
|
this.valueType = valueType; |
2563 |
|
|
} |
2564 |
|
|
|
2565 |
|
|
public int size() { return m.size(); } |
2566 |
|
|
public boolean isEmpty() { return m.isEmpty(); } |
2567 |
|
|
public boolean containsKey(Object key) { return m.containsKey(key); } |
2568 |
|
|
public boolean containsValue(Object v) { return m.containsValue(v); } |
2569 |
|
|
public V get(Object key) { return m.get(key); } |
2570 |
|
|
public V remove(Object key) { return m.remove(key); } |
2571 |
|
|
public void clear() { m.clear(); } |
2572 |
|
|
public Set<K> keySet() { return m.keySet(); } |
2573 |
|
|
public Collection<V> values() { return m.values(); } |
2574 |
jsr166 |
1.23 |
public boolean equals(Object o) { return o == this || m.equals(o); } |
2575 |
dl |
1.1 |
public int hashCode() { return m.hashCode(); } |
2576 |
|
|
public String toString() { return m.toString(); } |
2577 |
|
|
|
2578 |
|
|
public V put(K key, V value) { |
2579 |
|
|
typeCheck(key, value); |
2580 |
|
|
return m.put(key, value); |
2581 |
|
|
} |
2582 |
|
|
|
2583 |
|
|
public void putAll(Map<? extends K, ? extends V> t) { |
2584 |
|
|
// See CheckCollection.addAll, above, for an explanation |
2585 |
|
|
K[] keys = null; |
2586 |
|
|
try { |
2587 |
|
|
keys = t.keySet().toArray(zeroLengthKeyArray()); |
2588 |
jsr166 |
1.6 |
} catch (ArrayStoreException e) { |
2589 |
dl |
1.1 |
throw new ClassCastException(); |
2590 |
|
|
} |
2591 |
|
|
V[] values = null; |
2592 |
|
|
try { |
2593 |
|
|
values = t.values().toArray(zeroLengthValueArray()); |
2594 |
jsr166 |
1.6 |
} catch (ArrayStoreException e) { |
2595 |
dl |
1.1 |
throw new ClassCastException(); |
2596 |
|
|
} |
2597 |
|
|
|
2598 |
|
|
if (keys.length != values.length) |
2599 |
|
|
throw new ConcurrentModificationException(); |
2600 |
|
|
|
2601 |
|
|
for (int i = 0; i < keys.length; i++) |
2602 |
|
|
m.put(keys[i], values[i]); |
2603 |
|
|
} |
2604 |
|
|
|
2605 |
|
|
// Lazily initialized |
2606 |
|
|
private K[] zeroLengthKeyArray = null; |
2607 |
|
|
private V[] zeroLengthValueArray = null; |
2608 |
|
|
|
2609 |
|
|
/* |
2610 |
jsr166 |
1.4 |
* We don't need locking or volatile, because it's OK if we create |
2611 |
dl |
1.1 |
* several zeroLengthValueArrays, and they're immutable. |
2612 |
|
|
*/ |
2613 |
|
|
private K[] zeroLengthKeyArray() { |
2614 |
|
|
if (zeroLengthKeyArray == null) |
2615 |
|
|
zeroLengthKeyArray = (K[]) Array.newInstance(keyType, 0); |
2616 |
|
|
return zeroLengthKeyArray; |
2617 |
|
|
} |
2618 |
|
|
private V[] zeroLengthValueArray() { |
2619 |
|
|
if (zeroLengthValueArray == null) |
2620 |
|
|
zeroLengthValueArray = (V[]) Array.newInstance(valueType, 0); |
2621 |
|
|
return zeroLengthValueArray; |
2622 |
|
|
} |
2623 |
|
|
|
2624 |
|
|
private transient Set<Map.Entry<K,V>> entrySet = null; |
2625 |
|
|
|
2626 |
|
|
public Set<Map.Entry<K,V>> entrySet() { |
2627 |
|
|
if (entrySet==null) |
2628 |
|
|
entrySet = new CheckedEntrySet<K,V>(m.entrySet(), valueType); |
2629 |
|
|
return entrySet; |
2630 |
|
|
} |
2631 |
|
|
|
2632 |
|
|
/** |
2633 |
|
|
* We need this class in addition to CheckedSet as Map.Entry permits |
2634 |
|
|
* modification of the backing Map via the setValue operation. This |
2635 |
|
|
* class is subtle: there are many possible attacks that must be |
2636 |
|
|
* thwarted. |
2637 |
|
|
* |
2638 |
|
|
* @serial exclude |
2639 |
|
|
*/ |
2640 |
|
|
static class CheckedEntrySet<K,V> implements Set<Map.Entry<K,V>> { |
2641 |
|
|
Set<Map.Entry<K,V>> s; |
2642 |
|
|
Class<V> valueType; |
2643 |
|
|
|
2644 |
|
|
CheckedEntrySet(Set<Map.Entry<K, V>> s, Class<V> valueType) { |
2645 |
|
|
this.s = s; |
2646 |
|
|
this.valueType = valueType; |
2647 |
|
|
} |
2648 |
|
|
|
2649 |
|
|
public int size() { return s.size(); } |
2650 |
|
|
public boolean isEmpty() { return s.isEmpty(); } |
2651 |
|
|
public String toString() { return s.toString(); } |
2652 |
|
|
public int hashCode() { return s.hashCode(); } |
2653 |
|
|
public boolean remove(Object o) { return s.remove(o); } |
2654 |
|
|
public boolean removeAll(Collection<?> coll) { |
2655 |
|
|
return s.removeAll(coll); |
2656 |
|
|
} |
2657 |
|
|
public boolean retainAll(Collection<?> coll) { |
2658 |
|
|
return s.retainAll(coll); |
2659 |
|
|
} |
2660 |
|
|
public void clear() { |
2661 |
|
|
s.clear(); |
2662 |
|
|
} |
2663 |
|
|
|
2664 |
jsr166 |
1.5 |
public boolean add(Map.Entry<K, V> e){ |
2665 |
dl |
1.1 |
throw new UnsupportedOperationException(); |
2666 |
|
|
} |
2667 |
|
|
public boolean addAll(Collection<? extends Map.Entry<K, V>> coll) { |
2668 |
|
|
throw new UnsupportedOperationException(); |
2669 |
|
|
} |
2670 |
|
|
|
2671 |
|
|
|
2672 |
|
|
public Iterator<Map.Entry<K,V>> iterator() { |
2673 |
|
|
return new Iterator<Map.Entry<K,V>>() { |
2674 |
|
|
Iterator<Map.Entry<K, V>> i = s.iterator(); |
2675 |
|
|
|
2676 |
|
|
public boolean hasNext() { return i.hasNext(); } |
2677 |
|
|
public void remove() { i.remove(); } |
2678 |
|
|
|
2679 |
|
|
public Map.Entry<K,V> next() { |
2680 |
|
|
return new CheckedEntry<K,V>(i.next(), valueType); |
2681 |
|
|
} |
2682 |
|
|
}; |
2683 |
|
|
} |
2684 |
|
|
|
2685 |
|
|
public Object[] toArray() { |
2686 |
|
|
Object[] source = s.toArray(); |
2687 |
|
|
|
2688 |
|
|
/* |
2689 |
|
|
* Ensure that we don't get an ArrayStoreException even if |
2690 |
|
|
* s.toArray returns an array of something other than Object |
2691 |
|
|
*/ |
2692 |
|
|
Object[] dest = (CheckedEntry.class.isInstance( |
2693 |
|
|
source.getClass().getComponentType()) ? source : |
2694 |
|
|
new Object[source.length]); |
2695 |
|
|
|
2696 |
|
|
for (int i = 0; i < source.length; i++) |
2697 |
|
|
dest[i] = new CheckedEntry<K,V>((Map.Entry<K,V>)source[i], |
2698 |
|
|
valueType); |
2699 |
|
|
return dest; |
2700 |
|
|
} |
2701 |
|
|
|
2702 |
|
|
public <T> T[] toArray(T[] a) { |
2703 |
|
|
// We don't pass a to s.toArray, to avoid window of |
2704 |
|
|
// vulnerability wherein an unscrupulous multithreaded client |
2705 |
|
|
// could get his hands on raw (unwrapped) Entries from s. |
2706 |
jsr166 |
1.10 |
Object[] arr = s.toArray(a.length==0 ? a : Arrays.copyOf(a, 0)); |
2707 |
dl |
1.1 |
|
2708 |
|
|
for (int i=0; i<arr.length; i++) |
2709 |
|
|
arr[i] = new CheckedEntry<K,V>((Map.Entry<K,V>)arr[i], |
2710 |
|
|
valueType); |
2711 |
|
|
if (arr.length > a.length) |
2712 |
|
|
return (T[])arr; |
2713 |
|
|
|
2714 |
|
|
System.arraycopy(arr, 0, a, 0, arr.length); |
2715 |
|
|
if (a.length > arr.length) |
2716 |
|
|
a[arr.length] = null; |
2717 |
|
|
return a; |
2718 |
|
|
} |
2719 |
|
|
|
2720 |
|
|
/** |
2721 |
|
|
* This method is overridden to protect the backing set against |
2722 |
|
|
* an object with a nefarious equals function that senses |
2723 |
|
|
* that the equality-candidate is Map.Entry and calls its |
2724 |
|
|
* setValue method. |
2725 |
|
|
*/ |
2726 |
|
|
public boolean contains(Object o) { |
2727 |
|
|
if (!(o instanceof Map.Entry)) |
2728 |
|
|
return false; |
2729 |
|
|
return s.contains( |
2730 |
|
|
new CheckedEntry<K,V>((Map.Entry<K,V>) o, valueType)); |
2731 |
|
|
} |
2732 |
|
|
|
2733 |
|
|
/** |
2734 |
|
|
* The next two methods are overridden to protect against |
2735 |
|
|
* an unscrupulous collection whose contains(Object o) method |
2736 |
|
|
* senses when o is a Map.Entry, and calls o.setValue. |
2737 |
|
|
*/ |
2738 |
|
|
public boolean containsAll(Collection<?> coll) { |
2739 |
|
|
Iterator<?> e = coll.iterator(); |
2740 |
|
|
while (e.hasNext()) |
2741 |
|
|
if (!contains(e.next())) // Invokes safe contains() above |
2742 |
|
|
return false; |
2743 |
|
|
return true; |
2744 |
|
|
} |
2745 |
|
|
|
2746 |
|
|
public boolean equals(Object o) { |
2747 |
|
|
if (o == this) |
2748 |
|
|
return true; |
2749 |
|
|
if (!(o instanceof Set)) |
2750 |
|
|
return false; |
2751 |
|
|
Set<?> that = (Set<?>) o; |
2752 |
|
|
if (that.size() != s.size()) |
2753 |
|
|
return false; |
2754 |
|
|
return containsAll(that); // Invokes safe containsAll() above |
2755 |
|
|
} |
2756 |
|
|
|
2757 |
|
|
/** |
2758 |
|
|
* This "wrapper class" serves two purposes: it prevents |
2759 |
|
|
* the client from modifying the backing Map, by short-circuiting |
2760 |
|
|
* the setValue method, and it protects the backing Map against |
2761 |
|
|
* an ill-behaved Map.Entry that attempts to modify another |
2762 |
|
|
* Map Entry when asked to perform an equality check. |
2763 |
|
|
*/ |
2764 |
|
|
private static class CheckedEntry<K,V> implements Map.Entry<K,V> { |
2765 |
|
|
private Map.Entry<K, V> e; |
2766 |
|
|
private Class<V> valueType; |
2767 |
|
|
|
2768 |
|
|
CheckedEntry(Map.Entry<K, V> e, Class<V> valueType) { |
2769 |
|
|
this.e = e; |
2770 |
|
|
this.valueType = valueType; |
2771 |
|
|
} |
2772 |
|
|
|
2773 |
|
|
public K getKey() { return e.getKey(); } |
2774 |
|
|
public V getValue() { return e.getValue(); } |
2775 |
|
|
public int hashCode() { return e.hashCode(); } |
2776 |
|
|
public String toString() { return e.toString(); } |
2777 |
|
|
|
2778 |
|
|
|
2779 |
|
|
public V setValue(V value) { |
2780 |
|
|
if (!valueType.isInstance(value)) |
2781 |
|
|
throw new ClassCastException("Attempt to insert " + |
2782 |
|
|
value.getClass() + |
2783 |
|
|
" value into collection with value type " + valueType); |
2784 |
|
|
return e.setValue(value); |
2785 |
|
|
} |
2786 |
|
|
|
2787 |
|
|
public boolean equals(Object o) { |
2788 |
|
|
if (!(o instanceof Map.Entry)) |
2789 |
|
|
return false; |
2790 |
|
|
Map.Entry t = (Map.Entry)o; |
2791 |
|
|
return eq(e.getKey(), t.getKey()) && |
2792 |
|
|
eq(e.getValue(), t.getValue()); |
2793 |
|
|
} |
2794 |
|
|
} |
2795 |
|
|
} |
2796 |
|
|
} |
2797 |
|
|
|
2798 |
|
|
/** |
2799 |
|
|
* Returns a dynamically typesafe view of the specified sorted map. Any |
2800 |
|
|
* attempt to insert a mapping whose key or value have the wrong type will |
2801 |
|
|
* result in an immediate <tt>ClassCastException</tt>. Similarly, any |
2802 |
|
|
* attempt to modify the value currently associated with a key will result |
2803 |
|
|
* in an immediate <tt>ClassCastException</tt>, whether the modification |
2804 |
|
|
* is attempted directly through the map itself, or through a {@link |
2805 |
|
|
* Map.Entry} instance obtained from the map's {@link Map#entrySet() entry |
2806 |
|
|
* set} view. |
2807 |
|
|
* |
2808 |
|
|
* <p>Assuming a map contains no incorrectly typed keys or values |
2809 |
|
|
* prior to the time a dynamically typesafe view is generated, and |
2810 |
|
|
* that all subsequent access to the map takes place through the view |
2811 |
|
|
* (or one of its collection views), it is <i>guaranteed</i> that the |
2812 |
|
|
* map cannot contain an incorrectly typed key or value. |
2813 |
|
|
* |
2814 |
|
|
* <p>A discussion of the use of dynamically typesafe views may be |
2815 |
|
|
* found in the documentation for the {@link #checkedCollection checkedCollection} |
2816 |
|
|
* method. |
2817 |
|
|
* |
2818 |
|
|
* <p>The returned map will be serializable if the specified map is |
2819 |
|
|
* serializable. |
2820 |
|
|
* |
2821 |
|
|
* @param m the map for which a dynamically typesafe view is to be |
2822 |
|
|
* returned |
2823 |
|
|
* @param keyType the type of key that <tt>m</tt> is permitted to hold |
2824 |
|
|
* @param valueType the type of value that <tt>m</tt> is permitted to hold |
2825 |
|
|
* @return a dynamically typesafe view of the specified map |
2826 |
|
|
* @since 1.5 |
2827 |
|
|
*/ |
2828 |
|
|
public static <K,V> SortedMap<K,V> checkedSortedMap(SortedMap<K, V> m, |
2829 |
|
|
Class<K> keyType, |
2830 |
|
|
Class<V> valueType) { |
2831 |
|
|
return new CheckedSortedMap<K,V>(m, keyType, valueType); |
2832 |
|
|
} |
2833 |
|
|
|
2834 |
|
|
/** |
2835 |
|
|
* @serial include |
2836 |
|
|
*/ |
2837 |
|
|
static class CheckedSortedMap<K,V> extends CheckedMap<K,V> |
2838 |
|
|
implements SortedMap<K,V>, Serializable |
2839 |
|
|
{ |
2840 |
|
|
private static final long serialVersionUID = 1599671320688067438L; |
2841 |
|
|
|
2842 |
|
|
private final SortedMap<K, V> sm; |
2843 |
|
|
|
2844 |
|
|
CheckedSortedMap(SortedMap<K, V> m, |
2845 |
|
|
Class<K> keyType, Class<V> valueType) { |
2846 |
|
|
super(m, keyType, valueType); |
2847 |
|
|
sm = m; |
2848 |
|
|
} |
2849 |
|
|
|
2850 |
|
|
public Comparator<? super K> comparator() { return sm.comparator(); } |
2851 |
|
|
public K firstKey() { return sm.firstKey(); } |
2852 |
|
|
public K lastKey() { return sm.lastKey(); } |
2853 |
|
|
|
2854 |
|
|
public SortedMap<K,V> subMap(K fromKey, K toKey) { |
2855 |
|
|
return new CheckedSortedMap<K,V>(sm.subMap(fromKey, toKey), |
2856 |
|
|
keyType, valueType); |
2857 |
|
|
} |
2858 |
|
|
|
2859 |
|
|
public SortedMap<K,V> headMap(K toKey) { |
2860 |
|
|
return new CheckedSortedMap<K,V>(sm.headMap(toKey), |
2861 |
|
|
keyType, valueType); |
2862 |
|
|
} |
2863 |
|
|
|
2864 |
|
|
public SortedMap<K,V> tailMap(K fromKey) { |
2865 |
|
|
return new CheckedSortedMap<K,V>(sm.tailMap(fromKey), |
2866 |
|
|
keyType, valueType); |
2867 |
|
|
} |
2868 |
|
|
} |
2869 |
|
|
|
2870 |
|
|
// Miscellaneous |
2871 |
|
|
|
2872 |
|
|
/** |
2873 |
|
|
* The empty set (immutable). This set is serializable. |
2874 |
|
|
* |
2875 |
|
|
* @see #emptySet() |
2876 |
|
|
*/ |
2877 |
|
|
public static final Set EMPTY_SET = new EmptySet(); |
2878 |
|
|
|
2879 |
|
|
/** |
2880 |
|
|
* Returns the empty set (immutable). This set is serializable. |
2881 |
|
|
* Unlike the like-named field, this method is parameterized. |
2882 |
|
|
* |
2883 |
|
|
* <p>This example illustrates the type-safe way to obtain an empty set: |
2884 |
|
|
* <pre> |
2885 |
|
|
* Set<String> s = Collections.emptySet(); |
2886 |
|
|
* </pre> |
2887 |
|
|
* Implementation note: Implementations of this method need not |
2888 |
|
|
* create a separate <tt>Set</tt> object for each call. Using this |
2889 |
|
|
* method is likely to have comparable cost to using the like-named |
2890 |
|
|
* field. (Unlike this method, the field does not provide type safety.) |
2891 |
|
|
* |
2892 |
|
|
* @see #EMPTY_SET |
2893 |
|
|
* @since 1.5 |
2894 |
|
|
*/ |
2895 |
|
|
public static final <T> Set<T> emptySet() { |
2896 |
|
|
return (Set<T>) EMPTY_SET; |
2897 |
|
|
} |
2898 |
|
|
|
2899 |
|
|
/** |
2900 |
|
|
* @serial include |
2901 |
|
|
*/ |
2902 |
|
|
private static class EmptySet extends AbstractSet<Object> implements Serializable { |
2903 |
|
|
// use serialVersionUID from JDK 1.2.2 for interoperability |
2904 |
|
|
private static final long serialVersionUID = 1582296315990362920L; |
2905 |
|
|
|
2906 |
|
|
public Iterator<Object> iterator() { |
2907 |
|
|
return new Iterator<Object>() { |
2908 |
|
|
public boolean hasNext() { |
2909 |
|
|
return false; |
2910 |
|
|
} |
2911 |
|
|
public Object next() { |
2912 |
|
|
throw new NoSuchElementException(); |
2913 |
|
|
} |
2914 |
|
|
public void remove() { |
2915 |
|
|
throw new UnsupportedOperationException(); |
2916 |
|
|
} |
2917 |
|
|
}; |
2918 |
|
|
} |
2919 |
|
|
|
2920 |
|
|
public int size() {return 0;} |
2921 |
|
|
|
2922 |
|
|
public boolean contains(Object obj) {return false;} |
2923 |
|
|
|
2924 |
|
|
// Preserves singleton property |
2925 |
|
|
private Object readResolve() { |
2926 |
|
|
return EMPTY_SET; |
2927 |
|
|
} |
2928 |
|
|
} |
2929 |
|
|
|
2930 |
|
|
/** |
2931 |
|
|
* The empty list (immutable). This list is serializable. |
2932 |
|
|
* |
2933 |
|
|
* @see #emptyList() |
2934 |
|
|
*/ |
2935 |
|
|
public static final List EMPTY_LIST = new EmptyList(); |
2936 |
|
|
|
2937 |
|
|
/** |
2938 |
|
|
* Returns the empty list (immutable). This list is serializable. |
2939 |
|
|
* |
2940 |
|
|
* <p>This example illustrates the type-safe way to obtain an empty list: |
2941 |
|
|
* <pre> |
2942 |
|
|
* List<String> s = Collections.emptyList(); |
2943 |
|
|
* </pre> |
2944 |
|
|
* Implementation note: Implementations of this method need not |
2945 |
|
|
* create a separate <tt>List</tt> object for each call. Using this |
2946 |
|
|
* method is likely to have comparable cost to using the like-named |
2947 |
|
|
* field. (Unlike this method, the field does not provide type safety.) |
2948 |
|
|
* |
2949 |
|
|
* @see #EMPTY_LIST |
2950 |
|
|
* @since 1.5 |
2951 |
|
|
*/ |
2952 |
|
|
public static final <T> List<T> emptyList() { |
2953 |
|
|
return (List<T>) EMPTY_LIST; |
2954 |
|
|
} |
2955 |
|
|
|
2956 |
|
|
/** |
2957 |
|
|
* @serial include |
2958 |
|
|
*/ |
2959 |
|
|
private static class EmptyList |
2960 |
|
|
extends AbstractList<Object> |
2961 |
|
|
implements RandomAccess, Serializable { |
2962 |
|
|
// use serialVersionUID from JDK 1.2.2 for interoperability |
2963 |
|
|
private static final long serialVersionUID = 8842843931221139166L; |
2964 |
|
|
|
2965 |
|
|
public int size() {return 0;} |
2966 |
|
|
|
2967 |
|
|
public boolean contains(Object obj) {return false;} |
2968 |
|
|
|
2969 |
|
|
public Object get(int index) { |
2970 |
|
|
throw new IndexOutOfBoundsException("Index: "+index); |
2971 |
|
|
} |
2972 |
|
|
|
2973 |
|
|
// Preserves singleton property |
2974 |
|
|
private Object readResolve() { |
2975 |
|
|
return EMPTY_LIST; |
2976 |
|
|
} |
2977 |
|
|
} |
2978 |
|
|
|
2979 |
|
|
/** |
2980 |
|
|
* The empty map (immutable). This map is serializable. |
2981 |
|
|
* |
2982 |
|
|
* @see #emptyMap() |
2983 |
|
|
* @since 1.3 |
2984 |
|
|
*/ |
2985 |
|
|
public static final Map EMPTY_MAP = new EmptyMap(); |
2986 |
|
|
|
2987 |
|
|
/** |
2988 |
|
|
* Returns the empty map (immutable). This map is serializable. |
2989 |
|
|
* |
2990 |
|
|
* <p>This example illustrates the type-safe way to obtain an empty set: |
2991 |
|
|
* <pre> |
2992 |
|
|
* Map<String, Date> s = Collections.emptyMap(); |
2993 |
|
|
* </pre> |
2994 |
|
|
* Implementation note: Implementations of this method need not |
2995 |
|
|
* create a separate <tt>Map</tt> object for each call. Using this |
2996 |
|
|
* method is likely to have comparable cost to using the like-named |
2997 |
|
|
* field. (Unlike this method, the field does not provide type safety.) |
2998 |
|
|
* |
2999 |
|
|
* @see #EMPTY_MAP |
3000 |
|
|
* @since 1.5 |
3001 |
|
|
*/ |
3002 |
|
|
public static final <K,V> Map<K,V> emptyMap() { |
3003 |
|
|
return (Map<K,V>) EMPTY_MAP; |
3004 |
|
|
} |
3005 |
|
|
|
3006 |
|
|
private static class EmptyMap |
3007 |
|
|
extends AbstractMap<Object,Object> |
3008 |
|
|
implements Serializable { |
3009 |
|
|
|
3010 |
|
|
private static final long serialVersionUID = 6428348081105594320L; |
3011 |
|
|
|
3012 |
|
|
public int size() {return 0;} |
3013 |
|
|
|
3014 |
|
|
public boolean isEmpty() {return true;} |
3015 |
|
|
|
3016 |
|
|
public boolean containsKey(Object key) {return false;} |
3017 |
|
|
|
3018 |
|
|
public boolean containsValue(Object value) {return false;} |
3019 |
|
|
|
3020 |
|
|
public Object get(Object key) {return null;} |
3021 |
|
|
|
3022 |
|
|
public Set<Object> keySet() {return Collections.<Object>emptySet();} |
3023 |
|
|
|
3024 |
|
|
public Collection<Object> values() {return Collections.<Object>emptySet();} |
3025 |
|
|
|
3026 |
|
|
public Set<Map.Entry<Object,Object>> entrySet() { |
3027 |
|
|
return Collections.emptySet(); |
3028 |
|
|
} |
3029 |
|
|
|
3030 |
|
|
public boolean equals(Object o) { |
3031 |
|
|
return (o instanceof Map) && ((Map)o).size()==0; |
3032 |
|
|
} |
3033 |
|
|
|
3034 |
|
|
public int hashCode() {return 0;} |
3035 |
|
|
|
3036 |
|
|
// Preserves singleton property |
3037 |
|
|
private Object readResolve() { |
3038 |
|
|
return EMPTY_MAP; |
3039 |
|
|
} |
3040 |
|
|
} |
3041 |
|
|
|
3042 |
|
|
/** |
3043 |
|
|
* Returns an immutable set containing only the specified object. |
3044 |
|
|
* The returned set is serializable. |
3045 |
|
|
* |
3046 |
|
|
* @param o the sole object to be stored in the returned set. |
3047 |
|
|
* @return an immutable set containing only the specified object. |
3048 |
|
|
*/ |
3049 |
|
|
public static <T> Set<T> singleton(T o) { |
3050 |
|
|
return new SingletonSet<T>(o); |
3051 |
|
|
} |
3052 |
|
|
|
3053 |
|
|
/** |
3054 |
|
|
* @serial include |
3055 |
|
|
*/ |
3056 |
|
|
private static class SingletonSet<E> |
3057 |
|
|
extends AbstractSet<E> |
3058 |
|
|
implements Serializable |
3059 |
|
|
{ |
3060 |
|
|
// use serialVersionUID from JDK 1.2.2 for interoperability |
3061 |
|
|
private static final long serialVersionUID = 3193687207550431679L; |
3062 |
|
|
|
3063 |
|
|
final private E element; |
3064 |
|
|
|
3065 |
jsr166 |
1.5 |
SingletonSet(E e) {element = e;} |
3066 |
dl |
1.1 |
|
3067 |
|
|
public Iterator<E> iterator() { |
3068 |
|
|
return new Iterator<E>() { |
3069 |
|
|
private boolean hasNext = true; |
3070 |
|
|
public boolean hasNext() { |
3071 |
|
|
return hasNext; |
3072 |
|
|
} |
3073 |
|
|
public E next() { |
3074 |
|
|
if (hasNext) { |
3075 |
|
|
hasNext = false; |
3076 |
|
|
return element; |
3077 |
|
|
} |
3078 |
|
|
throw new NoSuchElementException(); |
3079 |
|
|
} |
3080 |
|
|
public void remove() { |
3081 |
|
|
throw new UnsupportedOperationException(); |
3082 |
|
|
} |
3083 |
|
|
}; |
3084 |
|
|
} |
3085 |
|
|
|
3086 |
|
|
public int size() {return 1;} |
3087 |
|
|
|
3088 |
|
|
public boolean contains(Object o) {return eq(o, element);} |
3089 |
|
|
} |
3090 |
|
|
|
3091 |
|
|
/** |
3092 |
|
|
* Returns an immutable list containing only the specified object. |
3093 |
|
|
* The returned list is serializable. |
3094 |
|
|
* |
3095 |
|
|
* @param o the sole object to be stored in the returned list. |
3096 |
|
|
* @return an immutable list containing only the specified object. |
3097 |
|
|
* @since 1.3 |
3098 |
|
|
*/ |
3099 |
|
|
public static <T> List<T> singletonList(T o) { |
3100 |
|
|
return new SingletonList<T>(o); |
3101 |
|
|
} |
3102 |
|
|
|
3103 |
|
|
private static class SingletonList<E> |
3104 |
|
|
extends AbstractList<E> |
3105 |
|
|
implements RandomAccess, Serializable { |
3106 |
|
|
|
3107 |
|
|
static final long serialVersionUID = 3093736618740652951L; |
3108 |
|
|
|
3109 |
|
|
private final E element; |
3110 |
|
|
|
3111 |
|
|
SingletonList(E obj) {element = obj;} |
3112 |
|
|
|
3113 |
|
|
public int size() {return 1;} |
3114 |
|
|
|
3115 |
|
|
public boolean contains(Object obj) {return eq(obj, element);} |
3116 |
|
|
|
3117 |
|
|
public E get(int index) { |
3118 |
|
|
if (index != 0) |
3119 |
|
|
throw new IndexOutOfBoundsException("Index: "+index+", Size: 1"); |
3120 |
|
|
return element; |
3121 |
|
|
} |
3122 |
|
|
} |
3123 |
|
|
|
3124 |
|
|
/** |
3125 |
|
|
* Returns an immutable map, mapping only the specified key to the |
3126 |
|
|
* specified value. The returned map is serializable. |
3127 |
|
|
* |
3128 |
|
|
* @param key the sole key to be stored in the returned map. |
3129 |
|
|
* @param value the value to which the returned map maps <tt>key</tt>. |
3130 |
|
|
* @return an immutable map containing only the specified key-value |
3131 |
|
|
* mapping. |
3132 |
|
|
* @since 1.3 |
3133 |
|
|
*/ |
3134 |
|
|
public static <K,V> Map<K,V> singletonMap(K key, V value) { |
3135 |
|
|
return new SingletonMap<K,V>(key, value); |
3136 |
|
|
} |
3137 |
|
|
|
3138 |
|
|
private static class SingletonMap<K,V> |
3139 |
|
|
extends AbstractMap<K,V> |
3140 |
|
|
implements Serializable { |
3141 |
|
|
private static final long serialVersionUID = -6979724477215052911L; |
3142 |
|
|
|
3143 |
|
|
private final K k; |
3144 |
|
|
private final V v; |
3145 |
|
|
|
3146 |
|
|
SingletonMap(K key, V value) { |
3147 |
|
|
k = key; |
3148 |
|
|
v = value; |
3149 |
|
|
} |
3150 |
|
|
|
3151 |
|
|
public int size() {return 1;} |
3152 |
|
|
|
3153 |
|
|
public boolean isEmpty() {return false;} |
3154 |
|
|
|
3155 |
|
|
public boolean containsKey(Object key) {return eq(key, k);} |
3156 |
|
|
|
3157 |
|
|
public boolean containsValue(Object value) {return eq(value, v);} |
3158 |
|
|
|
3159 |
|
|
public V get(Object key) {return (eq(key, k) ? v : null);} |
3160 |
|
|
|
3161 |
|
|
private transient Set<K> keySet = null; |
3162 |
|
|
private transient Set<Map.Entry<K,V>> entrySet = null; |
3163 |
|
|
private transient Collection<V> values = null; |
3164 |
|
|
|
3165 |
|
|
public Set<K> keySet() { |
3166 |
|
|
if (keySet==null) |
3167 |
|
|
keySet = singleton(k); |
3168 |
|
|
return keySet; |
3169 |
|
|
} |
3170 |
|
|
|
3171 |
|
|
public Set<Map.Entry<K,V>> entrySet() { |
3172 |
|
|
if (entrySet==null) |
3173 |
jsr166 |
1.4 |
entrySet = Collections.<Map.Entry<K,V>>singleton( |
3174 |
|
|
new SimpleImmutableEntry<K,V>(k, v)); |
3175 |
dl |
1.1 |
return entrySet; |
3176 |
|
|
} |
3177 |
|
|
|
3178 |
|
|
public Collection<V> values() { |
3179 |
|
|
if (values==null) |
3180 |
|
|
values = singleton(v); |
3181 |
|
|
return values; |
3182 |
|
|
} |
3183 |
|
|
|
3184 |
|
|
} |
3185 |
|
|
|
3186 |
|
|
/** |
3187 |
|
|
* Returns an immutable list consisting of <tt>n</tt> copies of the |
3188 |
|
|
* specified object. The newly allocated data object is tiny (it contains |
3189 |
|
|
* a single reference to the data object). This method is useful in |
3190 |
|
|
* combination with the <tt>List.addAll</tt> method to grow lists. |
3191 |
|
|
* The returned list is serializable. |
3192 |
|
|
* |
3193 |
|
|
* @param n the number of elements in the returned list. |
3194 |
|
|
* @param o the element to appear repeatedly in the returned list. |
3195 |
|
|
* @return an immutable list consisting of <tt>n</tt> copies of the |
3196 |
|
|
* specified object. |
3197 |
|
|
* @throws IllegalArgumentException if n < 0. |
3198 |
|
|
* @see List#addAll(Collection) |
3199 |
|
|
* @see List#addAll(int, Collection) |
3200 |
|
|
*/ |
3201 |
|
|
public static <T> List<T> nCopies(int n, T o) { |
3202 |
jsr166 |
1.14 |
if (n < 0) |
3203 |
|
|
throw new IllegalArgumentException("List length = " + n); |
3204 |
dl |
1.1 |
return new CopiesList<T>(n, o); |
3205 |
|
|
} |
3206 |
|
|
|
3207 |
|
|
/** |
3208 |
|
|
* @serial include |
3209 |
|
|
*/ |
3210 |
|
|
private static class CopiesList<E> |
3211 |
|
|
extends AbstractList<E> |
3212 |
|
|
implements RandomAccess, Serializable |
3213 |
|
|
{ |
3214 |
|
|
static final long serialVersionUID = 2739099268398711800L; |
3215 |
|
|
|
3216 |
jsr166 |
1.14 |
final int n; |
3217 |
|
|
final E element; |
3218 |
dl |
1.1 |
|
3219 |
jsr166 |
1.5 |
CopiesList(int n, E e) { |
3220 |
jsr166 |
1.14 |
assert n >= 0; |
3221 |
dl |
1.1 |
this.n = n; |
3222 |
jsr166 |
1.5 |
element = e; |
3223 |
dl |
1.1 |
} |
3224 |
|
|
|
3225 |
|
|
public int size() { |
3226 |
|
|
return n; |
3227 |
|
|
} |
3228 |
|
|
|
3229 |
|
|
public boolean contains(Object obj) { |
3230 |
|
|
return n != 0 && eq(obj, element); |
3231 |
|
|
} |
3232 |
|
|
|
3233 |
jsr166 |
1.14 |
public int indexOf(Object o) { |
3234 |
|
|
return contains(o) ? 0 : -1; |
3235 |
|
|
} |
3236 |
|
|
|
3237 |
|
|
public int lastIndexOf(Object o) { |
3238 |
|
|
return contains(o) ? n - 1 : -1; |
3239 |
|
|
} |
3240 |
|
|
|
3241 |
dl |
1.1 |
public E get(int index) { |
3242 |
jsr166 |
1.14 |
if (index < 0 || index >= n) |
3243 |
dl |
1.1 |
throw new IndexOutOfBoundsException("Index: "+index+ |
3244 |
|
|
", Size: "+n); |
3245 |
|
|
return element; |
3246 |
|
|
} |
3247 |
jsr166 |
1.14 |
|
3248 |
|
|
public Object[] toArray() { |
3249 |
|
|
final Object[] a = new Object[n]; |
3250 |
|
|
if (element != null) |
3251 |
|
|
Arrays.fill(a, 0, n, element); |
3252 |
|
|
return a; |
3253 |
|
|
} |
3254 |
|
|
|
3255 |
|
|
public <T> T[] toArray(T[] a) { |
3256 |
|
|
final int n = this.n; |
3257 |
|
|
if (a.length < n) { |
3258 |
|
|
a = (T[])java.lang.reflect.Array |
3259 |
|
|
.newInstance(a.getClass().getComponentType(), n); |
3260 |
|
|
if (element != null) |
3261 |
|
|
Arrays.fill(a, 0, n, element); |
3262 |
|
|
} else { |
3263 |
|
|
Arrays.fill(a, 0, n, element); |
3264 |
|
|
if (a.length > n) |
3265 |
|
|
a[n] = null; |
3266 |
|
|
} |
3267 |
|
|
return a; |
3268 |
|
|
} |
3269 |
|
|
|
3270 |
|
|
public List<E> subList(int fromIndex, int toIndex) { |
3271 |
|
|
if (fromIndex < 0) |
3272 |
|
|
throw new IndexOutOfBoundsException("fromIndex = " + fromIndex); |
3273 |
|
|
if (toIndex > n) |
3274 |
|
|
throw new IndexOutOfBoundsException("toIndex = " + toIndex); |
3275 |
|
|
if (fromIndex > toIndex) |
3276 |
|
|
throw new IllegalArgumentException("fromIndex(" + fromIndex + |
3277 |
|
|
") > toIndex(" + toIndex + ")"); |
3278 |
|
|
return new CopiesList(toIndex - fromIndex, element); |
3279 |
|
|
} |
3280 |
dl |
1.1 |
} |
3281 |
|
|
|
3282 |
|
|
/** |
3283 |
|
|
* Returns a comparator that imposes the reverse of the <i>natural |
3284 |
|
|
* ordering</i> on a collection of objects that implement the |
3285 |
|
|
* <tt>Comparable</tt> interface. (The natural ordering is the ordering |
3286 |
|
|
* imposed by the objects' own <tt>compareTo</tt> method.) This enables a |
3287 |
|
|
* simple idiom for sorting (or maintaining) collections (or arrays) of |
3288 |
|
|
* objects that implement the <tt>Comparable</tt> interface in |
3289 |
|
|
* reverse-natural-order. For example, suppose a is an array of |
3290 |
|
|
* strings. Then: <pre> |
3291 |
|
|
* Arrays.sort(a, Collections.reverseOrder()); |
3292 |
|
|
* </pre> sorts the array in reverse-lexicographic (alphabetical) order.<p> |
3293 |
|
|
* |
3294 |
|
|
* The returned comparator is serializable. |
3295 |
|
|
* |
3296 |
|
|
* @return a comparator that imposes the reverse of the <i>natural |
3297 |
|
|
* ordering</i> on a collection of objects that implement |
3298 |
|
|
* the <tt>Comparable</tt> interface. |
3299 |
|
|
* @see Comparable |
3300 |
|
|
*/ |
3301 |
|
|
public static <T> Comparator<T> reverseOrder() { |
3302 |
|
|
return (Comparator<T>) REVERSE_ORDER; |
3303 |
|
|
} |
3304 |
|
|
|
3305 |
|
|
private static final Comparator REVERSE_ORDER = new ReverseComparator(); |
3306 |
|
|
|
3307 |
|
|
/** |
3308 |
|
|
* @serial include |
3309 |
|
|
*/ |
3310 |
|
|
private static class ReverseComparator<T> |
3311 |
|
|
implements Comparator<Comparable<Object>>, Serializable { |
3312 |
|
|
|
3313 |
|
|
// use serialVersionUID from JDK 1.2.2 for interoperability |
3314 |
|
|
private static final long serialVersionUID = 7207038068494060240L; |
3315 |
|
|
|
3316 |
|
|
public int compare(Comparable<Object> c1, Comparable<Object> c2) { |
3317 |
|
|
return c2.compareTo(c1); |
3318 |
|
|
} |
3319 |
jsr166 |
1.22 |
|
3320 |
|
|
private Object readResolve() { return reverseOrder(); } |
3321 |
dl |
1.1 |
} |
3322 |
|
|
|
3323 |
|
|
/** |
3324 |
|
|
* Returns a comparator that imposes the reverse ordering of the specified |
3325 |
|
|
* comparator. If the specified comparator is null, this method is |
3326 |
|
|
* equivalent to {@link #reverseOrder()} (in other words, it returns a |
3327 |
|
|
* comparator that imposes the reverse of the <i>natural ordering</i> on a |
3328 |
|
|
* collection of objects that implement the Comparable interface). |
3329 |
|
|
* |
3330 |
|
|
* <p>The returned comparator is serializable (assuming the specified |
3331 |
|
|
* comparator is also serializable or null). |
3332 |
|
|
* |
3333 |
|
|
* @return a comparator that imposes the reverse ordering of the |
3334 |
|
|
* specified comparator. |
3335 |
|
|
* @since 1.5 |
3336 |
|
|
*/ |
3337 |
|
|
public static <T> Comparator<T> reverseOrder(Comparator<T> cmp) { |
3338 |
|
|
if (cmp == null) |
3339 |
jsr166 |
1.22 |
return reverseOrder(); |
3340 |
jsr166 |
1.4 |
|
3341 |
dl |
1.1 |
return new ReverseComparator2<T>(cmp); |
3342 |
|
|
} |
3343 |
jsr166 |
1.4 |
|
3344 |
dl |
1.1 |
/** |
3345 |
|
|
* @serial include |
3346 |
|
|
*/ |
3347 |
|
|
private static class ReverseComparator2<T> implements Comparator<T>, |
3348 |
|
|
Serializable |
3349 |
|
|
{ |
3350 |
|
|
private static final long serialVersionUID = 4374092139857L; |
3351 |
jsr166 |
1.4 |
|
3352 |
dl |
1.1 |
/** |
3353 |
|
|
* The comparator specified in the static factory. This will never |
3354 |
|
|
* be null, as the static factory returns a ReverseComparator |
3355 |
|
|
* instance if its argument is null. |
3356 |
|
|
* |
3357 |
|
|
* @serial |
3358 |
|
|
*/ |
3359 |
|
|
private Comparator<T> cmp; |
3360 |
jsr166 |
1.4 |
|
3361 |
dl |
1.1 |
ReverseComparator2(Comparator<T> cmp) { |
3362 |
|
|
assert cmp != null; |
3363 |
|
|
this.cmp = cmp; |
3364 |
|
|
} |
3365 |
jsr166 |
1.4 |
|
3366 |
dl |
1.1 |
public int compare(T t1, T t2) { |
3367 |
|
|
return cmp.compare(t2, t1); |
3368 |
|
|
} |
3369 |
|
|
} |
3370 |
|
|
|
3371 |
|
|
/** |
3372 |
|
|
* Returns an enumeration over the specified collection. This provides |
3373 |
|
|
* interoperability with legacy APIs that require an enumeration |
3374 |
|
|
* as input. |
3375 |
|
|
* |
3376 |
|
|
* @param c the collection for which an enumeration is to be returned. |
3377 |
|
|
* @return an enumeration over the specified collection. |
3378 |
|
|
* @see Enumeration |
3379 |
|
|
*/ |
3380 |
|
|
public static <T> Enumeration<T> enumeration(final Collection<T> c) { |
3381 |
|
|
return new Enumeration<T>() { |
3382 |
|
|
Iterator<T> i = c.iterator(); |
3383 |
|
|
|
3384 |
|
|
public boolean hasMoreElements() { |
3385 |
|
|
return i.hasNext(); |
3386 |
|
|
} |
3387 |
|
|
|
3388 |
|
|
public T nextElement() { |
3389 |
|
|
return i.next(); |
3390 |
|
|
} |
3391 |
|
|
}; |
3392 |
|
|
} |
3393 |
|
|
|
3394 |
|
|
/** |
3395 |
|
|
* Returns an array list containing the elements returned by the |
3396 |
|
|
* specified enumeration in the order they are returned by the |
3397 |
|
|
* enumeration. This method provides interoperability between |
3398 |
|
|
* legacy APIs that return enumerations and new APIs that require |
3399 |
|
|
* collections. |
3400 |
|
|
* |
3401 |
|
|
* @param e enumeration providing elements for the returned |
3402 |
|
|
* array list |
3403 |
|
|
* @return an array list containing the elements returned |
3404 |
|
|
* by the specified enumeration. |
3405 |
|
|
* @since 1.4 |
3406 |
|
|
* @see Enumeration |
3407 |
|
|
* @see ArrayList |
3408 |
|
|
*/ |
3409 |
|
|
public static <T> ArrayList<T> list(Enumeration<T> e) { |
3410 |
|
|
ArrayList<T> l = new ArrayList<T>(); |
3411 |
|
|
while (e.hasMoreElements()) |
3412 |
|
|
l.add(e.nextElement()); |
3413 |
|
|
return l; |
3414 |
|
|
} |
3415 |
|
|
|
3416 |
|
|
/** |
3417 |
|
|
* Returns true if the specified arguments are equal, or both null. |
3418 |
|
|
*/ |
3419 |
|
|
private static boolean eq(Object o1, Object o2) { |
3420 |
|
|
return (o1==null ? o2==null : o1.equals(o2)); |
3421 |
|
|
} |
3422 |
|
|
|
3423 |
|
|
/** |
3424 |
|
|
* Returns the number of elements in the specified collection equal to the |
3425 |
|
|
* specified object. More formally, returns the number of elements |
3426 |
|
|
* <tt>e</tt> in the collection such that |
3427 |
|
|
* <tt>(o == null ? e == null : o.equals(e))</tt>. |
3428 |
|
|
* |
3429 |
|
|
* @param c the collection in which to determine the frequency |
3430 |
|
|
* of <tt>o</tt> |
3431 |
|
|
* @param o the object whose frequency is to be determined |
3432 |
|
|
* @throws NullPointerException if <tt>c</tt> is null |
3433 |
|
|
* @since 1.5 |
3434 |
|
|
*/ |
3435 |
|
|
public static int frequency(Collection<?> c, Object o) { |
3436 |
|
|
int result = 0; |
3437 |
|
|
if (o == null) { |
3438 |
|
|
for (Object e : c) |
3439 |
|
|
if (e == null) |
3440 |
|
|
result++; |
3441 |
|
|
} else { |
3442 |
|
|
for (Object e : c) |
3443 |
|
|
if (o.equals(e)) |
3444 |
|
|
result++; |
3445 |
|
|
} |
3446 |
|
|
return result; |
3447 |
|
|
} |
3448 |
|
|
|
3449 |
|
|
/** |
3450 |
|
|
* Returns <tt>true</tt> if the two specified collections have no |
3451 |
|
|
* elements in common. |
3452 |
|
|
* |
3453 |
|
|
* <p>Care must be exercised if this method is used on collections that |
3454 |
|
|
* do not comply with the general contract for <tt>Collection</tt>. |
3455 |
|
|
* Implementations may elect to iterate over either collection and test |
3456 |
|
|
* for containment in the other collection (or to perform any equivalent |
3457 |
|
|
* computation). If either collection uses a nonstandard equality test |
3458 |
|
|
* (as does a {@link SortedSet} whose ordering is not <i>compatible with |
3459 |
|
|
* equals</i>, or the key set of an {@link IdentityHashMap}), both |
3460 |
|
|
* collections must use the same nonstandard equality test, or the |
3461 |
|
|
* result of this method is undefined. |
3462 |
|
|
* |
3463 |
|
|
* <p>Note that it is permissible to pass the same collection in both |
3464 |
|
|
* parameters, in which case the method will return true if and only if |
3465 |
|
|
* the collection is empty. |
3466 |
|
|
* |
3467 |
|
|
* @param c1 a collection |
3468 |
|
|
* @param c2 a collection |
3469 |
|
|
* @throws NullPointerException if either collection is null |
3470 |
|
|
* @since 1.5 |
3471 |
|
|
*/ |
3472 |
|
|
public static boolean disjoint(Collection<?> c1, Collection<?> c2) { |
3473 |
|
|
/* |
3474 |
|
|
* We're going to iterate through c1 and test for inclusion in c2. |
3475 |
|
|
* If c1 is a Set and c2 isn't, swap the collections. Otherwise, |
3476 |
|
|
* place the shorter collection in c1. Hopefully this heuristic |
3477 |
|
|
* will minimize the cost of the operation. |
3478 |
|
|
*/ |
3479 |
|
|
if ((c1 instanceof Set) && !(c2 instanceof Set) || |
3480 |
|
|
(c1.size() > c2.size())) { |
3481 |
|
|
Collection<?> tmp = c1; |
3482 |
|
|
c1 = c2; |
3483 |
|
|
c2 = tmp; |
3484 |
|
|
} |
3485 |
jsr166 |
1.4 |
|
3486 |
dl |
1.1 |
for (Object e : c1) |
3487 |
|
|
if (c2.contains(e)) |
3488 |
|
|
return false; |
3489 |
|
|
return true; |
3490 |
|
|
} |
3491 |
|
|
|
3492 |
|
|
/** |
3493 |
|
|
* Adds all of the specified elements to the specified collection. |
3494 |
|
|
* Elements to be added may be specified individually or as an array. |
3495 |
|
|
* The behavior of this convenience method is identical to that of |
3496 |
|
|
* <tt>c.addAll(Arrays.asList(elements))</tt>, but this method is likely |
3497 |
|
|
* to run significantly faster under most implementations. |
3498 |
|
|
* |
3499 |
|
|
* <p>When elements are specified individually, this method provides a |
3500 |
|
|
* convenient way to add a few elements to an existing collection: |
3501 |
|
|
* <pre> |
3502 |
|
|
* Collections.addAll(flavors, "Peaches 'n Plutonium", "Rocky Racoon"); |
3503 |
|
|
* </pre> |
3504 |
|
|
* |
3505 |
|
|
* @param c the collection into which <tt>elements</tt> are to be inserted |
3506 |
jsr166 |
1.19 |
* @param elements the elements to insert into <tt>c</tt> |
3507 |
dl |
1.1 |
* @return <tt>true</tt> if the collection changed as a result of the call |
3508 |
|
|
* @throws UnsupportedOperationException if <tt>c</tt> does not support |
3509 |
jsr166 |
1.19 |
* the <tt>add</tt> operation |
3510 |
dl |
1.1 |
* @throws NullPointerException if <tt>elements</tt> contains one or more |
3511 |
jsr166 |
1.6 |
* null values and <tt>c</tt> does not permit null elements, or |
3512 |
dl |
1.1 |
* if <tt>c</tt> or <tt>elements</tt> are <tt>null</tt> |
3513 |
jsr166 |
1.6 |
* @throws IllegalArgumentException if some property of a value in |
3514 |
dl |
1.1 |
* <tt>elements</tt> prevents it from being added to <tt>c</tt> |
3515 |
|
|
* @see Collection#addAll(Collection) |
3516 |
|
|
* @since 1.5 |
3517 |
|
|
*/ |
3518 |
jsr166 |
1.19 |
public static <T> boolean addAll(Collection<? super T> c, T... elements) { |
3519 |
dl |
1.1 |
boolean result = false; |
3520 |
jsr166 |
1.19 |
for (T element : elements) |
3521 |
|
|
result |= c.add(element); |
3522 |
dl |
1.1 |
return result; |
3523 |
|
|
} |
3524 |
|
|
|
3525 |
|
|
/** |
3526 |
|
|
* Returns a set backed by the specified map. The resulting set displays |
3527 |
|
|
* the same ordering, concurrency, and performance characteristics as the |
3528 |
|
|
* backing map. In essence, this factory method provides a {@link Set} |
3529 |
|
|
* implementation corresponding to any {@link Map} implementation. There |
3530 |
|
|
* is no need to use this method on a {@link Map} implementation that |
3531 |
|
|
* already has a corresponding {@link Set} implementation (such as {@link |
3532 |
|
|
* HashMap} or {@link TreeMap}). |
3533 |
|
|
* |
3534 |
|
|
* <p>Each method invocation on the set returned by this method results in |
3535 |
|
|
* exactly one method invocation on the backing map or its <tt>keySet</tt> |
3536 |
|
|
* view, with one exception. The <tt>addAll</tt> method is implemented |
3537 |
|
|
* as a sequence of <tt>put</tt> invocations on the backing map. |
3538 |
|
|
* |
3539 |
|
|
* <p>The specified map must be empty at the time this method is invoked, |
3540 |
|
|
* and should not be accessed directly after this method returns. These |
3541 |
|
|
* conditions are ensured if the map is created empty, passed directly |
3542 |
|
|
* to this method, and no reference to the map is retained, as illustrated |
3543 |
|
|
* in the following code fragment: |
3544 |
|
|
* <pre> |
3545 |
jsr166 |
1.15 |
* Set<Object> weakHashSet = Collections.newSetFromMap( |
3546 |
dl |
1.1 |
* new WeakHashMap<Object, Boolean>()); |
3547 |
|
|
* </pre> |
3548 |
|
|
* |
3549 |
|
|
* @param map the backing map |
3550 |
|
|
* @return the set backed by the map |
3551 |
|
|
* @throws IllegalArgumentException if <tt>map</tt> is not empty |
3552 |
jsr166 |
1.12 |
* @since 1.6 |
3553 |
dl |
1.1 |
*/ |
3554 |
jsr166 |
1.14 |
public static <E> Set<E> newSetFromMap(Map<E, Boolean> map) { |
3555 |
|
|
return new SetFromMap<E>(map); |
3556 |
dl |
1.1 |
} |
3557 |
|
|
|
3558 |
jsr166 |
1.14 |
private static class SetFromMap<E> extends AbstractSet<E> |
3559 |
dl |
1.1 |
implements Set<E>, Serializable |
3560 |
|
|
{ |
3561 |
|
|
private final Map<E, Boolean> m; // The backing map |
3562 |
jsr166 |
1.23 |
private transient Set<E> s; // Its keySet |
3563 |
dl |
1.1 |
|
3564 |
jsr166 |
1.14 |
SetFromMap(Map<E, Boolean> map) { |
3565 |
dl |
1.1 |
if (!map.isEmpty()) |
3566 |
|
|
throw new IllegalArgumentException("Map is non-empty"); |
3567 |
|
|
m = map; |
3568 |
jsr166 |
1.23 |
s = map.keySet(); |
3569 |
dl |
1.1 |
} |
3570 |
|
|
|
3571 |
jsr166 |
1.23 |
public void clear() { m.clear(); } |
3572 |
dl |
1.1 |
public int size() { return m.size(); } |
3573 |
|
|
public boolean isEmpty() { return m.isEmpty(); } |
3574 |
|
|
public boolean contains(Object o) { return m.containsKey(o); } |
3575 |
|
|
public boolean remove(Object o) { return m.remove(o) != null; } |
3576 |
jsr166 |
1.23 |
public boolean add(E e) { return m.put(e, Boolean.TRUE) == null; } |
3577 |
|
|
public Iterator<E> iterator() { return s.iterator(); } |
3578 |
|
|
public Object[] toArray() { return s.toArray(); } |
3579 |
|
|
public <T> T[] toArray(T[] a) { return s.toArray(a); } |
3580 |
|
|
public String toString() { return s.toString(); } |
3581 |
|
|
public int hashCode() { return s.hashCode(); } |
3582 |
|
|
public boolean equals(Object o) { return o == this || s.equals(o); } |
3583 |
|
|
public boolean containsAll(Collection<?> c) {return s.containsAll(c);} |
3584 |
|
|
public boolean removeAll(Collection<?> c) {return s.removeAll(c);} |
3585 |
|
|
public boolean retainAll(Collection<?> c) {return s.retainAll(c);} |
3586 |
|
|
// addAll is the only inherited implementation |
3587 |
dl |
1.1 |
|
3588 |
|
|
private static final long serialVersionUID = 2454657854757543876L; |
3589 |
|
|
|
3590 |
jsr166 |
1.23 |
private void readObject(java.io.ObjectInputStream stream) |
3591 |
dl |
1.1 |
throws IOException, ClassNotFoundException |
3592 |
|
|
{ |
3593 |
jsr166 |
1.23 |
stream.defaultReadObject(); |
3594 |
|
|
s = m.keySet(); |
3595 |
dl |
1.1 |
} |
3596 |
|
|
} |
3597 |
|
|
|
3598 |
|
|
/** |
3599 |
|
|
* Returns a view of a {@link Deque} as a Last-in-first-out (Lifo) |
3600 |
|
|
* {@link Queue}. Method <tt>add</tt> is mapped to <tt>push</tt>, |
3601 |
|
|
* <tt>remove</tt> is mapped to <tt>pop</tt> and so on. This |
3602 |
|
|
* view can be useful when you would like to use a method |
3603 |
|
|
* requiring a <tt>Queue</tt> but you need Lifo ordering. |
3604 |
jsr166 |
1.17 |
* |
3605 |
jsr166 |
1.24 |
* <p>Each method invocation on the queue returned by this method |
3606 |
|
|
* results in exactly one method invocation on the backing deque, with |
3607 |
|
|
* one exception. The {@link Queue#addAll addAll} method is |
3608 |
|
|
* implemented as a sequence of {@link Deque#addFirst addFirst} |
3609 |
|
|
* invocations on the backing deque. |
3610 |
|
|
* |
3611 |
jsr166 |
1.13 |
* @param deque the deque |
3612 |
dl |
1.1 |
* @return the queue |
3613 |
|
|
* @since 1.6 |
3614 |
|
|
*/ |
3615 |
|
|
public static <T> Queue<T> asLifoQueue(Deque<T> deque) { |
3616 |
|
|
return new AsLIFOQueue<T>(deque); |
3617 |
|
|
} |
3618 |
|
|
|
3619 |
jsr166 |
1.4 |
static class AsLIFOQueue<E> extends AbstractQueue<E> |
3620 |
dl |
1.1 |
implements Queue<E>, Serializable { |
3621 |
dl |
1.8 |
private static final long serialVersionUID = 1802017725587941708L; |
3622 |
dl |
1.1 |
private final Deque<E> q; |
3623 |
jsr166 |
1.23 |
AsLIFOQueue(Deque<E> q) { this.q = q; } |
3624 |
|
|
public boolean add(E e) { q.addFirst(e); return true; } |
3625 |
|
|
public boolean offer(E e) { return q.offerFirst(e); } |
3626 |
|
|
public E poll() { return q.pollFirst(); } |
3627 |
|
|
public E remove() { return q.removeFirst(); } |
3628 |
|
|
public E peek() { return q.peekFirst(); } |
3629 |
|
|
public E element() { return q.getFirst(); } |
3630 |
|
|
public void clear() { q.clear(); } |
3631 |
|
|
public int size() { return q.size(); } |
3632 |
|
|
public boolean isEmpty() { return q.isEmpty(); } |
3633 |
|
|
public boolean contains(Object o) { return q.contains(o); } |
3634 |
|
|
public boolean remove(Object o) { return q.remove(o); } |
3635 |
|
|
public Iterator<E> iterator() { return q.iterator(); } |
3636 |
|
|
public Object[] toArray() { return q.toArray(); } |
3637 |
|
|
public <T> T[] toArray(T[] a) { return q.toArray(a); } |
3638 |
|
|
public String toString() { return q.toString(); } |
3639 |
|
|
public boolean containsAll(Collection<?> c) {return q.containsAll(c);} |
3640 |
|
|
public boolean removeAll(Collection<?> c) {return q.removeAll(c);} |
3641 |
|
|
public boolean retainAll(Collection<?> c) {return q.retainAll(c);} |
3642 |
|
|
// We use inherited addAll; forwarding addAll would be wrong |
3643 |
dl |
1.1 |
} |
3644 |
|
|
} |