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dl |
1.1 |
/* |
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jsr166 |
1.17 |
* Copyright 1997-2006 Sun Microsystems, Inc. All Rights Reserved. |
3 |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 |
dl |
1.1 |
* |
5 |
jsr166 |
1.17 |
* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Sun designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Sun in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
13 |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
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* CA 95054 USA or visit www.sun.com if you need additional information or |
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* have any questions. |
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dl |
1.1 |
*/ |
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package java.util; |
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/** |
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jsr166 |
1.13 |
* This class provides a skeletal implementation of the {@link List} |
30 |
dl |
1.1 |
* interface to minimize the effort required to implement this interface |
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* backed by a "random access" data store (such as an array). For sequential |
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jsr166 |
1.13 |
* access data (such as a linked list), {@link AbstractSequentialList} should |
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jsr166 |
1.12 |
* be used in preference to this class. |
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dl |
1.1 |
* |
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jsr166 |
1.13 |
* <p>To implement an unmodifiable list, the programmer needs only to extend |
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* this class and provide implementations for the {@link #get(int)} and |
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* {@link List#size() size()} methods. |
38 |
dl |
1.1 |
* |
39 |
jsr166 |
1.13 |
* <p>To implement a modifiable list, the programmer must additionally |
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* override the {@link #set(int, Object) set(int, E)} method (which otherwise |
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* throws an {@code UnsupportedOperationException}). If the list is |
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* variable-size the programmer must additionally override the |
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* {@link #add(int, Object) add(int, E)} and {@link #remove(int)} methods. |
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dl |
1.1 |
* |
45 |
jsr166 |
1.12 |
* <p>The programmer should generally provide a void (no argument) and collection |
46 |
jsr166 |
1.13 |
* constructor, as per the recommendation in the {@link Collection} interface |
47 |
jsr166 |
1.12 |
* specification. |
48 |
dl |
1.1 |
* |
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jsr166 |
1.12 |
* <p>Unlike the other abstract collection implementations, the programmer does |
50 |
dl |
1.1 |
* <i>not</i> have to provide an iterator implementation; the iterator and |
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* list iterator are implemented by this class, on top of the "random access" |
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jsr166 |
1.13 |
* methods: |
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* {@link #get(int)}, |
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* {@link #set(int, Object) set(int, E)}, |
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* {@link #add(int, Object) add(int, E)} and |
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* {@link #remove(int)}. |
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dl |
1.1 |
* |
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jsr166 |
1.13 |
* <p>The documentation for each non-abstract method in this class describes its |
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dl |
1.1 |
* implementation in detail. Each of these methods may be overridden if the |
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jsr166 |
1.12 |
* collection being implemented admits a more efficient implementation. |
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dl |
1.1 |
* |
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jsr166 |
1.12 |
* <p>This class is a member of the |
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jsr166 |
1.11 |
* <a href="{@docRoot}/../technotes/guides/collections/index.html"> |
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dl |
1.1 |
* Java Collections Framework</a>. |
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* |
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* @author Josh Bloch |
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* @author Neal Gafter |
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jsr166 |
1.7 |
* @version %I%, %G% |
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1.1 |
* @since 1.2 |
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*/ |
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public abstract class AbstractList<E> extends AbstractCollection<E> implements List<E> { |
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/** |
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* Sole constructor. (For invocation by subclass constructors, typically |
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* implicit.) |
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*/ |
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protected AbstractList() { |
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} |
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/** |
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* Appends the specified element to the end of this list (optional |
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* operation). |
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* |
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* <p>Lists that support this operation may place limitations on what |
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* elements may be added to this list. In particular, some |
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* lists will refuse to add null elements, and others will impose |
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* restrictions on the type of elements that may be added. List |
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* classes should clearly specify in their documentation any restrictions |
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* on what elements may be added. |
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* |
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jsr166 |
1.12 |
* <p>This implementation calls {@code add(size(), e)}. |
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dl |
1.1 |
* |
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* <p>Note that this implementation throws an |
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jsr166 |
1.13 |
* {@code UnsupportedOperationException} unless |
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* {@link #add(int, Object) add(int, E)} is overridden. |
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dl |
1.1 |
* |
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* @param e element to be appended to this list |
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jsr166 |
1.12 |
* @return {@code true} (as specified by {@link Collection#add}) |
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* @throws UnsupportedOperationException if the {@code add} operation |
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dl |
1.1 |
* is not supported by this list |
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* @throws ClassCastException if the class of the specified element |
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* prevents it from being added to this list |
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* @throws NullPointerException if the specified element is null and this |
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* list does not permit null elements |
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* @throws IllegalArgumentException if some property of this element |
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* prevents it from being added to this list |
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*/ |
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public boolean add(E e) { |
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add(size(), e); |
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return true; |
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} |
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/** |
114 |
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* {@inheritDoc} |
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* |
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* @throws IndexOutOfBoundsException {@inheritDoc} |
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*/ |
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abstract public E get(int index); |
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120 |
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/** |
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* {@inheritDoc} |
122 |
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* |
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* <p>This implementation always throws an |
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jsr166 |
1.12 |
* {@code UnsupportedOperationException}. |
125 |
dl |
1.1 |
* |
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* @throws UnsupportedOperationException {@inheritDoc} |
127 |
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* @throws ClassCastException {@inheritDoc} |
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* @throws NullPointerException {@inheritDoc} |
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* @throws IllegalArgumentException {@inheritDoc} |
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* @throws IndexOutOfBoundsException {@inheritDoc} |
131 |
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*/ |
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public E set(int index, E element) { |
133 |
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throw new UnsupportedOperationException(); |
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} |
135 |
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136 |
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/** |
137 |
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* {@inheritDoc} |
138 |
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* |
139 |
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* <p>This implementation always throws an |
140 |
jsr166 |
1.12 |
* {@code UnsupportedOperationException}. |
141 |
dl |
1.1 |
* |
142 |
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* @throws UnsupportedOperationException {@inheritDoc} |
143 |
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* @throws ClassCastException {@inheritDoc} |
144 |
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* @throws NullPointerException {@inheritDoc} |
145 |
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* @throws IllegalArgumentException {@inheritDoc} |
146 |
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* @throws IndexOutOfBoundsException {@inheritDoc} |
147 |
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*/ |
148 |
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public void add(int index, E element) { |
149 |
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throw new UnsupportedOperationException(); |
150 |
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} |
151 |
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152 |
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/** |
153 |
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* {@inheritDoc} |
154 |
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* |
155 |
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* <p>This implementation always throws an |
156 |
jsr166 |
1.12 |
* {@code UnsupportedOperationException}. |
157 |
dl |
1.1 |
* |
158 |
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* @throws UnsupportedOperationException {@inheritDoc} |
159 |
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* @throws IndexOutOfBoundsException {@inheritDoc} |
160 |
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*/ |
161 |
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public E remove(int index) { |
162 |
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throw new UnsupportedOperationException(); |
163 |
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} |
164 |
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165 |
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166 |
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// Search Operations |
167 |
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168 |
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/** |
169 |
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* {@inheritDoc} |
170 |
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* |
171 |
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* <p>This implementation first gets a list iterator (with |
172 |
jsr166 |
1.12 |
* {@code listIterator()}). Then, it iterates over the list until the |
173 |
dl |
1.1 |
* specified element is found or the end of the list is reached. |
174 |
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* |
175 |
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* @throws ClassCastException {@inheritDoc} |
176 |
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* @throws NullPointerException {@inheritDoc} |
177 |
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*/ |
178 |
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public int indexOf(Object o) { |
179 |
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ListIterator<E> e = listIterator(); |
180 |
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if (o==null) { |
181 |
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while (e.hasNext()) |
182 |
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if (e.next()==null) |
183 |
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return e.previousIndex(); |
184 |
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} else { |
185 |
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while (e.hasNext()) |
186 |
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if (o.equals(e.next())) |
187 |
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return e.previousIndex(); |
188 |
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} |
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return -1; |
190 |
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} |
191 |
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192 |
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/** |
193 |
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* {@inheritDoc} |
194 |
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* |
195 |
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* <p>This implementation first gets a list iterator that points to the end |
196 |
jsr166 |
1.12 |
* of the list (with {@code listIterator(size())}). Then, it iterates |
197 |
dl |
1.1 |
* backwards over the list until the specified element is found, or the |
198 |
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* beginning of the list is reached. |
199 |
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* |
200 |
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* @throws ClassCastException {@inheritDoc} |
201 |
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* @throws NullPointerException {@inheritDoc} |
202 |
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*/ |
203 |
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public int lastIndexOf(Object o) { |
204 |
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ListIterator<E> e = listIterator(size()); |
205 |
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if (o==null) { |
206 |
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while (e.hasPrevious()) |
207 |
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if (e.previous()==null) |
208 |
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return e.nextIndex(); |
209 |
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} else { |
210 |
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while (e.hasPrevious()) |
211 |
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if (o.equals(e.previous())) |
212 |
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return e.nextIndex(); |
213 |
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} |
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return -1; |
215 |
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} |
216 |
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217 |
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|
218 |
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// Bulk Operations |
219 |
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|
220 |
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/** |
221 |
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* Removes all of the elements from this list (optional operation). |
222 |
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* The list will be empty after this call returns. |
223 |
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* |
224 |
jsr166 |
1.12 |
* <p>This implementation calls {@code removeRange(0, size())}. |
225 |
dl |
1.1 |
* |
226 |
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* <p>Note that this implementation throws an |
227 |
jsr166 |
1.12 |
* {@code UnsupportedOperationException} unless {@code remove(int |
228 |
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* index)} or {@code removeRange(int fromIndex, int toIndex)} is |
229 |
dl |
1.1 |
* overridden. |
230 |
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* |
231 |
jsr166 |
1.12 |
* @throws UnsupportedOperationException if the {@code clear} operation |
232 |
dl |
1.1 |
* is not supported by this list |
233 |
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*/ |
234 |
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public void clear() { |
235 |
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removeRange(0, size()); |
236 |
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} |
237 |
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|
238 |
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/** |
239 |
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* {@inheritDoc} |
240 |
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* |
241 |
jsr166 |
1.13 |
* <p>This implementation gets an iterator over the specified collection |
242 |
|
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* and iterates over it, inserting the elements obtained from the |
243 |
|
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* iterator into this list at the appropriate position, one at a time, |
244 |
|
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* using {@code add(int, E)}. |
245 |
|
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* Many implementations will override this method for efficiency. |
246 |
dl |
1.1 |
* |
247 |
|
|
* <p>Note that this implementation throws an |
248 |
jsr166 |
1.13 |
* {@code UnsupportedOperationException} unless |
249 |
|
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* {@link #add(int, Object) add(int, E)} is overridden. |
250 |
dl |
1.1 |
* |
251 |
|
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* @throws UnsupportedOperationException {@inheritDoc} |
252 |
|
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* @throws ClassCastException {@inheritDoc} |
253 |
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* @throws NullPointerException {@inheritDoc} |
254 |
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* @throws IllegalArgumentException {@inheritDoc} |
255 |
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* @throws IndexOutOfBoundsException {@inheritDoc} |
256 |
|
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*/ |
257 |
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public boolean addAll(int index, Collection<? extends E> c) { |
258 |
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boolean modified = false; |
259 |
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Iterator<? extends E> e = c.iterator(); |
260 |
|
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while (e.hasNext()) { |
261 |
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add(index++, e.next()); |
262 |
|
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modified = true; |
263 |
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} |
264 |
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return modified; |
265 |
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} |
266 |
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267 |
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|
268 |
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// Iterators |
269 |
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|
270 |
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/** |
271 |
jsr166 |
1.14 |
* Returns an iterator over the elements in this list in proper sequence. |
272 |
dl |
1.1 |
* |
273 |
jsr166 |
1.13 |
* <p>This implementation returns a straightforward implementation of the |
274 |
jsr166 |
1.12 |
* iterator interface, relying on the backing list's {@code size()}, |
275 |
jsr166 |
1.13 |
* {@code get(int)}, and {@code remove(int)} methods. |
276 |
dl |
1.1 |
* |
277 |
jsr166 |
1.13 |
* <p>Note that the iterator returned by this method will throw an |
278 |
jsr166 |
1.12 |
* {@code UnsupportedOperationException} in response to its |
279 |
|
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* {@code remove} method unless the list's {@code remove(int)} method is |
280 |
jsr166 |
1.13 |
* overridden. |
281 |
dl |
1.1 |
* |
282 |
jsr166 |
1.13 |
* <p>This implementation can be made to throw runtime exceptions in the |
283 |
|
|
* face of concurrent modification, as described in the specification |
284 |
|
|
* for the (protected) {@code modCount} field. |
285 |
dl |
1.1 |
* |
286 |
|
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* @return an iterator over the elements in this list in proper sequence |
287 |
|
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* |
288 |
|
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* @see #modCount |
289 |
|
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*/ |
290 |
|
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public Iterator<E> iterator() { |
291 |
|
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return new Itr(); |
292 |
|
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} |
293 |
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|
294 |
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/** |
295 |
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* {@inheritDoc} |
296 |
|
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* |
297 |
jsr166 |
1.12 |
* <p>This implementation returns {@code listIterator(0)}. |
298 |
dl |
1.1 |
* |
299 |
|
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* @see #listIterator(int) |
300 |
|
|
*/ |
301 |
|
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public ListIterator<E> listIterator() { |
302 |
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return listIterator(0); |
303 |
|
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} |
304 |
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|
305 |
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/** |
306 |
|
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* {@inheritDoc} |
307 |
|
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* |
308 |
|
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* <p>This implementation returns a straightforward implementation of the |
309 |
jsr166 |
1.12 |
* {@code ListIterator} interface that extends the implementation of the |
310 |
|
|
* {@code Iterator} interface returned by the {@code iterator()} method. |
311 |
|
|
* The {@code ListIterator} implementation relies on the backing list's |
312 |
jsr166 |
1.14 |
* {@code get(int)}, {@code set(int, E)}, {@code add(int, E)} |
313 |
jsr166 |
1.12 |
* and {@code remove(int)} methods. |
314 |
dl |
1.1 |
* |
315 |
|
|
* <p>Note that the list iterator returned by this implementation will |
316 |
jsr166 |
1.12 |
* throw an {@code UnsupportedOperationException} in response to its |
317 |
|
|
* {@code remove}, {@code set} and {@code add} methods unless the |
318 |
jsr166 |
1.13 |
* list's {@code remove(int)}, {@code set(int, E)}, and |
319 |
|
|
* {@code add(int, E)} methods are overridden. |
320 |
dl |
1.1 |
* |
321 |
|
|
* <p>This implementation can be made to throw runtime exceptions in the |
322 |
|
|
* face of concurrent modification, as described in the specification for |
323 |
jsr166 |
1.12 |
* the (protected) {@code modCount} field. |
324 |
dl |
1.1 |
* |
325 |
|
|
* @throws IndexOutOfBoundsException {@inheritDoc} |
326 |
|
|
* |
327 |
|
|
* @see #modCount |
328 |
|
|
*/ |
329 |
|
|
public ListIterator<E> listIterator(final int index) { |
330 |
|
|
if (index<0 || index>size()) |
331 |
|
|
throw new IndexOutOfBoundsException("Index: "+index); |
332 |
|
|
|
333 |
|
|
return new ListItr(index); |
334 |
|
|
} |
335 |
|
|
|
336 |
|
|
private class Itr implements Iterator<E> { |
337 |
|
|
/** |
338 |
|
|
* Index of element to be returned by subsequent call to next. |
339 |
|
|
*/ |
340 |
|
|
int cursor = 0; |
341 |
|
|
|
342 |
|
|
/** |
343 |
|
|
* Index of element returned by most recent call to next or |
344 |
|
|
* previous. Reset to -1 if this element is deleted by a call |
345 |
|
|
* to remove. |
346 |
|
|
*/ |
347 |
|
|
int lastRet = -1; |
348 |
|
|
|
349 |
|
|
/** |
350 |
|
|
* The modCount value that the iterator believes that the backing |
351 |
|
|
* List should have. If this expectation is violated, the iterator |
352 |
|
|
* has detected concurrent modification. |
353 |
|
|
*/ |
354 |
|
|
int expectedModCount = modCount; |
355 |
|
|
|
356 |
dl |
1.4 |
public boolean hasNext() { |
357 |
|
|
return cursor != size(); |
358 |
dl |
1.1 |
} |
359 |
|
|
|
360 |
dl |
1.4 |
public E next() { |
361 |
dl |
1.8 |
checkForComodification(); |
362 |
|
|
try { |
363 |
|
|
E next = get(cursor); |
364 |
|
|
lastRet = cursor++; |
365 |
|
|
return next; |
366 |
|
|
} catch (IndexOutOfBoundsException e) { |
367 |
|
|
checkForComodification(); |
368 |
|
|
throw new NoSuchElementException(); |
369 |
|
|
} |
370 |
dl |
1.1 |
} |
371 |
|
|
|
372 |
dl |
1.4 |
public void remove() { |
373 |
dl |
1.1 |
if (lastRet == -1) |
374 |
|
|
throw new IllegalStateException(); |
375 |
dl |
1.8 |
checkForComodification(); |
376 |
|
|
|
377 |
dl |
1.1 |
try { |
378 |
|
|
AbstractList.this.remove(lastRet); |
379 |
|
|
if (lastRet < cursor) |
380 |
|
|
cursor--; |
381 |
|
|
lastRet = -1; |
382 |
|
|
expectedModCount = modCount; |
383 |
|
|
} catch (IndexOutOfBoundsException e) { |
384 |
|
|
throw new ConcurrentModificationException(); |
385 |
|
|
} |
386 |
|
|
} |
387 |
dl |
1.8 |
|
388 |
|
|
final void checkForComodification() { |
389 |
|
|
if (modCount != expectedModCount) |
390 |
|
|
throw new ConcurrentModificationException(); |
391 |
|
|
} |
392 |
dl |
1.1 |
} |
393 |
jsr166 |
1.6 |
|
394 |
dl |
1.4 |
private class ListItr extends Itr implements ListIterator<E> { |
395 |
dl |
1.1 |
ListItr(int index) { |
396 |
|
|
cursor = index; |
397 |
|
|
} |
398 |
|
|
|
399 |
|
|
public boolean hasPrevious() { |
400 |
dl |
1.4 |
return cursor != 0; |
401 |
dl |
1.1 |
} |
402 |
|
|
|
403 |
dl |
1.8 |
public E previous() { |
404 |
|
|
checkForComodification(); |
405 |
|
|
try { |
406 |
|
|
int i = cursor - 1; |
407 |
|
|
E previous = get(i); |
408 |
|
|
lastRet = cursor = i; |
409 |
|
|
return previous; |
410 |
|
|
} catch (IndexOutOfBoundsException e) { |
411 |
|
|
checkForComodification(); |
412 |
|
|
throw new NoSuchElementException(); |
413 |
|
|
} |
414 |
|
|
} |
415 |
|
|
|
416 |
dl |
1.1 |
public int nextIndex() { |
417 |
|
|
return cursor; |
418 |
|
|
} |
419 |
|
|
|
420 |
|
|
public int previousIndex() { |
421 |
dl |
1.8 |
return cursor-1; |
422 |
dl |
1.1 |
} |
423 |
|
|
|
424 |
|
|
public void set(E e) { |
425 |
|
|
if (lastRet == -1) |
426 |
|
|
throw new IllegalStateException(); |
427 |
dl |
1.8 |
checkForComodification(); |
428 |
|
|
|
429 |
dl |
1.1 |
try { |
430 |
|
|
AbstractList.this.set(lastRet, e); |
431 |
|
|
expectedModCount = modCount; |
432 |
|
|
} catch (IndexOutOfBoundsException ex) { |
433 |
|
|
throw new ConcurrentModificationException(); |
434 |
|
|
} |
435 |
|
|
} |
436 |
|
|
|
437 |
|
|
public void add(E e) { |
438 |
dl |
1.8 |
checkForComodification(); |
439 |
|
|
|
440 |
dl |
1.1 |
try { |
441 |
|
|
int i = cursor; |
442 |
|
|
AbstractList.this.add(i, e); |
443 |
|
|
cursor = i + 1; |
444 |
|
|
lastRet = -1; |
445 |
|
|
expectedModCount = modCount; |
446 |
|
|
} catch (IndexOutOfBoundsException ex) { |
447 |
|
|
throw new ConcurrentModificationException(); |
448 |
|
|
} |
449 |
|
|
} |
450 |
|
|
} |
451 |
|
|
|
452 |
|
|
/** |
453 |
|
|
* {@inheritDoc} |
454 |
|
|
* |
455 |
|
|
* <p>This implementation returns a list that subclasses |
456 |
jsr166 |
1.12 |
* {@code AbstractList}. The subclass stores, in private fields, the |
457 |
dl |
1.1 |
* offset of the subList within the backing list, the size of the subList |
458 |
|
|
* (which can change over its lifetime), and the expected |
459 |
jsr166 |
1.12 |
* {@code modCount} value of the backing list. There are two variants |
460 |
|
|
* of the subclass, one of which implements {@code RandomAccess}. |
461 |
|
|
* If this list implements {@code RandomAccess} the returned list will |
462 |
|
|
* be an instance of the subclass that implements {@code RandomAccess}. |
463 |
|
|
* |
464 |
jsr166 |
1.14 |
* <p>The subclass's {@code set(int, E)}, {@code get(int)}, |
465 |
|
|
* {@code add(int, E)}, {@code remove(int)}, {@code addAll(int, |
466 |
jsr166 |
1.12 |
* Collection)} and {@code removeRange(int, int)} methods all |
467 |
dl |
1.1 |
* delegate to the corresponding methods on the backing abstract list, |
468 |
|
|
* after bounds-checking the index and adjusting for the offset. The |
469 |
jsr166 |
1.12 |
* {@code addAll(Collection c)} method merely returns {@code addAll(size, |
470 |
|
|
* c)}. |
471 |
dl |
1.1 |
* |
472 |
jsr166 |
1.12 |
* <p>The {@code listIterator(int)} method returns a "wrapper object" |
473 |
dl |
1.1 |
* over a list iterator on the backing list, which is created with the |
474 |
jsr166 |
1.12 |
* corresponding method on the backing list. The {@code iterator} method |
475 |
|
|
* merely returns {@code listIterator()}, and the {@code size} method |
476 |
|
|
* merely returns the subclass's {@code size} field. |
477 |
dl |
1.1 |
* |
478 |
jsr166 |
1.12 |
* <p>All methods first check to see if the actual {@code modCount} of |
479 |
dl |
1.1 |
* the backing list is equal to its expected value, and throw a |
480 |
jsr166 |
1.12 |
* {@code ConcurrentModificationException} if it is not. |
481 |
dl |
1.1 |
* |
482 |
|
|
* @throws IndexOutOfBoundsException endpoint index value out of range |
483 |
jsr166 |
1.14 |
* {@code (fromIndex < 0 || toIndex > size)} |
484 |
dl |
1.1 |
* @throws IllegalArgumentException if the endpoint indices are out of order |
485 |
jsr166 |
1.14 |
* {@code (fromIndex > toIndex)} |
486 |
dl |
1.1 |
*/ |
487 |
|
|
public List<E> subList(int fromIndex, int toIndex) { |
488 |
|
|
return (this instanceof RandomAccess ? |
489 |
dl |
1.8 |
new RandomAccessSubList(this, this, fromIndex, fromIndex, toIndex) : |
490 |
|
|
new SubList(this, this, fromIndex, fromIndex, toIndex)); |
491 |
dl |
1.1 |
} |
492 |
|
|
|
493 |
|
|
// Comparison and hashing |
494 |
|
|
|
495 |
|
|
/** |
496 |
|
|
* Compares the specified object with this list for equality. Returns |
497 |
jsr166 |
1.12 |
* {@code true} if and only if the specified object is also a list, both |
498 |
dl |
1.1 |
* lists have the same size, and all corresponding pairs of elements in |
499 |
jsr166 |
1.12 |
* the two lists are <i>equal</i>. (Two elements {@code e1} and |
500 |
|
|
* {@code e2} are <i>equal</i> if {@code (e1==null ? e2==null : |
501 |
|
|
* e1.equals(e2))}.) In other words, two lists are defined to be |
502 |
jsr166 |
1.13 |
* equal if they contain the same elements in the same order. |
503 |
dl |
1.1 |
* |
504 |
jsr166 |
1.13 |
* <p>This implementation first checks if the specified object is this |
505 |
jsr166 |
1.12 |
* list. If so, it returns {@code true}; if not, it checks if the |
506 |
|
|
* specified object is a list. If not, it returns {@code false}; if so, |
507 |
dl |
1.1 |
* it iterates over both lists, comparing corresponding pairs of elements. |
508 |
jsr166 |
1.12 |
* If any comparison returns {@code false}, this method returns |
509 |
|
|
* {@code false}. If either iterator runs out of elements before the |
510 |
|
|
* other it returns {@code false} (as the lists are of unequal length); |
511 |
|
|
* otherwise it returns {@code true} when the iterations complete. |
512 |
dl |
1.1 |
* |
513 |
|
|
* @param o the object to be compared for equality with this list |
514 |
jsr166 |
1.12 |
* @return {@code true} if the specified object is equal to this list |
515 |
dl |
1.1 |
*/ |
516 |
|
|
public boolean equals(Object o) { |
517 |
|
|
if (o == this) |
518 |
|
|
return true; |
519 |
|
|
if (!(o instanceof List)) |
520 |
|
|
return false; |
521 |
|
|
|
522 |
|
|
ListIterator<E> e1 = listIterator(); |
523 |
|
|
ListIterator e2 = ((List) o).listIterator(); |
524 |
|
|
while(e1.hasNext() && e2.hasNext()) { |
525 |
|
|
E o1 = e1.next(); |
526 |
|
|
Object o2 = e2.next(); |
527 |
|
|
if (!(o1==null ? o2==null : o1.equals(o2))) |
528 |
|
|
return false; |
529 |
|
|
} |
530 |
|
|
return !(e1.hasNext() || e2.hasNext()); |
531 |
|
|
} |
532 |
|
|
|
533 |
|
|
/** |
534 |
jsr166 |
1.13 |
* Returns the hash code value for this list. |
535 |
dl |
1.1 |
* |
536 |
jsr166 |
1.13 |
* <p>This implementation uses exactly the code that is used to define the |
537 |
dl |
1.1 |
* list hash function in the documentation for the {@link List#hashCode} |
538 |
|
|
* method. |
539 |
|
|
* |
540 |
|
|
* @return the hash code value for this list |
541 |
|
|
*/ |
542 |
|
|
public int hashCode() { |
543 |
|
|
int hashCode = 1; |
544 |
|
|
Iterator<E> i = iterator(); |
545 |
|
|
while (i.hasNext()) { |
546 |
|
|
E obj = i.next(); |
547 |
|
|
hashCode = 31*hashCode + (obj==null ? 0 : obj.hashCode()); |
548 |
|
|
} |
549 |
|
|
return hashCode; |
550 |
|
|
} |
551 |
|
|
|
552 |
|
|
/** |
553 |
|
|
* Removes from this list all of the elements whose index is between |
554 |
jsr166 |
1.12 |
* {@code fromIndex}, inclusive, and {@code toIndex}, exclusive. |
555 |
dl |
1.1 |
* Shifts any succeeding elements to the left (reduces their index). |
556 |
jsr166 |
1.12 |
* This call shortens the ArrayList by {@code (toIndex - fromIndex)} |
557 |
|
|
* elements. (If {@code toIndex==fromIndex}, this operation has no |
558 |
jsr166 |
1.13 |
* effect.) |
559 |
dl |
1.1 |
* |
560 |
jsr166 |
1.13 |
* <p>This method is called by the {@code clear} operation on this list |
561 |
dl |
1.1 |
* and its subLists. Overriding this method to take advantage of |
562 |
|
|
* the internals of the list implementation can <i>substantially</i> |
563 |
jsr166 |
1.12 |
* improve the performance of the {@code clear} operation on this list |
564 |
jsr166 |
1.13 |
* and its subLists. |
565 |
dl |
1.1 |
* |
566 |
jsr166 |
1.13 |
* <p>This implementation gets a list iterator positioned before |
567 |
jsr166 |
1.12 |
* {@code fromIndex}, and repeatedly calls {@code ListIterator.next} |
568 |
|
|
* followed by {@code ListIterator.remove} until the entire range has |
569 |
|
|
* been removed. <b>Note: if {@code ListIterator.remove} requires linear |
570 |
dl |
1.1 |
* time, this implementation requires quadratic time.</b> |
571 |
|
|
* |
572 |
|
|
* @param fromIndex index of first element to be removed |
573 |
|
|
* @param toIndex index after last element to be removed |
574 |
|
|
*/ |
575 |
|
|
protected void removeRange(int fromIndex, int toIndex) { |
576 |
|
|
ListIterator<E> it = listIterator(fromIndex); |
577 |
|
|
for (int i=0, n=toIndex-fromIndex; i<n; i++) { |
578 |
|
|
it.next(); |
579 |
|
|
it.remove(); |
580 |
|
|
} |
581 |
|
|
} |
582 |
|
|
|
583 |
|
|
/** |
584 |
|
|
* The number of times this list has been <i>structurally modified</i>. |
585 |
|
|
* Structural modifications are those that change the size of the |
586 |
|
|
* list, or otherwise perturb it in such a fashion that iterations in |
587 |
jsr166 |
1.13 |
* progress may yield incorrect results. |
588 |
dl |
1.1 |
* |
589 |
jsr166 |
1.13 |
* <p>This field is used by the iterator and list iterator implementation |
590 |
jsr166 |
1.12 |
* returned by the {@code iterator} and {@code listIterator} methods. |
591 |
dl |
1.1 |
* If the value of this field changes unexpectedly, the iterator (or list |
592 |
jsr166 |
1.12 |
* iterator) will throw a {@code ConcurrentModificationException} in |
593 |
|
|
* response to the {@code next}, {@code remove}, {@code previous}, |
594 |
|
|
* {@code set} or {@code add} operations. This provides |
595 |
dl |
1.1 |
* <i>fail-fast</i> behavior, rather than non-deterministic behavior in |
596 |
jsr166 |
1.13 |
* the face of concurrent modification during iteration. |
597 |
dl |
1.1 |
* |
598 |
jsr166 |
1.13 |
* <p><b>Use of this field by subclasses is optional.</b> If a subclass |
599 |
dl |
1.1 |
* wishes to provide fail-fast iterators (and list iterators), then it |
600 |
jsr166 |
1.14 |
* merely has to increment this field in its {@code add(int, E)} and |
601 |
jsr166 |
1.12 |
* {@code remove(int)} methods (and any other methods that it overrides |
602 |
dl |
1.1 |
* that result in structural modifications to the list). A single call to |
603 |
jsr166 |
1.14 |
* {@code add(int, E)} or {@code remove(int)} must add no more than |
604 |
dl |
1.1 |
* one to this field, or the iterators (and list iterators) will throw |
605 |
jsr166 |
1.12 |
* bogus {@code ConcurrentModificationExceptions}. If an implementation |
606 |
dl |
1.1 |
* does not wish to provide fail-fast iterators, this field may be |
607 |
|
|
* ignored. |
608 |
|
|
*/ |
609 |
|
|
protected transient int modCount = 0; |
610 |
|
|
} |
611 |
|
|
|
612 |
dl |
1.8 |
/** |
613 |
|
|
* Generic sublists. Non-nested to enable construction by other |
614 |
|
|
* classes in this package. |
615 |
|
|
*/ |
616 |
dl |
1.1 |
class SubList<E> extends AbstractList<E> { |
617 |
dl |
1.8 |
/* |
618 |
|
|
* A SubList has both a "base", the ultimate backing list, as well |
619 |
|
|
* as a "parent", which is the list or sublist creating this |
620 |
|
|
* sublist. All methods that may cause structural modifications |
621 |
|
|
* must propagate through the parent link, with O(k) performance |
622 |
|
|
* where k is sublist depth. For example in the case of a |
623 |
|
|
* sub-sub-list, invoking remove(x) will result in a chain of |
624 |
|
|
* three remove calls. However, all other non-structurally |
625 |
|
|
* modifying methods can bypass this chain, and relay directly to |
626 |
|
|
* the base list. In particular, doing so signficantly speeds up |
627 |
|
|
* the performance of iterators for deeply-nested sublists. |
628 |
|
|
*/ |
629 |
|
|
final AbstractList<E> base; // Backing list |
630 |
|
|
final AbstractList<E> parent; // Parent list |
631 |
|
|
final int baseOffset; // index wrt base |
632 |
|
|
final int parentOffset; // index wrt parent |
633 |
|
|
int length; // Number of elements in this sublist |
634 |
|
|
|
635 |
|
|
SubList(AbstractList<E> base, |
636 |
jsr166 |
1.9 |
AbstractList<E> parent, |
637 |
|
|
int baseIndex, |
638 |
|
|
int fromIndex, |
639 |
dl |
1.8 |
int toIndex) { |
640 |
dl |
1.1 |
if (fromIndex < 0) |
641 |
|
|
throw new IndexOutOfBoundsException("fromIndex = " + fromIndex); |
642 |
dl |
1.8 |
if (toIndex > parent.size()) |
643 |
dl |
1.1 |
throw new IndexOutOfBoundsException("toIndex = " + toIndex); |
644 |
|
|
if (fromIndex > toIndex) |
645 |
|
|
throw new IllegalArgumentException("fromIndex(" + fromIndex + |
646 |
|
|
") > toIndex(" + toIndex + ")"); |
647 |
dl |
1.8 |
this.base = base; |
648 |
|
|
this.parent = parent; |
649 |
|
|
this.baseOffset = baseIndex; |
650 |
|
|
this.parentOffset = fromIndex; |
651 |
|
|
this.length = toIndex - fromIndex; |
652 |
|
|
this.modCount = base.modCount; |
653 |
|
|
} |
654 |
|
|
|
655 |
|
|
/** |
656 |
|
|
* Returns an IndexOutOfBoundsException with nicer message |
657 |
|
|
*/ |
658 |
|
|
private IndexOutOfBoundsException indexError(int index) { |
659 |
jsr166 |
1.9 |
return new IndexOutOfBoundsException("Index: " + index + |
660 |
dl |
1.8 |
", Size: " + length); |
661 |
dl |
1.1 |
} |
662 |
|
|
|
663 |
|
|
public E set(int index, E element) { |
664 |
dl |
1.8 |
if (index < 0 || index >= length) |
665 |
|
|
throw indexError(index); |
666 |
|
|
if (base.modCount != modCount) |
667 |
|
|
throw new ConcurrentModificationException(); |
668 |
|
|
return base.set(index + baseOffset, element); |
669 |
dl |
1.1 |
} |
670 |
|
|
|
671 |
|
|
public E get(int index) { |
672 |
dl |
1.8 |
if (index < 0 || index >= length) |
673 |
|
|
throw indexError(index); |
674 |
|
|
if (base.modCount != modCount) |
675 |
|
|
throw new ConcurrentModificationException(); |
676 |
|
|
return base.get(index + baseOffset); |
677 |
dl |
1.1 |
} |
678 |
|
|
|
679 |
|
|
public int size() { |
680 |
dl |
1.8 |
if (base.modCount != modCount) |
681 |
|
|
throw new ConcurrentModificationException(); |
682 |
|
|
return length; |
683 |
dl |
1.1 |
} |
684 |
|
|
|
685 |
|
|
public void add(int index, E element) { |
686 |
dl |
1.8 |
if (index < 0 || index>length) |
687 |
|
|
throw indexError(index); |
688 |
|
|
if (base.modCount != modCount) |
689 |
|
|
throw new ConcurrentModificationException(); |
690 |
|
|
parent.add(index + parentOffset, element); |
691 |
|
|
length++; |
692 |
|
|
modCount = base.modCount; |
693 |
dl |
1.1 |
} |
694 |
|
|
|
695 |
|
|
public E remove(int index) { |
696 |
dl |
1.8 |
if (index < 0 || index >= length) |
697 |
|
|
throw indexError(index); |
698 |
|
|
if (base.modCount != modCount) |
699 |
|
|
throw new ConcurrentModificationException(); |
700 |
|
|
E result = parent.remove(index + parentOffset); |
701 |
|
|
length--; |
702 |
|
|
modCount = base.modCount; |
703 |
dl |
1.1 |
return result; |
704 |
|
|
} |
705 |
|
|
|
706 |
|
|
protected void removeRange(int fromIndex, int toIndex) { |
707 |
dl |
1.8 |
if (base.modCount != modCount) |
708 |
|
|
throw new ConcurrentModificationException(); |
709 |
|
|
parent.removeRange(fromIndex + parentOffset, toIndex + parentOffset); |
710 |
|
|
length -= (toIndex-fromIndex); |
711 |
|
|
modCount = base.modCount; |
712 |
dl |
1.1 |
} |
713 |
|
|
|
714 |
|
|
public boolean addAll(Collection<? extends E> c) { |
715 |
dl |
1.8 |
return addAll(length, c); |
716 |
dl |
1.1 |
} |
717 |
|
|
|
718 |
|
|
public boolean addAll(int index, Collection<? extends E> c) { |
719 |
dl |
1.8 |
if (index < 0 || index > length) |
720 |
|
|
throw indexError(index); |
721 |
dl |
1.1 |
int cSize = c.size(); |
722 |
|
|
if (cSize==0) |
723 |
|
|
return false; |
724 |
|
|
|
725 |
dl |
1.8 |
if (base.modCount != modCount) |
726 |
|
|
throw new ConcurrentModificationException(); |
727 |
|
|
parent.addAll(parentOffset + index, c); |
728 |
|
|
length += cSize; |
729 |
|
|
modCount = base.modCount; |
730 |
dl |
1.1 |
return true; |
731 |
|
|
} |
732 |
|
|
|
733 |
dl |
1.8 |
public List<E> subList(int fromIndex, int toIndex) { |
734 |
jsr166 |
1.9 |
return new SubList(base, this, fromIndex + baseOffset, |
735 |
dl |
1.8 |
fromIndex, toIndex); |
736 |
|
|
} |
737 |
|
|
|
738 |
dl |
1.1 |
public Iterator<E> iterator() { |
739 |
dl |
1.8 |
return new SubListIterator(this, 0); |
740 |
|
|
} |
741 |
|
|
|
742 |
|
|
public ListIterator<E> listIterator() { |
743 |
|
|
return new SubListIterator(this, 0); |
744 |
dl |
1.1 |
} |
745 |
|
|
|
746 |
dl |
1.8 |
public ListIterator<E> listIterator(int index) { |
747 |
|
|
if (index < 0 || index>length) |
748 |
|
|
throw indexError(index); |
749 |
|
|
return new SubListIterator(this, index); |
750 |
|
|
} |
751 |
dl |
1.1 |
|
752 |
dl |
1.8 |
/** |
753 |
|
|
* Generic sublist iterator obeying fastfail semantics via |
754 |
|
|
* modCount. The hasNext and next methods locally check for |
755 |
|
|
* in-range indices before relaying to backing list to get |
756 |
|
|
* element. If this either encounters an unexpected modCount or |
757 |
|
|
* fails, the backing list must have been concurrently modified, |
758 |
|
|
* and is so reported. The add and remove methods performing |
759 |
|
|
* structural modifications instead relay them through the |
760 |
|
|
* sublist. |
761 |
|
|
*/ |
762 |
|
|
private static final class SubListIterator<E> implements ListIterator<E> { |
763 |
|
|
final SubList<E> outer; // Sublist creating this iteraor |
764 |
|
|
final AbstractList<E> base; // base list |
765 |
|
|
final int offset; // Cursor offset wrt base |
766 |
|
|
int cursor; // Current index |
767 |
|
|
int fence; // Upper bound on cursor |
768 |
|
|
int lastRet; // Index of returned element, or -1 |
769 |
jsr166 |
1.9 |
int expectedModCount; // Expected modCount of base |
770 |
dl |
1.8 |
|
771 |
|
|
SubListIterator(SubList<E> list, int index) { |
772 |
|
|
this.lastRet = -1; |
773 |
|
|
this.cursor = index; |
774 |
|
|
this.outer = list; |
775 |
|
|
this.offset = list.baseOffset; |
776 |
|
|
this.fence = list.length; |
777 |
|
|
this.base = list.base; |
778 |
|
|
this.expectedModCount = base.modCount; |
779 |
|
|
} |
780 |
dl |
1.1 |
|
781 |
dl |
1.8 |
public boolean hasNext() { |
782 |
|
|
return cursor < fence; |
783 |
|
|
} |
784 |
dl |
1.1 |
|
785 |
dl |
1.8 |
public boolean hasPrevious() { |
786 |
|
|
return cursor > 0; |
787 |
|
|
} |
788 |
dl |
1.1 |
|
789 |
dl |
1.8 |
public int nextIndex() { |
790 |
|
|
return cursor; |
791 |
|
|
} |
792 |
dl |
1.1 |
|
793 |
dl |
1.8 |
public int previousIndex() { |
794 |
|
|
return cursor - 1; |
795 |
|
|
} |
796 |
dl |
1.1 |
|
797 |
dl |
1.8 |
public E next() { |
798 |
|
|
int i = cursor; |
799 |
|
|
if (cursor >= fence) |
800 |
|
|
throw new NoSuchElementException(); |
801 |
|
|
if (expectedModCount == base.modCount) { |
802 |
|
|
try { |
803 |
|
|
Object next = base.get(i + offset); |
804 |
|
|
lastRet = i; |
805 |
|
|
cursor = i + 1; |
806 |
|
|
return (E)next; |
807 |
|
|
} catch (IndexOutOfBoundsException fallThrough) { |
808 |
|
|
} |
809 |
dl |
1.1 |
} |
810 |
dl |
1.8 |
throw new ConcurrentModificationException(); |
811 |
|
|
} |
812 |
dl |
1.1 |
|
813 |
dl |
1.8 |
public E previous() { |
814 |
|
|
int i = cursor - 1; |
815 |
|
|
if (i < 0) |
816 |
|
|
throw new NoSuchElementException(); |
817 |
|
|
if (expectedModCount == base.modCount) { |
818 |
|
|
try { |
819 |
|
|
Object prev = base.get(i + offset); |
820 |
|
|
lastRet = i; |
821 |
|
|
cursor = i; |
822 |
|
|
return (E)prev; |
823 |
|
|
} catch (IndexOutOfBoundsException fallThrough) { |
824 |
|
|
} |
825 |
dl |
1.1 |
} |
826 |
dl |
1.8 |
throw new ConcurrentModificationException(); |
827 |
|
|
} |
828 |
dl |
1.1 |
|
829 |
dl |
1.8 |
public void set(E e) { |
830 |
|
|
if (lastRet < 0) |
831 |
|
|
throw new IllegalStateException(); |
832 |
|
|
if (expectedModCount != base.modCount) |
833 |
|
|
throw new ConcurrentModificationException(); |
834 |
|
|
try { |
835 |
|
|
outer.set(lastRet, e); |
836 |
|
|
expectedModCount = base.modCount; |
837 |
|
|
} catch (IndexOutOfBoundsException ex) { |
838 |
|
|
throw new ConcurrentModificationException(); |
839 |
dl |
1.1 |
} |
840 |
dl |
1.8 |
} |
841 |
dl |
1.1 |
|
842 |
dl |
1.8 |
public void remove() { |
843 |
|
|
int i = lastRet; |
844 |
|
|
if (i < 0) |
845 |
|
|
throw new IllegalStateException(); |
846 |
|
|
if (expectedModCount != base.modCount) |
847 |
|
|
throw new ConcurrentModificationException(); |
848 |
|
|
try { |
849 |
|
|
outer.remove(i); |
850 |
|
|
if (i < cursor) |
851 |
|
|
cursor--; |
852 |
|
|
lastRet = -1; |
853 |
|
|
fence = outer.length; |
854 |
|
|
expectedModCount = base.modCount; |
855 |
|
|
} catch (IndexOutOfBoundsException ex) { |
856 |
|
|
throw new ConcurrentModificationException(); |
857 |
dl |
1.1 |
} |
858 |
dl |
1.8 |
} |
859 |
dl |
1.1 |
|
860 |
dl |
1.8 |
public void add(E e) { |
861 |
|
|
if (expectedModCount != base.modCount) |
862 |
|
|
throw new ConcurrentModificationException(); |
863 |
|
|
try { |
864 |
|
|
int i = cursor; |
865 |
|
|
outer.add(i, e); |
866 |
|
|
cursor = i + 1; |
867 |
|
|
lastRet = -1; |
868 |
|
|
fence = outer.length; |
869 |
|
|
expectedModCount = base.modCount; |
870 |
|
|
} catch (IndexOutOfBoundsException ex) { |
871 |
|
|
throw new ConcurrentModificationException(); |
872 |
dl |
1.1 |
} |
873 |
dl |
1.8 |
} |
874 |
dl |
1.1 |
} |
875 |
|
|
|
876 |
|
|
} |
877 |
|
|
|
878 |
|
|
class RandomAccessSubList<E> extends SubList<E> implements RandomAccess { |
879 |
dl |
1.8 |
RandomAccessSubList(AbstractList<E> base, |
880 |
jsr166 |
1.9 |
AbstractList<E> parent, int baseIndex, |
881 |
dl |
1.8 |
int fromIndex, int toIndex) { |
882 |
|
|
super(base, parent, baseIndex, fromIndex, toIndex); |
883 |
dl |
1.1 |
} |
884 |
|
|
|
885 |
|
|
public List<E> subList(int fromIndex, int toIndex) { |
886 |
dl |
1.8 |
return new RandomAccessSubList(base, this, fromIndex + baseOffset, |
887 |
|
|
fromIndex, toIndex); |
888 |
dl |
1.1 |
} |
889 |
|
|
} |