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/* |
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* %W% %E% |
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* |
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* Copyright 2006 Sun Microsystems, Inc. All rights reserved. |
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* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. |
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*/ |
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|
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package java.util; |
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|
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/** |
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* This class provides a skeletal implementation of the {@link List} |
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* interface to minimize the effort required to implement this interface |
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* backed by a "random access" data store (such as an array). For sequential |
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* access data (such as a linked list), {@link AbstractSequentialList} should |
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* be used in preference to this class. |
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* |
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* <p>To implement an unmodifiable list, the programmer needs only to extend |
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* this class and provide implementations for the {@link #get(int)} and |
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* {@link List#size() size()} methods. |
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* |
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* <p>To implement a modifiable list, the programmer must additionally |
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* override the {@link #set(int, Object) set(int, E)} method (which otherwise |
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* throws an {@code UnsupportedOperationException}). If the list is |
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* variable-size the programmer must additionally override the |
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* {@link #add(int, Object) add(int, E)} and {@link #remove(int)} methods. |
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* |
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* <p>The programmer should generally provide a void (no argument) and collection |
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* constructor, as per the recommendation in the {@link Collection} interface |
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* specification. |
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* |
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* <p>Unlike the other abstract collection implementations, the programmer does |
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* <i>not</i> have to provide an iterator implementation; the iterator and |
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* list iterator are implemented by this class, on top of the "random access" |
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* methods: |
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* {@link #get(int)}, |
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* {@link #set(int, Object) set(int, E)}, |
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* {@link #add(int, Object) add(int, E)} and |
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* {@link #remove(int)}. |
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* |
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* <p>The documentation for each non-abstract method in this class describes its |
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* implementation in detail. Each of these methods may be overridden if the |
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* collection being implemented admits a more efficient implementation. |
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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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* @author Josh Bloch |
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* @author Neal Gafter |
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* @version %I%, %G% |
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* @since 1.2 |
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*/ |
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|
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public abstract class AbstractList<E> extends AbstractCollection<E> implements List<E> { |
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/** |
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* Sole constructor. (For invocation by subclass constructors, typically |
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* implicit.) |
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*/ |
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protected AbstractList() { |
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} |
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|
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/** |
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* Appends the specified element to the end of this list (optional |
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* operation). |
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* |
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* <p>Lists that support this operation may place limitations on what |
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* elements may be added to this list. In particular, some |
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* lists will refuse to add null elements, and others will impose |
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* restrictions on the type of elements that may be added. List |
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* classes should clearly specify in their documentation any restrictions |
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* on what elements may be added. |
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* |
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* <p>This implementation calls {@code add(size(), e)}. |
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* |
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* <p>Note that this implementation throws an |
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* {@code UnsupportedOperationException} unless |
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* {@link #add(int, Object) add(int, E)} is overridden. |
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* |
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* @param e element to be appended to this list |
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* @return {@code true} (as specified by {@link Collection#add}) |
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* @throws UnsupportedOperationException if the {@code add} operation |
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* is not supported by this list |
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* @throws ClassCastException if the class of the specified element |
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* prevents it from being added to this list |
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* @throws NullPointerException if the specified element is null and this |
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* list does not permit null elements |
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* @throws IllegalArgumentException if some property of this element |
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* prevents it from being added to this list |
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*/ |
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public boolean add(E e) { |
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add(size(), e); |
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return true; |
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} |
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|
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/** |
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* {@inheritDoc} |
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* |
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* @throws IndexOutOfBoundsException {@inheritDoc} |
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*/ |
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abstract public E get(int index); |
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|
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/** |
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* {@inheritDoc} |
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* |
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* <p>This implementation always throws an |
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* {@code UnsupportedOperationException}. |
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* |
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* @throws UnsupportedOperationException {@inheritDoc} |
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* @throws ClassCastException {@inheritDoc} |
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* @throws NullPointerException {@inheritDoc} |
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* @throws IllegalArgumentException {@inheritDoc} |
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* @throws IndexOutOfBoundsException {@inheritDoc} |
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*/ |
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public E set(int index, E element) { |
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throw new UnsupportedOperationException(); |
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} |
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|
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/** |
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* {@inheritDoc} |
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* |
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* <p>This implementation always throws an |
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* {@code UnsupportedOperationException}. |
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* |
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* @throws UnsupportedOperationException {@inheritDoc} |
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* @throws ClassCastException {@inheritDoc} |
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* @throws NullPointerException {@inheritDoc} |
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* @throws IllegalArgumentException {@inheritDoc} |
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* @throws IndexOutOfBoundsException {@inheritDoc} |
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*/ |
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public void add(int index, E element) { |
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throw new UnsupportedOperationException(); |
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} |
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|
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/** |
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* {@inheritDoc} |
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* |
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* <p>This implementation always throws an |
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* {@code UnsupportedOperationException}. |
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* |
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* @throws UnsupportedOperationException {@inheritDoc} |
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* @throws IndexOutOfBoundsException {@inheritDoc} |
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*/ |
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public E remove(int index) { |
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throw new UnsupportedOperationException(); |
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} |
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|
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|
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// Search Operations |
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|
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/** |
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* {@inheritDoc} |
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* |
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* <p>This implementation first gets a list iterator (with |
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* {@code listIterator()}). Then, it iterates over the list until the |
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* specified element is found or the end of the list is reached. |
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* |
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* @throws ClassCastException {@inheritDoc} |
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* @throws NullPointerException {@inheritDoc} |
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*/ |
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public int indexOf(Object o) { |
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ListIterator<E> e = listIterator(); |
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if (o==null) { |
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while (e.hasNext()) |
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if (e.next()==null) |
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return e.previousIndex(); |
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} else { |
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while (e.hasNext()) |
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if (o.equals(e.next())) |
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return e.previousIndex(); |
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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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* {@inheritDoc} |
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* |
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* <p>This implementation first gets a list iterator that points to the end |
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* of the list (with {@code listIterator(size())}). Then, it iterates |
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* backwards over the list until the specified element is found, or the |
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* beginning of the list is reached. |
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* |
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* @throws ClassCastException {@inheritDoc} |
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* @throws NullPointerException {@inheritDoc} |
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*/ |
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public int lastIndexOf(Object o) { |
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ListIterator<E> e = listIterator(size()); |
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if (o==null) { |
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while (e.hasPrevious()) |
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if (e.previous()==null) |
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return e.nextIndex(); |
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} else { |
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while (e.hasPrevious()) |
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if (o.equals(e.previous())) |
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return e.nextIndex(); |
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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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// Bulk Operations |
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|
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/** |
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* Removes all of the elements from this list (optional operation). |
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* The list will be empty after this call returns. |
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* |
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* <p>This implementation calls {@code removeRange(0, size())}. |
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* |
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* <p>Note that this implementation throws an |
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* {@code UnsupportedOperationException} unless {@code remove(int |
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* index)} or {@code removeRange(int fromIndex, int toIndex)} is |
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* overridden. |
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* |
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* @throws UnsupportedOperationException if the {@code clear} operation |
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* is not supported by this list |
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*/ |
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public void clear() { |
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removeRange(0, size()); |
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} |
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|
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/** |
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* {@inheritDoc} |
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* |
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* <p>This implementation gets an iterator over the specified collection |
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* and iterates over it, inserting the elements obtained from the |
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* iterator into this list at the appropriate position, one at a time, |
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* using {@code add(int, E)}. |
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* Many implementations will override this method for efficiency. |
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* |
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* <p>Note that this implementation throws an |
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* {@code UnsupportedOperationException} unless |
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* {@link #add(int, Object) add(int, E)} is overridden. |
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* |
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* @throws UnsupportedOperationException {@inheritDoc} |
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* @throws ClassCastException {@inheritDoc} |
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* @throws NullPointerException {@inheritDoc} |
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* @throws IllegalArgumentException {@inheritDoc} |
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* @throws IndexOutOfBoundsException {@inheritDoc} |
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*/ |
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public boolean addAll(int index, Collection<? extends E> c) { |
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boolean modified = false; |
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Iterator<? extends E> e = c.iterator(); |
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while (e.hasNext()) { |
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add(index++, e.next()); |
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modified = true; |
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} |
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return modified; |
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} |
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|
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|
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// Iterators |
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|
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/** |
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* Returns an iterator over the elements in this list in proper sequence. |
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* |
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* <p>This implementation returns a straightforward implementation of the |
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* iterator interface, relying on the backing list's {@code size()}, |
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* {@code get(int)}, and {@code remove(int)} methods. |
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* |
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* <p>Note that the iterator returned by this method will throw an |
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* {@code UnsupportedOperationException} in response to its |
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* {@code remove} method unless the list's {@code remove(int)} method is |
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* overridden. |
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* |
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* <p>This implementation can be made to throw runtime exceptions in the |
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* face of concurrent modification, as described in the specification |
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* for the (protected) {@code modCount} field. |
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* |
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* @return an iterator over the elements in this list in proper sequence |
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* |
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* @see #modCount |
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*/ |
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public Iterator<E> iterator() { |
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return new Itr(); |
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} |
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|
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/** |
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* {@inheritDoc} |
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* |
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* <p>This implementation returns {@code listIterator(0)}. |
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* |
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* @see #listIterator(int) |
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*/ |
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public ListIterator<E> listIterator() { |
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return listIterator(0); |
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} |
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|
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/** |
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* {@inheritDoc} |
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* |
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* <p>This implementation returns a straightforward implementation of the |
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* {@code ListIterator} interface that extends the implementation of the |
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* {@code Iterator} interface returned by the {@code iterator()} method. |
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* The {@code ListIterator} implementation relies on the backing list's |
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* {@code get(int)}, {@code set(int, E)}, {@code add(int, E)} |
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* and {@code remove(int)} methods. |
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* |
297 |
* <p>Note that the list iterator returned by this implementation will |
298 |
* throw an {@code UnsupportedOperationException} in response to its |
299 |
* {@code remove}, {@code set} and {@code add} methods unless the |
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* list's {@code remove(int)}, {@code set(int, E)}, and |
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* {@code add(int, E)} methods are overridden. |
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* |
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* <p>This implementation can be made to throw runtime exceptions in the |
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* face of concurrent modification, as described in the specification for |
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* the (protected) {@code modCount} field. |
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* |
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* @throws IndexOutOfBoundsException {@inheritDoc} |
308 |
* |
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* @see #modCount |
310 |
*/ |
311 |
public ListIterator<E> listIterator(final int index) { |
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if (index<0 || index>size()) |
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throw new IndexOutOfBoundsException("Index: "+index); |
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|
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return new ListItr(index); |
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} |
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|
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private class Itr implements Iterator<E> { |
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/** |
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* Index of element to be returned by subsequent call to next. |
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*/ |
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int cursor = 0; |
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|
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/** |
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* Index of element returned by most recent call to next or |
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* previous. Reset to -1 if this element is deleted by a call |
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* to remove. |
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*/ |
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int lastRet = -1; |
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|
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/** |
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* The modCount value that the iterator believes that the backing |
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* List should have. If this expectation is violated, the iterator |
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* has detected concurrent modification. |
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*/ |
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int expectedModCount = modCount; |
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|
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public boolean hasNext() { |
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return cursor != size(); |
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} |
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|
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public E next() { |
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checkForComodification(); |
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try { |
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E next = get(cursor); |
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lastRet = cursor++; |
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return next; |
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} catch (IndexOutOfBoundsException e) { |
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checkForComodification(); |
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throw new NoSuchElementException(); |
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} |
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} |
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|
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public void remove() { |
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if (lastRet == -1) |
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throw new IllegalStateException(); |
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checkForComodification(); |
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|
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try { |
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AbstractList.this.remove(lastRet); |
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if (lastRet < cursor) |
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cursor--; |
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lastRet = -1; |
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expectedModCount = modCount; |
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} catch (IndexOutOfBoundsException e) { |
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throw new ConcurrentModificationException(); |
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} |
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} |
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|
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final void checkForComodification() { |
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if (modCount != expectedModCount) |
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throw new ConcurrentModificationException(); |
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} |
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} |
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|
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private class ListItr extends Itr implements ListIterator<E> { |
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ListItr(int index) { |
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cursor = index; |
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} |
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|
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public boolean hasPrevious() { |
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return cursor != 0; |
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} |
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|
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public E previous() { |
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checkForComodification(); |
387 |
try { |
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int i = cursor - 1; |
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E previous = get(i); |
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lastRet = cursor = i; |
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return previous; |
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} catch (IndexOutOfBoundsException e) { |
393 |
checkForComodification(); |
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throw new NoSuchElementException(); |
395 |
} |
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} |
397 |
|
398 |
public int nextIndex() { |
399 |
return cursor; |
400 |
} |
401 |
|
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public int previousIndex() { |
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return cursor-1; |
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} |
405 |
|
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public void set(E e) { |
407 |
if (lastRet == -1) |
408 |
throw new IllegalStateException(); |
409 |
checkForComodification(); |
410 |
|
411 |
try { |
412 |
AbstractList.this.set(lastRet, e); |
413 |
expectedModCount = modCount; |
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} catch (IndexOutOfBoundsException ex) { |
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throw new ConcurrentModificationException(); |
416 |
} |
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} |
418 |
|
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public void add(E e) { |
420 |
checkForComodification(); |
421 |
|
422 |
try { |
423 |
int i = cursor; |
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AbstractList.this.add(i, e); |
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cursor = i + 1; |
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lastRet = -1; |
427 |
expectedModCount = modCount; |
428 |
} catch (IndexOutOfBoundsException ex) { |
429 |
throw new ConcurrentModificationException(); |
430 |
} |
431 |
} |
432 |
} |
433 |
|
434 |
/** |
435 |
* {@inheritDoc} |
436 |
* |
437 |
* <p>This implementation returns a list that subclasses |
438 |
* {@code AbstractList}. The subclass stores, in private fields, the |
439 |
* offset of the subList within the backing list, the size of the subList |
440 |
* (which can change over its lifetime), and the expected |
441 |
* {@code modCount} value of the backing list. There are two variants |
442 |
* of the subclass, one of which implements {@code RandomAccess}. |
443 |
* If this list implements {@code RandomAccess} the returned list will |
444 |
* be an instance of the subclass that implements {@code RandomAccess}. |
445 |
* |
446 |
* <p>The subclass's {@code set(int, E)}, {@code get(int)}, |
447 |
* {@code add(int, E)}, {@code remove(int)}, {@code addAll(int, |
448 |
* Collection)} and {@code removeRange(int, int)} methods all |
449 |
* delegate to the corresponding methods on the backing abstract list, |
450 |
* after bounds-checking the index and adjusting for the offset. The |
451 |
* {@code addAll(Collection c)} method merely returns {@code addAll(size, |
452 |
* c)}. |
453 |
* |
454 |
* <p>The {@code listIterator(int)} method returns a "wrapper object" |
455 |
* over a list iterator on the backing list, which is created with the |
456 |
* corresponding method on the backing list. The {@code iterator} method |
457 |
* merely returns {@code listIterator()}, and the {@code size} method |
458 |
* merely returns the subclass's {@code size} field. |
459 |
* |
460 |
* <p>All methods first check to see if the actual {@code modCount} of |
461 |
* the backing list is equal to its expected value, and throw a |
462 |
* {@code ConcurrentModificationException} if it is not. |
463 |
* |
464 |
* @throws IndexOutOfBoundsException endpoint index value out of range |
465 |
* {@code (fromIndex < 0 || toIndex > size)} |
466 |
* @throws IllegalArgumentException if the endpoint indices are out of order |
467 |
* {@code (fromIndex > toIndex)} |
468 |
*/ |
469 |
public List<E> subList(int fromIndex, int toIndex) { |
470 |
return (this instanceof RandomAccess ? |
471 |
new RandomAccessSubList(this, this, fromIndex, fromIndex, toIndex) : |
472 |
new SubList(this, this, fromIndex, fromIndex, toIndex)); |
473 |
} |
474 |
|
475 |
// Comparison and hashing |
476 |
|
477 |
/** |
478 |
* Compares the specified object with this list for equality. Returns |
479 |
* {@code true} if and only if the specified object is also a list, both |
480 |
* lists have the same size, and all corresponding pairs of elements in |
481 |
* the two lists are <i>equal</i>. (Two elements {@code e1} and |
482 |
* {@code e2} are <i>equal</i> if {@code (e1==null ? e2==null : |
483 |
* e1.equals(e2))}.) In other words, two lists are defined to be |
484 |
* equal if they contain the same elements in the same order. |
485 |
* |
486 |
* <p>This implementation first checks if the specified object is this |
487 |
* list. If so, it returns {@code true}; if not, it checks if the |
488 |
* specified object is a list. If not, it returns {@code false}; if so, |
489 |
* it iterates over both lists, comparing corresponding pairs of elements. |
490 |
* If any comparison returns {@code false}, this method returns |
491 |
* {@code false}. If either iterator runs out of elements before the |
492 |
* other it returns {@code false} (as the lists are of unequal length); |
493 |
* otherwise it returns {@code true} when the iterations complete. |
494 |
* |
495 |
* @param o the object to be compared for equality with this list |
496 |
* @return {@code true} if the specified object is equal to this list |
497 |
*/ |
498 |
public boolean equals(Object o) { |
499 |
if (o == this) |
500 |
return true; |
501 |
if (!(o instanceof List)) |
502 |
return false; |
503 |
|
504 |
ListIterator<E> e1 = listIterator(); |
505 |
ListIterator e2 = ((List) o).listIterator(); |
506 |
while(e1.hasNext() && e2.hasNext()) { |
507 |
E o1 = e1.next(); |
508 |
Object o2 = e2.next(); |
509 |
if (!(o1==null ? o2==null : o1.equals(o2))) |
510 |
return false; |
511 |
} |
512 |
return !(e1.hasNext() || e2.hasNext()); |
513 |
} |
514 |
|
515 |
/** |
516 |
* Returns the hash code value for this list. |
517 |
* |
518 |
* <p>This implementation uses exactly the code that is used to define the |
519 |
* list hash function in the documentation for the {@link List#hashCode} |
520 |
* method. |
521 |
* |
522 |
* @return the hash code value for this list |
523 |
*/ |
524 |
public int hashCode() { |
525 |
int hashCode = 1; |
526 |
Iterator<E> i = iterator(); |
527 |
while (i.hasNext()) { |
528 |
E obj = i.next(); |
529 |
hashCode = 31*hashCode + (obj==null ? 0 : obj.hashCode()); |
530 |
} |
531 |
return hashCode; |
532 |
} |
533 |
|
534 |
/** |
535 |
* Removes from this list all of the elements whose index is between |
536 |
* {@code fromIndex}, inclusive, and {@code toIndex}, exclusive. |
537 |
* Shifts any succeeding elements to the left (reduces their index). |
538 |
* This call shortens the ArrayList by {@code (toIndex - fromIndex)} |
539 |
* elements. (If {@code toIndex==fromIndex}, this operation has no |
540 |
* effect.) |
541 |
* |
542 |
* <p>This method is called by the {@code clear} operation on this list |
543 |
* and its subLists. Overriding this method to take advantage of |
544 |
* the internals of the list implementation can <i>substantially</i> |
545 |
* improve the performance of the {@code clear} operation on this list |
546 |
* and its subLists. |
547 |
* |
548 |
* <p>This implementation gets a list iterator positioned before |
549 |
* {@code fromIndex}, and repeatedly calls {@code ListIterator.next} |
550 |
* followed by {@code ListIterator.remove} until the entire range has |
551 |
* been removed. <b>Note: if {@code ListIterator.remove} requires linear |
552 |
* time, this implementation requires quadratic time.</b> |
553 |
* |
554 |
* @param fromIndex index of first element to be removed |
555 |
* @param toIndex index after last element to be removed |
556 |
*/ |
557 |
protected void removeRange(int fromIndex, int toIndex) { |
558 |
ListIterator<E> it = listIterator(fromIndex); |
559 |
for (int i=0, n=toIndex-fromIndex; i<n; i++) { |
560 |
it.next(); |
561 |
it.remove(); |
562 |
} |
563 |
} |
564 |
|
565 |
/** |
566 |
* The number of times this list has been <i>structurally modified</i>. |
567 |
* Structural modifications are those that change the size of the |
568 |
* list, or otherwise perturb it in such a fashion that iterations in |
569 |
* progress may yield incorrect results. |
570 |
* |
571 |
* <p>This field is used by the iterator and list iterator implementation |
572 |
* returned by the {@code iterator} and {@code listIterator} methods. |
573 |
* If the value of this field changes unexpectedly, the iterator (or list |
574 |
* iterator) will throw a {@code ConcurrentModificationException} in |
575 |
* response to the {@code next}, {@code remove}, {@code previous}, |
576 |
* {@code set} or {@code add} operations. This provides |
577 |
* <i>fail-fast</i> behavior, rather than non-deterministic behavior in |
578 |
* the face of concurrent modification during iteration. |
579 |
* |
580 |
* <p><b>Use of this field by subclasses is optional.</b> If a subclass |
581 |
* wishes to provide fail-fast iterators (and list iterators), then it |
582 |
* merely has to increment this field in its {@code add(int, E)} and |
583 |
* {@code remove(int)} methods (and any other methods that it overrides |
584 |
* that result in structural modifications to the list). A single call to |
585 |
* {@code add(int, E)} or {@code remove(int)} must add no more than |
586 |
* one to this field, or the iterators (and list iterators) will throw |
587 |
* bogus {@code ConcurrentModificationExceptions}. If an implementation |
588 |
* does not wish to provide fail-fast iterators, this field may be |
589 |
* ignored. |
590 |
*/ |
591 |
protected transient int modCount = 0; |
592 |
} |
593 |
|
594 |
/** |
595 |
* Generic sublists. Non-nested to enable construction by other |
596 |
* classes in this package. |
597 |
*/ |
598 |
class SubList<E> extends AbstractList<E> { |
599 |
/* |
600 |
* A SubList has both a "base", the ultimate backing list, as well |
601 |
* as a "parent", which is the list or sublist creating this |
602 |
* sublist. All methods that may cause structural modifications |
603 |
* must propagate through the parent link, with O(k) performance |
604 |
* where k is sublist depth. For example in the case of a |
605 |
* sub-sub-list, invoking remove(x) will result in a chain of |
606 |
* three remove calls. However, all other non-structurally |
607 |
* modifying methods can bypass this chain, and relay directly to |
608 |
* the base list. In particular, doing so signficantly speeds up |
609 |
* the performance of iterators for deeply-nested sublists. |
610 |
*/ |
611 |
final AbstractList<E> base; // Backing list |
612 |
final AbstractList<E> parent; // Parent list |
613 |
final int baseOffset; // index wrt base |
614 |
final int parentOffset; // index wrt parent |
615 |
int length; // Number of elements in this sublist |
616 |
|
617 |
SubList(AbstractList<E> base, |
618 |
AbstractList<E> parent, |
619 |
int baseIndex, |
620 |
int fromIndex, |
621 |
int toIndex) { |
622 |
if (fromIndex < 0) |
623 |
throw new IndexOutOfBoundsException("fromIndex = " + fromIndex); |
624 |
if (toIndex > parent.size()) |
625 |
throw new IndexOutOfBoundsException("toIndex = " + toIndex); |
626 |
if (fromIndex > toIndex) |
627 |
throw new IllegalArgumentException("fromIndex(" + fromIndex + |
628 |
") > toIndex(" + toIndex + ")"); |
629 |
this.base = base; |
630 |
this.parent = parent; |
631 |
this.baseOffset = baseIndex; |
632 |
this.parentOffset = fromIndex; |
633 |
this.length = toIndex - fromIndex; |
634 |
this.modCount = base.modCount; |
635 |
} |
636 |
|
637 |
/** |
638 |
* Returns an IndexOutOfBoundsException with nicer message |
639 |
*/ |
640 |
private IndexOutOfBoundsException indexError(int index) { |
641 |
return new IndexOutOfBoundsException("Index: " + index + |
642 |
", Size: " + length); |
643 |
} |
644 |
|
645 |
public E set(int index, E element) { |
646 |
if (index < 0 || index >= length) |
647 |
throw indexError(index); |
648 |
if (base.modCount != modCount) |
649 |
throw new ConcurrentModificationException(); |
650 |
return base.set(index + baseOffset, element); |
651 |
} |
652 |
|
653 |
public E get(int index) { |
654 |
if (index < 0 || index >= length) |
655 |
throw indexError(index); |
656 |
if (base.modCount != modCount) |
657 |
throw new ConcurrentModificationException(); |
658 |
return base.get(index + baseOffset); |
659 |
} |
660 |
|
661 |
public int size() { |
662 |
if (base.modCount != modCount) |
663 |
throw new ConcurrentModificationException(); |
664 |
return length; |
665 |
} |
666 |
|
667 |
public void add(int index, E element) { |
668 |
if (index < 0 || index>length) |
669 |
throw indexError(index); |
670 |
if (base.modCount != modCount) |
671 |
throw new ConcurrentModificationException(); |
672 |
parent.add(index + parentOffset, element); |
673 |
length++; |
674 |
modCount = base.modCount; |
675 |
} |
676 |
|
677 |
public E remove(int index) { |
678 |
if (index < 0 || index >= length) |
679 |
throw indexError(index); |
680 |
if (base.modCount != modCount) |
681 |
throw new ConcurrentModificationException(); |
682 |
E result = parent.remove(index + parentOffset); |
683 |
length--; |
684 |
modCount = base.modCount; |
685 |
return result; |
686 |
} |
687 |
|
688 |
protected void removeRange(int fromIndex, int toIndex) { |
689 |
if (base.modCount != modCount) |
690 |
throw new ConcurrentModificationException(); |
691 |
parent.removeRange(fromIndex + parentOffset, toIndex + parentOffset); |
692 |
length -= (toIndex-fromIndex); |
693 |
modCount = base.modCount; |
694 |
} |
695 |
|
696 |
public boolean addAll(Collection<? extends E> c) { |
697 |
return addAll(length, c); |
698 |
} |
699 |
|
700 |
public boolean addAll(int index, Collection<? extends E> c) { |
701 |
if (index < 0 || index > length) |
702 |
throw indexError(index); |
703 |
int cSize = c.size(); |
704 |
if (cSize==0) |
705 |
return false; |
706 |
|
707 |
if (base.modCount != modCount) |
708 |
throw new ConcurrentModificationException(); |
709 |
parent.addAll(parentOffset + index, c); |
710 |
length += cSize; |
711 |
modCount = base.modCount; |
712 |
return true; |
713 |
} |
714 |
|
715 |
public List<E> subList(int fromIndex, int toIndex) { |
716 |
return new SubList(base, this, fromIndex + baseOffset, |
717 |
fromIndex, toIndex); |
718 |
} |
719 |
|
720 |
public Iterator<E> iterator() { |
721 |
return new SubListIterator(this, 0); |
722 |
} |
723 |
|
724 |
public ListIterator<E> listIterator() { |
725 |
return new SubListIterator(this, 0); |
726 |
} |
727 |
|
728 |
public ListIterator<E> listIterator(int index) { |
729 |
if (index < 0 || index>length) |
730 |
throw indexError(index); |
731 |
return new SubListIterator(this, index); |
732 |
} |
733 |
|
734 |
/** |
735 |
* Generic sublist iterator obeying fastfail semantics via |
736 |
* modCount. The hasNext and next methods locally check for |
737 |
* in-range indices before relaying to backing list to get |
738 |
* element. If this either encounters an unexpected modCount or |
739 |
* fails, the backing list must have been concurrently modified, |
740 |
* and is so reported. The add and remove methods performing |
741 |
* structural modifications instead relay them through the |
742 |
* sublist. |
743 |
*/ |
744 |
private static final class SubListIterator<E> implements ListIterator<E> { |
745 |
final SubList<E> outer; // Sublist creating this iteraor |
746 |
final AbstractList<E> base; // base list |
747 |
final int offset; // Cursor offset wrt base |
748 |
int cursor; // Current index |
749 |
int fence; // Upper bound on cursor |
750 |
int lastRet; // Index of returned element, or -1 |
751 |
int expectedModCount; // Expected modCount of base |
752 |
|
753 |
SubListIterator(SubList<E> list, int index) { |
754 |
this.lastRet = -1; |
755 |
this.cursor = index; |
756 |
this.outer = list; |
757 |
this.offset = list.baseOffset; |
758 |
this.fence = list.length; |
759 |
this.base = list.base; |
760 |
this.expectedModCount = base.modCount; |
761 |
} |
762 |
|
763 |
public boolean hasNext() { |
764 |
return cursor < fence; |
765 |
} |
766 |
|
767 |
public boolean hasPrevious() { |
768 |
return cursor > 0; |
769 |
} |
770 |
|
771 |
public int nextIndex() { |
772 |
return cursor; |
773 |
} |
774 |
|
775 |
public int previousIndex() { |
776 |
return cursor - 1; |
777 |
} |
778 |
|
779 |
public E next() { |
780 |
int i = cursor; |
781 |
if (cursor >= fence) |
782 |
throw new NoSuchElementException(); |
783 |
if (expectedModCount == base.modCount) { |
784 |
try { |
785 |
Object next = base.get(i + offset); |
786 |
lastRet = i; |
787 |
cursor = i + 1; |
788 |
return (E)next; |
789 |
} catch (IndexOutOfBoundsException fallThrough) { |
790 |
} |
791 |
} |
792 |
throw new ConcurrentModificationException(); |
793 |
} |
794 |
|
795 |
public E previous() { |
796 |
int i = cursor - 1; |
797 |
if (i < 0) |
798 |
throw new NoSuchElementException(); |
799 |
if (expectedModCount == base.modCount) { |
800 |
try { |
801 |
Object prev = base.get(i + offset); |
802 |
lastRet = i; |
803 |
cursor = i; |
804 |
return (E)prev; |
805 |
} catch (IndexOutOfBoundsException fallThrough) { |
806 |
} |
807 |
} |
808 |
throw new ConcurrentModificationException(); |
809 |
} |
810 |
|
811 |
public void set(E e) { |
812 |
if (lastRet < 0) |
813 |
throw new IllegalStateException(); |
814 |
if (expectedModCount != base.modCount) |
815 |
throw new ConcurrentModificationException(); |
816 |
try { |
817 |
outer.set(lastRet, e); |
818 |
expectedModCount = base.modCount; |
819 |
} catch (IndexOutOfBoundsException ex) { |
820 |
throw new ConcurrentModificationException(); |
821 |
} |
822 |
} |
823 |
|
824 |
public void remove() { |
825 |
int i = lastRet; |
826 |
if (i < 0) |
827 |
throw new IllegalStateException(); |
828 |
if (expectedModCount != base.modCount) |
829 |
throw new ConcurrentModificationException(); |
830 |
try { |
831 |
outer.remove(i); |
832 |
if (i < cursor) |
833 |
cursor--; |
834 |
lastRet = -1; |
835 |
fence = outer.length; |
836 |
expectedModCount = base.modCount; |
837 |
} catch (IndexOutOfBoundsException ex) { |
838 |
throw new ConcurrentModificationException(); |
839 |
} |
840 |
} |
841 |
|
842 |
public void add(E e) { |
843 |
if (expectedModCount != base.modCount) |
844 |
throw new ConcurrentModificationException(); |
845 |
try { |
846 |
int i = cursor; |
847 |
outer.add(i, e); |
848 |
cursor = i + 1; |
849 |
lastRet = -1; |
850 |
fence = outer.length; |
851 |
expectedModCount = base.modCount; |
852 |
} catch (IndexOutOfBoundsException ex) { |
853 |
throw new ConcurrentModificationException(); |
854 |
} |
855 |
} |
856 |
} |
857 |
|
858 |
} |
859 |
|
860 |
class RandomAccessSubList<E> extends SubList<E> implements RandomAccess { |
861 |
RandomAccessSubList(AbstractList<E> base, |
862 |
AbstractList<E> parent, int baseIndex, |
863 |
int fromIndex, int toIndex) { |
864 |
super(base, parent, baseIndex, fromIndex, toIndex); |
865 |
} |
866 |
|
867 |
public List<E> subList(int fromIndex, int toIndex) { |
868 |
return new RandomAccessSubList(base, this, fromIndex + baseOffset, |
869 |
fromIndex, toIndex); |
870 |
} |
871 |
} |