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Comparing jsr166/src/main/java/util/ArrayList.java (file contents):
Revision 1.30 by jsr166, Sun Sep 5 21:32:19 2010 UTC vs.
Revision 1.47 by jsr166, Mon Dec 5 00:08:01 2016 UTC

#	Line 1 | Line 1
1		/*
2	<	* Copyright (c) 1997, 2008, Oracle and/or its affiliates. All rights reserved.
2	>	* Copyright (c) 1997, 2016, 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.  Sun designates this
7	>	* published by the Free Software Foundation.  Oracle designates this
8		* particular file as subject to the "Classpath" exception as provided
9	<	* by Sun in the LICENSE file that accompanied this code.
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
#	Line 25 | Line 25
25
26		package java.util;
27
28	+	import java.util.function.Consumer;
29	+	import java.util.function.Predicate;
30	+	import java.util.function.UnaryOperator;
31	+
32		/**
33	<	* Resizable-array implementation of the <tt>List</tt> interface.  Implements
33	>	* Resizable-array implementation of the {@code List} interface.  Implements
34		* all optional list operations, and permits all elements, including
35	<	* <tt>null</tt>.  In addition to implementing the <tt>List</tt> interface,
35	>	* {@code null}.  In addition to implementing the {@code List} interface,
36		* this class provides methods to manipulate the size of the array that is
37		* used internally to store the list.  (This class is roughly equivalent to
38	<	* <tt>Vector</tt>, except that it is unsynchronized.)
38	>	* {@code Vector}, except that it is unsynchronized.)
39		*
40	<	* <p>The <tt>size</tt>, <tt>isEmpty</tt>, <tt>get</tt>, <tt>set</tt>,
41	<	* <tt>iterator</tt>, and <tt>listIterator</tt> operations run in constant
42	<	* time.  The <tt>add</tt> operation runs in <i>amortized constant time</i>,
40	>	* <p>The {@code size}, {@code isEmpty}, {@code get}, {@code set},
41	>	* {@code iterator}, and {@code listIterator} operations run in constant
42	>	* time.  The {@code add} operation runs in <i>amortized constant time</i>,
43		* that is, adding n elements requires O(n) time.  All of the other operations
44		* run in linear time (roughly speaking).  The constant factor is low compared
45	<	* to that for the <tt>LinkedList</tt> implementation.
45	>	* to that for the {@code LinkedList} implementation.
46		*
47	<	* <p>Each <tt>ArrayList</tt> instance has a <i>capacity</i>.  The capacity is
47	>	* <p>Each {@code ArrayList} instance has a <i>capacity</i>.  The capacity is
48		* the size of the array used to store the elements in the list.  It is always
49		* at least as large as the list size.  As elements are added to an ArrayList,
50		* its capacity grows automatically.  The details of the growth policy are not
51		* specified beyond the fact that adding an element has constant amortized
52		* time cost.
53		*
54	<	* <p>An application can increase the capacity of an <tt>ArrayList</tt> instance
55	<	* before adding a large number of elements using the <tt>ensureCapacity</tt>
54	>	* <p>An application can increase the capacity of an {@code ArrayList} instance
55	>	* before adding a large number of elements using the {@code ensureCapacity}
56		* operation.  This may reduce the amount of incremental reallocation.
57		*
58		* <p><strong>Note that this implementation is not synchronized.</strong>
59	<	* If multiple threads access an <tt>ArrayList</tt> instance concurrently,
59	>	* If multiple threads access an {@code ArrayList} instance concurrently,
60		* and at least one of the threads modifies the list structurally, it
61		* <i>must</i> be synchronized externally.  (A structural modification is
62		* any operation that adds or deletes one or more elements, or explicitly
#	Line 66 | Line 70 | package java.util;
70		* unsynchronized access to the list:<pre>
71		*   List list = Collections.synchronizedList(new ArrayList(...));</pre>
72		*
73	<	* <p><a name="fail-fast"/>
73	>	* <p id="fail-fast">
74		* The iterators returned by this class's {@link #iterator() iterator} and
75		* {@link #listIterator(int) listIterator} methods are <em>fail-fast</em>:
76		* if the list is structurally modified at any time after the iterator is
#	Line 90 | Line 94 | package java.util;
94		* <a href="{@docRoot}/../technotes/guides/collections/index.html">
95		* Java Collections Framework</a>.
96		*
97	+	* @param <E> the type of elements in this list
98	+	*
99		* @author  Josh Bloch
100		* @author  Neal Gafter
101		* @see     Collection
#	Line 98 | Line 104 | package java.util;
104		* @see     Vector
105		* @since   1.2
106		*/
101	–
107		public class ArrayList<E> extends AbstractList<E>
108		implements List<E>, RandomAccess, Cloneable, java.io.Serializable
109		{
110		private static final long serialVersionUID = 8683452581122892189L;
111
112		/**
113	+	* Default initial capacity.
114	+	*/
115	+	private static final int DEFAULT_CAPACITY = 10;
116	+
117	+	/**
118	+	* Shared empty array instance used for empty instances.
119	+	*/
120	+	private static final Object[] EMPTY_ELEMENTDATA = {};
121	+
122	+	/**
123	+	* Shared empty array instance used for default sized empty instances. We
124	+	* distinguish this from EMPTY_ELEMENTDATA to know how much to inflate when
125	+	* first element is added.
126	+	*/
127	+	private static final Object[] DEFAULTCAPACITY_EMPTY_ELEMENTDATA = {};
128	+
129	+	/**
130		* The array buffer into which the elements of the ArrayList are stored.
131	<	* The capacity of the ArrayList is the length of this array buffer.
131	>	* The capacity of the ArrayList is the length of this array buffer. Any
132	>	* empty ArrayList with elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA
133	>	* will be expanded to DEFAULT_CAPACITY when the first element is added.
134		*/
135	<	private transient Object[] elementData;
135	>	transient Object[] elementData; // non-private to simplify nested class access
136
137		/**
138		* The size of the ArrayList (the number of elements it contains).
#	Line 120 | Line 144 | public class ArrayList<E> extends Abstra
144		/**
145		* Constructs an empty list with the specified initial capacity.
146		*
147	<	* @param   initialCapacity   the initial capacity of the list
148	<	* @exception IllegalArgumentException if the specified initial capacity
149	<	*            is negative
147	>	* @param  initialCapacity  the initial capacity of the list
148	>	* @throws IllegalArgumentException if the specified initial capacity
149	>	*         is negative
150		*/
151		public ArrayList(int initialCapacity) {
152	<	super();
153	<	if (initialCapacity < 0)
152	>	if (initialCapacity > 0) {
153	>	this.elementData = new Object[initialCapacity];
154	>	} else if (initialCapacity == 0) {
155	>	this.elementData = EMPTY_ELEMENTDATA;
156	>	} else {
157		throw new IllegalArgumentException("Illegal Capacity: "+
158		initialCapacity);
159	<	this.elementData = new Object[initialCapacity];
159	>	}
160		}
161
162		/**
163		* Constructs an empty list with an initial capacity of ten.
164		*/
165		public ArrayList() {
166	<	this(10);
166	>	this.elementData = DEFAULTCAPACITY_EMPTY_ELEMENTDATA;
167		}
168
169		/**
#	Line 149 | Line 176 | public class ArrayList<E> extends Abstra
176		*/
177		public ArrayList(Collection<? extends E> c) {
178		elementData = c.toArray();
179	<	size = elementData.length;
180	<	// c.toArray might (incorrectly) not return Object[] (see 6260652)
181	<	if (elementData.getClass() != Object[].class)
182	<	elementData = Arrays.copyOf(elementData, size, Object[].class);
179	>	if ((size = elementData.length) != 0) {
180	>	// defend against c.toArray (incorrectly) not returning Object[]
181	>	// (see e.g. https://bugs.openjdk.java.net/browse/JDK-6260652)
182	>	if (elementData.getClass() != Object[].class)
183	>	elementData = Arrays.copyOf(elementData, size, Object[].class);
184	>	} else {
185	>	// replace with empty array.
186	>	this.elementData = EMPTY_ELEMENTDATA;
187	>	}
188		}
189
190		/**
191	<	* Trims the capacity of this <tt>ArrayList</tt> instance to be the
191	>	* Trims the capacity of this {@code ArrayList} instance to be the
192		* list's current size.  An application can use this operation to minimize
193	<	* the storage of an <tt>ArrayList</tt> instance.
193	>	* the storage of an {@code ArrayList} instance.
194		*/
195		public void trimToSize() {
196		modCount++;
197	<	int oldCapacity = elementData.length;
198	<	if (size < oldCapacity) {
199	<	elementData = Arrays.copyOf(elementData, size);
197	>	if (size < elementData.length) {
198	>	elementData = (size == 0)
199	>	? EMPTY_ELEMENTDATA
200	>	: Arrays.copyOf(elementData, size);
201		}
202		}
203
204		/**
205	<	* Increases the capacity of this <tt>ArrayList</tt> instance, if
205	>	* Increases the capacity of this {@code ArrayList} instance, if
206		* necessary, to ensure that it can hold at least the number of elements
207		* specified by the minimum capacity argument.
208		*
209	<	* @param   minCapacity   the desired minimum capacity
209	>	* @param minCapacity the desired minimum capacity
210		*/
211		public void ensureCapacity(int minCapacity) {
212	<	modCount++;
213	<	int oldCapacity = elementData.length;
214	<	if (minCapacity > oldCapacity) {
215	<	int newCapacity = (oldCapacity * 3)/2 + 1;
216	<	if (newCapacity < minCapacity)
184	<	newCapacity = minCapacity;
185	<	// minCapacity is usually close to size, so this is a win:
186	<	elementData = Arrays.copyOf(elementData, newCapacity);
212	>	if (minCapacity > elementData.length
213	>	&& !(elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA
214	>	&& minCapacity <= DEFAULT_CAPACITY)) {
215	>	modCount++;
216	>	grow(minCapacity);
217		}
218		}
219
220		/**
221	+	* The maximum size of array to allocate (unless necessary).
222	+	* Some VMs reserve some header words in an array.
223	+	* Attempts to allocate larger arrays may result in
224	+	* OutOfMemoryError: Requested array size exceeds VM limit
225	+	*/
226	+	private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;
227	+
228	+	/**
229	+	* Increases the capacity to ensure that it can hold at least the
230	+	* number of elements specified by the minimum capacity argument.
231	+	*
232	+	* @param minCapacity the desired minimum capacity
233	+	* @throws OutOfMemoryError if minCapacity is less than zero
234	+	*/
235	+	private Object[] grow(int minCapacity) {
236	+	return elementData = Arrays.copyOf(elementData,
237	+	newCapacity(minCapacity));
238	+	}
239	+
240	+	private Object[] grow() {
241	+	return grow(size + 1);
242	+	}
243	+
244	+	/**
245	+	* Returns a capacity at least as large as the given minimum capacity.
246	+	* Returns the current capacity increased by 50% if that suffices.
247	+	* Will not return a capacity greater than MAX_ARRAY_SIZE unless
248	+	* the given minimum capacity is greater than MAX_ARRAY_SIZE.
249	+	*
250	+	* @param minCapacity the desired minimum capacity
251	+	* @throws OutOfMemoryError if minCapacity is less than zero
252	+	*/
253	+	private int newCapacity(int minCapacity) {
254	+	// overflow-conscious code
255	+	int oldCapacity = elementData.length;
256	+	int newCapacity = oldCapacity + (oldCapacity >> 1);
257	+	if (newCapacity - minCapacity <= 0) {
258	+	if (elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA)
259	+	return Math.max(DEFAULT_CAPACITY, minCapacity);
260	+	if (minCapacity < 0) // overflow
261	+	throw new OutOfMemoryError();
262	+	return minCapacity;
263	+	}
264	+	return (newCapacity - MAX_ARRAY_SIZE <= 0)
265	+	? newCapacity
266	+	: hugeCapacity(minCapacity);
267	+	}
268	+
269	+	private static int hugeCapacity(int minCapacity) {
270	+	if (minCapacity < 0) // overflow
271	+	throw new OutOfMemoryError();
272	+	return (minCapacity > MAX_ARRAY_SIZE)
273	+	? Integer.MAX_VALUE
274	+	: MAX_ARRAY_SIZE;
275	+	}
276	+
277	+	/**
278		* Returns the number of elements in this list.
279		*
280		* @return the number of elements in this list
#	Line 197 | Line 284 | public class ArrayList<E> extends Abstra
284		}
285
286		/**
287	<	* Returns <tt>true</tt> if this list contains no elements.
287	>	* Returns {@code true} if this list contains no elements.
288		*
289	<	* @return <tt>true</tt> if this list contains no elements
289	>	* @return {@code true} if this list contains no elements
290		*/
291		public boolean isEmpty() {
292		return size == 0;
293		}
294
295		/**
296	<	* Returns <tt>true</tt> if this list contains the specified element.
297	<	* More formally, returns <tt>true</tt> if and only if this list contains
298	<	* at least one element <tt>e</tt> such that
299	<	* <tt>(o==null&nbsp;?&nbsp;e==null&nbsp;:&nbsp;o.equals(e))</tt>.
296	>	* Returns {@code true} if this list contains the specified element.
297	>	* More formally, returns {@code true} if and only if this list contains
298	>	* at least one element {@code e} such that
299	>	* {@code Objects.equals(o, e)}.
300		*
301		* @param o element whose presence in this list is to be tested
302	<	* @return <tt>true</tt> if this list contains the specified element
302	>	* @return {@code true} if this list contains the specified element
303		*/
304		public boolean contains(Object o) {
305		return indexOf(o) >= 0;
#	Line 221 | Line 308 | public class ArrayList<E> extends Abstra
308		/**
309		* Returns the index of the first occurrence of the specified element
310		* in this list, or -1 if this list does not contain the element.
311	<	* More formally, returns the lowest index <tt>i</tt> such that
312	<	* <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>,
311	>	* More formally, returns the lowest index {@code i} such that
312	>	* {@code Objects.equals(o, get(i))},
313		* or -1 if there is no such index.
314		*/
315		public int indexOf(Object o) {
#	Line 241 | Line 328 | public class ArrayList<E> extends Abstra
328		/**
329		* Returns the index of the last occurrence of the specified element
330		* in this list, or -1 if this list does not contain the element.
331	<	* More formally, returns the highest index <tt>i</tt> such that
332	<	* <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>,
331	>	* More formally, returns the highest index {@code i} such that
332	>	* {@code Objects.equals(o, get(i))},
333		* or -1 if there is no such index.
334		*/
335		public int lastIndexOf(Object o) {
#	Line 259 | Line 346 | public class ArrayList<E> extends Abstra
346		}
347
348		/**
349	<	* Returns a shallow copy of this <tt>ArrayList</tt> instance.  (The
349	>	* Returns a shallow copy of this {@code ArrayList} instance.  (The
350		* elements themselves are not copied.)
351		*
352	<	* @return a clone of this <tt>ArrayList</tt> instance
352	>	* @return a clone of this {@code ArrayList} instance
353		*/
354		public Object clone() {
355		try {
356	<	@SuppressWarnings("unchecked")
270	<	ArrayList<E> v = (ArrayList<E>) super.clone();
356	>	ArrayList<?> v = (ArrayList<?>) super.clone();
357		v.elementData = Arrays.copyOf(elementData, size);
358		v.modCount = 0;
359		return v;
360		} catch (CloneNotSupportedException e) {
361		// this shouldn't happen, since we are Cloneable
362	<	throw new InternalError();
362	>	throw new InternalError(e);
363		}
364		}
365
#	Line 306 | Line 392 | public class ArrayList<E> extends Abstra
392		* <p>If the list fits in the specified array with room to spare
393		* (i.e., the array has more elements than the list), the element in
394		* the array immediately following the end of the collection is set to
395	<	* <tt>null</tt>.  (This is useful in determining the length of the
395	>	* {@code null}.  (This is useful in determining the length of the
396		* list <i>only</i> if the caller knows that the list does not contain
397		* any null elements.)
398		*
#	Line 337 | Line 423 | public class ArrayList<E> extends Abstra
423		return (E) elementData[index];
424		}
425
426	+	@SuppressWarnings("unchecked")
427	+	static <E> E elementAt(Object[] es, int index) {
428	+	return (E) es[index];
429	+	}
430	+
431		/**
432		* Returns the element at the specified position in this list.
433		*
#	Line 345 | Line 436 | public class ArrayList<E> extends Abstra
436		* @throws IndexOutOfBoundsException {@inheritDoc}
437		*/
438		public E get(int index) {
439	<	rangeCheck(index);
349	<
439	>	Objects.checkIndex(index, size);
440		return elementData(index);
441		}
442
#	Line 360 | Line 450 | public class ArrayList<E> extends Abstra
450		* @throws IndexOutOfBoundsException {@inheritDoc}
451		*/
452		public E set(int index, E element) {
453	<	rangeCheck(index);
364	<
453	>	Objects.checkIndex(index, size);
454		E oldValue = elementData(index);
455		elementData[index] = element;
456		return oldValue;
457		}
458
459		/**
460	+	* This helper method split out from add(E) to keep method
461	+	* bytecode size under 35 (the -XX:MaxInlineSize default value),
462	+	* which helps when add(E) is called in a C1-compiled loop.
463	+	*/
464	+	private void add(E e, Object[] elementData, int s) {
465	+	if (s == elementData.length)
466	+	elementData = grow();
467	+	elementData[s] = e;
468	+	size = s + 1;
469	+	}
470	+
471	+	/**
472		* Appends the specified element to the end of this list.
473		*
474		* @param e element to be appended to this list
475	<	* @return <tt>true</tt> (as specified by {@link Collection#add})
475	>	* @return {@code true} (as specified by {@link Collection#add})
476		*/
477		public boolean add(E e) {
478	<	ensureCapacity(size + 1);  // Increments modCount!!
479	<	elementData[size++] = e;
478	>	modCount++;
479	>	add(e, elementData, size);
480		return true;
481		}
482
#	Line 390 | Line 491 | public class ArrayList<E> extends Abstra
491		*/
492		public void add(int index, E element) {
493		rangeCheckForAdd(index);
494	<
495	<	ensureCapacity(size+1);  // Increments modCount!!
496	<	System.arraycopy(elementData, index, elementData, index + 1,
497	<	size - index);
494	>	modCount++;
495	>	final int s;
496	>	Object[] elementData;
497	>	if ((s = size) == (elementData = this.elementData).length)
498	>	elementData = grow();
499	>	System.arraycopy(elementData, index,
500	>	elementData, index + 1,
501	>	s - index);
502		elementData[index] = element;
503	<	size++;
503	>	size = s + 1;
504	>	// checkInvariants();
505		}
506
507		/**
#	Line 408 | Line 514 | public class ArrayList<E> extends Abstra
514		* @throws IndexOutOfBoundsException {@inheritDoc}
515		*/
516		public E remove(int index) {
517	<	rangeCheck(index);
517	>	Objects.checkIndex(index, size);
518
519		modCount++;
520		E oldValue = elementData(index);
#	Line 417 | Line 523 | public class ArrayList<E> extends Abstra
523		if (numMoved > 0)
524		System.arraycopy(elementData, index+1, elementData, index,
525		numMoved);
526	<	elementData[--size] = null; // Let gc do its work
526	>	elementData[--size] = null; // clear to let GC do its work
527
528	+	// checkInvariants();
529		return oldValue;
530		}
531
#	Line 426 | Line 533 | public class ArrayList<E> extends Abstra
533		* Removes the first occurrence of the specified element from this list,
534		* if it is present.  If the list does not contain the element, it is
535		* unchanged.  More formally, removes the element with the lowest index
536	<	* <tt>i</tt> such that
537	<	* <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>
538	<	* (if such an element exists).  Returns <tt>true</tt> if this list
536	>	* {@code i} such that
537	>	* {@code Objects.equals(o, get(i))}
538	>	* (if such an element exists).  Returns {@code true} if this list
539		* contained the specified element (or equivalently, if this list
540		* changed as a result of the call).
541		*
542		* @param o element to be removed from this list, if present
543	<	* @return <tt>true</tt> if this list contained the specified element
543	>	* @return {@code true} if this list contained the specified element
544		*/
545		public boolean remove(Object o) {
546		if (o == null) {
#	Line 452 | Line 559 | public class ArrayList<E> extends Abstra
559		return false;
560		}
561
562	<	/*
562	>	/**
563		* Private remove method that skips bounds checking and does not
564		* return the value removed.
565		*/
#	Line 462 | Line 569 | public class ArrayList<E> extends Abstra
569		if (numMoved > 0)
570		System.arraycopy(elementData, index+1, elementData, index,
571		numMoved);
572	<	elementData[--size] = null; // Let gc do its work
572	>	elementData[--size] = null; // clear to let GC do its work
573		}
574
575		/**
#	Line 471 | Line 578 | public class ArrayList<E> extends Abstra
578		*/
579		public void clear() {
580		modCount++;
581	<
582	<	// Let gc do its work
583	<	for (int i = 0; i < size; i++)
477	<	elementData[i] = null;
478	<
479	<	size = 0;
581	>	final Object[] es = elementData;
582	>	for (int to = size, i = size = 0; i < to; i++)
583	>	es[i] = null;
584		}
585
586		/**
#	Line 489 | Line 593 | public class ArrayList<E> extends Abstra
593		* list is nonempty.)
594		*
595		* @param c collection containing elements to be added to this list
596	<	* @return <tt>true</tt> if this list changed as a result of the call
596	>	* @return {@code true} if this list changed as a result of the call
597		* @throws NullPointerException if the specified collection is null
598		*/
599		public boolean addAll(Collection<? extends E> c) {
600		Object[] a = c.toArray();
601	+	modCount++;
602		int numNew = a.length;
603	<	ensureCapacity(size + numNew);  // Increments modCount
604	<	System.arraycopy(a, 0, elementData, size, numNew);
605	<	size += numNew;
606	<	return numNew != 0;
603	>	if (numNew == 0)
604	>	return false;
605	>	Object[] elementData;
606	>	final int s;
607	>	if (numNew > (elementData = this.elementData).length - (s = size))
608	>	elementData = grow(s + numNew);
609	>	System.arraycopy(a, 0, elementData, s, numNew);
610	>	size = s + numNew;
611	>	// checkInvariants();
612	>	return true;
613		}
614
615		/**
#	Line 512 | Line 623 | public class ArrayList<E> extends Abstra
623		* @param index index at which to insert the first element from the
624		*              specified collection
625		* @param c collection containing elements to be added to this list
626	<	* @return <tt>true</tt> if this list changed as a result of the call
626	>	* @return {@code true} if this list changed as a result of the call
627		* @throws IndexOutOfBoundsException {@inheritDoc}
628		* @throws NullPointerException if the specified collection is null
629		*/
#	Line 520 | Line 631 | public class ArrayList<E> extends Abstra
631		rangeCheckForAdd(index);
632
633		Object[] a = c.toArray();
634	+	modCount++;
635		int numNew = a.length;
636	<	ensureCapacity(size + numNew);  // Increments modCount
636	>	if (numNew == 0)
637	>	return false;
638	>	Object[] elementData;
639	>	final int s;
640	>	if (numNew > (elementData = this.elementData).length - (s = size))
641	>	elementData = grow(s + numNew);
642
643	<	int numMoved = size - index;
643	>	int numMoved = s - index;
644		if (numMoved > 0)
645	<	System.arraycopy(elementData, index, elementData, index + numNew,
645	>	System.arraycopy(elementData, index,
646	>	elementData, index + numNew,
647		numMoved);
530	–
648		System.arraycopy(a, 0, elementData, index, numNew);
649	<	size += numNew;
650	<	return numNew != 0;
649	>	size = s + numNew;
650	>	// checkInvariants();
651	>	return true;
652		}
653
654		/**
#	Line 543 | Line 661 | public class ArrayList<E> extends Abstra
661		* @throws IndexOutOfBoundsException if {@code fromIndex} or
662		*         {@code toIndex} is out of range
663		*         ({@code fromIndex < 0 ||
546	–	*          fromIndex >= size() ||
664		*          toIndex > size() ||
665		*          toIndex < fromIndex})
666		*/
667		protected void removeRange(int fromIndex, int toIndex) {
668	+	if (fromIndex > toIndex) {
669	+	throw new IndexOutOfBoundsException(
670	+	outOfBoundsMsg(fromIndex, toIndex));
671	+	}
672		modCount++;
673	<	int numMoved = size - toIndex;
674	<	System.arraycopy(elementData, toIndex, elementData, fromIndex,
554	<	numMoved);
555	<
556	<	// Let gc do its work
557	<	int newSize = size - (toIndex-fromIndex);
558	<	while (size != newSize)
559	<	elementData[--size] = null;
673	>	shiftTailOverGap(elementData, fromIndex, toIndex);
674	>	// checkInvariants();
675		}
676
677	<	/**
678	<	* Checks if the given index is in range.  If not, throws an appropriate
679	<	* runtime exception.  This method does *not* check if the index is
680	<	* negative: It is always used immediately prior to an array access,
681	<	* which throws an ArrayIndexOutOfBoundsException if index is negative.
567	<	*/
568	<	private void rangeCheck(int index) {
569	<	if (index >= size)
570	<	throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
677	>	/** Erases the gap from lo to hi, by sliding down following elements. */
678	>	private void shiftTailOverGap(Object[] es, int lo, int hi) {
679	>	System.arraycopy(es, hi, es, lo, size - hi);
680	>	for (int to = size, i = (size -= hi - lo); i < to; i++)
681	>	es[i] = null;
682		}
683
684		/**
#	Line 588 | Line 699 | public class ArrayList<E> extends Abstra
699		}
700
701		/**
702	+	* A version used in checking (fromIndex > toIndex) condition
703	+	*/
704	+	private static String outOfBoundsMsg(int fromIndex, int toIndex) {
705	+	return "From Index: " + fromIndex + " > To Index: " + toIndex;
706	+	}
707	+
708	+	/**
709		* Removes from this list all of its elements that are contained in the
710		* specified collection.
711		*
712		* @param c collection containing elements to be removed from this list
713		* @return {@code true} if this list changed as a result of the call
714		* @throws ClassCastException if the class of an element of this list
715	<	*         is incompatible with the specified collection (optional)
715	>	*         is incompatible with the specified collection
716	>	* (<a href="Collection.html#optional-restrictions">optional</a>)
717		* @throws NullPointerException if this list contains a null element and the
718	<	*         specified collection does not permit null elements (optional),
718	>	*         specified collection does not permit null elements
719	>	* (<a href="Collection.html#optional-restrictions">optional</a>),
720		*         or if the specified collection is null
721		* @see Collection#contains(Object)
722		*/
723		public boolean removeAll(Collection<?> c) {
724	<	return batchRemove(c, false);
724	>	return batchRemove(c, false, 0, size);
725		}
726
727		/**
#	Line 612 | Line 732 | public class ArrayList<E> extends Abstra
732		* @param c collection containing elements to be retained in this list
733		* @return {@code true} if this list changed as a result of the call
734		* @throws ClassCastException if the class of an element of this list
735	<	*         is incompatible with the specified collection (optional)
735	>	*         is incompatible with the specified collection
736	>	* (<a href="Collection.html#optional-restrictions">optional</a>)
737		* @throws NullPointerException if this list contains a null element and the
738	<	*         specified collection does not permit null elements (optional),
738	>	*         specified collection does not permit null elements
739	>	* (<a href="Collection.html#optional-restrictions">optional</a>),
740		*         or if the specified collection is null
741		* @see Collection#contains(Object)
742		*/
743		public boolean retainAll(Collection<?> c) {
744	<	return batchRemove(c, true);
744	>	return batchRemove(c, true, 0, size);
745		}
746
747	<	private boolean batchRemove(Collection<?> c, boolean complement) {
748	<	final Object[] elementData = this.elementData;
749	<	int r = 0, w = 0;
750	<	boolean modified = false;
751	<	try {
752	<	for (; r < size; r++)
753	<	if (c.contains(elementData[r]) == complement)
754	<	elementData[w++] = elementData[r];
755	<	} finally {
756	<	// Preserve behavioral compatibility with AbstractCollection,
757	<	// even if c.contains() throws.
758	<	if (r != size) {
759	<	System.arraycopy(elementData, r,
760	<	elementData, w,
761	<	size - r);
762	<	w += size - r;
763	<	}
764	<	if (w != size) {
765	<	for (int i = w; i < size; i++)
766	<	elementData[i] = null;
767	<	modCount += size - w;
768	<	size = w;
769	<	modified = true;
747	>	boolean batchRemove(Collection<?> c, boolean complement,
748	>	final int from, final int end) {
749	>	Objects.requireNonNull(c);
750	>	final Object[] es = elementData;
751	>	final boolean modified;
752	>	int r;
753	>	// Optimize for initial run of survivors
754	>	for (r = from; r < end && c.contains(es[r]) == complement; r++)
755	>	;
756	>	if (modified = (r < end)) {
757	>	int w = r++;
758	>	try {
759	>	for (Object e; r < end; r++)
760	>	if (c.contains(e = es[r]) == complement)
761	>	es[w++] = e;
762	>	} catch (Throwable ex) {
763	>	// Preserve behavioral compatibility with AbstractCollection,
764	>	// even if c.contains() throws.
765	>	System.arraycopy(es, r, es, w, end - r);
766	>	w += end - r;
767	>	throw ex;
768	>	} finally {
769	>	modCount += end - w;
770	>	shiftTailOverGap(es, w, end);
771		}
772		}
773	+	// checkInvariants();
774		return modified;
775		}
776
777		/**
778	<	* Save the state of the <tt>ArrayList</tt> instance to a stream (that
779	<	* is, serialize it).
778	>	* Saves the state of the {@code ArrayList} instance to a stream
779	>	* (that is, serializes it).
780		*
781	<	* @serialData The length of the array backing the <tt>ArrayList</tt>
781	>	* @param s the stream
782	>	* @throws java.io.IOException if an I/O error occurs
783	>	* @serialData The length of the array backing the {@code ArrayList}
784		*             instance is emitted (int), followed by all of its elements
785	<	*             (each an <tt>Object</tt>) in the proper order.
785	>	*             (each an {@code Object}) in the proper order.
786		*/
787		private void writeObject(java.io.ObjectOutputStream s)
788	<	throws java.io.IOException{
788	>	throws java.io.IOException {
789		// Write out element count, and any hidden stuff
790		int expectedModCount = modCount;
791		s.defaultWriteObject();
792
793	<	// Write out array length
794	<	s.writeInt(elementData.length);
793	>	// Write out size as capacity for behavioural compatibility with clone()
794	>	s.writeInt(size);
795
796		// Write out all elements in the proper order.
797	<	for (int i=0; i<size; i++)
797	>	for (int i=0; i<size; i++) {
798		s.writeObject(elementData[i]);
799	+	}
800
801		if (modCount != expectedModCount) {
802		throw new ConcurrentModificationException();
803		}
677	–
804		}
805
806		/**
807	<	* Reconstitute the <tt>ArrayList</tt> instance from a stream (that is,
808	<	* deserialize it).
807	>	* Reconstitutes the {@code ArrayList} instance from a stream (that is,
808	>	* deserializes it).
809	>	* @param s the stream
810	>	* @throws ClassNotFoundException if the class of a serialized object
811	>	*         could not be found
812	>	* @throws java.io.IOException if an I/O error occurs
813		*/
814		private void readObject(java.io.ObjectInputStream s)
815		throws java.io.IOException, ClassNotFoundException {
816	+
817		// Read in size, and any hidden stuff
818		s.defaultReadObject();
819
820	<	// Read in array length and allocate array
821	<	int arrayLength = s.readInt();
822	<	Object[] a = elementData = new Object[arrayLength];
823	<
824	<	// Read in all elements in the proper order.
825	<	for (int i=0; i<size; i++)
826	<	a[i] = s.readObject();
820	>	// Read in capacity
821	>	s.readInt(); // ignored
822	>
823	>	if (size > 0) {
824	>	// like clone(), allocate array based upon size not capacity
825	>	Object[] elements = new Object[size];
826	>
827	>	// Read in all elements in the proper order.
828	>	for (int i = 0; i < size; i++) {
829	>	elements[i] = s.readObject();
830	>	}
831	>
832	>	elementData = elements;
833	>	} else if (size == 0) {
834	>	elementData = EMPTY_ELEMENTDATA;
835	>	} else {
836	>	throw new java.io.InvalidObjectException("Invalid size: " + size);
837	>	}
838		}
839
840		/**
#	Line 708 | Line 850 | public class ArrayList<E> extends Abstra
850		* @throws IndexOutOfBoundsException {@inheritDoc}
851		*/
852		public ListIterator<E> listIterator(int index) {
853	<	if (index < 0 || index > size)
712	<	throw new IndexOutOfBoundsException("Index: "+index);
853	>	rangeCheckForAdd(index);
854		return new ListItr(index);
855		}
856
#	Line 744 | Line 885 | public class ArrayList<E> extends Abstra
885		int lastRet = -1; // index of last element returned; -1 if no such
886		int expectedModCount = modCount;
887
888	+	// prevent creating a synthetic constructor
889	+	Itr() {}
890	+
891		public boolean hasNext() {
892		return cursor != size;
893		}
#	Line 776 | Line 920 | public class ArrayList<E> extends Abstra
920		}
921		}
922
923	+	@Override
924	+	public void forEachRemaining(Consumer<? super E> action) {
925	+	Objects.requireNonNull(action);
926	+	final int size = ArrayList.this.size;
927	+	int i = cursor;
928	+	if (i < size) {
929	+	final Object[] es = elementData;
930	+	if (i >= es.length)
931	+	throw new ConcurrentModificationException();
932	+	for (; i < size && modCount == expectedModCount; i++)
933	+	action.accept(elementAt(es, i));
934	+	// update once at end to reduce heap write traffic
935	+	cursor = i;
936	+	lastRet = i - 1;
937	+	checkForComodification();
938	+	}
939	+	}
940	+
941		final void checkForComodification() {
942		if (modCount != expectedModCount)
943		throw new ConcurrentModificationException();
#	Line 874 | Line 1036 | public class ArrayList<E> extends Abstra
1036		*/
1037		public List<E> subList(int fromIndex, int toIndex) {
1038		subListRangeCheck(fromIndex, toIndex, size);
1039	<	return new SubList(this, 0, fromIndex, toIndex);
1039	>	return new SubList<>(this, fromIndex, toIndex);
1040		}
1041
1042	<	static void subListRangeCheck(int fromIndex, int toIndex, int size) {
1043	<	if (fromIndex < 0)
1044	<	throw new IndexOutOfBoundsException("fromIndex = " + fromIndex);
883	<	if (toIndex > size)
884	<	throw new IndexOutOfBoundsException("toIndex = " + toIndex);
885	<	if (fromIndex > toIndex)
886	<	throw new IllegalArgumentException("fromIndex(" + fromIndex +
887	<	") > toIndex(" + toIndex + ")");
888	<	}
889	<
890	<	private class SubList extends AbstractList<E> implements RandomAccess {
891	<	private final AbstractList<E> parent;
892	<	private final int parentOffset;
1042	>	private static class SubList<E> extends AbstractList<E> implements RandomAccess {
1043	>	private final ArrayList<E> root;
1044	>	private final SubList<E> parent;
1045		private final int offset;
1046	<	int size;
1046	>	private int size;
1047
1048	<	SubList(AbstractList<E> parent,
1049	<	int offset, int fromIndex, int toIndex) {
1048	>	/**
1049	>	* Constructs a sublist of an arbitrary ArrayList.
1050	>	*/
1051	>	public SubList(ArrayList<E> root, int fromIndex, int toIndex) {
1052	>	this.root = root;
1053	>	this.parent = null;
1054	>	this.offset = fromIndex;
1055	>	this.size = toIndex - fromIndex;
1056	>	this.modCount = root.modCount;
1057	>	}
1058	>
1059	>	/**
1060	>	* Constructs a sublist of another SubList.
1061	>	*/
1062	>	private SubList(SubList<E> parent, int fromIndex, int toIndex) {
1063	>	this.root = parent.root;
1064		this.parent = parent;
1065	<	this.parentOffset = fromIndex;
900	<	this.offset = offset + fromIndex;
1065	>	this.offset = parent.offset + fromIndex;
1066		this.size = toIndex - fromIndex;
1067	<	this.modCount = ArrayList.this.modCount;
1067	>	this.modCount = root.modCount;
1068		}
1069
1070	<	public E set(int index, E e) {
1071	<	rangeCheck(index);
1070	>	public E set(int index, E element) {
1071	>	Objects.checkIndex(index, size);
1072		checkForComodification();
1073	<	E oldValue = ArrayList.this.elementData(offset + index);
1074	<	ArrayList.this.elementData[offset + index] = e;
1073	>	E oldValue = root.elementData(offset + index);
1074	>	root.elementData[offset + index] = element;
1075		return oldValue;
1076		}
1077
1078		public E get(int index) {
1079	<	rangeCheck(index);
1079	>	Objects.checkIndex(index, size);
1080		checkForComodification();
1081	<	return ArrayList.this.elementData(offset + index);
1081	>	return root.elementData(offset + index);
1082		}
1083
1084		public int size() {
1085		checkForComodification();
1086	<	return this.size;
1086	>	return size;
1087		}
1088
1089	<	public void add(int index, E e) {
1089	>	public void add(int index, E element) {
1090		rangeCheckForAdd(index);
1091		checkForComodification();
1092	<	parent.add(parentOffset + index, e);
1093	<	this.modCount = parent.modCount;
929	<	this.size++;
1092	>	root.add(offset + index, element);
1093	>	updateSizeAndModCount(1);
1094		}
1095
1096		public E remove(int index) {
1097	<	rangeCheck(index);
1097	>	Objects.checkIndex(index, size);
1098		checkForComodification();
1099	<	E result = parent.remove(parentOffset + index);
1100	<	this.modCount = parent.modCount;
937	<	this.size--;
1099	>	E result = root.remove(offset + index);
1100	>	updateSizeAndModCount(-1);
1101		return result;
1102		}
1103
1104		protected void removeRange(int fromIndex, int toIndex) {
1105		checkForComodification();
1106	<	parent.removeRange(parentOffset + fromIndex,
1107	<	parentOffset + toIndex);
945	<	this.modCount = parent.modCount;
946	<	this.size -= toIndex - fromIndex;
1106	>	root.removeRange(offset + fromIndex, offset + toIndex);
1107	>	updateSizeAndModCount(fromIndex - toIndex);
1108		}
1109
1110		public boolean addAll(Collection<? extends E> c) {
#	Line 955 | Line 1116 | public class ArrayList<E> extends Abstra
1116		int cSize = c.size();
1117		if (cSize==0)
1118		return false;
958	–
1119		checkForComodification();
1120	<	parent.addAll(parentOffset + index, c);
1121	<	this.modCount = parent.modCount;
962	<	this.size += cSize;
1120	>	root.addAll(offset + index, c);
1121	>	updateSizeAndModCount(cSize);
1122		return true;
1123		}
1124
1125	+	public boolean removeAll(Collection<?> c) {
1126	+	return batchRemove(c, false);
1127	+	}
1128	+
1129	+	public boolean retainAll(Collection<?> c) {
1130	+	return batchRemove(c, true);
1131	+	}
1132	+
1133	+	private boolean batchRemove(Collection<?> c, boolean complement) {
1134	+	checkForComodification();
1135	+	int oldSize = root.size;
1136	+	boolean modified =
1137	+	root.batchRemove(c, complement, offset, offset + size);
1138	+	if (modified)
1139	+	updateSizeAndModCount(root.size - oldSize);
1140	+	return modified;
1141	+	}
1142	+
1143	+	public boolean removeIf(Predicate<? super E> filter) {
1144	+	checkForComodification();
1145	+	int oldSize = root.size;
1146	+	boolean modified = root.removeIf(filter, offset, offset + size);
1147	+	if (modified)
1148	+	updateSizeAndModCount(root.size - oldSize);
1149	+	return modified;
1150	+	}
1151	+
1152		public Iterator<E> iterator() {
1153		return listIterator();
1154		}
1155
1156	<	public ListIterator<E> listIterator(final int index) {
1156	>	public ListIterator<E> listIterator(int index) {
1157		checkForComodification();
1158		rangeCheckForAdd(index);
973	–	final int offset = this.offset;
1159
1160		return new ListIterator<E>() {
1161		int cursor = index;
1162		int lastRet = -1;
1163	<	int expectedModCount = ArrayList.this.modCount;
1163	>	int expectedModCount = root.modCount;
1164
1165		public boolean hasNext() {
1166		return cursor != SubList.this.size;
#	Line 987 | Line 1172 | public class ArrayList<E> extends Abstra
1172		int i = cursor;
1173		if (i >= SubList.this.size)
1174		throw new NoSuchElementException();
1175	<	Object[] elementData = ArrayList.this.elementData;
1175	>	Object[] elementData = root.elementData;
1176		if (offset + i >= elementData.length)
1177		throw new ConcurrentModificationException();
1178		cursor = i + 1;
#	Line 1004 | Line 1189 | public class ArrayList<E> extends Abstra
1189		int i = cursor - 1;
1190		if (i < 0)
1191		throw new NoSuchElementException();
1192	<	Object[] elementData = ArrayList.this.elementData;
1192	>	Object[] elementData = root.elementData;
1193		if (offset + i >= elementData.length)
1194		throw new ConcurrentModificationException();
1195		cursor = i;
1196		return (E) elementData[offset + (lastRet = i)];
1197		}
1198
1199	+	public void forEachRemaining(Consumer<? super E> action) {
1200	+	Objects.requireNonNull(action);
1201	+	final int size = SubList.this.size;
1202	+	int i = cursor;
1203	+	if (i < size) {
1204	+	final Object[] es = root.elementData;
1205	+	if (offset + i >= es.length)
1206	+	throw new ConcurrentModificationException();
1207	+	for (; i < size && modCount == expectedModCount; i++)
1208	+	action.accept(elementAt(es, offset + i));
1209	+	// update once at end to reduce heap write traffic
1210	+	cursor = i;
1211	+	lastRet = i - 1;
1212	+	checkForComodification();
1213	+	}
1214	+	}
1215	+
1216		public int nextIndex() {
1217		return cursor;
1218		}
#	Line 1028 | Line 1230 | public class ArrayList<E> extends Abstra
1230		SubList.this.remove(lastRet);
1231		cursor = lastRet;
1232		lastRet = -1;
1233	<	expectedModCount = ArrayList.this.modCount;
1233	>	expectedModCount = root.modCount;
1234		} catch (IndexOutOfBoundsException ex) {
1235		throw new ConcurrentModificationException();
1236		}
#	Line 1040 | Line 1242 | public class ArrayList<E> extends Abstra
1242		checkForComodification();
1243
1244		try {
1245	<	ArrayList.this.set(offset + lastRet, e);
1245	>	root.set(offset + lastRet, e);
1246		} catch (IndexOutOfBoundsException ex) {
1247		throw new ConcurrentModificationException();
1248		}
#	Line 1054 | Line 1256 | public class ArrayList<E> extends Abstra
1256		SubList.this.add(i, e);
1257		cursor = i + 1;
1258		lastRet = -1;
1259	<	expectedModCount = ArrayList.this.modCount;
1259	>	expectedModCount = root.modCount;
1260		} catch (IndexOutOfBoundsException ex) {
1261		throw new ConcurrentModificationException();
1262		}
1263		}
1264
1265		final void checkForComodification() {
1266	<	if (expectedModCount != ArrayList.this.modCount)
1266	>	if (root.modCount != expectedModCount)
1267		throw new ConcurrentModificationException();
1268		}
1269		};
#	Line 1069 | Line 1271 | public class ArrayList<E> extends Abstra
1271
1272		public List<E> subList(int fromIndex, int toIndex) {
1273		subListRangeCheck(fromIndex, toIndex, size);
1274	<	return new SubList(this, offset, fromIndex, toIndex);
1073	<	}
1074	<
1075	<	private void rangeCheck(int index) {
1076	<	if (index < 0 || index >= this.size)
1077	<	throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
1274	>	return new SubList<>(this, fromIndex, toIndex);
1275		}
1276
1277		private void rangeCheckForAdd(int index) {
#	Line 1087 | Line 1284 | public class ArrayList<E> extends Abstra
1284		}
1285
1286		private void checkForComodification() {
1287	<	if (ArrayList.this.modCount != this.modCount)
1287	>	if (root.modCount != modCount)
1288	>	throw new ConcurrentModificationException();
1289	>	}
1290	>
1291	>	private void updateSizeAndModCount(int sizeChange) {
1292	>	SubList<E> slist = this;
1293	>	do {
1294	>	slist.size += sizeChange;
1295	>	slist.modCount = root.modCount;
1296	>	slist = slist.parent;
1297	>	} while (slist != null);
1298	>	}
1299	>
1300	>	public Spliterator<E> spliterator() {
1301	>	checkForComodification();
1302	>
1303	>	// ArrayListSpliterator not used here due to late-binding
1304	>	return new Spliterator<E>() {
1305	>	private int index = offset; // current index, modified on advance/split
1306	>	private int fence = -1; // -1 until used; then one past last index
1307	>	private int expectedModCount; // initialized when fence set
1308	>
1309	>	private int getFence() { // initialize fence to size on first use
1310	>	int hi; // (a specialized variant appears in method forEach)
1311	>	if ((hi = fence) < 0) {
1312	>	expectedModCount = modCount;
1313	>	hi = fence = offset + size;
1314	>	}
1315	>	return hi;
1316	>	}
1317	>
1318	>	public ArrayList<E>.ArrayListSpliterator trySplit() {
1319	>	int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
1320	>	// ArrayListSpliterator can be used here as the source is already bound
1321	>	return (lo >= mid) ? null : // divide range in half unless too small
1322	>	root.new ArrayListSpliterator(lo, index = mid, expectedModCount);
1323	>	}
1324	>
1325	>	public boolean tryAdvance(Consumer<? super E> action) {
1326	>	Objects.requireNonNull(action);
1327	>	int hi = getFence(), i = index;
1328	>	if (i < hi) {
1329	>	index = i + 1;
1330	>	@SuppressWarnings("unchecked") E e = (E)root.elementData[i];
1331	>	action.accept(e);
1332	>	if (root.modCount != expectedModCount)
1333	>	throw new ConcurrentModificationException();
1334	>	return true;
1335	>	}
1336	>	return false;
1337	>	}
1338	>
1339	>	public void forEachRemaining(Consumer<? super E> action) {
1340	>	Objects.requireNonNull(action);
1341	>	int i, hi, mc; // hoist accesses and checks from loop
1342	>	ArrayList<E> lst = root;
1343	>	Object[] a;
1344	>	if ((a = lst.elementData) != null) {
1345	>	if ((hi = fence) < 0) {
1346	>	mc = modCount;
1347	>	hi = offset + size;
1348	>	}
1349	>	else
1350	>	mc = expectedModCount;
1351	>	if ((i = index) >= 0 && (index = hi) <= a.length) {
1352	>	for (; i < hi; ++i) {
1353	>	@SuppressWarnings("unchecked") E e = (E) a[i];
1354	>	action.accept(e);
1355	>	}
1356	>	if (lst.modCount == mc)
1357	>	return;
1358	>	}
1359	>	}
1360	>	throw new ConcurrentModificationException();
1361	>	}
1362	>
1363	>	public long estimateSize() {
1364	>	return getFence() - index;
1365	>	}
1366	>
1367	>	public int characteristics() {
1368	>	return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED;
1369	>	}
1370	>	};
1371	>	}
1372	>	}
1373	>
1374	>	@Override
1375	>	public void forEach(Consumer<? super E> action) {
1376	>	Objects.requireNonNull(action);
1377	>	final int expectedModCount = modCount;
1378	>	final Object[] es = elementData;
1379	>	final int size = this.size;
1380	>	for (int i = 0; modCount == expectedModCount && i < size; i++)
1381	>	action.accept(elementAt(es, i));
1382	>	if (modCount != expectedModCount)
1383	>	throw new ConcurrentModificationException();
1384	>	}
1385	>
1386	>	/**
1387	>	* Creates a <em><a href="Spliterator.html#binding">late-binding</a></em>
1388	>	* and <em>fail-fast</em> {@link Spliterator} over the elements in this
1389	>	* list.
1390	>	*
1391	>	* <p>The {@code Spliterator} reports {@link Spliterator#SIZED},
1392	>	* {@link Spliterator#SUBSIZED}, and {@link Spliterator#ORDERED}.
1393	>	* Overriding implementations should document the reporting of additional
1394	>	* characteristic values.
1395	>	*
1396	>	* @return a {@code Spliterator} over the elements in this list
1397	>	* @since 1.8
1398	>	*/
1399	>	@Override
1400	>	public Spliterator<E> spliterator() {
1401	>	return new ArrayListSpliterator(0, -1, 0);
1402	>	}
1403	>
1404	>	/** Index-based split-by-two, lazily initialized Spliterator */
1405	>	final class ArrayListSpliterator implements Spliterator<E> {
1406	>
1407	>	/*
1408	>	* If ArrayLists were immutable, or structurally immutable (no
1409	>	* adds, removes, etc), we could implement their spliterators
1410	>	* with Arrays.spliterator. Instead we detect as much
1411	>	* interference during traversal as practical without
1412	>	* sacrificing much performance. We rely primarily on
1413	>	* modCounts. These are not guaranteed to detect concurrency
1414	>	* violations, and are sometimes overly conservative about
1415	>	* within-thread interference, but detect enough problems to
1416	>	* be worthwhile in practice. To carry this out, we (1) lazily
1417	>	* initialize fence and expectedModCount until the latest
1418	>	* point that we need to commit to the state we are checking
1419	>	* against; thus improving precision.  (This doesn't apply to
1420	>	* SubLists, that create spliterators with current non-lazy
1421	>	* values).  (2) We perform only a single
1422	>	* ConcurrentModificationException check at the end of forEach
1423	>	* (the most performance-sensitive method). When using forEach
1424	>	* (as opposed to iterators), we can normally only detect
1425	>	* interference after actions, not before. Further
1426	>	* CME-triggering checks apply to all other possible
1427	>	* violations of assumptions for example null or too-small
1428	>	* elementData array given its size(), that could only have
1429	>	* occurred due to interference.  This allows the inner loop
1430	>	* of forEach to run without any further checks, and
1431	>	* simplifies lambda-resolution. While this does entail a
1432	>	* number of checks, note that in the common case of
1433	>	* list.stream().forEach(a), no checks or other computation
1434	>	* occur anywhere other than inside forEach itself.  The other
1435	>	* less-often-used methods cannot take advantage of most of
1436	>	* these streamlinings.
1437	>	*/
1438	>
1439	>	private int index; // current index, modified on advance/split
1440	>	private int fence; // -1 until used; then one past last index
1441	>	private int expectedModCount; // initialized when fence set
1442	>
1443	>	/** Create new spliterator covering the given range */
1444	>	ArrayListSpliterator(int origin, int fence, int expectedModCount) {
1445	>	this.index = origin;
1446	>	this.fence = fence;
1447	>	this.expectedModCount = expectedModCount;
1448	>	}
1449	>
1450	>	private int getFence() { // initialize fence to size on first use
1451	>	int hi; // (a specialized variant appears in method forEach)
1452	>	if ((hi = fence) < 0) {
1453	>	expectedModCount = modCount;
1454	>	hi = fence = size;
1455	>	}
1456	>	return hi;
1457	>	}
1458	>
1459	>	public ArrayListSpliterator trySplit() {
1460	>	int hi = getFence(), lo = index, mid = (lo + hi) >>> 1;
1461	>	return (lo >= mid) ? null : // divide range in half unless too small
1462	>	new ArrayListSpliterator(lo, index = mid, expectedModCount);
1463	>	}
1464	>
1465	>	public boolean tryAdvance(Consumer<? super E> action) {
1466	>	if (action == null)
1467	>	throw new NullPointerException();
1468	>	int hi = getFence(), i = index;
1469	>	if (i < hi) {
1470	>	index = i + 1;
1471	>	@SuppressWarnings("unchecked") E e = (E)elementData[i];
1472	>	action.accept(e);
1473	>	if (modCount != expectedModCount)
1474	>	throw new ConcurrentModificationException();
1475	>	return true;
1476	>	}
1477	>	return false;
1478	>	}
1479	>
1480	>	public void forEachRemaining(Consumer<? super E> action) {
1481	>	int i, hi, mc; // hoist accesses and checks from loop
1482	>	Object[] a;
1483	>	if (action == null)
1484	>	throw new NullPointerException();
1485	>	if ((a = elementData) != null) {
1486	>	if ((hi = fence) < 0) {
1487	>	mc = modCount;
1488	>	hi = size;
1489	>	}
1490	>	else
1491	>	mc = expectedModCount;
1492	>	if ((i = index) >= 0 && (index = hi) <= a.length) {
1493	>	for (; i < hi; ++i) {
1494	>	@SuppressWarnings("unchecked") E e = (E) a[i];
1495	>	action.accept(e);
1496	>	}
1497	>	if (modCount == mc)
1498	>	return;
1499	>	}
1500	>	}
1501	>	throw new ConcurrentModificationException();
1502	>	}
1503	>
1504	>	public long estimateSize() {
1505	>	return getFence() - index;
1506	>	}
1507	>
1508	>	public int characteristics() {
1509	>	return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED;
1510	>	}
1511	>	}
1512	>
1513	>	// A tiny bit set implementation
1514	>
1515	>	private static long[] nBits(int n) {
1516	>	return new long[((n - 1) >> 6) + 1];
1517	>	}
1518	>	private static void setBit(long[] bits, int i) {
1519	>	bits[i >> 6] |= 1L << i;
1520	>	}
1521	>	private static boolean isClear(long[] bits, int i) {
1522	>	return (bits[i >> 6] & (1L << i)) == 0;
1523	>	}
1524	>
1525	>	@Override
1526	>	public boolean removeIf(Predicate<? super E> filter) {
1527	>	return removeIf(filter, 0, size);
1528	>	}
1529	>
1530	>	/**
1531	>	* Removes all elements satisfying the given predicate, from index
1532	>	* i (inclusive) to index end (exclusive).
1533	>	*/
1534	>	boolean removeIf(Predicate<? super E> filter, int i, final int end) {
1535	>	Objects.requireNonNull(filter);
1536	>	int expectedModCount = modCount;
1537	>	final Object[] es = elementData;
1538	>	// Optimize for initial run of survivors
1539	>	for (; i < end && !filter.test(elementAt(es, i)); i++)
1540	>	;
1541	>	// Tolerate predicates that reentrantly access the collection for
1542	>	// read (but writers still get CME), so traverse once to find
1543	>	// elements to delete, a second pass to physically expunge.
1544	>	if (i < end) {
1545	>	final int beg = i;
1546	>	final long[] deathRow = nBits(end - beg);
1547	>	deathRow[0] = 1L;   // set bit 0
1548	>	for (i = beg + 1; i < end; i++)
1549	>	if (filter.test(elementAt(es, i)))
1550	>	setBit(deathRow, i - beg);
1551	>	if (modCount != expectedModCount)
1552	>	throw new ConcurrentModificationException();
1553	>	expectedModCount++;
1554	>	modCount++;
1555	>	int w = beg;
1556	>	for (i = beg; i < end; i++)
1557	>	if (isClear(deathRow, i - beg))
1558	>	es[w++] = es[i];
1559	>	shiftTailOverGap(es, w, end);
1560	>	// checkInvariants();
1561	>	return true;
1562	>	} else {
1563	>	if (modCount != expectedModCount)
1564		throw new ConcurrentModificationException();
1565	+	// checkInvariants();
1566	+	return false;
1567		}
1568		}
1569	+
1570	+	@Override
1571	+	public void replaceAll(UnaryOperator<E> operator) {
1572	+	Objects.requireNonNull(operator);
1573	+	final int expectedModCount = modCount;
1574	+	final Object[] es = elementData;
1575	+	final int size = this.size;
1576	+	for (int i = 0; modCount == expectedModCount && i < size; i++)
1577	+	es[i] = operator.apply(elementAt(es, i));
1578	+	if (modCount != expectedModCount)
1579	+	throw new ConcurrentModificationException();
1580	+	modCount++;
1581	+	// checkInvariants();
1582	+	}
1583	+
1584	+	@Override
1585	+	@SuppressWarnings("unchecked")
1586	+	public void sort(Comparator<? super E> c) {
1587	+	final int expectedModCount = modCount;
1588	+	Arrays.sort((E[]) elementData, 0, size, c);
1589	+	if (modCount != expectedModCount)
1590	+	throw new ConcurrentModificationException();
1591	+	modCount++;
1592	+	// checkInvariants();
1593	+	}
1594	+
1595	+	void checkInvariants() {
1596	+	// assert size >= 0;
1597	+	// assert size == elementData.length || elementData[size] == null;
1598	+	}
1599		}

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