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Comparing jsr166/src/main/java/util/AbstractList.java (file contents):
Revision 1.5 by jsr166, Mon Dec 5 02:56:59 2005 UTC vs.
Revision 1.24 by jsr166, Sun Sep 5 21:32:18 2010 UTC

#	Line 1 | Line 1
1		/*
2	<	* %W% %E%
2	>	* Copyright (c) 1997, 2007, Oracle and/or its affiliates. All rights reserved.
3	>	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4		*
5	<	* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
6	<	* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
5	>	* This code is free software; you can redistribute it and/or modify it
6	>	* under the terms of the GNU General Public License version 2 only, as
7	>	* published by the Free Software Foundation.  Sun designates this
8	>	* particular file as subject to the "Classpath" exception as provided
9	>	* by Sun in the LICENSE file that accompanied this code.
10	>	*
11	>	* This code is distributed in the hope that it will be useful, but WITHOUT
12	>	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13	>	* FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14	>	* version 2 for more details (a copy is included in the LICENSE file that
15	>	* accompanied this code).
16	>	*
17	>	* You should have received a copy of the GNU General Public License version
18	>	* 2 along with this work; if not, write to the Free Software Foundation,
19	>	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20	>	*
21	>	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22	>	* or visit www.oracle.com if you need additional information or have any
23	>	* questions.
24		*/
25
26		package java.util;
27
28		/**
29	<	* This class provides a skeletal implementation of the <tt>List</tt>
29	>	* This class provides a skeletal implementation of the {@link List}
30		* interface to minimize the effort required to implement this interface
31		* backed by a "random access" data store (such as an array).  For sequential
32	<	* access data (such as a linked list), <tt>AbstractSequentialList</tt> should
33	<	* be used in preference to this class.<p>
32	>	* access data (such as a linked list), {@link AbstractSequentialList} should
33	>	* be used in preference to this class.
34	>	*
35	>	* <p>To implement an unmodifiable list, the programmer needs only to extend
36	>	* this class and provide implementations for the {@link #get(int)} and
37	>	* {@link List#size() size()} methods.
38		*
39	<	* To implement an unmodifiable list, the programmer needs only to extend this
40	<	* class and provide implementations for the <tt>get(int index)</tt> and
41	<	* <tt>size()</tt> methods.<p>
42	<	*
43	<	* To implement a modifiable list, the programmer must additionally override
22	<	* the <tt>set(int index, Object element)</tt> method (which otherwise throws
23	<	* an <tt>UnsupportedOperationException</tt>.  If the list is variable-size
24	<	* the programmer must additionally override the <tt>add(int index, Object
25	<	* element)</tt> and <tt>remove(int index)</tt> methods.<p>
26	<	*
27	<	* The programmer should generally provide a void (no argument) and collection
28	<	* constructor, as per the recommendation in the <tt>Collection</tt> interface
29	<	* specification.<p>
39	>	* <p>To implement a modifiable list, the programmer must additionally
40	>	* override the {@link #set(int, Object) set(int, E)} method (which otherwise
41	>	* throws an {@code UnsupportedOperationException}).  If the list is
42	>	* variable-size the programmer must additionally override the
43	>	* {@link #add(int, Object) add(int, E)} and {@link #remove(int)} methods.
44		*
45	<	* Unlike the other abstract collection implementations, the programmer does
45	>	* <p>The programmer should generally provide a void (no argument) and collection
46	>	* constructor, as per the recommendation in the {@link Collection} interface
47	>	* specification.
48	>	*
49	>	* <p>Unlike the other abstract collection implementations, the programmer does
50		* <i>not</i> have to provide an iterator implementation; the iterator and
51		* list iterator are implemented by this class, on top of the "random access"
52	<	* methods: <tt>get(int index)</tt>, <tt>set(int index, E element)</tt>,
53	<	* <tt>add(int index, E element)</tt> and <tt>remove(int index)</tt>.<p>
52	>	* methods:
53	>	* {@link #get(int)},
54	>	* {@link #set(int, Object) set(int, E)},
55	>	* {@link #add(int, Object) add(int, E)} and
56	>	* {@link #remove(int)}.
57		*
58	<	* The documentation for each non-abstract methods in this class describes its
58	>	* <p>The documentation for each non-abstract method in this class describes its
59		* implementation in detail.  Each of these methods may be overridden if the
60	<	* collection being implemented admits a more efficient implementation.<p>
60	>	* collection being implemented admits a more efficient implementation.
61		*
62	<	* This class is a member of the
63	<	* <a href="{@docRoot}/../guide/collections/index.html">
62	>	* <p>This class is a member of the
63	>	* <a href="{@docRoot}/../technotes/guides/collections/index.html">
64		* Java Collections Framework</a>.
65		*
66		* @author  Josh Bloch
67		* @author  Neal Gafter
47	–	* @version 1.37, 01/18/03
48	–	* @see Collection
49	–	* @see List
50	–	* @see AbstractSequentialList
51	–	* @see AbstractCollection
68		* @since 1.2
69		*/
70
#	Line 71 | Line 87 | public abstract class AbstractList<E> ex
87		* classes should clearly specify in their documentation any restrictions
88		* on what elements may be added.
89		*
90	<	* <p>This implementation calls <tt>add(size(), e)</tt>.
90	>	* <p>This implementation calls {@code add(size(), e)}.
91		*
92		* <p>Note that this implementation throws an
93	<	* <tt>UnsupportedOperationException</tt> unless <tt>add(int, Object)</tt>
94	<	* is overridden.
93	>	* {@code UnsupportedOperationException} unless
94	>	* {@link #add(int, Object) add(int, E)} is overridden.
95		*
96		* @param e element to be appended to this list
97	<	* @return <tt>true</tt> (as specified by {@link Collection#add})
98	<	* @throws UnsupportedOperationException if the <tt>add</tt> operation
97	>	* @return {@code true} (as specified by {@link Collection#add})
98	>	* @throws UnsupportedOperationException if the {@code add} operation
99		*         is not supported by this list
100		* @throws ClassCastException if the class of the specified element
101		*         prevents it from being added to this list
#	Line 89 | Line 105 | public abstract class AbstractList<E> ex
105		*         prevents it from being added to this list
106		*/
107		public boolean add(E e) {
108	<	add(size(), e);
109	<	return true;
108	>	add(size(), e);
109	>	return true;
110		}
111
112		/**
#	Line 104 | Line 120 | public abstract class AbstractList<E> ex
120		* {@inheritDoc}
121		*
122		* <p>This implementation always throws an
123	<	* <tt>UnsupportedOperationException</tt>.
123	>	* {@code UnsupportedOperationException}.
124		*
125		* @throws UnsupportedOperationException {@inheritDoc}
126		* @throws ClassCastException            {@inheritDoc}
#	Line 113 | Line 129 | public abstract class AbstractList<E> ex
129		* @throws IndexOutOfBoundsException     {@inheritDoc}
130		*/
131		public E set(int index, E element) {
132	<	throw new UnsupportedOperationException();
132	>	throw new UnsupportedOperationException();
133		}
134
135		/**
136		* {@inheritDoc}
137		*
138		* <p>This implementation always throws an
139	<	* <tt>UnsupportedOperationException</tt>.
139	>	* {@code UnsupportedOperationException}.
140		*
141		* @throws UnsupportedOperationException {@inheritDoc}
142		* @throws ClassCastException            {@inheritDoc}
#	Line 129 | Line 145 | public abstract class AbstractList<E> ex
145		* @throws IndexOutOfBoundsException     {@inheritDoc}
146		*/
147		public void add(int index, E element) {
148	<	throw new UnsupportedOperationException();
148	>	throw new UnsupportedOperationException();
149		}
150
151		/**
152		* {@inheritDoc}
153		*
154		* <p>This implementation always throws an
155	<	* <tt>UnsupportedOperationException</tt>.
155	>	* {@code UnsupportedOperationException}.
156		*
157		* @throws UnsupportedOperationException {@inheritDoc}
158		* @throws IndexOutOfBoundsException     {@inheritDoc}
159		*/
160		public E remove(int index) {
161	<	throw new UnsupportedOperationException();
161	>	throw new UnsupportedOperationException();
162		}
163
164
#	Line 152 | Line 168 | public abstract class AbstractList<E> ex
168		* {@inheritDoc}
169		*
170		* <p>This implementation first gets a list iterator (with
171	<	* <tt>listIterator()</tt>).  Then, it iterates over the list until the
171	>	* {@code listIterator()}).  Then, it iterates over the list until the
172		* specified element is found or the end of the list is reached.
173		*
174		* @throws ClassCastException   {@inheritDoc}
175		* @throws NullPointerException {@inheritDoc}
176		*/
177		public int indexOf(Object o) {
178	<	ListIterator<E> e = listIterator();
179	<	if (o==null) {
180	<	while (e.hasNext())
181	<	if (e.next()==null)
182	<	return e.previousIndex();
183	<	} else {
184	<	while (e.hasNext())
185	<	if (o.equals(e.next()))
186	<	return e.previousIndex();
187	<	}
188	<	return -1;
178	>	ListIterator<E> it = listIterator();
179	>	if (o==null) {
180	>	while (it.hasNext())
181	>	if (it.next()==null)
182	>	return it.previousIndex();
183	>	} else {
184	>	while (it.hasNext())
185	>	if (o.equals(it.next()))
186	>	return it.previousIndex();
187	>	}
188	>	return -1;
189		}
190
191		/**
192		* {@inheritDoc}
193		*
194		* <p>This implementation first gets a list iterator that points to the end
195	<	* of the list (with <tt>listIterator(size())</tt>).  Then, it iterates
195	>	* of the list (with {@code listIterator(size())}).  Then, it iterates
196		* backwards over the list until the specified element is found, or the
197		* beginning of the list is reached.
198		*
#	Line 184 | Line 200 | public abstract class AbstractList<E> ex
200		* @throws NullPointerException {@inheritDoc}
201		*/
202		public int lastIndexOf(Object o) {
203	<	ListIterator<E> e = listIterator(size());
204	<	if (o==null) {
205	<	while (e.hasPrevious())
206	<	if (e.previous()==null)
207	<	return e.nextIndex();
208	<	} else {
209	<	while (e.hasPrevious())
210	<	if (o.equals(e.previous()))
211	<	return e.nextIndex();
212	<	}
213	<	return -1;
203	>	ListIterator<E> it = listIterator(size());
204	>	if (o==null) {
205	>	while (it.hasPrevious())
206	>	if (it.previous()==null)
207	>	return it.nextIndex();
208	>	} else {
209	>	while (it.hasPrevious())
210	>	if (o.equals(it.previous()))
211	>	return it.nextIndex();
212	>	}
213	>	return -1;
214		}
215
216
#	Line 204 | Line 220 | public abstract class AbstractList<E> ex
220		* Removes all of the elements from this list (optional operation).
221		* The list will be empty after this call returns.
222		*
223	<	* <p>This implementation calls <tt>removeRange(0, size())</tt>.
223	>	* <p>This implementation calls {@code removeRange(0, size())}.
224		*
225		* <p>Note that this implementation throws an
226	<	* <tt>UnsupportedOperationException</tt> unless <tt>remove(int
227	<	* index)</tt> or <tt>removeRange(int fromIndex, int toIndex)</tt> is
226	>	* {@code UnsupportedOperationException} unless {@code remove(int
227	>	* index)} or {@code removeRange(int fromIndex, int toIndex)} is
228		* overridden.
229		*
230	<	* @throws UnsupportedOperationException if the <tt>clear</tt> operation
230	>	* @throws UnsupportedOperationException if the {@code clear} operation
231		*         is not supported by this list
232		*/
233		public void clear() {
#	Line 221 | Line 237 | public abstract class AbstractList<E> ex
237		/**
238		* {@inheritDoc}
239		*
240	<	* <p>This implementation gets an iterator over the specified collection and
241	<	* iterates over it, inserting the elements obtained from the iterator
242	<	* into this list at the appropriate position, one at a time, using
243	<	* <tt>add(int, Object)</tt>.  Many implementations will override this
244	<	* method for efficiency.
240	>	* <p>This implementation gets an iterator over the specified collection
241	>	* and iterates over it, inserting the elements obtained from the
242	>	* iterator into this list at the appropriate position, one at a time,
243	>	* using {@code add(int, E)}.
244	>	* Many implementations will override this method for efficiency.
245		*
246		* <p>Note that this implementation throws an
247	<	* <tt>UnsupportedOperationException</tt> unless <tt>add(int, Object)</tt>
248	<	* is overridden.
247	>	* {@code UnsupportedOperationException} unless
248	>	* {@link #add(int, Object) add(int, E)} is overridden.
249		*
250		* @throws UnsupportedOperationException {@inheritDoc}
251		* @throws ClassCastException            {@inheritDoc}
#	Line 238 | Line 254 | public abstract class AbstractList<E> ex
254		* @throws IndexOutOfBoundsException     {@inheritDoc}
255		*/
256		public boolean addAll(int index, Collection<? extends E> c) {
257	<	boolean modified = false;
258	<	Iterator<? extends E> e = c.iterator();
259	<	while (e.hasNext()) {
260	<	add(index++, e.next());
261	<	modified = true;
262	<	}
263	<	return modified;
257	>	rangeCheckForAdd(index);
258	>	boolean modified = false;
259	>	for (E e : c) {
260	>	add(index++, e);
261	>	modified = true;
262	>	}
263	>	return modified;
264		}
265
266
267		// Iterators
268
269		/**
270	<	* Returns an iterator over the elements in this list in proper
255	<	* sequence. <p>
270	>	* Returns an iterator over the elements in this list in proper sequence.
271		*
272	<	* This implementation returns a straightforward implementation of the
273	<	* iterator interface, relying on the backing list's <tt>size()</tt>,
274	<	* <tt>get(int)</tt>, and <tt>remove(int)</tt> methods.<p>
260	<	*
261	<	* Note that the iterator returned by this method will throw an
262	<	* <tt>UnsupportedOperationException</tt> in response to its
263	<	* <tt>remove</tt> method unless the list's <tt>remove(int)</tt> method is
264	<	* overridden.<p>
265	<	*
266	<	* This implementation can be made to throw runtime exceptions in the face
267	<	* of concurrent modification, as described in the specification for the
268	<	* (protected) <tt>modCount</tt> field.
272	>	* <p>This implementation returns a straightforward implementation of the
273	>	* iterator interface, relying on the backing list's {@code size()},
274	>	* {@code get(int)}, and {@code remove(int)} methods.
275		*
276	<	* @return an iterator over the elements in this list in proper sequence
276	>	* <p>Note that the iterator returned by this method will throw an
277	>	* {@link UnsupportedOperationException} in response to its
278	>	* {@code remove} method unless the list's {@code remove(int)} method is
279	>	* overridden.
280		*
281	<	* @see #modCount
281	>	* <p>This implementation can be made to throw runtime exceptions in the
282	>	* face of concurrent modification, as described in the specification
283	>	* for the (protected) {@link #modCount} field.
284	>	*
285	>	* @return an iterator over the elements in this list in proper sequence
286		*/
287		public Iterator<E> iterator() {
288	<	return new Itr();
288	>	return new Itr();
289		}
290
291		/**
292		* {@inheritDoc}
293		*
294	<	* <p>This implementation returns <tt>listIterator(0)</tt>.
294	>	* <p>This implementation returns {@code listIterator(0)}.
295		*
296		* @see #listIterator(int)
297		*/
298		public ListIterator<E> listIterator() {
299	<	return listIterator(0);
299	>	return listIterator(0);
300		}
301
302		/**
303		* {@inheritDoc}
304		*
305		* <p>This implementation returns a straightforward implementation of the
306	<	* <tt>ListIterator</tt> interface that extends the implementation of the
307	<	* <tt>Iterator</tt> interface returned by the <tt>iterator()</tt> method.
308	<	* The <tt>ListIterator</tt> implementation relies on the backing list's
309	<	* <tt>get(int)</tt>, <tt>set(int, Object)</tt>, <tt>add(int, Object)</tt>
310	<	* and <tt>remove(int)</tt> methods.
306	>	* {@code ListIterator} interface that extends the implementation of the
307	>	* {@code Iterator} interface returned by the {@code iterator()} method.
308	>	* The {@code ListIterator} implementation relies on the backing list's
309	>	* {@code get(int)}, {@code set(int, E)}, {@code add(int, E)}
310	>	* and {@code remove(int)} methods.
311		*
312		* <p>Note that the list iterator returned by this implementation will
313	<	* throw an <tt>UnsupportedOperationException</tt> in response to its
314	<	* <tt>remove</tt>, <tt>set</tt> and <tt>add</tt> methods unless the
315	<	* list's <tt>remove(int)</tt>, <tt>set(int, Object)</tt>, and
316	<	* <tt>add(int, Object)</tt> methods are overridden.
313	>	* throw an {@link UnsupportedOperationException} in response to its
314	>	* {@code remove}, {@code set} and {@code add} methods unless the
315	>	* list's {@code remove(int)}, {@code set(int, E)}, and
316	>	* {@code add(int, E)} methods are overridden.
317		*
318		* <p>This implementation can be made to throw runtime exceptions in the
319		* face of concurrent modification, as described in the specification for
320	<	* the (protected) <tt>modCount</tt> field.
320	>	* the (protected) {@link #modCount} field.
321		*
322		* @throws IndexOutOfBoundsException {@inheritDoc}
310	–	*
311	–	* @see #modCount
323		*/
324		public ListIterator<E> listIterator(final int index) {
325	<	if (index<0 || index>size())
315	<	throw new IndexOutOfBoundsException("Index: "+index);
325	>	rangeCheckForAdd(index);
326
327	<	return new ListItr(index);
327	>	return new ListItr(index);
328		}
329
330		private class Itr implements Iterator<E> {
331	<	/**
332	<	* Index of element to be returned by subsequent call to next.
333	<	*/
334	<	int cursor = 0;
335	<
336	<	/**
337	<	* Index of element returned by most recent call to next or
338	<	* previous.  Reset to -1 if this element is deleted by a call
339	<	* to remove.
340	<	*/
341	<	int lastRet = -1;
342	<
343	<	/**
344	<	* The modCount value that the iterator believes that the backing
345	<	* List should have.  If this expectation is violated, the iterator
346	<	* has detected concurrent modification.
347	<	*/
348	<	int expectedModCount = modCount;
331	>	/**
332	>	* Index of element to be returned by subsequent call to next.
333	>	*/
334	>	int cursor = 0;
335	>
336	>	/**
337	>	* Index of element returned by most recent call to next or
338	>	* previous.  Reset to -1 if this element is deleted by a call
339	>	* to remove.
340	>	*/
341	>	int lastRet = -1;
342	>
343	>	/**
344	>	* The modCount value that the iterator believes that the backing
345	>	* List should have.  If this expectation is violated, the iterator
346	>	* has detected concurrent modification.
347	>	*/
348	>	int expectedModCount = modCount;
349
350	<	public boolean hasNext() {
350	>	public boolean hasNext() {
351		return cursor != size();
352	<	}
352	>	}
353
354	<	public E next() {
354	>	public E next() {
355	>	checkForComodification();
356		try {
357		int i = cursor;
358		E next = get(i);
359		lastRet = i;
360		cursor = i + 1;
361		return next;
362	<	} catch (IndexOutOfBoundsException ex) {
362	>	} catch (IndexOutOfBoundsException e) {
363	>	checkForComodification();
364		throw new NoSuchElementException();
365	<	} finally {
366	<	if (expectedModCount != modCount)
367	<	throw new ConcurrentModificationException();
368	<	}
369	<	}
370	<
371	<	public void remove() {
372	<	if (lastRet == -1)
373	<	throw new IllegalStateException();
374	<	if (expectedModCount != modCount)
375	<	throw new ConcurrentModificationException();
376	<	try {
377	<	AbstractList.this.remove(lastRet);
378	<	if (lastRet < cursor)
379	<	cursor--;
380	<	lastRet = -1;
381	<	expectedModCount = modCount;
382	<	} catch (IndexOutOfBoundsException e) {
383	<	throw new ConcurrentModificationException();
384	<	}
385	<	}
365	>	}
366	>	}
367	>
368	>	public void remove() {
369	>	if (lastRet < 0)
370	>	throw new IllegalStateException();
371	>	checkForComodification();
372	>
373	>	try {
374	>	AbstractList.this.remove(lastRet);
375	>	if (lastRet < cursor)
376	>	cursor--;
377	>	lastRet = -1;
378	>	expectedModCount = modCount;
379	>	} catch (IndexOutOfBoundsException e) {
380	>	throw new ConcurrentModificationException();
381	>	}
382	>	}
383	>
384	>	final void checkForComodification() {
385	>	if (modCount != expectedModCount)
386	>	throw new ConcurrentModificationException();
387	>	}
388		}
389	<
389	>
390		private class ListItr extends Itr implements ListIterator<E> {
391	<	ListItr(int index) {
392	<	cursor = index;
393	<	}
394	<
395	<	public boolean hasPrevious() {
396	<	return cursor != 0;
397	<	}
384	<
385	<	public int nextIndex() {
386	<	return cursor;
387	<	}
388	<
389	<	public int previousIndex() {
390	<	return cursor - 1;
391	<	}
391	>	ListItr(int index) {
392	>	cursor = index;
393	>	}
394	>
395	>	public boolean hasPrevious() {
396	>	return cursor != 0;
397	>	}
398
399		public E previous() {
400	+	checkForComodification();
401		try {
402		int i = cursor - 1;
403	<	E prev = get(i);
404	<	lastRet = i;
405	<	cursor = i;
406	<	return prev;
407	<	} catch (IndexOutOfBoundsException ex) {
403	>	E previous = get(i);
404	>	lastRet = cursor = i;
405	>	return previous;
406	>	} catch (IndexOutOfBoundsException e) {
407	>	checkForComodification();
408		throw new NoSuchElementException();
402	–	} finally {
403	–	if (expectedModCount != modCount)
404	–	throw new ConcurrentModificationException();
409		}
410		}
411
412	<	public void set(E e) {
413	<	if (lastRet == -1)
414	<	throw new IllegalStateException();
415	<	if (expectedModCount != modCount)
416	<	throw new ConcurrentModificationException();
417	<	try {
418	<	AbstractList.this.set(lastRet, e);
415	<	expectedModCount = modCount;
416	<	} catch (IndexOutOfBoundsException ex) {
417	<	throw new ConcurrentModificationException();
418	<	}
419	<	}
412	>	public int nextIndex() {
413	>	return cursor;
414	>	}
415	>
416	>	public int previousIndex() {
417	>	return cursor-1;
418	>	}
419
420	<	public void add(E e) {
421	<	if (expectedModCount != modCount)
420	>	public void set(E e) {
421	>	if (lastRet < 0)
422	>	throw new IllegalStateException();
423	>	checkForComodification();
424	>
425	>	try {
426	>	AbstractList.this.set(lastRet, e);
427	>	expectedModCount = modCount;
428	>	} catch (IndexOutOfBoundsException ex) {
429		throw new ConcurrentModificationException();
430	<	try {
430	>	}
431	>	}
432	>
433	>	public void add(E e) {
434	>	checkForComodification();
435	>
436	>	try {
437		int i = cursor;
438	<	AbstractList.this.add(i, e);
438	>	AbstractList.this.add(i, e);
439	>	lastRet = -1;
440		cursor = i + 1;
441	<	lastRet = -1;
442	<	expectedModCount = modCount;
443	<	} catch (IndexOutOfBoundsException ex) {
444	<	throw new ConcurrentModificationException();
445	<	}
433	<	}
441	>	expectedModCount = modCount;
442	>	} catch (IndexOutOfBoundsException ex) {
443	>	throw new ConcurrentModificationException();
444	>	}
445	>	}
446		}
447
448		/**
449		* {@inheritDoc}
450		*
451		* <p>This implementation returns a list that subclasses
452	<	* <tt>AbstractList</tt>.  The subclass stores, in private fields, the
452	>	* {@code AbstractList}.  The subclass stores, in private fields, the
453		* offset of the subList within the backing list, the size of the subList
454		* (which can change over its lifetime), and the expected
455	<	* <tt>modCount</tt> value of the backing list.  There are two variants
456	<	* of the subclass, one of which implements <tt>RandomAccess</tt>.
457	<	* If this list implements <tt>RandomAccess</tt> the returned list will
458	<	* be an instance of the subclass that implements <tt>RandomAccess</tt>.
459	<	*
460	<	* <p>The subclass's <tt>set(int, Object)</tt>, <tt>get(int)</tt>,
461	<	* <tt>add(int, Object)</tt>, <tt>remove(int)</tt>, <tt>addAll(int,
462	<	* Collection)</tt> and <tt>removeRange(int, int)</tt> methods all
455	>	* {@code modCount} value of the backing list.  There are two variants
456	>	* of the subclass, one of which implements {@code RandomAccess}.
457	>	* If this list implements {@code RandomAccess} the returned list will
458	>	* be an instance of the subclass that implements {@code RandomAccess}.
459	>	*
460	>	* <p>The subclass's {@code set(int, E)}, {@code get(int)},
461	>	* {@code add(int, E)}, {@code remove(int)}, {@code addAll(int,
462	>	* Collection)} and {@code removeRange(int, int)} methods all
463		* delegate to the corresponding methods on the backing abstract list,
464		* after bounds-checking the index and adjusting for the offset.  The
465	<	* <tt>addAll(Collection c)</tt> method merely returns <tt>addAll(size,
466	<	* c)</tt>.
465	>	* {@code addAll(Collection c)} method merely returns {@code addAll(size,
466	>	* c)}.
467		*
468	<	* <p>The <tt>listIterator(int)</tt> method returns a "wrapper object"
468	>	* <p>The {@code listIterator(int)} method returns a "wrapper object"
469		* over a list iterator on the backing list, which is created with the
470	<	* corresponding method on the backing list.  The <tt>iterator</tt> method
471	<	* merely returns <tt>listIterator()</tt>, and the <tt>size</tt> method
472	<	* merely returns the subclass's <tt>size</tt> field.
470	>	* corresponding method on the backing list.  The {@code iterator} method
471	>	* merely returns {@code listIterator()}, and the {@code size} method
472	>	* merely returns the subclass's {@code size} field.
473		*
474	<	* <p>All methods first check to see if the actual <tt>modCount</tt> of
474	>	* <p>All methods first check to see if the actual {@code modCount} of
475		* the backing list is equal to its expected value, and throw a
476	<	* <tt>ConcurrentModificationException</tt> if it is not.
476	>	* {@code ConcurrentModificationException} if it is not.
477		*
478	<	* @throws IndexOutOfBoundsException endpoint index value out of range
479	<	*         <tt>(fromIndex &lt; 0 || toIndex &gt; size)</tt>
478	>	* @throws IndexOutOfBoundsException if an endpoint index value is out of range
479	>	*         {@code (fromIndex < 0 || toIndex > size)}
480		* @throws IllegalArgumentException if the endpoint indices are out of order
481	<	*         <tt>(fromIndex &gt; toIndex)</tt>
481	>	*         {@code (fromIndex > toIndex)}
482		*/
483		public List<E> subList(int fromIndex, int toIndex) {
484		return (this instanceof RandomAccess ?
#	Line 478 | Line 490 | public abstract class AbstractList<E> ex
490
491		/**
492		* Compares the specified object with this list for equality.  Returns
493	<	* <tt>true</tt> if and only if the specified object is also a list, both
493	>	* {@code true} if and only if the specified object is also a list, both
494		* lists have the same size, and all corresponding pairs of elements in
495	<	* the two lists are <i>equal</i>.  (Two elements <tt>e1</tt> and
496	<	* <tt>e2</tt> are <i>equal</i> if <tt>(e1==null ? e2==null :
497	<	* e1.equals(e2))</tt>.)  In other words, two lists are defined to be
495	>	* the two lists are <i>equal</i>.  (Two elements {@code e1} and
496	>	* {@code e2} are <i>equal</i> if {@code (e1==null ? e2==null :
497	>	* e1.equals(e2))}.)  In other words, two lists are defined to be
498		* equal if they contain the same elements in the same order.<p>
499		*
500		* This implementation first checks if the specified object is this
501	<	* list. If so, it returns <tt>true</tt>; if not, it checks if the
502	<	* specified object is a list. If not, it returns <tt>false</tt>; if so,
501	>	* list. If so, it returns {@code true}; if not, it checks if the
502	>	* specified object is a list. If not, it returns {@code false}; if so,
503		* it iterates over both lists, comparing corresponding pairs of elements.
504	<	* If any comparison returns <tt>false</tt>, this method returns
505	<	* <tt>false</tt>.  If either iterator runs out of elements before the
506	<	* other it returns <tt>false</tt> (as the lists are of unequal length);
507	<	* otherwise it returns <tt>true</tt> when the iterations complete.
504	>	* If any comparison returns {@code false}, this method returns
505	>	* {@code false}.  If either iterator runs out of elements before the
506	>	* other it returns {@code false} (as the lists are of unequal length);
507	>	* otherwise it returns {@code true} when the iterations complete.
508		*
509		* @param o the object to be compared for equality with this list
510	<	* @return <tt>true</tt> if the specified object is equal to this list
510	>	* @return {@code true} if the specified object is equal to this list
511		*/
512		public boolean equals(Object o) {
513	<	if (o == this)
514	<	return true;
515	<	if (!(o instanceof List))
516	<	return false;
517	<
518	<	ListIterator<E> e1 = listIterator();
519	<	ListIterator e2 = ((List) o).listIterator();
520	<	while(e1.hasNext() && e2.hasNext()) {
521	<	E o1 = e1.next();
522	<	Object o2 = e2.next();
523	<	if (!(o1==null ? o2==null : o1.equals(o2)))
524	<	return false;
525	<	}
526	<	return !(e1.hasNext() || e2.hasNext());
513	>	if (o == this)
514	>	return true;
515	>	if (!(o instanceof List))
516	>	return false;
517	>
518	>	ListIterator<E> e1 = listIterator();
519	>	ListIterator e2 = ((List) o).listIterator();
520	>	while (e1.hasNext() && e2.hasNext()) {
521	>	E o1 = e1.next();
522	>	Object o2 = e2.next();
523	>	if (!(o1==null ? o2==null : o1.equals(o2)))
524	>	return false;
525	>	}
526	>	return !(e1.hasNext() || e2.hasNext());
527		}
528
529		/**
530	<	* Returns the hash code value for this list. <p>
530	>	* Returns the hash code value for this list.
531		*
532	<	* This implementation uses exactly the code that is used to define the
532	>	* <p>This implementation uses exactly the code that is used to define the
533		* list hash function in the documentation for the {@link List#hashCode}
534		* method.
535		*
536		* @return the hash code value for this list
537		*/
538		public int hashCode() {
539	<	int hashCode = 1;
540	<	Iterator<E> i = iterator();
541	<	while (i.hasNext()) {
542	<	E obj = i.next();
531	<	hashCode = 31*hashCode + (obj==null ? 0 : obj.hashCode());
532	<	}
533	<	return hashCode;
539	>	int hashCode = 1;
540	>	for (E e : this)
541	>	hashCode = 31*hashCode + (e==null ? 0 : e.hashCode());
542	>	return hashCode;
543		}
544
545		/**
546		* Removes from this list all of the elements whose index is between
547	<	* <tt>fromIndex</tt>, inclusive, and <tt>toIndex</tt>, exclusive.
547	>	* {@code fromIndex}, inclusive, and {@code toIndex}, exclusive.
548		* Shifts any succeeding elements to the left (reduces their index).
549	<	* This call shortens the ArrayList by <tt>(toIndex - fromIndex)</tt>
550	<	* elements.  (If <tt>toIndex==fromIndex</tt>, this operation has no
542	<	* effect.)<p>
549	>	* This call shortens the list by {@code (toIndex - fromIndex)} elements.
550	>	* (If {@code toIndex==fromIndex}, this operation has no effect.)
551		*
552	<	* This method is called by the <tt>clear</tt> operation on this list
552	>	* <p>This method is called by the {@code clear} operation on this list
553		* and its subLists.  Overriding this method to take advantage of
554		* the internals of the list implementation can <i>substantially</i>
555	<	* improve the performance of the <tt>clear</tt> operation on this list
556	<	* and its subLists.<p>
555	>	* improve the performance of the {@code clear} operation on this list
556	>	* and its subLists.
557		*
558	<	* This implementation gets a list iterator positioned before
559	<	* <tt>fromIndex</tt>, and repeatedly calls <tt>ListIterator.next</tt>
560	<	* followed by <tt>ListIterator.remove</tt> until the entire range has
561	<	* been removed.  <b>Note: if <tt>ListIterator.remove</tt> requires linear
558	>	* <p>This implementation gets a list iterator positioned before
559	>	* {@code fromIndex}, and repeatedly calls {@code ListIterator.next}
560	>	* followed by {@code ListIterator.remove} until the entire range has
561	>	* been removed.  <b>Note: if {@code ListIterator.remove} requires linear
562		* time, this implementation requires quadratic time.</b>
563		*
564		* @param fromIndex index of first element to be removed
#	Line 568 | Line 576 | public abstract class AbstractList<E> ex
576		* The number of times this list has been <i>structurally modified</i>.
577		* Structural modifications are those that change the size of the
578		* list, or otherwise perturb it in such a fashion that iterations in
579	<	* progress may yield incorrect results.<p>
579	>	* progress may yield incorrect results.
580		*
581	<	* This field is used by the iterator and list iterator implementation
582	<	* returned by the <tt>iterator</tt> and <tt>listIterator</tt> methods.
581	>	* <p>This field is used by the iterator and list iterator implementation
582	>	* returned by the {@code iterator} and {@code listIterator} methods.
583		* If the value of this field changes unexpectedly, the iterator (or list
584	<	* iterator) will throw a <tt>ConcurrentModificationException</tt> in
585	<	* response to the <tt>next</tt>, <tt>remove</tt>, <tt>previous</tt>,
586	<	* <tt>set</tt> or <tt>add</tt> operations.  This provides
584	>	* iterator) will throw a {@code ConcurrentModificationException} in
585	>	* response to the {@code next}, {@code remove}, {@code previous},
586	>	* {@code set} or {@code add} operations.  This provides
587		* <i>fail-fast</i> behavior, rather than non-deterministic behavior in
588	<	* the face of concurrent modification during iteration.<p>
588	>	* the face of concurrent modification during iteration.
589		*
590	<	* <b>Use of this field by subclasses is optional.</b> If a subclass
590	>	* <p><b>Use of this field by subclasses is optional.</b> If a subclass
591		* wishes to provide fail-fast iterators (and list iterators), then it
592	<	* merely has to increment this field in its <tt>add(int, Object)</tt> and
593	<	* <tt>remove(int)</tt> methods (and any other methods that it overrides
592	>	* merely has to increment this field in its {@code add(int, E)} and
593	>	* {@code remove(int)} methods (and any other methods that it overrides
594		* that result in structural modifications to the list).  A single call to
595	<	* <tt>add(int, Object)</tt> or <tt>remove(int)</tt> must add no more than
595	>	* {@code add(int, E)} or {@code remove(int)} must add no more than
596		* one to this field, or the iterators (and list iterators) will throw
597	<	* bogus <tt>ConcurrentModificationExceptions</tt>.  If an implementation
597	>	* bogus {@code ConcurrentModificationExceptions}.  If an implementation
598		* does not wish to provide fail-fast iterators, this field may be
599		* ignored.
600		*/
601		protected transient int modCount = 0;
602	+
603	+	private void rangeCheckForAdd(int index) {
604	+	if (index < 0 || index > size())
605	+	throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
606	+	}
607	+
608	+	private String outOfBoundsMsg(int index) {
609	+	return "Index: "+index+", Size: "+size();
610	+	}
611		}
612
613		class SubList<E> extends AbstractList<E> {
614	<	private AbstractList<E> l;
615	<	private int offset;
614	>	private final AbstractList<E> l;
615	>	private final int offset;
616		private int size;
600	–	private int expectedModCount;
617
618		SubList(AbstractList<E> list, int fromIndex, int toIndex) {
619		if (fromIndex < 0)
#	Line 610 | Line 626 | class SubList<E> extends AbstractList<E>
626		l = list;
627		offset = fromIndex;
628		size = toIndex - fromIndex;
629	<	expectedModCount = l.modCount;
629	>	this.modCount = l.modCount;
630		}
631
632		public E set(int index, E element) {
#	Line 631 | Line 647 | class SubList<E> extends AbstractList<E>
647		}
648
649		public void add(int index, E element) {
650	<	if (index<0 || index>size)
635	<	throw new IndexOutOfBoundsException();
650	>	rangeCheckForAdd(index);
651		checkForComodification();
652		l.add(index+offset, element);
653	<	expectedModCount = l.modCount;
653	>	this.modCount = l.modCount;
654		size++;
640	–	modCount++;
655		}
656
657		public E remove(int index) {
658		rangeCheck(index);
659		checkForComodification();
660		E result = l.remove(index+offset);
661	<	expectedModCount = l.modCount;
661	>	this.modCount = l.modCount;
662		size--;
649	–	modCount++;
663		return result;
664		}
665
666		protected void removeRange(int fromIndex, int toIndex) {
667		checkForComodification();
668		l.removeRange(fromIndex+offset, toIndex+offset);
669	<	expectedModCount = l.modCount;
669	>	this.modCount = l.modCount;
670		size -= (toIndex-fromIndex);
658	–	modCount++;
671		}
672
673		public boolean addAll(Collection<? extends E> c) {
#	Line 663 | Line 675 | class SubList<E> extends AbstractList<E>
675		}
676
677		public boolean addAll(int index, Collection<? extends E> c) {
678	<	if (index<0 || index>size)
667	<	throw new IndexOutOfBoundsException(
668	<	"Index: "+index+", Size: "+size);
678	>	rangeCheckForAdd(index);
679		int cSize = c.size();
680		if (cSize==0)
681		return false;
682
683		checkForComodification();
684		l.addAll(offset+index, c);
685	<	expectedModCount = l.modCount;
685	>	this.modCount = l.modCount;
686		size += cSize;
677	–	modCount++;
687		return true;
688		}
689
#	Line 684 | Line 693 | class SubList<E> extends AbstractList<E>
693
694		public ListIterator<E> listIterator(final int index) {
695		checkForComodification();
696	<	if (index<0 || index>size)
688	<	throw new IndexOutOfBoundsException(
689	<	"Index: "+index+", Size: "+size);
696	>	rangeCheckForAdd(index);
697
698		return new ListIterator<E>() {
699	<	private ListIterator<E> i = l.listIterator(index+offset);
699	>	private final ListIterator<E> i = l.listIterator(index+offset);
700
701		public boolean hasNext() {
702		return nextIndex() < size;
#	Line 723 | Line 730 | class SubList<E> extends AbstractList<E>
730
731		public void remove() {
732		i.remove();
733	<	expectedModCount = l.modCount;
733	>	SubList.this.modCount = l.modCount;
734		size--;
728	–	modCount++;
735		}
736
737		public void set(E e) {
#	Line 734 | Line 740 | class SubList<E> extends AbstractList<E>
740
741		public void add(E e) {
742		i.add(e);
743	<	expectedModCount = l.modCount;
743	>	SubList.this.modCount = l.modCount;
744		size++;
739	–	modCount++;
745		}
746		};
747		}
#	Line 746 | Line 751 | class SubList<E> extends AbstractList<E>
751		}
752
753		private void rangeCheck(int index) {
754	<	if (index<0 || index>=size)
755	<	throw new IndexOutOfBoundsException("Index: "+index+
756	<	",Size: "+size);
754	>	if (index < 0 || index >= size)
755	>	throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
756	>	}
757	>
758	>	private void rangeCheckForAdd(int index) {
759	>	if (index < 0 || index > size)
760	>	throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
761	>	}
762	>
763	>	private String outOfBoundsMsg(int index) {
764	>	return "Index: "+index+", Size: "+size;
765		}
766
767		private void checkForComodification() {
768	<	if (l.modCount != expectedModCount)
768	>	if (this.modCount != l.modCount)
769		throw new ConcurrentModificationException();
770		}
771		}

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