My first initial commit with all of mine experimental changes.

Dmitry Kabak (userdima committed 13 years ago

Commit d37b88d1 parent 3f5b46618352 files · +2598093 −-8690Browse files

Showing the changes to java/pkg/java/util/AbstractList.java (1 of 18352 files). Show all

Unified · Split

java/pkg/java/util/AbstractList.java+781−0

@@ -0,0 +1,781 @@
	1	+/*
	2	+ * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
	3	+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	4	+ *
	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. Oracle designates this
	8	+ * particular file as subject to the "Classpath" exception as provided
	9	+ * by Oracle 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 {@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), {@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	+ * <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	+ * <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:
	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	+ * <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.
	61	+ *
	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
	68	+ * @since 1.2
	69	+ */
	70	+
	71	+public abstract class AbstractList<E> extends AbstractCollection<E> implements List<E> {
	72	+ /**
	73	+ * Sole constructor. (For invocation by subclass constructors, typically
	74	+ * implicit.)
	75	+ */
	76	+ protected AbstractList() {
	77	+ }
	78	+
	79	+ /**
	80	+ * Appends the specified element to the end of this list (optional
	81	+ * operation).
	82	+ *
	83	+ * <p>Lists that support this operation may place limitations on what
	84	+ * elements may be added to this list. In particular, some
	85	+ * lists will refuse to add null elements, and others will impose
	86	+ * restrictions on the type of elements that may be added. List
	87	+ * classes should clearly specify in their documentation any restrictions
	88	+ * on what elements may be added.
	89	+ *
	90	+ * <p>This implementation calls {@code add(size(), e)}.
	91	+ *
	92	+ * <p>Note that this implementation throws an
	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 {@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
	102	+ * @throws NullPointerException if the specified element is null and this
	103	+ * list does not permit null elements
	104	+ * @throws IllegalArgumentException if some property of this element
	105	+ * prevents it from being added to this list
	106	+ */
	107	+ public boolean add(E e) {
	108	+ add(size(), e);
	109	+ return true;
	110	+ }
	111	+
	112	+ /**
	113	+ * {@inheritDoc}
	114	+ *
	115	+ * @throws IndexOutOfBoundsException {@inheritDoc}
	116	+ */
	117	+ abstract public E get(int index);
	118	+
	119	+ /**
	120	+ * {@inheritDoc}
	121	+ *
	122	+ * <p>This implementation always throws an
	123	+ * {@code UnsupportedOperationException}.
	124	+ *
	125	+ * @throws UnsupportedOperationException {@inheritDoc}
	126	+ * @throws ClassCastException {@inheritDoc}
	127	+ * @throws NullPointerException {@inheritDoc}
	128	+ * @throws IllegalArgumentException {@inheritDoc}
	129	+ * @throws IndexOutOfBoundsException {@inheritDoc}
	130	+ */
	131	+ public E set(int index, E element) {
	132	+ throw new UnsupportedOperationException();
	133	+ }
	134	+
	135	+ /**
	136	+ * {@inheritDoc}
	137	+ *
	138	+ * <p>This implementation always throws an
	139	+ * {@code UnsupportedOperationException}.
	140	+ *
	141	+ * @throws UnsupportedOperationException {@inheritDoc}
	142	+ * @throws ClassCastException {@inheritDoc}
	143	+ * @throws NullPointerException {@inheritDoc}
	144	+ * @throws IllegalArgumentException {@inheritDoc}
	145	+ * @throws IndexOutOfBoundsException {@inheritDoc}
	146	+ */
	147	+ public void add(int index, E element) {
	148	+ throw new UnsupportedOperationException();
	149	+ }
	150	+
	151	+ /**
	152	+ * {@inheritDoc}
	153	+ *
	154	+ * <p>This implementation always throws an
	155	+ * {@code UnsupportedOperationException}.
	156	+ *
	157	+ * @throws UnsupportedOperationException {@inheritDoc}
	158	+ * @throws IndexOutOfBoundsException {@inheritDoc}
	159	+ */
	160	+ public E remove(int index) {
	161	+ throw new UnsupportedOperationException();
	162	+ }
	163	+
	164	+
	165	+ // Search Operations
	166	+
	167	+ /**
	168	+ * {@inheritDoc}
	169	+ *
	170	+ * <p>This implementation first gets a list iterator (with
	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> 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 {@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	+ *
	199	+ * @throws ClassCastException {@inheritDoc}
	200	+ * @throws NullPointerException {@inheritDoc}
	201	+ */
	202	+ public int lastIndexOf(Object o) {
	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	+
	217	+ // Bulk Operations
	218	+
	219	+ /**
	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 {@code removeRange(0, size())}.
	224	+ *
	225	+ * <p>Note that this implementation throws an
	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 {@code clear} operation
	231	+ * is not supported by this list
	232	+ */
	233	+ public void clear() {
	234	+ removeRange(0, size());
	235	+ }
	236	+
	237	+ /**
	238	+ * {@inheritDoc}
	239	+ *
	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	+ * {@code UnsupportedOperationException} unless
	248	+ * {@link #add(int, Object) add(int, E)} is overridden.
	249	+ *
	250	+ * @throws UnsupportedOperationException {@inheritDoc}
	251	+ * @throws ClassCastException {@inheritDoc}
	252	+ * @throws NullPointerException {@inheritDoc}
	253	+ * @throws IllegalArgumentException {@inheritDoc}
	254	+ * @throws IndexOutOfBoundsException {@inheritDoc}
	255	+ */
	256	+ public boolean addAll(int index, Collection<? extends E> c) {
	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 sequence.
	271	+ *
	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	+ * <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	+ * <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();
	289	+ }
	290	+
	291	+ /**
	292	+ * {@inheritDoc}
	293	+ *
	294	+ * <p>This implementation returns {@code listIterator(0)}.
	295	+ *
	296	+ * @see #listIterator(int)
	297	+ */
	298	+ public ListIterator<E> listIterator() {
	299	+ return listIterator(0);
	300	+ }
	301	+
	302	+ /**
	303	+ * {@inheritDoc}
	304	+ *
	305	+ * <p>This implementation returns a straightforward implementation of the
	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 {@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) {@link #modCount} field.
	321	+ *
	322	+ * @throws IndexOutOfBoundsException {@inheritDoc}
	323	+ */
	324	+ public ListIterator<E> listIterator(final int index) {
	325	+ rangeCheckForAdd(index);
	326	+
	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;
	349	+
	350	+ public boolean hasNext() {
	351	+ return cursor != size();
	352	+ }
	353	+
	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 e) {
	363	+ checkForComodification();
	364	+ throw new NoSuchElementException();
	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	+
	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	+ }
	398	+
	399	+ public E previous() {
	400	+ checkForComodification();
	401	+ try {
	402	+ int i = cursor - 1;
	403	+ E previous = get(i);
	404	+ lastRet = cursor = i;
	405	+ return previous;
	406	+ } catch (IndexOutOfBoundsException e) {
	407	+ checkForComodification();
	408	+ throw new NoSuchElementException();
	409	+ }
	410	+ }
	411	+
	412	+ public int nextIndex() {
	413	+ return cursor;
	414	+ }
	415	+
	416	+ public int previousIndex() {
	417	+ return cursor-1;
	418	+ }
	419	+
	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	+ }
	431	+ }
	432	+
	433	+ public void add(E e) {
	434	+ checkForComodification();
	435	+
	436	+ try {
	437	+ int i = cursor;
	438	+ AbstractList.this.add(i, e);
	439	+ lastRet = -1;
	440	+ cursor = i + 1;
	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	+ * {@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	+ * {@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	+ * {@code addAll(Collection c)} method merely returns {@code addAll(size,
	466	+ * c)}.
	467	+ *
	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 {@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 {@code modCount} of
	475	+ * the backing list is equal to its expected value, and throw a
	476	+ * {@code ConcurrentModificationException} if it is not.
	477	+ *
	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	+ * {@code (fromIndex > toIndex)}
	482	+ */
	483	+ public List<E> subList(int fromIndex, int toIndex) {
	484	+ return (this instanceof RandomAccess ?
	485	+ new RandomAccessSubList<>(this, fromIndex, toIndex) :
	486	+ new SubList<>(this, fromIndex, toIndex));
	487	+ }
	488	+
	489	+ // Comparison and hashing
	490	+
	491	+ /**
	492	+ * Compares the specified object with this list for equality. Returns
	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 {@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 {@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 {@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 {@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());
	527	+ }
	528	+
	529	+ /**
	530	+ * Returns the hash code value for this list.
	531	+ *
	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	+ 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	+ * {@code fromIndex}, inclusive, and {@code toIndex}, exclusive.
	548	+ * Shifts any succeeding elements to the left (reduces their index).
	549	+ * This call shortens the list by {@code (toIndex - fromIndex)} elements.
	550	+ * (If {@code toIndex==fromIndex}, this operation has no effect.)
	551	+ *
	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 {@code clear} operation on this list
	556	+ * and its subLists.
	557	+ *
	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
	565	+ * @param toIndex index after last element to be removed
	566	+ */
	567	+ protected void removeRange(int fromIndex, int toIndex) {
	568	+ ListIterator<E> it = listIterator(fromIndex);
	569	+ for (int i=0, n=toIndex-fromIndex; i<n; i++) {
	570	+ it.next();
	571	+ it.remove();
	572	+ }
	573	+ }
	574	+
	575	+ /**
	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.
	580	+ *
	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 {@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.
	589	+ *
	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 {@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	+ * {@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 {@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 final AbstractList<E> l;
	615	+ private final int offset;
	616	+ private int size;
	617	+
	618	+ SubList(AbstractList<E> list, int fromIndex, int toIndex) {
	619	+ if (fromIndex < 0)
	620	+ throw new IndexOutOfBoundsException("fromIndex = " + fromIndex);
	621	+ if (toIndex > list.size())
	622	+ throw new IndexOutOfBoundsException("toIndex = " + toIndex);
	623	+ if (fromIndex > toIndex)
	624	+ throw new IllegalArgumentException("fromIndex(" + fromIndex +
	625	+ ") > toIndex(" + toIndex + ")");
	626	+ l = list;
	627	+ offset = fromIndex;
	628	+ size = toIndex - fromIndex;
	629	+ this.modCount = l.modCount;
	630	+ }
	631	+
	632	+ public E set(int index, E element) {
	633	+ rangeCheck(index);
	634	+ checkForComodification();
	635	+ return l.set(index+offset, element);
	636	+ }
	637	+
	638	+ public E get(int index) {
	639	+ rangeCheck(index);
	640	+ checkForComodification();
	641	+ return l.get(index+offset);
	642	+ }
	643	+
	644	+ public int size() {
	645	+ checkForComodification();
	646	+ return size;
	647	+ }
	648	+
	649	+ public void add(int index, E element) {
	650	+ rangeCheckForAdd(index);
	651	+ checkForComodification();
	652	+ l.add(index+offset, element);
	653	+ this.modCount = l.modCount;
	654	+ size++;
	655	+ }
	656	+
	657	+ public E remove(int index) {
	658	+ rangeCheck(index);
	659	+ checkForComodification();
	660	+ E result = l.remove(index+offset);
	661	+ this.modCount = l.modCount;
	662	+ size--;
	663	+ return result;
	664	+ }
	665	+
	666	+ protected void removeRange(int fromIndex, int toIndex) {
	667	+ checkForComodification();
	668	+ l.removeRange(fromIndex+offset, toIndex+offset);
	669	+ this.modCount = l.modCount;
	670	+ size -= (toIndex-fromIndex);
	671	+ }
	672	+
	673	+ public boolean addAll(Collection<? extends E> c) {
	674	+ return addAll(size, c);
	675	+ }
	676	+
	677	+ public boolean addAll(int index, Collection<? extends E> c) {
	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	+ this.modCount = l.modCount;
	686	+ size += cSize;
	687	+ return true;
	688	+ }
	689	+
	690	+ public Iterator<E> iterator() {
	691	+ return listIterator();
	692	+ }
	693	+
	694	+ public ListIterator<E> listIterator(final int index) {
	695	+ checkForComodification();
	696	+ rangeCheckForAdd(index);
	697	+
	698	+ return new ListIterator<E>() {
	699	+ private final ListIterator<E> i = l.listIterator(index+offset);
	700	+
	701	+ public boolean hasNext() {
	702	+ return nextIndex() < size;
	703	+ }
	704	+
	705	+ public E next() {
	706	+ if (hasNext())
	707	+ return i.next();
	708	+ else
	709	+ throw new NoSuchElementException();
	710	+ }
	711	+
	712	+ public boolean hasPrevious() {
	713	+ return previousIndex() >= 0;
	714	+ }
	715	+
	716	+ public E previous() {
	717	+ if (hasPrevious())
	718	+ return i.previous();
	719	+ else
	720	+ throw new NoSuchElementException();
	721	+ }
	722	+
	723	+ public int nextIndex() {
	724	+ return i.nextIndex() - offset;
	725	+ }
	726	+
	727	+ public int previousIndex() {
	728	+ return i.previousIndex() - offset;
	729	+ }
	730	+
	731	+ public void remove() {
	732	+ i.remove();
	733	+ SubList.this.modCount = l.modCount;
	734	+ size--;
	735	+ }
	736	+
	737	+ public void set(E e) {
	738	+ i.set(e);
	739	+ }
	740	+
	741	+ public void add(E e) {
	742	+ i.add(e);
	743	+ SubList.this.modCount = l.modCount;
	744	+ size++;
	745	+ }
	746	+ };
	747	+ }
	748	+
	749	+ public List<E> subList(int fromIndex, int toIndex) {
	750	+ return new SubList<>(this, fromIndex, toIndex);
	751	+ }
	752	+
	753	+ private void rangeCheck(int index) {
	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 (this.modCount != l.modCount)
	769	+ throw new ConcurrentModificationException();
	770	+ }
	771	+}
	772	+
	773	+class RandomAccessSubList<E> extends SubList<E> implements RandomAccess {
	774	+ RandomAccessSubList(AbstractList<E> list, int fromIndex, int toIndex) {
	775	+ super(list, fromIndex, toIndex);
	776	+ }
	777	+
	778	+ public List<E> subList(int fromIndex, int toIndex) {
	779	+ return new RandomAccessSubList<>(this, fromIndex, toIndex);
	780	+ }
	781	+}