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/* |
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* Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved. |
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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* |
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* This code is free software; you can redistribute it and/or modify it |
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* under the terms of the GNU General Public License version 2 only, as |
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* published by the Free Software Foundation. Oracle designates this |
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* particular file as subject to the "Classpath" exception as provided |
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* by Oracle in the LICENSE file that accompanied this code. |
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* |
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* This code is distributed in the hope that it will be useful, but WITHOUT |
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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* version 2 for more details (a copy is included in the LICENSE file that |
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* accompanied this code). |
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* |
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* You should have received a copy of the GNU General Public License version |
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* 2 along with this work; if not, write to the Free Software Foundation, |
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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* |
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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* or visit www.oracle.com if you need additional information or have any |
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* questions. |
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*/ |
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|
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package java.util; |
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|
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import java.util.function.Consumer; |
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import java.util.function.Predicate; |
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import java.util.function.UnaryOperator; |
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|
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/** |
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* Resizable-array implementation of the {@code List} interface. Implements |
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* all optional list operations, and permits all elements, including |
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* {@code null}. In addition to implementing the {@code List} interface, |
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* this class provides methods to manipulate the size of the array that is |
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* used internally to store the list. (This class is roughly equivalent to |
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* {@code Vector}, except that it is unsynchronized.) |
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* |
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* <p>The {@code size}, {@code isEmpty}, {@code get}, {@code set}, |
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* {@code iterator}, and {@code listIterator} operations run in constant |
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* time. The {@code add} operation runs in <i>amortized constant time</i>, |
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* that is, adding n elements requires O(n) time. All of the other operations |
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* run in linear time (roughly speaking). The constant factor is low compared |
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* to that for the {@code LinkedList} implementation. |
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* |
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* <p>Each {@code ArrayList} instance has a <i>capacity</i>. The capacity is |
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* the size of the array used to store the elements in the list. It is always |
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* at least as large as the list size. As elements are added to an ArrayList, |
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* its capacity grows automatically. The details of the growth policy are not |
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* specified beyond the fact that adding an element has constant amortized |
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* time cost. |
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* |
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* <p>An application can increase the capacity of an {@code ArrayList} instance |
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* before adding a large number of elements using the {@code ensureCapacity} |
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* operation. This may reduce the amount of incremental reallocation. |
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* |
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* <p><strong>Note that this implementation is not synchronized.</strong> |
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* If multiple threads access an {@code ArrayList} instance concurrently, |
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* and at least one of the threads modifies the list structurally, it |
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* <i>must</i> be synchronized externally. (A structural modification is |
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* any operation that adds or deletes one or more elements, or explicitly |
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* resizes the backing array; merely setting the value of an element is not |
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* a structural modification.) This is typically accomplished by |
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* synchronizing on some object that naturally encapsulates the list. |
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* |
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* If no such object exists, the list should be "wrapped" using the |
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* {@link Collections#synchronizedList Collections.synchronizedList} |
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* method. This is best done at creation time, to prevent accidental |
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* unsynchronized access to the list:<pre> |
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* List list = Collections.synchronizedList(new ArrayList(...));</pre> |
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* |
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* <p id="fail-fast"> |
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* The iterators returned by this class's {@link #iterator() iterator} and |
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* {@link #listIterator(int) listIterator} methods are <em>fail-fast</em>: |
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* if the list is structurally modified at any time after the iterator is |
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* created, in any way except through the iterator's own |
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* {@link ListIterator#remove() remove} or |
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* {@link ListIterator#add(Object) add} methods, the iterator will throw a |
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* {@link ConcurrentModificationException}. Thus, in the face of |
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* concurrent modification, the iterator fails quickly and cleanly, rather |
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* than risking arbitrary, non-deterministic behavior at an undetermined |
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* time in the future. |
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* |
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* <p>Note that the fail-fast behavior of an iterator cannot be guaranteed |
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* as it is, generally speaking, impossible to make any hard guarantees in the |
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* presence of unsynchronized concurrent modification. Fail-fast iterators |
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* throw {@code ConcurrentModificationException} on a best-effort basis. |
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* Therefore, it would be wrong to write a program that depended on this |
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* exception for its correctness: <i>the fail-fast behavior of iterators |
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* should be used only to detect bugs.</i> |
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* |
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* <p>This class is a member of the |
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* <a href="{@docRoot}/../technotes/guides/collections/index.html"> |
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* Java Collections Framework</a>. |
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* |
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* @param <E> the type of elements in this list |
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* |
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* @author Josh Bloch |
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* @author Neal Gafter |
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* @see Collection |
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* @see List |
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* @see LinkedList |
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* @see Vector |
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* @since 1.2 |
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*/ |
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public class ArrayList<E> extends AbstractList<E> |
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implements List<E>, RandomAccess, Cloneable, java.io.Serializable |
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{ |
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private static final long serialVersionUID = 8683452581122892189L; |
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|
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/** |
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* Default initial capacity. |
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*/ |
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private static final int DEFAULT_CAPACITY = 10; |
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|
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/** |
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* Shared empty array instance used for empty instances. |
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*/ |
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private static final Object[] EMPTY_ELEMENTDATA = {}; |
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|
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/** |
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* Shared empty array instance used for default sized empty instances. We |
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* distinguish this from EMPTY_ELEMENTDATA to know how much to inflate when |
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* first element is added. |
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*/ |
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private static final Object[] DEFAULTCAPACITY_EMPTY_ELEMENTDATA = {}; |
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|
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/** |
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* The array buffer into which the elements of the ArrayList are stored. |
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* The capacity of the ArrayList is the length of this array buffer. Any |
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* empty ArrayList with elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA |
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* will be expanded to DEFAULT_CAPACITY when the first element is added. |
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*/ |
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transient Object[] elementData; // non-private to simplify nested class access |
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|
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/** |
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* The size of the ArrayList (the number of elements it contains). |
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* |
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* @serial |
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*/ |
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private int size; |
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|
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/** |
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* Constructs an empty list with the specified initial capacity. |
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* |
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* @param initialCapacity the initial capacity of the list |
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* @throws IllegalArgumentException if the specified initial capacity |
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* is negative |
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*/ |
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public ArrayList(int initialCapacity) { |
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if (initialCapacity > 0) { |
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this.elementData = new Object[initialCapacity]; |
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} else if (initialCapacity == 0) { |
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this.elementData = EMPTY_ELEMENTDATA; |
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} else { |
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throw new IllegalArgumentException("Illegal Capacity: "+ |
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initialCapacity); |
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} |
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} |
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|
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/** |
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* Constructs an empty list with an initial capacity of ten. |
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*/ |
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public ArrayList() { |
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this.elementData = DEFAULTCAPACITY_EMPTY_ELEMENTDATA; |
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} |
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|
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/** |
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* Constructs a list containing the elements of the specified |
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* collection, in the order they are returned by the collection's |
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* iterator. |
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* |
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* @param c the collection whose elements are to be placed into this list |
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* @throws NullPointerException if the specified collection is null |
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*/ |
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public ArrayList(Collection<? extends E> c) { |
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elementData = c.toArray(); |
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if ((size = elementData.length) != 0) { |
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// defend against c.toArray (incorrectly) not returning Object[] |
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// (see e.g. https://bugs.openjdk.java.net/browse/JDK-6260652) |
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if (elementData.getClass() != Object[].class) |
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elementData = Arrays.copyOf(elementData, size, Object[].class); |
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} else { |
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// replace with empty array. |
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this.elementData = EMPTY_ELEMENTDATA; |
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} |
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} |
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|
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/** |
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* Trims the capacity of this {@code ArrayList} instance to be the |
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* list's current size. An application can use this operation to minimize |
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* the storage of an {@code ArrayList} instance. |
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*/ |
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public void trimToSize() { |
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modCount++; |
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if (size < elementData.length) { |
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elementData = (size == 0) |
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? EMPTY_ELEMENTDATA |
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: Arrays.copyOf(elementData, size); |
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} |
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} |
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|
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/** |
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* Increases the capacity of this {@code ArrayList} instance, if |
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* necessary, to ensure that it can hold at least the number of elements |
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* specified by the minimum capacity argument. |
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* |
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* @param minCapacity the desired minimum capacity |
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*/ |
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public void ensureCapacity(int minCapacity) { |
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if (minCapacity > elementData.length |
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&& !(elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA |
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&& minCapacity <= DEFAULT_CAPACITY)) { |
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modCount++; |
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grow(minCapacity); |
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} |
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} |
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|
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/** |
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* The maximum size of array to allocate (unless necessary). |
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* Some VMs reserve some header words in an array. |
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* Attempts to allocate larger arrays may result in |
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* OutOfMemoryError: Requested array size exceeds VM limit |
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*/ |
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private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8; |
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|
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/** |
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* Increases the capacity to ensure that it can hold at least the |
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* number of elements specified by the minimum capacity argument. |
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* |
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* @param minCapacity the desired minimum capacity |
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* @throws OutOfMemoryError if minCapacity is less than zero |
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*/ |
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private Object[] grow(int minCapacity) { |
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return elementData = Arrays.copyOf(elementData, |
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newCapacity(minCapacity)); |
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} |
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|
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private Object[] grow() { |
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return grow(size + 1); |
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} |
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|
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/** |
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* Returns a capacity at least as large as the given minimum capacity. |
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* Returns the current capacity increased by 50% if that suffices. |
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* Will not return a capacity greater than MAX_ARRAY_SIZE unless |
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* the given minimum capacity is greater than MAX_ARRAY_SIZE. |
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* |
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* @param minCapacity the desired minimum capacity |
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* @throws OutOfMemoryError if minCapacity is less than zero |
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*/ |
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private int newCapacity(int minCapacity) { |
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// overflow-conscious code |
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int oldCapacity = elementData.length; |
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int newCapacity = oldCapacity + (oldCapacity >> 1); |
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if (newCapacity - minCapacity <= 0) { |
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if (elementData == DEFAULTCAPACITY_EMPTY_ELEMENTDATA) |
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return Math.max(DEFAULT_CAPACITY, minCapacity); |
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if (minCapacity < 0) // overflow |
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throw new OutOfMemoryError(); |
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return minCapacity; |
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} |
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return (newCapacity - MAX_ARRAY_SIZE <= 0) |
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? newCapacity |
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: hugeCapacity(minCapacity); |
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} |
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|
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private static int hugeCapacity(int minCapacity) { |
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if (minCapacity < 0) // overflow |
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throw new OutOfMemoryError(); |
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return (minCapacity > MAX_ARRAY_SIZE) |
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? Integer.MAX_VALUE |
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: MAX_ARRAY_SIZE; |
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} |
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|
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/** |
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* Returns the number of elements in this list. |
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* |
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* @return the number of elements in this list |
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*/ |
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public int size() { |
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return size; |
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} |
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|
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/** |
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* Returns {@code true} if this list contains no elements. |
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* |
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* @return {@code true} if this list contains no elements |
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*/ |
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public boolean isEmpty() { |
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return size == 0; |
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} |
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|
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/** |
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* Returns {@code true} if this list contains the specified element. |
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* More formally, returns {@code true} if and only if this list contains |
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* at least one element {@code e} such that |
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* {@code Objects.equals(o, e)}. |
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* |
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* @param o element whose presence in this list is to be tested |
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* @return {@code true} if this list contains the specified element |
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*/ |
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public boolean contains(Object o) { |
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return indexOf(o) >= 0; |
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} |
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|
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/** |
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* Returns the index of the first occurrence of the specified element |
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* in this list, or -1 if this list does not contain the element. |
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* More formally, returns the lowest index {@code i} such that |
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* {@code Objects.equals(o, get(i))}, |
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* or -1 if there is no such index. |
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*/ |
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public int indexOf(Object o) { |
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if (o == null) { |
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for (int i = 0; i < size; i++) |
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if (elementData[i]==null) |
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return i; |
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} else { |
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for (int i = 0; i < size; i++) |
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if (o.equals(elementData[i])) |
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return i; |
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} |
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return -1; |
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} |
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|
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/** |
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* Returns the index of the last occurrence of the specified element |
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* in this list, or -1 if this list does not contain the element. |
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* More formally, returns the highest index {@code i} such that |
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* {@code Objects.equals(o, get(i))}, |
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* or -1 if there is no such index. |
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*/ |
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public int lastIndexOf(Object o) { |
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if (o == null) { |
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for (int i = size-1; i >= 0; i--) |
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if (elementData[i]==null) |
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return i; |
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} else { |
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for (int i = size-1; i >= 0; i--) |
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if (o.equals(elementData[i])) |
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return i; |
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} |
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return -1; |
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} |
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|
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/** |
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* Returns a shallow copy of this {@code ArrayList} instance. (The |
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* elements themselves are not copied.) |
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* |
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* @return a clone of this {@code ArrayList} instance |
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*/ |
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public Object clone() { |
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try { |
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ArrayList<?> v = (ArrayList<?>) super.clone(); |
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v.elementData = Arrays.copyOf(elementData, size); |
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v.modCount = 0; |
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return v; |
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} catch (CloneNotSupportedException e) { |
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// this shouldn't happen, since we are Cloneable |
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throw new InternalError(e); |
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} |
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} |
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|
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/** |
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* Returns an array containing all of the elements in this list |
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* in proper sequence (from first to last element). |
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* |
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* <p>The returned array will be "safe" in that no references to it are |
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* maintained by this list. (In other words, this method must allocate |
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* a new array). The caller is thus free to modify the returned array. |
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* |
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* <p>This method acts as bridge between array-based and collection-based |
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* APIs. |
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* |
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* @return an array containing all of the elements in this list in |
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* proper sequence |
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*/ |
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public Object[] toArray() { |
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return Arrays.copyOf(elementData, size); |
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} |
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|
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/** |
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* Returns an array containing all of the elements in this list in proper |
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* sequence (from first to last element); the runtime type of the returned |
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* array is that of the specified array. If the list fits in the |
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* specified array, it is returned therein. Otherwise, a new array is |
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* allocated with the runtime type of the specified array and the size of |
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* this list. |
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* |
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* <p>If the list fits in the specified array with room to spare |
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* (i.e., the array has more elements than the list), the element in |
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* the array immediately following the end of the collection is set to |
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* {@code null}. (This is useful in determining the length of the |
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* list <i>only</i> if the caller knows that the list does not contain |
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* any null elements.) |
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* |
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* @param a the array into which the elements of the list are to |
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* be stored, if it is big enough; otherwise, a new array of the |
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* same runtime type is allocated for this purpose. |
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* @return an array containing the elements of the list |
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* @throws ArrayStoreException if the runtime type of the specified array |
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* is not a supertype of the runtime type of every element in |
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* this list |
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* @throws NullPointerException if the specified array is null |
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*/ |
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@SuppressWarnings("unchecked") |
409 |
public <T> T[] toArray(T[] a) { |
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if (a.length < size) |
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// Make a new array of a's runtime type, but my contents: |
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return (T[]) Arrays.copyOf(elementData, size, a.getClass()); |
413 |
System.arraycopy(elementData, 0, a, 0, size); |
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if (a.length > size) |
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a[size] = null; |
416 |
return a; |
417 |
} |
418 |
|
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// Positional Access Operations |
420 |
|
421 |
@SuppressWarnings("unchecked") |
422 |
E elementData(int index) { |
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 |
* |
434 |
* @param index index of the element to return |
435 |
* @return the element at the specified position in this list |
436 |
* @throws IndexOutOfBoundsException {@inheritDoc} |
437 |
*/ |
438 |
public E get(int index) { |
439 |
Objects.checkIndex(index, size); |
440 |
return elementData(index); |
441 |
} |
442 |
|
443 |
/** |
444 |
* Replaces the element at the specified position in this list with |
445 |
* the specified element. |
446 |
* |
447 |
* @param index index of the element to replace |
448 |
* @param element element to be stored at the specified position |
449 |
* @return the element previously at the specified position |
450 |
* @throws IndexOutOfBoundsException {@inheritDoc} |
451 |
*/ |
452 |
public E set(int index, E element) { |
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 {@code true} (as specified by {@link Collection#add}) |
476 |
*/ |
477 |
public boolean add(E e) { |
478 |
modCount++; |
479 |
add(e, elementData, size); |
480 |
return true; |
481 |
} |
482 |
|
483 |
/** |
484 |
* Inserts the specified element at the specified position in this |
485 |
* list. Shifts the element currently at that position (if any) and |
486 |
* any subsequent elements to the right (adds one to their indices). |
487 |
* |
488 |
* @param index index at which the specified element is to be inserted |
489 |
* @param element element to be inserted |
490 |
* @throws IndexOutOfBoundsException {@inheritDoc} |
491 |
*/ |
492 |
public void add(int index, E element) { |
493 |
rangeCheckForAdd(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 = s + 1; |
504 |
// checkInvariants(); |
505 |
} |
506 |
|
507 |
/** |
508 |
* Removes the element at the specified position in this list. |
509 |
* Shifts any subsequent elements to the left (subtracts one from their |
510 |
* indices). |
511 |
* |
512 |
* @param index the index of the element to be removed |
513 |
* @return the element that was removed from the list |
514 |
* @throws IndexOutOfBoundsException {@inheritDoc} |
515 |
*/ |
516 |
public E remove(int index) { |
517 |
Objects.checkIndex(index, size); |
518 |
|
519 |
modCount++; |
520 |
E oldValue = elementData(index); |
521 |
|
522 |
int numMoved = size - index - 1; |
523 |
if (numMoved > 0) |
524 |
System.arraycopy(elementData, index+1, elementData, index, |
525 |
numMoved); |
526 |
elementData[--size] = null; // clear to let GC do its work |
527 |
|
528 |
// checkInvariants(); |
529 |
return oldValue; |
530 |
} |
531 |
|
532 |
/** |
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 |
* {@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 {@code true} if this list contained the specified element |
544 |
*/ |
545 |
public boolean remove(Object o) { |
546 |
if (o == null) { |
547 |
for (int index = 0; index < size; index++) |
548 |
if (elementData[index] == null) { |
549 |
fastRemove(index); |
550 |
return true; |
551 |
} |
552 |
} else { |
553 |
for (int index = 0; index < size; index++) |
554 |
if (o.equals(elementData[index])) { |
555 |
fastRemove(index); |
556 |
return true; |
557 |
} |
558 |
} |
559 |
return false; |
560 |
} |
561 |
|
562 |
/** |
563 |
* Private remove method that skips bounds checking and does not |
564 |
* return the value removed. |
565 |
*/ |
566 |
private void fastRemove(int index) { |
567 |
modCount++; |
568 |
int numMoved = size - index - 1; |
569 |
if (numMoved > 0) |
570 |
System.arraycopy(elementData, index+1, elementData, index, |
571 |
numMoved); |
572 |
elementData[--size] = null; // clear to let GC do its work |
573 |
} |
574 |
|
575 |
/** |
576 |
* Removes all of the elements from this list. The list will |
577 |
* be empty after this call returns. |
578 |
*/ |
579 |
public void clear() { |
580 |
modCount++; |
581 |
Arrays.fill(elementData, 0, size, null); |
582 |
size = 0; |
583 |
} |
584 |
|
585 |
/** |
586 |
* Appends all of the elements in the specified collection to the end of |
587 |
* this list, in the order that they are returned by the |
588 |
* specified collection's Iterator. The behavior of this operation is |
589 |
* undefined if the specified collection is modified while the operation |
590 |
* is in progress. (This implies that the behavior of this call is |
591 |
* undefined if the specified collection is this list, and this |
592 |
* list is nonempty.) |
593 |
* |
594 |
* @param c collection containing elements to be added to this list |
595 |
* @return {@code true} if this list changed as a result of the call |
596 |
* @throws NullPointerException if the specified collection is null |
597 |
*/ |
598 |
public boolean addAll(Collection<? extends E> c) { |
599 |
Object[] a = c.toArray(); |
600 |
modCount++; |
601 |
int numNew = a.length; |
602 |
if (numNew == 0) |
603 |
return false; |
604 |
Object[] elementData; |
605 |
final int s; |
606 |
if (numNew > (elementData = this.elementData).length - (s = size)) |
607 |
elementData = grow(s + numNew); |
608 |
System.arraycopy(a, 0, elementData, s, numNew); |
609 |
size = s + numNew; |
610 |
// checkInvariants(); |
611 |
return true; |
612 |
} |
613 |
|
614 |
/** |
615 |
* Inserts all of the elements in the specified collection into this |
616 |
* list, starting at the specified position. Shifts the element |
617 |
* currently at that position (if any) and any subsequent elements to |
618 |
* the right (increases their indices). The new elements will appear |
619 |
* in the list in the order that they are returned by the |
620 |
* specified collection's iterator. |
621 |
* |
622 |
* @param index index at which to insert the first element from the |
623 |
* specified collection |
624 |
* @param c collection containing elements to be added to this list |
625 |
* @return {@code true} if this list changed as a result of the call |
626 |
* @throws IndexOutOfBoundsException {@inheritDoc} |
627 |
* @throws NullPointerException if the specified collection is null |
628 |
*/ |
629 |
public boolean addAll(int index, Collection<? extends E> c) { |
630 |
rangeCheckForAdd(index); |
631 |
|
632 |
Object[] a = c.toArray(); |
633 |
modCount++; |
634 |
int numNew = a.length; |
635 |
if (numNew == 0) |
636 |
return false; |
637 |
Object[] elementData; |
638 |
final int s; |
639 |
if (numNew > (elementData = this.elementData).length - (s = size)) |
640 |
elementData = grow(s + numNew); |
641 |
|
642 |
int numMoved = s - index; |
643 |
if (numMoved > 0) |
644 |
System.arraycopy(elementData, index, |
645 |
elementData, index + numNew, |
646 |
numMoved); |
647 |
System.arraycopy(a, 0, elementData, index, numNew); |
648 |
size = s + numNew; |
649 |
// checkInvariants(); |
650 |
return true; |
651 |
} |
652 |
|
653 |
/** |
654 |
* Removes from this list all of the elements whose index is between |
655 |
* {@code fromIndex}, inclusive, and {@code toIndex}, exclusive. |
656 |
* Shifts any succeeding elements to the left (reduces their index). |
657 |
* This call shortens the list by {@code (toIndex - fromIndex)} elements. |
658 |
* (If {@code toIndex==fromIndex}, this operation has no effect.) |
659 |
* |
660 |
* @throws IndexOutOfBoundsException if {@code fromIndex} or |
661 |
* {@code toIndex} is out of range |
662 |
* ({@code fromIndex < 0 || |
663 |
* toIndex > size() || |
664 |
* toIndex < fromIndex}) |
665 |
*/ |
666 |
protected void removeRange(int fromIndex, int toIndex) { |
667 |
if (fromIndex > toIndex) { |
668 |
throw new IndexOutOfBoundsException( |
669 |
outOfBoundsMsg(fromIndex, toIndex)); |
670 |
} |
671 |
modCount++; |
672 |
final Object[] es = elementData; |
673 |
final int oldSize = size; |
674 |
System.arraycopy(es, toIndex, es, fromIndex, oldSize - toIndex); |
675 |
Arrays.fill(es, size -= (toIndex - fromIndex), oldSize, null); |
676 |
// checkInvariants(); |
677 |
} |
678 |
|
679 |
/** |
680 |
* A version of rangeCheck used by add and addAll. |
681 |
*/ |
682 |
private void rangeCheckForAdd(int index) { |
683 |
if (index > size || index < 0) |
684 |
throw new IndexOutOfBoundsException(outOfBoundsMsg(index)); |
685 |
} |
686 |
|
687 |
/** |
688 |
* Constructs an IndexOutOfBoundsException detail message. |
689 |
* Of the many possible refactorings of the error handling code, |
690 |
* this "outlining" performs best with both server and client VMs. |
691 |
*/ |
692 |
private String outOfBoundsMsg(int index) { |
693 |
return "Index: "+index+", Size: "+size; |
694 |
} |
695 |
|
696 |
/** |
697 |
* A version used in checking (fromIndex > toIndex) condition |
698 |
*/ |
699 |
private static String outOfBoundsMsg(int fromIndex, int toIndex) { |
700 |
return "From Index: " + fromIndex + " > To Index: " + toIndex; |
701 |
} |
702 |
|
703 |
/** |
704 |
* Removes from this list all of its elements that are contained in the |
705 |
* specified collection. |
706 |
* |
707 |
* @param c collection containing elements to be removed from this list |
708 |
* @return {@code true} if this list changed as a result of the call |
709 |
* @throws ClassCastException if the class of an element of this list |
710 |
* is incompatible with the specified collection |
711 |
* (<a href="Collection.html#optional-restrictions">optional</a>) |
712 |
* @throws NullPointerException if this list contains a null element and the |
713 |
* specified collection does not permit null elements |
714 |
* (<a href="Collection.html#optional-restrictions">optional</a>), |
715 |
* or if the specified collection is null |
716 |
* @see Collection#contains(Object) |
717 |
*/ |
718 |
public boolean removeAll(Collection<?> c) { |
719 |
return batchRemove(c, false, 0, size); |
720 |
} |
721 |
|
722 |
/** |
723 |
* Retains only the elements in this list that are contained in the |
724 |
* specified collection. In other words, removes from this list all |
725 |
* of its elements that are not contained in the specified collection. |
726 |
* |
727 |
* @param c collection containing elements to be retained in this list |
728 |
* @return {@code true} if this list changed as a result of the call |
729 |
* @throws ClassCastException if the class of an element of this list |
730 |
* is incompatible with the specified collection |
731 |
* (<a href="Collection.html#optional-restrictions">optional</a>) |
732 |
* @throws NullPointerException if this list contains a null element and the |
733 |
* specified collection does not permit null elements |
734 |
* (<a href="Collection.html#optional-restrictions">optional</a>), |
735 |
* or if the specified collection is null |
736 |
* @see Collection#contains(Object) |
737 |
*/ |
738 |
public boolean retainAll(Collection<?> c) { |
739 |
return batchRemove(c, true, 0, size); |
740 |
} |
741 |
|
742 |
boolean batchRemove(Collection<?> c, boolean complement, |
743 |
final int from, final int end) { |
744 |
Objects.requireNonNull(c); |
745 |
final Object[] es = elementData; |
746 |
final boolean modified; |
747 |
int r; |
748 |
// Optimize for initial run of survivors |
749 |
for (r = from; r < end && c.contains(es[r]) == complement; r++) |
750 |
; |
751 |
if (modified = (r < end)) { |
752 |
int w = r++; |
753 |
try { |
754 |
for (Object e; r < end; r++) |
755 |
if (c.contains(e = es[r]) == complement) |
756 |
es[w++] = e; |
757 |
} catch (Throwable ex) { |
758 |
// Preserve behavioral compatibility with AbstractCollection, |
759 |
// even if c.contains() throws. |
760 |
System.arraycopy(es, r, es, w, end - r); |
761 |
w += end - r; |
762 |
throw ex; |
763 |
} finally { |
764 |
final int oldSize = size, deleted = end - w; |
765 |
modCount += deleted; |
766 |
System.arraycopy(es, end, es, w, oldSize - end); |
767 |
Arrays.fill(es, size -= deleted, oldSize, null); |
768 |
} |
769 |
} |
770 |
// checkInvariants(); |
771 |
return modified; |
772 |
} |
773 |
|
774 |
/** |
775 |
* Save the state of the {@code ArrayList} instance to a stream (that |
776 |
* is, serialize it). |
777 |
* |
778 |
* @serialData The length of the array backing the {@code ArrayList} |
779 |
* instance is emitted (int), followed by all of its elements |
780 |
* (each an {@code Object}) in the proper order. |
781 |
*/ |
782 |
private void writeObject(java.io.ObjectOutputStream s) |
783 |
throws java.io.IOException{ |
784 |
// Write out element count, and any hidden stuff |
785 |
int expectedModCount = modCount; |
786 |
s.defaultWriteObject(); |
787 |
|
788 |
// Write out size as capacity for behavioural compatibility with clone() |
789 |
s.writeInt(size); |
790 |
|
791 |
// Write out all elements in the proper order. |
792 |
for (int i=0; i<size; i++) { |
793 |
s.writeObject(elementData[i]); |
794 |
} |
795 |
|
796 |
if (modCount != expectedModCount) { |
797 |
throw new ConcurrentModificationException(); |
798 |
} |
799 |
} |
800 |
|
801 |
/** |
802 |
* Reconstitute the {@code ArrayList} instance from a stream (that is, |
803 |
* deserialize it). |
804 |
*/ |
805 |
private void readObject(java.io.ObjectInputStream s) |
806 |
throws java.io.IOException, ClassNotFoundException { |
807 |
|
808 |
// Read in size, and any hidden stuff |
809 |
s.defaultReadObject(); |
810 |
|
811 |
// Read in capacity |
812 |
s.readInt(); // ignored |
813 |
|
814 |
if (size > 0) { |
815 |
// like clone(), allocate array based upon size not capacity |
816 |
Object[] elements = new Object[size]; |
817 |
|
818 |
// Read in all elements in the proper order. |
819 |
for (int i = 0; i < size; i++) { |
820 |
elements[i] = s.readObject(); |
821 |
} |
822 |
|
823 |
elementData = elements; |
824 |
} else if (size == 0) { |
825 |
elementData = EMPTY_ELEMENTDATA; |
826 |
} else { |
827 |
throw new java.io.InvalidObjectException("Invalid size: " + size); |
828 |
} |
829 |
} |
830 |
|
831 |
/** |
832 |
* Returns a list iterator over the elements in this list (in proper |
833 |
* sequence), starting at the specified position in the list. |
834 |
* The specified index indicates the first element that would be |
835 |
* returned by an initial call to {@link ListIterator#next next}. |
836 |
* An initial call to {@link ListIterator#previous previous} would |
837 |
* return the element with the specified index minus one. |
838 |
* |
839 |
* <p>The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>. |
840 |
* |
841 |
* @throws IndexOutOfBoundsException {@inheritDoc} |
842 |
*/ |
843 |
public ListIterator<E> listIterator(int index) { |
844 |
rangeCheckForAdd(index); |
845 |
return new ListItr(index); |
846 |
} |
847 |
|
848 |
/** |
849 |
* Returns a list iterator over the elements in this list (in proper |
850 |
* sequence). |
851 |
* |
852 |
* <p>The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>. |
853 |
* |
854 |
* @see #listIterator(int) |
855 |
*/ |
856 |
public ListIterator<E> listIterator() { |
857 |
return new ListItr(0); |
858 |
} |
859 |
|
860 |
/** |
861 |
* Returns an iterator over the elements in this list in proper sequence. |
862 |
* |
863 |
* <p>The returned iterator is <a href="#fail-fast"><i>fail-fast</i></a>. |
864 |
* |
865 |
* @return an iterator over the elements in this list in proper sequence |
866 |
*/ |
867 |
public Iterator<E> iterator() { |
868 |
return new Itr(); |
869 |
} |
870 |
|
871 |
/** |
872 |
* An optimized version of AbstractList.Itr |
873 |
*/ |
874 |
private class Itr implements Iterator<E> { |
875 |
int cursor; // index of next element to return |
876 |
int lastRet = -1; // index of last element returned; -1 if no such |
877 |
int expectedModCount = modCount; |
878 |
|
879 |
// prevent creating a synthetic constructor |
880 |
Itr() {} |
881 |
|
882 |
public boolean hasNext() { |
883 |
return cursor != size; |
884 |
} |
885 |
|
886 |
@SuppressWarnings("unchecked") |
887 |
public E next() { |
888 |
checkForComodification(); |
889 |
int i = cursor; |
890 |
if (i >= size) |
891 |
throw new NoSuchElementException(); |
892 |
Object[] elementData = ArrayList.this.elementData; |
893 |
if (i >= elementData.length) |
894 |
throw new ConcurrentModificationException(); |
895 |
cursor = i + 1; |
896 |
return (E) elementData[lastRet = i]; |
897 |
} |
898 |
|
899 |
public void remove() { |
900 |
if (lastRet < 0) |
901 |
throw new IllegalStateException(); |
902 |
checkForComodification(); |
903 |
|
904 |
try { |
905 |
ArrayList.this.remove(lastRet); |
906 |
cursor = lastRet; |
907 |
lastRet = -1; |
908 |
expectedModCount = modCount; |
909 |
} catch (IndexOutOfBoundsException ex) { |
910 |
throw new ConcurrentModificationException(); |
911 |
} |
912 |
} |
913 |
|
914 |
@Override |
915 |
@SuppressWarnings("unchecked") |
916 |
public void forEachRemaining(Consumer<? super E> consumer) { |
917 |
Objects.requireNonNull(consumer); |
918 |
final int size = ArrayList.this.size; |
919 |
int i = cursor; |
920 |
if (i >= size) { |
921 |
return; |
922 |
} |
923 |
final Object[] elementData = ArrayList.this.elementData; |
924 |
if (i >= elementData.length) { |
925 |
throw new ConcurrentModificationException(); |
926 |
} |
927 |
while (i != size && modCount == expectedModCount) { |
928 |
consumer.accept((E) elementData[i++]); |
929 |
} |
930 |
// update once at end of iteration to reduce heap write traffic |
931 |
cursor = i; |
932 |
lastRet = i - 1; |
933 |
checkForComodification(); |
934 |
} |
935 |
|
936 |
final void checkForComodification() { |
937 |
if (modCount != expectedModCount) |
938 |
throw new ConcurrentModificationException(); |
939 |
} |
940 |
} |
941 |
|
942 |
/** |
943 |
* An optimized version of AbstractList.ListItr |
944 |
*/ |
945 |
private class ListItr extends Itr implements ListIterator<E> { |
946 |
ListItr(int index) { |
947 |
super(); |
948 |
cursor = index; |
949 |
} |
950 |
|
951 |
public boolean hasPrevious() { |
952 |
return cursor != 0; |
953 |
} |
954 |
|
955 |
public int nextIndex() { |
956 |
return cursor; |
957 |
} |
958 |
|
959 |
public int previousIndex() { |
960 |
return cursor - 1; |
961 |
} |
962 |
|
963 |
@SuppressWarnings("unchecked") |
964 |
public E previous() { |
965 |
checkForComodification(); |
966 |
int i = cursor - 1; |
967 |
if (i < 0) |
968 |
throw new NoSuchElementException(); |
969 |
Object[] elementData = ArrayList.this.elementData; |
970 |
if (i >= elementData.length) |
971 |
throw new ConcurrentModificationException(); |
972 |
cursor = i; |
973 |
return (E) elementData[lastRet = i]; |
974 |
} |
975 |
|
976 |
public void set(E e) { |
977 |
if (lastRet < 0) |
978 |
throw new IllegalStateException(); |
979 |
checkForComodification(); |
980 |
|
981 |
try { |
982 |
ArrayList.this.set(lastRet, e); |
983 |
} catch (IndexOutOfBoundsException ex) { |
984 |
throw new ConcurrentModificationException(); |
985 |
} |
986 |
} |
987 |
|
988 |
public void add(E e) { |
989 |
checkForComodification(); |
990 |
|
991 |
try { |
992 |
int i = cursor; |
993 |
ArrayList.this.add(i, e); |
994 |
cursor = i + 1; |
995 |
lastRet = -1; |
996 |
expectedModCount = modCount; |
997 |
} catch (IndexOutOfBoundsException ex) { |
998 |
throw new ConcurrentModificationException(); |
999 |
} |
1000 |
} |
1001 |
} |
1002 |
|
1003 |
/** |
1004 |
* Returns a view of the portion of this list between the specified |
1005 |
* {@code fromIndex}, inclusive, and {@code toIndex}, exclusive. (If |
1006 |
* {@code fromIndex} and {@code toIndex} are equal, the returned list is |
1007 |
* empty.) The returned list is backed by this list, so non-structural |
1008 |
* changes in the returned list are reflected in this list, and vice-versa. |
1009 |
* The returned list supports all of the optional list operations. |
1010 |
* |
1011 |
* <p>This method eliminates the need for explicit range operations (of |
1012 |
* the sort that commonly exist for arrays). Any operation that expects |
1013 |
* a list can be used as a range operation by passing a subList view |
1014 |
* instead of a whole list. For example, the following idiom |
1015 |
* removes a range of elements from a list: |
1016 |
* <pre> |
1017 |
* list.subList(from, to).clear(); |
1018 |
* </pre> |
1019 |
* Similar idioms may be constructed for {@link #indexOf(Object)} and |
1020 |
* {@link #lastIndexOf(Object)}, and all of the algorithms in the |
1021 |
* {@link Collections} class can be applied to a subList. |
1022 |
* |
1023 |
* <p>The semantics of the list returned by this method become undefined if |
1024 |
* the backing list (i.e., this list) is <i>structurally modified</i> in |
1025 |
* any way other than via the returned list. (Structural modifications are |
1026 |
* those that change the size of this list, or otherwise perturb it in such |
1027 |
* a fashion that iterations in progress may yield incorrect results.) |
1028 |
* |
1029 |
* @throws IndexOutOfBoundsException {@inheritDoc} |
1030 |
* @throws IllegalArgumentException {@inheritDoc} |
1031 |
*/ |
1032 |
public List<E> subList(int fromIndex, int toIndex) { |
1033 |
subListRangeCheck(fromIndex, toIndex, size); |
1034 |
return new SubList<>(this, fromIndex, toIndex); |
1035 |
} |
1036 |
|
1037 |
private static class SubList<E> extends AbstractList<E> implements RandomAccess { |
1038 |
private final ArrayList<E> root; |
1039 |
private final SubList<E> parent; |
1040 |
private final int offset; |
1041 |
private int size; |
1042 |
|
1043 |
/** |
1044 |
* Constructs a sublist of an arbitrary ArrayList. |
1045 |
*/ |
1046 |
public SubList(ArrayList<E> root, int fromIndex, int toIndex) { |
1047 |
this.root = root; |
1048 |
this.parent = null; |
1049 |
this.offset = fromIndex; |
1050 |
this.size = toIndex - fromIndex; |
1051 |
this.modCount = root.modCount; |
1052 |
} |
1053 |
|
1054 |
/** |
1055 |
* Constructs a sublist of another SubList. |
1056 |
*/ |
1057 |
private SubList(SubList<E> parent, int fromIndex, int toIndex) { |
1058 |
this.root = parent.root; |
1059 |
this.parent = parent; |
1060 |
this.offset = parent.offset + fromIndex; |
1061 |
this.size = toIndex - fromIndex; |
1062 |
this.modCount = root.modCount; |
1063 |
} |
1064 |
|
1065 |
public E set(int index, E element) { |
1066 |
Objects.checkIndex(index, size); |
1067 |
checkForComodification(); |
1068 |
E oldValue = root.elementData(offset + index); |
1069 |
root.elementData[offset + index] = element; |
1070 |
return oldValue; |
1071 |
} |
1072 |
|
1073 |
public E get(int index) { |
1074 |
Objects.checkIndex(index, size); |
1075 |
checkForComodification(); |
1076 |
return root.elementData(offset + index); |
1077 |
} |
1078 |
|
1079 |
public int size() { |
1080 |
checkForComodification(); |
1081 |
return size; |
1082 |
} |
1083 |
|
1084 |
public void add(int index, E element) { |
1085 |
rangeCheckForAdd(index); |
1086 |
checkForComodification(); |
1087 |
root.add(offset + index, element); |
1088 |
updateSizeAndModCount(1); |
1089 |
} |
1090 |
|
1091 |
public E remove(int index) { |
1092 |
Objects.checkIndex(index, size); |
1093 |
checkForComodification(); |
1094 |
E result = root.remove(offset + index); |
1095 |
updateSizeAndModCount(-1); |
1096 |
return result; |
1097 |
} |
1098 |
|
1099 |
protected void removeRange(int fromIndex, int toIndex) { |
1100 |
checkForComodification(); |
1101 |
root.removeRange(offset + fromIndex, offset + toIndex); |
1102 |
updateSizeAndModCount(fromIndex - toIndex); |
1103 |
} |
1104 |
|
1105 |
public boolean addAll(Collection<? extends E> c) { |
1106 |
return addAll(this.size, c); |
1107 |
} |
1108 |
|
1109 |
public boolean addAll(int index, Collection<? extends E> c) { |
1110 |
rangeCheckForAdd(index); |
1111 |
int cSize = c.size(); |
1112 |
if (cSize==0) |
1113 |
return false; |
1114 |
checkForComodification(); |
1115 |
root.addAll(offset + index, c); |
1116 |
updateSizeAndModCount(cSize); |
1117 |
return true; |
1118 |
} |
1119 |
|
1120 |
public boolean removeAll(Collection<?> c) { |
1121 |
return batchRemove(c, false); |
1122 |
} |
1123 |
|
1124 |
public boolean retainAll(Collection<?> c) { |
1125 |
return batchRemove(c, true); |
1126 |
} |
1127 |
|
1128 |
private boolean batchRemove(Collection<?> c, boolean complement) { |
1129 |
checkForComodification(); |
1130 |
int oldSize = root.size; |
1131 |
boolean modified = |
1132 |
root.batchRemove(c, complement, offset, offset + size); |
1133 |
if (modified) |
1134 |
updateSizeAndModCount(root.size - oldSize); |
1135 |
return modified; |
1136 |
} |
1137 |
|
1138 |
public boolean removeIf(Predicate<? super E> filter) { |
1139 |
checkForComodification(); |
1140 |
int oldSize = root.size; |
1141 |
boolean modified = root.removeIf(filter, offset, offset + size); |
1142 |
if (modified) |
1143 |
updateSizeAndModCount(root.size - oldSize); |
1144 |
return modified; |
1145 |
} |
1146 |
|
1147 |
public Iterator<E> iterator() { |
1148 |
return listIterator(); |
1149 |
} |
1150 |
|
1151 |
public ListIterator<E> listIterator(int index) { |
1152 |
checkForComodification(); |
1153 |
rangeCheckForAdd(index); |
1154 |
|
1155 |
return new ListIterator<E>() { |
1156 |
int cursor = index; |
1157 |
int lastRet = -1; |
1158 |
int expectedModCount = root.modCount; |
1159 |
|
1160 |
public boolean hasNext() { |
1161 |
return cursor != SubList.this.size; |
1162 |
} |
1163 |
|
1164 |
@SuppressWarnings("unchecked") |
1165 |
public E next() { |
1166 |
checkForComodification(); |
1167 |
int i = cursor; |
1168 |
if (i >= SubList.this.size) |
1169 |
throw new NoSuchElementException(); |
1170 |
Object[] elementData = root.elementData; |
1171 |
if (offset + i >= elementData.length) |
1172 |
throw new ConcurrentModificationException(); |
1173 |
cursor = i + 1; |
1174 |
return (E) elementData[offset + (lastRet = i)]; |
1175 |
} |
1176 |
|
1177 |
public boolean hasPrevious() { |
1178 |
return cursor != 0; |
1179 |
} |
1180 |
|
1181 |
@SuppressWarnings("unchecked") |
1182 |
public E previous() { |
1183 |
checkForComodification(); |
1184 |
int i = cursor - 1; |
1185 |
if (i < 0) |
1186 |
throw new NoSuchElementException(); |
1187 |
Object[] elementData = root.elementData; |
1188 |
if (offset + i >= elementData.length) |
1189 |
throw new ConcurrentModificationException(); |
1190 |
cursor = i; |
1191 |
return (E) elementData[offset + (lastRet = i)]; |
1192 |
} |
1193 |
|
1194 |
@SuppressWarnings("unchecked") |
1195 |
public void forEachRemaining(Consumer<? super E> consumer) { |
1196 |
Objects.requireNonNull(consumer); |
1197 |
final int size = SubList.this.size; |
1198 |
int i = cursor; |
1199 |
if (i >= size) { |
1200 |
return; |
1201 |
} |
1202 |
final Object[] elementData = root.elementData; |
1203 |
if (offset + i >= elementData.length) { |
1204 |
throw new ConcurrentModificationException(); |
1205 |
} |
1206 |
while (i != size && modCount == expectedModCount) { |
1207 |
consumer.accept((E) elementData[offset + (i++)]); |
1208 |
} |
1209 |
// update once at end of iteration to reduce heap write traffic |
1210 |
cursor = i; |
1211 |
lastRet = i - 1; |
1212 |
checkForComodification(); |
1213 |
} |
1214 |
|
1215 |
public int nextIndex() { |
1216 |
return cursor; |
1217 |
} |
1218 |
|
1219 |
public int previousIndex() { |
1220 |
return cursor - 1; |
1221 |
} |
1222 |
|
1223 |
public void remove() { |
1224 |
if (lastRet < 0) |
1225 |
throw new IllegalStateException(); |
1226 |
checkForComodification(); |
1227 |
|
1228 |
try { |
1229 |
SubList.this.remove(lastRet); |
1230 |
cursor = lastRet; |
1231 |
lastRet = -1; |
1232 |
expectedModCount = root.modCount; |
1233 |
} catch (IndexOutOfBoundsException ex) { |
1234 |
throw new ConcurrentModificationException(); |
1235 |
} |
1236 |
} |
1237 |
|
1238 |
public void set(E e) { |
1239 |
if (lastRet < 0) |
1240 |
throw new IllegalStateException(); |
1241 |
checkForComodification(); |
1242 |
|
1243 |
try { |
1244 |
root.set(offset + lastRet, e); |
1245 |
} catch (IndexOutOfBoundsException ex) { |
1246 |
throw new ConcurrentModificationException(); |
1247 |
} |
1248 |
} |
1249 |
|
1250 |
public void add(E e) { |
1251 |
checkForComodification(); |
1252 |
|
1253 |
try { |
1254 |
int i = cursor; |
1255 |
SubList.this.add(i, e); |
1256 |
cursor = i + 1; |
1257 |
lastRet = -1; |
1258 |
expectedModCount = root.modCount; |
1259 |
} catch (IndexOutOfBoundsException ex) { |
1260 |
throw new ConcurrentModificationException(); |
1261 |
} |
1262 |
} |
1263 |
|
1264 |
final void checkForComodification() { |
1265 |
if (root.modCount != expectedModCount) |
1266 |
throw new ConcurrentModificationException(); |
1267 |
} |
1268 |
}; |
1269 |
} |
1270 |
|
1271 |
public List<E> subList(int fromIndex, int toIndex) { |
1272 |
subListRangeCheck(fromIndex, toIndex, size); |
1273 |
return new SubList<>(this, fromIndex, toIndex); |
1274 |
} |
1275 |
|
1276 |
private void rangeCheckForAdd(int index) { |
1277 |
if (index < 0 || index > this.size) |
1278 |
throw new IndexOutOfBoundsException(outOfBoundsMsg(index)); |
1279 |
} |
1280 |
|
1281 |
private String outOfBoundsMsg(int index) { |
1282 |
return "Index: "+index+", Size: "+this.size; |
1283 |
} |
1284 |
|
1285 |
private void checkForComodification() { |
1286 |
if (root.modCount != modCount) |
1287 |
throw new ConcurrentModificationException(); |
1288 |
} |
1289 |
|
1290 |
private void updateSizeAndModCount(int sizeChange) { |
1291 |
SubList<E> slist = this; |
1292 |
do { |
1293 |
slist.size += sizeChange; |
1294 |
slist.modCount = root.modCount; |
1295 |
slist = slist.parent; |
1296 |
} while (slist != null); |
1297 |
} |
1298 |
|
1299 |
public Spliterator<E> spliterator() { |
1300 |
checkForComodification(); |
1301 |
|
1302 |
// ArrayListSpliterator is not used because late-binding logic |
1303 |
// is different here |
1304 |
return new Spliterator<>() { |
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 ArrayListSpliterator<E> trySplit() { |
1319 |
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1; |
1320 |
// ArrayListSpliterator could be used here as the source is already bound |
1321 |
return (lo >= mid) ? null : // divide range in half unless too small |
1322 |
new ArrayListSpliterator<>(root, lo, index = mid, |
1323 |
expectedModCount); |
1324 |
} |
1325 |
|
1326 |
public boolean tryAdvance(Consumer<? super E> action) { |
1327 |
Objects.requireNonNull(action); |
1328 |
int hi = getFence(), i = index; |
1329 |
if (i < hi) { |
1330 |
index = i + 1; |
1331 |
@SuppressWarnings("unchecked") E e = (E)root.elementData[i]; |
1332 |
action.accept(e); |
1333 |
if (root.modCount != expectedModCount) |
1334 |
throw new ConcurrentModificationException(); |
1335 |
return true; |
1336 |
} |
1337 |
return false; |
1338 |
} |
1339 |
|
1340 |
public void forEachRemaining(Consumer<? super E> action) { |
1341 |
Objects.requireNonNull(action); |
1342 |
int i, hi, mc; // hoist accesses and checks from loop |
1343 |
ArrayList<E> lst = root; |
1344 |
Object[] a; |
1345 |
if ((a = lst.elementData) != null) { |
1346 |
if ((hi = fence) < 0) { |
1347 |
mc = modCount; |
1348 |
hi = offset + size; |
1349 |
} |
1350 |
else |
1351 |
mc = expectedModCount; |
1352 |
if ((i = index) >= 0 && (index = hi) <= a.length) { |
1353 |
for (; i < hi; ++i) { |
1354 |
@SuppressWarnings("unchecked") E e = (E) a[i]; |
1355 |
action.accept(e); |
1356 |
} |
1357 |
if (lst.modCount == mc) |
1358 |
return; |
1359 |
} |
1360 |
} |
1361 |
throw new ConcurrentModificationException(); |
1362 |
} |
1363 |
|
1364 |
public long estimateSize() { |
1365 |
return (long) (getFence() - index); |
1366 |
} |
1367 |
|
1368 |
public int characteristics() { |
1369 |
return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED; |
1370 |
} |
1371 |
}; |
1372 |
} |
1373 |
} |
1374 |
|
1375 |
@Override |
1376 |
public void forEach(Consumer<? super E> action) { |
1377 |
Objects.requireNonNull(action); |
1378 |
final int expectedModCount = modCount; |
1379 |
final Object[] es = elementData; |
1380 |
final int size = this.size; |
1381 |
for (int i = 0; modCount == expectedModCount && i < size; i++) |
1382 |
action.accept(elementAt(es, i)); |
1383 |
if (modCount != expectedModCount) |
1384 |
throw new ConcurrentModificationException(); |
1385 |
} |
1386 |
|
1387 |
/** |
1388 |
* Creates a <em><a href="Spliterator.html#binding">late-binding</a></em> |
1389 |
* and <em>fail-fast</em> {@link Spliterator} over the elements in this |
1390 |
* list. |
1391 |
* |
1392 |
* <p>The {@code Spliterator} reports {@link Spliterator#SIZED}, |
1393 |
* {@link Spliterator#SUBSIZED}, and {@link Spliterator#ORDERED}. |
1394 |
* Overriding implementations should document the reporting of additional |
1395 |
* characteristic values. |
1396 |
* |
1397 |
* @return a {@code Spliterator} over the elements in this list |
1398 |
* @since 1.8 |
1399 |
*/ |
1400 |
@Override |
1401 |
public Spliterator<E> spliterator() { |
1402 |
return new ArrayListSpliterator<>(this, 0, -1, 0); |
1403 |
} |
1404 |
|
1405 |
/** Index-based split-by-two, lazily initialized Spliterator */ |
1406 |
static final class ArrayListSpliterator<E> implements Spliterator<E> { |
1407 |
|
1408 |
/* |
1409 |
* If ArrayLists were immutable, or structurally immutable (no |
1410 |
* adds, removes, etc), we could implement their spliterators |
1411 |
* with Arrays.spliterator. Instead we detect as much |
1412 |
* interference during traversal as practical without |
1413 |
* sacrificing much performance. We rely primarily on |
1414 |
* modCounts. These are not guaranteed to detect concurrency |
1415 |
* violations, and are sometimes overly conservative about |
1416 |
* within-thread interference, but detect enough problems to |
1417 |
* be worthwhile in practice. To carry this out, we (1) lazily |
1418 |
* initialize fence and expectedModCount until the latest |
1419 |
* point that we need to commit to the state we are checking |
1420 |
* against; thus improving precision. (This doesn't apply to |
1421 |
* SubLists, that create spliterators with current non-lazy |
1422 |
* values). (2) We perform only a single |
1423 |
* ConcurrentModificationException check at the end of forEach |
1424 |
* (the most performance-sensitive method). When using forEach |
1425 |
* (as opposed to iterators), we can normally only detect |
1426 |
* interference after actions, not before. Further |
1427 |
* CME-triggering checks apply to all other possible |
1428 |
* violations of assumptions for example null or too-small |
1429 |
* elementData array given its size(), that could only have |
1430 |
* occurred due to interference. This allows the inner loop |
1431 |
* of forEach to run without any further checks, and |
1432 |
* simplifies lambda-resolution. While this does entail a |
1433 |
* number of checks, note that in the common case of |
1434 |
* list.stream().forEach(a), no checks or other computation |
1435 |
* occur anywhere other than inside forEach itself. The other |
1436 |
* less-often-used methods cannot take advantage of most of |
1437 |
* these streamlinings. |
1438 |
*/ |
1439 |
|
1440 |
private final ArrayList<E> list; |
1441 |
private int index; // current index, modified on advance/split |
1442 |
private int fence; // -1 until used; then one past last index |
1443 |
private int expectedModCount; // initialized when fence set |
1444 |
|
1445 |
/** Create new spliterator covering the given range */ |
1446 |
ArrayListSpliterator(ArrayList<E> list, int origin, int fence, |
1447 |
int expectedModCount) { |
1448 |
this.list = list; // OK if null unless traversed |
1449 |
this.index = origin; |
1450 |
this.fence = fence; |
1451 |
this.expectedModCount = expectedModCount; |
1452 |
} |
1453 |
|
1454 |
private int getFence() { // initialize fence to size on first use |
1455 |
int hi; // (a specialized variant appears in method forEach) |
1456 |
ArrayList<E> lst; |
1457 |
if ((hi = fence) < 0) { |
1458 |
if ((lst = list) == null) |
1459 |
hi = fence = 0; |
1460 |
else { |
1461 |
expectedModCount = lst.modCount; |
1462 |
hi = fence = lst.size; |
1463 |
} |
1464 |
} |
1465 |
return hi; |
1466 |
} |
1467 |
|
1468 |
public ArrayListSpliterator<E> trySplit() { |
1469 |
int hi = getFence(), lo = index, mid = (lo + hi) >>> 1; |
1470 |
return (lo >= mid) ? null : // divide range in half unless too small |
1471 |
new ArrayListSpliterator<>(list, lo, index = mid, |
1472 |
expectedModCount); |
1473 |
} |
1474 |
|
1475 |
public boolean tryAdvance(Consumer<? super E> action) { |
1476 |
if (action == null) |
1477 |
throw new NullPointerException(); |
1478 |
int hi = getFence(), i = index; |
1479 |
if (i < hi) { |
1480 |
index = i + 1; |
1481 |
@SuppressWarnings("unchecked") E e = (E)list.elementData[i]; |
1482 |
action.accept(e); |
1483 |
if (list.modCount != expectedModCount) |
1484 |
throw new ConcurrentModificationException(); |
1485 |
return true; |
1486 |
} |
1487 |
return false; |
1488 |
} |
1489 |
|
1490 |
public void forEachRemaining(Consumer<? super E> action) { |
1491 |
int i, hi, mc; // hoist accesses and checks from loop |
1492 |
ArrayList<E> lst; Object[] a; |
1493 |
if (action == null) |
1494 |
throw new NullPointerException(); |
1495 |
if ((lst = list) != null && (a = lst.elementData) != null) { |
1496 |
if ((hi = fence) < 0) { |
1497 |
mc = lst.modCount; |
1498 |
hi = lst.size; |
1499 |
} |
1500 |
else |
1501 |
mc = expectedModCount; |
1502 |
if ((i = index) >= 0 && (index = hi) <= a.length) { |
1503 |
for (; i < hi; ++i) { |
1504 |
@SuppressWarnings("unchecked") E e = (E) a[i]; |
1505 |
action.accept(e); |
1506 |
} |
1507 |
if (lst.modCount == mc) |
1508 |
return; |
1509 |
} |
1510 |
} |
1511 |
throw new ConcurrentModificationException(); |
1512 |
} |
1513 |
|
1514 |
public long estimateSize() { |
1515 |
return (long) (getFence() - index); |
1516 |
} |
1517 |
|
1518 |
public int characteristics() { |
1519 |
return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED; |
1520 |
} |
1521 |
} |
1522 |
|
1523 |
// A tiny bit set implementation |
1524 |
|
1525 |
private static long[] nBits(int n) { |
1526 |
return new long[((n - 1) >> 6) + 1]; |
1527 |
} |
1528 |
private static void setBit(long[] bits, int i) { |
1529 |
bits[i >> 6] |= 1L << i; |
1530 |
} |
1531 |
private static boolean isClear(long[] bits, int i) { |
1532 |
return (bits[i >> 6] & (1L << i)) == 0; |
1533 |
} |
1534 |
|
1535 |
@Override |
1536 |
public boolean removeIf(Predicate<? super E> filter) { |
1537 |
return removeIf(filter, 0, size); |
1538 |
} |
1539 |
|
1540 |
/** |
1541 |
* Removes all elements satisfying the given predicate, from index |
1542 |
* i (inclusive) to index end (exclusive). |
1543 |
*/ |
1544 |
boolean removeIf(Predicate<? super E> filter, int i, final int end) { |
1545 |
Objects.requireNonNull(filter); |
1546 |
int expectedModCount = modCount; |
1547 |
final Object[] es = elementData; |
1548 |
// Optimize for initial run of survivors |
1549 |
for (; i < end && !filter.test(elementAt(es, i)); i++) |
1550 |
; |
1551 |
// Tolerate predicates that reentrantly access the collection for |
1552 |
// read (but writers still get CME), so traverse once to find |
1553 |
// elements to delete, a second pass to physically expunge. |
1554 |
if (i < end) { |
1555 |
final int beg = i; |
1556 |
final long[] deathRow = nBits(end - beg); |
1557 |
deathRow[0] = 1L; // set bit 0 |
1558 |
for (i = beg + 1; i < end; i++) |
1559 |
if (filter.test(elementAt(es, i))) |
1560 |
setBit(deathRow, i - beg); |
1561 |
if (modCount != expectedModCount) |
1562 |
throw new ConcurrentModificationException(); |
1563 |
expectedModCount++; |
1564 |
modCount++; |
1565 |
int w = beg; |
1566 |
for (i = beg; i < end; i++) |
1567 |
if (isClear(deathRow, i - beg)) |
1568 |
es[w++] = es[i]; |
1569 |
final int oldSize = size; |
1570 |
System.arraycopy(es, end, es, w, oldSize - end); |
1571 |
Arrays.fill(es, size -= (end - w), oldSize, null); |
1572 |
// checkInvariants(); |
1573 |
return true; |
1574 |
} else { |
1575 |
if (modCount != expectedModCount) |
1576 |
throw new ConcurrentModificationException(); |
1577 |
// checkInvariants(); |
1578 |
return false; |
1579 |
} |
1580 |
} |
1581 |
|
1582 |
@Override |
1583 |
public void replaceAll(UnaryOperator<E> operator) { |
1584 |
Objects.requireNonNull(operator); |
1585 |
final int expectedModCount = modCount; |
1586 |
final Object[] es = elementData; |
1587 |
final int size = this.size; |
1588 |
for (int i = 0; modCount == expectedModCount && i < size; i++) |
1589 |
es[i] = operator.apply(elementAt(es, i)); |
1590 |
if (modCount != expectedModCount) |
1591 |
throw new ConcurrentModificationException(); |
1592 |
modCount++; |
1593 |
// checkInvariants(); |
1594 |
} |
1595 |
|
1596 |
@Override |
1597 |
@SuppressWarnings("unchecked") |
1598 |
public void sort(Comparator<? super E> c) { |
1599 |
final int expectedModCount = modCount; |
1600 |
Arrays.sort((E[]) elementData, 0, size, c); |
1601 |
if (modCount != expectedModCount) |
1602 |
throw new ConcurrentModificationException(); |
1603 |
modCount++; |
1604 |
// checkInvariants(); |
1605 |
} |
1606 |
|
1607 |
void checkInvariants() { |
1608 |
// assert size >= 0; |
1609 |
// assert size == elementData.length || elementData[size] == null; |
1610 |
} |
1611 |
} |