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/* |
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* @(#)LinkedList.java 1.43 01/12/03 |
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* %W% %E% |
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* |
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* Copyright 2002 Sun Microsystems, Inc. All rights reserved. |
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* Copyright 2005 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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package java.util; |
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/** |
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– |
* <b>JSR166: Added Queue operations</b>.<p> |
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* Linked list implementation of the <tt>List</tt> interface. Implements all |
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* optional list operations, and permits all elements (including |
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* <tt>null</tt>). In addition to implementing the <tt>List</tt> interface, |
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* the <tt>LinkedList</tt> class provides uniformly named methods to |
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* <tt>get</tt>, <tt>remove</tt> and <tt>insert</tt> an element at the |
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* beginning and end of the list. These operations allow linked lists to be |
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* used as a stack, queue, or double-ended queue (deque).<p> |
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* used as a stack, {@linkplain Queue queue}, or {@linkplain Deque |
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* double-ended queue}. <p> |
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* |
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* All of the stack/queue/deque operations could be easily recast in terms of |
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* the standard list operations. They're included here primarily for |
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* convenience, though they may run slightly faster than the equivalent List |
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* operations.<p> |
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* The class implements the <tt>Deque</tt> interface, providing |
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* first-in-first-out queue operations for <tt>add</tt>, |
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* <tt>poll</tt>, along with other stack and deque operations.<p> |
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* |
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* All of the operations perform as could be expected for a doubly-linked |
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* list. Operations that index into the list will traverse the list from |
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* the begining or the end, whichever is closer to the specified index.<p> |
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* the beginning or the end, whichever is closer to the specified index.<p> |
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* |
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* <b>Note that this implementation is not synchronized.</b> If multiple |
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* threads access a list concurrently, and at least one of the threads |
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* Collections.synchronizedList method. This is best done at creation time, |
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* to prevent accidental unsynchronized access to the list: <pre> |
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* List list = Collections.synchronizedList(new LinkedList(...)); |
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* </pre><p> |
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* </pre> |
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* |
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* The iterators returned by the this class's <tt>iterator</tt> and |
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* <p>The iterators returned by this class's <tt>iterator</tt> and |
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* <tt>listIterator</tt> methods are <i>fail-fast</i>: if the list is |
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* structurally modified at any time after the iterator is created, in any way |
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* except through the Iterator's own <tt>remove</tt> or <tt>add</tt> methods, |
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* the iterator will throw a <tt>ConcurrentModificationException</tt>. Thus, |
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* in the face of concurrent modification, the iterator fails quickly and |
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* cleanly, rather than risking arbitrary, non-deterministic behavior at an |
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* undetermined time in the future. |
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* structurally modified at any time after the iterator is created, in |
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* any way except through the Iterator's own <tt>remove</tt> or |
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* <tt>add</tt> methods, the iterator will throw a {@link |
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* ConcurrentModificationException}. Thus, in the face of concurrent |
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* modification, the iterator fails quickly and cleanly, rather than |
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* 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 <tt>ConcurrentModificationException</tt> on a best-effort basis. |
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* throw <tt>ConcurrentModificationException</tt> 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}/../guide/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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* @version 1.43, 12/03/01 |
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* @see java.util.List |
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* @see java.util.ArrayList |
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* @see java.util.Vector |
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* @see java.util.Collections#synchronizedList(java.util.List) |
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* @version %I%, %G% |
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* @see List |
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* @see ArrayList |
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* @see Vector |
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* @see Collections#synchronizedList(List) |
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* @since 1.2 |
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* @param <E> the type of elements held in this collection |
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*/ |
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|
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public class LinkedList extends AbstractSequentialList |
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implements List, Queue, Cloneable, java.io.Serializable |
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public class LinkedList<E> |
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extends AbstractSequentialList<E> |
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implements List<E>, Deque<E>, Cloneable, java.io.Serializable |
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{ |
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private transient Entry header = new Entry(null, null, null); |
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private transient Entry<E> header = new Entry<E>(null, null, null); |
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private transient int size = 0; |
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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 LinkedList(Collection c) { |
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this(); |
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addAll(c); |
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public LinkedList(Collection<? extends E> c) { |
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this(); |
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addAll(c); |
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} |
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/** |
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* @return the first element in this list. |
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* @throws NoSuchElementException if this list is empty. |
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*/ |
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public Object getFirst() { |
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if (size==0) |
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throw new NoSuchElementException(); |
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public E getFirst() { |
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if (size==0) |
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throw new NoSuchElementException(); |
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|
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return header.next.element; |
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return header.next.element; |
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} |
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/** |
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* @return the last element in this list. |
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* @throws NoSuchElementException if this list is empty. |
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*/ |
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public Object getLast() { |
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if (size==0) |
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throw new NoSuchElementException(); |
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public E getLast() { |
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> |
if (size==0) |
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throw new NoSuchElementException(); |
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|
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return header.previous.element; |
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return header.previous.element; |
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} |
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/** |
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* @return the first element from this list. |
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* @throws NoSuchElementException if this list is empty. |
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*/ |
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public Object removeFirst() { |
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Object first = header.next.element; |
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remove(header.next); |
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return first; |
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> |
public E removeFirst() { |
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> |
return remove(header.next); |
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} |
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|
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/** |
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* @return the last element from this list. |
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* @throws NoSuchElementException if this list is empty. |
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*/ |
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public Object removeLast() { |
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Object last = header.previous.element; |
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remove(header.previous); |
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return last; |
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> |
public E removeLast() { |
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> |
return remove(header.previous); |
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} |
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|
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/** |
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* Inserts the given element at the beginning of this list. |
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* |
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> |
* |
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* @param o the element to be inserted at the beginning of this list. |
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*/ |
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< |
public void addFirst(Object o) { |
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addBefore(o, header.next); |
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public void addFirst(E o) { |
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addBefore(o, header.next); |
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} |
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|
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/** |
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* Appends the given element to the end of this list. (Identical in |
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* function to the <tt>add</tt> method; included only for consistency.) |
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* |
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> |
* |
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* @param o the element to be inserted at the end of this list. |
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*/ |
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public void addLast(Object o) { |
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addBefore(o, header); |
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public void addLast(E o) { |
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addBefore(o, header); |
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} |
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|
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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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return size; |
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} |
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|
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/** |
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* @return <tt>true</tt> (as per the general contract of |
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* <tt>Collection.add</tt>). |
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*/ |
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< |
public boolean add(Object o) { |
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addBefore(o, header); |
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> |
public boolean add(E o) { |
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> |
addBefore(o, header); |
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return true; |
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} |
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|
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*/ |
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public boolean remove(Object o) { |
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if (o==null) { |
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< |
for (Entry e = header.next; e != header; e = e.next) { |
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> |
for (Entry<E> e = header.next; e != header; e = e.next) { |
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if (e.element==null) { |
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remove(e); |
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return true; |
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} |
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} |
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} else { |
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< |
for (Entry e = header.next; e != header; e = e.next) { |
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> |
for (Entry<E> e = header.next; e != header; e = e.next) { |
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if (o.equals(e.element)) { |
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remove(e); |
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return true; |
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* @return <tt>true</tt> if this list changed as a result of the call. |
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* @throws NullPointerException if the specified collection is null. |
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*/ |
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< |
public boolean addAll(Collection c) { |
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> |
public boolean addAll(Collection<? extends E> c) { |
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return addAll(size, c); |
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} |
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|
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* specified collection's iterator. |
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* |
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* @param index index at which to insert first element |
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< |
* from the specified collection. |
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> |
* from the specified collection. |
| 254 |
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* @param c elements to be inserted into this list. |
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* @return <tt>true</tt> if this list changed as a result of the call. |
| 256 |
< |
* @throws IndexOutOfBoundsException if the specified index is out of |
| 257 |
< |
* range (<tt>index < 0 || index > size()</tt>). |
| 256 |
> |
* @throws IndexOutOfBoundsException if the index is out of range |
| 257 |
> |
* (<tt>index < 0 || index > size()</tt>). |
| 258 |
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* @throws NullPointerException if the specified collection is null. |
| 259 |
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*/ |
| 260 |
< |
public boolean addAll(int index, Collection c) { |
| 261 |
< |
int numNew = c.size(); |
| 262 |
< |
if (numNew==0) { |
| 263 |
< |
if (index < 0 || index >= size) |
| 264 |
< |
throw new IndexOutOfBoundsException(); |
| 265 |
< |
else |
| 266 |
< |
return false; |
| 267 |
< |
} |
| 268 |
< |
modCount++; |
| 269 |
< |
|
| 270 |
< |
Entry successor = (index==size ? header : entry(index)); |
| 271 |
< |
Entry predecessor = successor.previous; |
| 272 |
< |
Iterator it = c.iterator(); |
| 273 |
< |
for (int i=0; i<numNew; i++) { |
| 272 |
< |
Entry e = new Entry(it.next(), successor, predecessor); |
| 260 |
> |
public boolean addAll(int index, Collection<? extends E> c) { |
| 261 |
> |
if (index < 0 || index > size) |
| 262 |
> |
throw new IndexOutOfBoundsException("Index: "+index+ |
| 263 |
> |
", Size: "+size); |
| 264 |
> |
Object[] a = c.toArray(); |
| 265 |
> |
int numNew = a.length; |
| 266 |
> |
if (numNew==0) |
| 267 |
> |
return false; |
| 268 |
> |
modCount++; |
| 269 |
> |
|
| 270 |
> |
Entry<E> successor = (index==size ? header : entry(index)); |
| 271 |
> |
Entry<E> predecessor = successor.previous; |
| 272 |
> |
for (int i=0; i<numNew; i++) { |
| 273 |
> |
Entry<E> e = new Entry<E>((E)a[i], successor, predecessor); |
| 274 |
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predecessor.next = e; |
| 275 |
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predecessor = e; |
| 276 |
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} |
| 284 |
|
* Removes all of the elements from this list. |
| 285 |
|
*/ |
| 286 |
|
public void clear() { |
| 287 |
< |
modCount++; |
| 287 |
> |
Entry<E> e = header.next; |
| 288 |
> |
while (e != header) { |
| 289 |
> |
Entry<E> next = e.next; |
| 290 |
> |
e.next = e.previous = null; |
| 291 |
> |
e.element = null; |
| 292 |
> |
e = next; |
| 293 |
> |
} |
| 294 |
|
header.next = header.previous = header; |
| 295 |
|
size = 0; |
| 296 |
+ |
modCount++; |
| 297 |
|
} |
| 298 |
|
|
| 299 |
|
|
| 304 |
|
* |
| 305 |
|
* @param index index of element to return. |
| 306 |
|
* @return the element at the specified position in this list. |
| 307 |
< |
* |
| 308 |
< |
* @throws IndexOutOfBoundsException if the specified index is is out of |
| 309 |
< |
* range (<tt>index < 0 || index >= size()</tt>). |
| 307 |
> |
* |
| 308 |
> |
* @throws IndexOutOfBoundsException if the index is out of range |
| 309 |
> |
* (<tt>index < 0 || index > size()</tt>). |
| 310 |
|
*/ |
| 311 |
< |
public Object get(int index) { |
| 311 |
> |
public E get(int index) { |
| 312 |
|
return entry(index).element; |
| 313 |
|
} |
| 314 |
|
|
| 319 |
|
* @param index index of element to replace. |
| 320 |
|
* @param element element to be stored at the specified position. |
| 321 |
|
* @return the element previously at the specified position. |
| 322 |
< |
* @throws IndexOutOfBoundsException if the specified index is out of |
| 323 |
< |
* range (<tt>index < 0 || index >= size()</tt>). |
| 322 |
> |
* @throws IndexOutOfBoundsException if the index is out of range |
| 323 |
> |
* (<tt>index < 0 || index > size()</tt>). |
| 324 |
|
*/ |
| 325 |
< |
public Object set(int index, Object element) { |
| 326 |
< |
Entry e = entry(index); |
| 327 |
< |
Object oldVal = e.element; |
| 325 |
> |
public E set(int index, E element) { |
| 326 |
> |
Entry<E> e = entry(index); |
| 327 |
> |
E oldVal = e.element; |
| 328 |
|
e.element = element; |
| 329 |
|
return oldVal; |
| 330 |
|
} |
| 336 |
|
* |
| 337 |
|
* @param index index at which the specified element is to be inserted. |
| 338 |
|
* @param element element to be inserted. |
| 339 |
< |
* |
| 340 |
< |
* @throws IndexOutOfBoundsException if the specified index is out of |
| 341 |
< |
* range (<tt>index < 0 || index > size()</tt>). |
| 339 |
> |
* |
| 340 |
> |
* @throws IndexOutOfBoundsException if the index is out of range |
| 341 |
> |
* (<tt>index < 0 || index > size()</tt>). |
| 342 |
|
*/ |
| 343 |
< |
public void add(int index, Object element) { |
| 343 |
> |
public void add(int index, E element) { |
| 344 |
|
addBefore(element, (index==size ? header : entry(index))); |
| 345 |
|
} |
| 346 |
|
|
| 351 |
|
* |
| 352 |
|
* @param index the index of the element to removed. |
| 353 |
|
* @return the element previously at the specified position. |
| 354 |
< |
* |
| 355 |
< |
* @throws IndexOutOfBoundsException if the specified index is out of |
| 356 |
< |
* range (<tt>index < 0 || index >= size()</tt>). |
| 354 |
> |
* |
| 355 |
> |
* @throws IndexOutOfBoundsException if the index is out of range |
| 356 |
> |
* (<tt>index < 0 || index > size()</tt>). |
| 357 |
|
*/ |
| 358 |
< |
public Object remove(int index) { |
| 359 |
< |
Entry e = entry(index); |
| 352 |
< |
remove(e); |
| 353 |
< |
return e.element; |
| 358 |
> |
public E remove(int index) { |
| 359 |
> |
return remove(entry(index)); |
| 360 |
|
} |
| 361 |
|
|
| 362 |
|
/** |
| 363 |
< |
* Return the indexed entry. |
| 363 |
> |
* Returns the indexed entry. |
| 364 |
|
*/ |
| 365 |
< |
private Entry entry(int index) { |
| 365 |
> |
private Entry<E> entry(int index) { |
| 366 |
|
if (index < 0 || index >= size) |
| 367 |
|
throw new IndexOutOfBoundsException("Index: "+index+ |
| 368 |
|
", Size: "+size); |
| 369 |
< |
Entry e = header; |
| 369 |
> |
Entry<E> e = header; |
| 370 |
|
if (index < (size >> 1)) { |
| 371 |
|
for (int i = 0; i <= index; i++) |
| 372 |
|
e = e.next; |
| 389 |
|
* |
| 390 |
|
* @param o element to search for. |
| 391 |
|
* @return the index in this list of the first occurrence of the |
| 392 |
< |
* specified element, or -1 if the list does not contain this |
| 393 |
< |
* element. |
| 392 |
> |
* specified element, or -1 if the list does not contain this |
| 393 |
> |
* element. |
| 394 |
|
*/ |
| 395 |
|
public int indexOf(Object o) { |
| 396 |
|
int index = 0; |
| 419 |
|
* |
| 420 |
|
* @param o element to search for. |
| 421 |
|
* @return the index in this list of the last occurrence of the |
| 422 |
< |
* specified element, or -1 if the list does not contain this |
| 423 |
< |
* element. |
| 422 |
> |
* specified element, or -1 if the list does not contain this |
| 423 |
> |
* element. |
| 424 |
|
*/ |
| 425 |
|
public int lastIndexOf(Object o) { |
| 426 |
|
int index = size; |
| 440 |
|
return -1; |
| 441 |
|
} |
| 442 |
|
|
| 443 |
+ |
// Queue operations. |
| 444 |
+ |
|
| 445 |
+ |
/** |
| 446 |
+ |
* Retrieves, but does not remove, the head (first element) of this list. |
| 447 |
+ |
* @return the head of this list, or <tt>null</tt> if this list is empty. |
| 448 |
+ |
* @since 1.5 |
| 449 |
+ |
*/ |
| 450 |
+ |
public E peek() { |
| 451 |
+ |
if (size==0) |
| 452 |
+ |
return null; |
| 453 |
+ |
return getFirst(); |
| 454 |
+ |
} |
| 455 |
+ |
|
| 456 |
+ |
/** |
| 457 |
+ |
* Retrieves, but does not remove, the head (first element) of this list. |
| 458 |
+ |
* @return the head of this list. |
| 459 |
+ |
* @throws NoSuchElementException if this list is empty. |
| 460 |
+ |
* @since 1.5 |
| 461 |
+ |
*/ |
| 462 |
+ |
public E element() { |
| 463 |
+ |
return getFirst(); |
| 464 |
+ |
} |
| 465 |
+ |
|
| 466 |
+ |
/** |
| 467 |
+ |
* Retrieves and removes the head (first element) of this list. |
| 468 |
+ |
* @return the head of this list, or <tt>null</tt> if this list is empty. |
| 469 |
+ |
* @since 1.5 |
| 470 |
+ |
*/ |
| 471 |
+ |
public E poll() { |
| 472 |
+ |
if (size==0) |
| 473 |
+ |
return null; |
| 474 |
+ |
return removeFirst(); |
| 475 |
+ |
} |
| 476 |
+ |
|
| 477 |
+ |
/** |
| 478 |
+ |
* Retrieves and removes the head (first element) of this list. |
| 479 |
+ |
* @return the head of this list. |
| 480 |
+ |
* @throws NoSuchElementException if this list is empty. |
| 481 |
+ |
* @since 1.5 |
| 482 |
+ |
*/ |
| 483 |
+ |
public E remove() { |
| 484 |
+ |
return removeFirst(); |
| 485 |
+ |
} |
| 486 |
+ |
|
| 487 |
+ |
/** |
| 488 |
+ |
* Adds the specified element as the tail (last element) of this list. |
| 489 |
+ |
* |
| 490 |
+ |
* @param o the element to add. |
| 491 |
+ |
* @return <tt>true</tt> (as per the general contract of |
| 492 |
+ |
* <tt>Queue.offer</tt>) |
| 493 |
+ |
* @since 1.5 |
| 494 |
+ |
*/ |
| 495 |
+ |
public boolean offer(E o) { |
| 496 |
+ |
return add(o); |
| 497 |
+ |
} |
| 498 |
+ |
|
| 499 |
+ |
// Deque operations |
| 500 |
+ |
/** |
| 501 |
+ |
* Inserts the specified element at the front of this list. |
| 502 |
+ |
* |
| 503 |
+ |
* @param e the element to insert |
| 504 |
+ |
* @return <tt>true</tt> (as per the spec for {@link Deque#offerFirst}) |
| 505 |
+ |
* @since 1.6 |
| 506 |
+ |
*/ |
| 507 |
+ |
public boolean offerFirst(E e) { |
| 508 |
+ |
addFirst(e); |
| 509 |
+ |
return true; |
| 510 |
+ |
} |
| 511 |
+ |
|
| 512 |
+ |
/** |
| 513 |
+ |
* Inserts the specified element at the end of this list. |
| 514 |
+ |
* |
| 515 |
+ |
* @param e the element to insert |
| 516 |
+ |
* @return <tt>true</tt> (as per the spec for {@link Deque#offerLast}) |
| 517 |
+ |
* @since 1.6 |
| 518 |
+ |
*/ |
| 519 |
+ |
public boolean offerLast(E e) { |
| 520 |
+ |
addLast(e); |
| 521 |
+ |
return true; |
| 522 |
+ |
} |
| 523 |
+ |
|
| 524 |
+ |
/** |
| 525 |
+ |
* Retrieves, but does not remove, the first element of this list, |
| 526 |
+ |
* returning <tt>null</tt> if this list is empty. |
| 527 |
+ |
* |
| 528 |
+ |
* @return the first element of this list, or <tt>null</tt> if |
| 529 |
+ |
* this list is empty |
| 530 |
+ |
* @since 1.6 |
| 531 |
+ |
*/ |
| 532 |
+ |
public E peekFirst() { |
| 533 |
+ |
if (size==0) |
| 534 |
+ |
return null; |
| 535 |
+ |
return getFirst(); |
| 536 |
+ |
} |
| 537 |
+ |
|
| 538 |
+ |
/** |
| 539 |
+ |
* Retrieves, but does not remove, the last element of this list, |
| 540 |
+ |
* returning <tt>null</tt> if this list is empty. |
| 541 |
+ |
* |
| 542 |
+ |
* @return the last element of this list, or <tt>null</tt> if this list |
| 543 |
+ |
* is empty |
| 544 |
+ |
* @since 1.6 |
| 545 |
+ |
*/ |
| 546 |
+ |
public E peekLast() { |
| 547 |
+ |
if (size==0) |
| 548 |
+ |
return null; |
| 549 |
+ |
return getLast(); |
| 550 |
+ |
} |
| 551 |
+ |
|
| 552 |
+ |
/** |
| 553 |
+ |
* Retrieves and removes the first element of this list, or |
| 554 |
+ |
* <tt>null</tt> if this list is empty. |
| 555 |
+ |
* |
| 556 |
+ |
* @return the first element of this list, or <tt>null</tt> if |
| 557 |
+ |
* this list is empty |
| 558 |
+ |
* @since 1.6 |
| 559 |
+ |
*/ |
| 560 |
+ |
public E pollFirst() { |
| 561 |
+ |
if (size==0) |
| 562 |
+ |
return null; |
| 563 |
+ |
return removeFirst(); |
| 564 |
+ |
} |
| 565 |
+ |
|
| 566 |
+ |
/** |
| 567 |
+ |
* Retrieves and removes the last element of this list, or |
| 568 |
+ |
* <tt>null</tt> if this list is empty. |
| 569 |
+ |
* |
| 570 |
+ |
* @return the last element of this list, or <tt>null</tt> if |
| 571 |
+ |
* this list is empty |
| 572 |
+ |
* @since 1.6 |
| 573 |
+ |
*/ |
| 574 |
+ |
public E pollLast() { |
| 575 |
+ |
if (size==0) |
| 576 |
+ |
return null; |
| 577 |
+ |
return removeLast(); |
| 578 |
+ |
} |
| 579 |
+ |
|
| 580 |
+ |
/** |
| 581 |
+ |
* Pushes an element onto the stack represented by this list. In other |
| 582 |
+ |
* words, inserts the element at the front of this list. |
| 583 |
+ |
* |
| 584 |
+ |
* <p>This method is equivalent to {@link #addFirst}. |
| 585 |
+ |
* |
| 586 |
+ |
* @param e the element to push |
| 587 |
+ |
* @since 1.6 |
| 588 |
+ |
*/ |
| 589 |
+ |
public void push(E e) { |
| 590 |
+ |
addFirst(e); |
| 591 |
+ |
} |
| 592 |
+ |
|
| 593 |
+ |
/** |
| 594 |
+ |
* Pops an element from the stack represented by this list. In other |
| 595 |
+ |
* words, removes and returns the first element of this list. |
| 596 |
+ |
* |
| 597 |
+ |
* <p>This method is equivalent to {@link #removeFirst()}. |
| 598 |
+ |
* |
| 599 |
+ |
* @return the element at the front of this list (which is the top |
| 600 |
+ |
* of the stack represented by this list) |
| 601 |
+ |
* @throws NoSuchElementException if this list is empty. |
| 602 |
+ |
* @since 1.6 |
| 603 |
+ |
*/ |
| 604 |
+ |
public E pop() { |
| 605 |
+ |
return removeFirst(); |
| 606 |
+ |
} |
| 607 |
+ |
|
| 608 |
+ |
/** |
| 609 |
+ |
* Removes the first occurrence of the specified element in this |
| 610 |
+ |
* list (when traversing the list from head to tail). If the list |
| 611 |
+ |
* does not contain the element, it is unchanged. |
| 612 |
+ |
* |
| 613 |
+ |
* @param o element to be removed from this list, if present |
| 614 |
+ |
* @return <tt>true</tt> if the list contained the specified element |
| 615 |
+ |
* @since 1.6 |
| 616 |
+ |
*/ |
| 617 |
+ |
public boolean removeFirstOccurrence(Object o) { |
| 618 |
+ |
return remove(o); |
| 619 |
+ |
} |
| 620 |
+ |
|
| 621 |
+ |
/** |
| 622 |
+ |
* Removes the last occurrence of the specified element in this |
| 623 |
+ |
* list (when traversing the list from head to tail). If the list |
| 624 |
+ |
* does not contain the element, it is unchanged. |
| 625 |
+ |
* |
| 626 |
+ |
* @param o element to be removed from this list, if present |
| 627 |
+ |
* @return <tt>true</tt> if the list contained the specified element |
| 628 |
+ |
* @since 1.6 |
| 629 |
+ |
*/ |
| 630 |
+ |
public boolean removeLastOccurrence(Object o) { |
| 631 |
+ |
if (o==null) { |
| 632 |
+ |
for (Entry e = header.previous; e != header; e = e.previous) { |
| 633 |
+ |
if (e.element==null) { |
| 634 |
+ |
remove(e); |
| 635 |
+ |
return true; |
| 636 |
+ |
} |
| 637 |
+ |
} |
| 638 |
+ |
} else { |
| 639 |
+ |
for (Entry e = header.previous; e != header; e = e.previous) { |
| 640 |
+ |
if (o.equals(e.element)) { |
| 641 |
+ |
remove(e); |
| 642 |
+ |
return true; |
| 643 |
+ |
} |
| 644 |
+ |
} |
| 645 |
+ |
} |
| 646 |
+ |
return false; |
| 647 |
+ |
} |
| 648 |
+ |
|
| 649 |
|
/** |
| 650 |
|
* Returns a list-iterator of the elements in this list (in proper |
| 651 |
|
* sequence), starting at the specified position in the list. |
| 661 |
|
* time in the future. |
| 662 |
|
* |
| 663 |
|
* @param index index of first element to be returned from the |
| 664 |
< |
* list-iterator (by a call to <tt>next</tt>). |
| 664 |
> |
* list-iterator (by a call to <tt>next</tt>). |
| 665 |
|
* @return a ListIterator of the elements in this list (in proper |
| 666 |
< |
* sequence), starting at the specified position in the list. |
| 667 |
< |
* @throws IndexOutOfBoundsException if index is out of range |
| 668 |
< |
* (<tt>index < 0 || index > size()</tt>). |
| 669 |
< |
* @see java.util.List#listIterator(int) |
| 670 |
< |
*/ |
| 671 |
< |
public ListIterator listIterator(int index) { |
| 672 |
< |
return new ListItr(index); |
| 673 |
< |
} |
| 674 |
< |
|
| 675 |
< |
private class ListItr implements ListIterator { |
| 676 |
< |
private Entry lastReturned = header; |
| 677 |
< |
private Entry next; |
| 678 |
< |
private int nextIndex; |
| 679 |
< |
private int expectedModCount = modCount; |
| 680 |
< |
|
| 681 |
< |
ListItr(int index) { |
| 682 |
< |
if (index < 0 || index > size) |
| 683 |
< |
throw new IndexOutOfBoundsException("Index: "+index+ |
| 684 |
< |
", Size: "+size); |
| 685 |
< |
if (index < (size >> 1)) { |
| 686 |
< |
next = header.next; |
| 687 |
< |
for (nextIndex=0; nextIndex<index; nextIndex++) |
| 688 |
< |
next = next.next; |
| 689 |
< |
} else { |
| 690 |
< |
next = header; |
| 691 |
< |
for (nextIndex=size; nextIndex>index; nextIndex--) |
| 692 |
< |
next = next.previous; |
| 693 |
< |
} |
| 694 |
< |
} |
| 666 |
> |
* sequence), starting at the specified position in the list. |
| 667 |
> |
* @throws IndexOutOfBoundsException if the index is out of range |
| 668 |
> |
* (<tt>index < 0 || index > size()</tt>). |
| 669 |
> |
* @see List#listIterator(int) |
| 670 |
> |
*/ |
| 671 |
> |
public ListIterator<E> listIterator(int index) { |
| 672 |
> |
return new ListItr(index); |
| 673 |
> |
} |
| 674 |
> |
|
| 675 |
> |
private class ListItr implements ListIterator<E> { |
| 676 |
> |
private Entry<E> lastReturned = header; |
| 677 |
> |
private Entry<E> next; |
| 678 |
> |
private int nextIndex; |
| 679 |
> |
private int expectedModCount = modCount; |
| 680 |
> |
|
| 681 |
> |
ListItr(int index) { |
| 682 |
> |
if (index < 0 || index > size) |
| 683 |
> |
throw new IndexOutOfBoundsException("Index: "+index+ |
| 684 |
> |
", Size: "+size); |
| 685 |
> |
if (index < (size >> 1)) { |
| 686 |
> |
next = header.next; |
| 687 |
> |
for (nextIndex=0; nextIndex<index; nextIndex++) |
| 688 |
> |
next = next.next; |
| 689 |
> |
} else { |
| 690 |
> |
next = header; |
| 691 |
> |
for (nextIndex=size; nextIndex>index; nextIndex--) |
| 692 |
> |
next = next.previous; |
| 693 |
> |
} |
| 694 |
> |
} |
| 695 |
> |
|
| 696 |
> |
public boolean hasNext() { |
| 697 |
> |
return nextIndex != size; |
| 698 |
> |
} |
| 699 |
> |
|
| 700 |
> |
public E next() { |
| 701 |
> |
checkForComodification(); |
| 702 |
> |
if (nextIndex == size) |
| 703 |
> |
throw new NoSuchElementException(); |
| 704 |
> |
|
| 705 |
> |
lastReturned = next; |
| 706 |
> |
next = next.next; |
| 707 |
> |
nextIndex++; |
| 708 |
> |
return lastReturned.element; |
| 709 |
> |
} |
| 710 |
> |
|
| 711 |
> |
public boolean hasPrevious() { |
| 712 |
> |
return nextIndex != 0; |
| 713 |
> |
} |
| 714 |
> |
|
| 715 |
> |
public E previous() { |
| 716 |
> |
if (nextIndex == 0) |
| 717 |
> |
throw new NoSuchElementException(); |
| 718 |
> |
|
| 719 |
> |
lastReturned = next = next.previous; |
| 720 |
> |
nextIndex--; |
| 721 |
> |
checkForComodification(); |
| 722 |
> |
return lastReturned.element; |
| 723 |
> |
} |
| 724 |
> |
|
| 725 |
> |
public int nextIndex() { |
| 726 |
> |
return nextIndex; |
| 727 |
> |
} |
| 728 |
> |
|
| 729 |
> |
public int previousIndex() { |
| 730 |
> |
return nextIndex-1; |
| 731 |
> |
} |
| 732 |
|
|
| 733 |
< |
public boolean hasNext() { |
| 485 |
< |
return nextIndex != size; |
| 486 |
< |
} |
| 487 |
< |
|
| 488 |
< |
public Object next() { |
| 489 |
< |
checkForComodification(); |
| 490 |
< |
if (nextIndex == size) |
| 491 |
< |
throw new NoSuchElementException(); |
| 492 |
< |
|
| 493 |
< |
lastReturned = next; |
| 494 |
< |
next = next.next; |
| 495 |
< |
nextIndex++; |
| 496 |
< |
return lastReturned.element; |
| 497 |
< |
} |
| 498 |
< |
|
| 499 |
< |
public boolean hasPrevious() { |
| 500 |
< |
return nextIndex != 0; |
| 501 |
< |
} |
| 502 |
< |
|
| 503 |
< |
public Object previous() { |
| 504 |
< |
if (nextIndex == 0) |
| 505 |
< |
throw new NoSuchElementException(); |
| 506 |
< |
|
| 507 |
< |
lastReturned = next = next.previous; |
| 508 |
< |
nextIndex--; |
| 509 |
< |
checkForComodification(); |
| 510 |
< |
return lastReturned.element; |
| 511 |
< |
} |
| 512 |
< |
|
| 513 |
< |
public int nextIndex() { |
| 514 |
< |
return nextIndex; |
| 515 |
< |
} |
| 516 |
< |
|
| 517 |
< |
public int previousIndex() { |
| 518 |
< |
return nextIndex-1; |
| 519 |
< |
} |
| 520 |
< |
|
| 521 |
< |
public void remove() { |
| 733 |
> |
public void remove() { |
| 734 |
|
checkForComodification(); |
| 735 |
+ |
Entry<E> lastNext = lastReturned.next; |
| 736 |
|
try { |
| 737 |
|
LinkedList.this.remove(lastReturned); |
| 738 |
|
} catch (NoSuchElementException e) { |
| 739 |
|
throw new IllegalStateException(); |
| 740 |
|
} |
| 741 |
< |
if (next==lastReturned) |
| 742 |
< |
next = lastReturned.next; |
| 741 |
> |
if (next==lastReturned) |
| 742 |
> |
next = lastNext; |
| 743 |
|
else |
| 744 |
< |
nextIndex--; |
| 745 |
< |
lastReturned = header; |
| 746 |
< |
expectedModCount++; |
| 747 |
< |
} |
| 748 |
< |
|
| 749 |
< |
public void set(Object o) { |
| 750 |
< |
if (lastReturned == header) |
| 751 |
< |
throw new IllegalStateException(); |
| 752 |
< |
checkForComodification(); |
| 753 |
< |
lastReturned.element = o; |
| 754 |
< |
} |
| 755 |
< |
|
| 756 |
< |
public void add(Object o) { |
| 757 |
< |
checkForComodification(); |
| 758 |
< |
lastReturned = header; |
| 759 |
< |
addBefore(o, next); |
| 760 |
< |
nextIndex++; |
| 761 |
< |
expectedModCount++; |
| 762 |
< |
} |
| 763 |
< |
|
| 764 |
< |
final void checkForComodification() { |
| 765 |
< |
if (modCount != expectedModCount) |
| 766 |
< |
throw new ConcurrentModificationException(); |
| 767 |
< |
} |
| 768 |
< |
} |
| 769 |
< |
|
| 770 |
< |
private static class Entry { |
| 771 |
< |
Object element; |
| 772 |
< |
Entry next; |
| 773 |
< |
Entry previous; |
| 774 |
< |
|
| 775 |
< |
Entry(Object element, Entry next, Entry previous) { |
| 776 |
< |
this.element = element; |
| 777 |
< |
this.next = next; |
| 778 |
< |
this.previous = previous; |
| 779 |
< |
} |
| 780 |
< |
} |
| 781 |
< |
|
| 782 |
< |
private Entry addBefore(Object o, Entry e) { |
| 783 |
< |
Entry newEntry = new Entry(o, e, e.previous); |
| 784 |
< |
newEntry.previous.next = newEntry; |
| 785 |
< |
newEntry.next.previous = newEntry; |
| 786 |
< |
size++; |
| 787 |
< |
modCount++; |
| 788 |
< |
return newEntry; |
| 789 |
< |
} |
| 790 |
< |
|
| 791 |
< |
private void remove(Entry e) { |
| 792 |
< |
if (e == header) |
| 793 |
< |
throw new NoSuchElementException(); |
| 794 |
< |
|
| 795 |
< |
e.previous.next = e.next; |
| 796 |
< |
e.next.previous = e.previous; |
| 797 |
< |
size--; |
| 798 |
< |
modCount++; |
| 744 |
> |
nextIndex--; |
| 745 |
> |
lastReturned = header; |
| 746 |
> |
expectedModCount++; |
| 747 |
> |
} |
| 748 |
> |
|
| 749 |
> |
public void set(E o) { |
| 750 |
> |
if (lastReturned == header) |
| 751 |
> |
throw new IllegalStateException(); |
| 752 |
> |
checkForComodification(); |
| 753 |
> |
lastReturned.element = o; |
| 754 |
> |
} |
| 755 |
> |
|
| 756 |
> |
public void add(E o) { |
| 757 |
> |
checkForComodification(); |
| 758 |
> |
lastReturned = header; |
| 759 |
> |
addBefore(o, next); |
| 760 |
> |
nextIndex++; |
| 761 |
> |
expectedModCount++; |
| 762 |
> |
} |
| 763 |
> |
|
| 764 |
> |
final void checkForComodification() { |
| 765 |
> |
if (modCount != expectedModCount) |
| 766 |
> |
throw new ConcurrentModificationException(); |
| 767 |
> |
} |
| 768 |
> |
} |
| 769 |
> |
|
| 770 |
> |
private static class Entry<E> { |
| 771 |
> |
E element; |
| 772 |
> |
Entry<E> next; |
| 773 |
> |
Entry<E> previous; |
| 774 |
> |
|
| 775 |
> |
Entry(E element, Entry<E> next, Entry<E> previous) { |
| 776 |
> |
this.element = element; |
| 777 |
> |
this.next = next; |
| 778 |
> |
this.previous = previous; |
| 779 |
> |
} |
| 780 |
> |
} |
| 781 |
> |
|
| 782 |
> |
private Entry<E> addBefore(E o, Entry<E> e) { |
| 783 |
> |
Entry<E> newEntry = new Entry<E>(o, e, e.previous); |
| 784 |
> |
newEntry.previous.next = newEntry; |
| 785 |
> |
newEntry.next.previous = newEntry; |
| 786 |
> |
size++; |
| 787 |
> |
modCount++; |
| 788 |
> |
return newEntry; |
| 789 |
> |
} |
| 790 |
> |
|
| 791 |
> |
private E remove(Entry<E> e) { |
| 792 |
> |
if (e == header) |
| 793 |
> |
throw new NoSuchElementException(); |
| 794 |
> |
|
| 795 |
> |
E result = e.element; |
| 796 |
> |
e.previous.next = e.next; |
| 797 |
> |
e.next.previous = e.previous; |
| 798 |
> |
e.next = e.previous = null; |
| 799 |
> |
e.element = null; |
| 800 |
> |
size--; |
| 801 |
> |
modCount++; |
| 802 |
> |
return result; |
| 803 |
|
} |
| 804 |
|
|
| 805 |
|
/** |
| 809 |
|
* @return a shallow copy of this <tt>LinkedList</tt> instance. |
| 810 |
|
*/ |
| 811 |
|
public Object clone() { |
| 812 |
< |
LinkedList clone = null; |
| 813 |
< |
try { |
| 814 |
< |
clone = (LinkedList)super.clone(); |
| 815 |
< |
} catch (CloneNotSupportedException e) { |
| 816 |
< |
throw new InternalError(); |
| 817 |
< |
} |
| 812 |
> |
LinkedList<E> clone = null; |
| 813 |
> |
try { |
| 814 |
> |
clone = (LinkedList<E>) super.clone(); |
| 815 |
> |
} catch (CloneNotSupportedException e) { |
| 816 |
> |
throw new InternalError(); |
| 817 |
> |
} |
| 818 |
|
|
| 819 |
|
// Put clone into "virgin" state |
| 820 |
< |
clone.header = new Entry(null, null, null); |
| 820 |
> |
clone.header = new Entry<E>(null, null, null); |
| 821 |
|
clone.header.next = clone.header.previous = clone.header; |
| 822 |
|
clone.size = 0; |
| 823 |
|
clone.modCount = 0; |
| 824 |
|
|
| 825 |
|
// Initialize clone with our elements |
| 826 |
< |
for (Entry e = header.next; e != header; e = e.next) |
| 826 |
> |
for (Entry<E> e = header.next; e != header; e = e.next) |
| 827 |
|
clone.add(e.element); |
| 828 |
|
|
| 829 |
|
return clone; |
| 834 |
|
* in the correct order. |
| 835 |
|
* |
| 836 |
|
* @return an array containing all of the elements in this list |
| 837 |
< |
* in the correct order. |
| 837 |
> |
* in the correct order. |
| 838 |
|
*/ |
| 839 |
|
public Object[] toArray() { |
| 840 |
< |
Object[] result = new Object[size]; |
| 840 |
> |
Object[] result = new Object[size]; |
| 841 |
|
int i = 0; |
| 842 |
< |
for (Entry e = header.next; e != header; e = e.next) |
| 842 |
> |
for (Entry<E> e = header.next; e != header; e = e.next) |
| 843 |
|
result[i++] = e.element; |
| 844 |
< |
return result; |
| 844 |
> |
return result; |
| 845 |
|
} |
| 846 |
|
|
| 847 |
|
/** |
| 859 |
|
* does not contain any null elements. |
| 860 |
|
* |
| 861 |
|
* @param a the array into which the elements of the list are to |
| 862 |
< |
* be stored, if it is big enough; otherwise, a new array of the |
| 863 |
< |
* same runtime type is allocated for this purpose. |
| 862 |
> |
* be stored, if it is big enough; otherwise, a new array of the |
| 863 |
> |
* same runtime type is allocated for this purpose. |
| 864 |
|
* @return an array containing the elements of the list. |
| 865 |
|
* @throws ArrayStoreException if the runtime type of a is not a |
| 866 |
|
* supertype of the runtime type of every element in this list. |
| 867 |
|
* @throws NullPointerException if the specified array is null. |
| 868 |
|
*/ |
| 869 |
< |
public Object[] toArray(Object a[]) { |
| 869 |
> |
public <T> T[] toArray(T[] a) { |
| 870 |
|
if (a.length < size) |
| 871 |
< |
a = (Object[])java.lang.reflect.Array.newInstance( |
| 871 |
> |
a = (T[])java.lang.reflect.Array.newInstance( |
| 872 |
|
a.getClass().getComponentType(), size); |
| 873 |
|
int i = 0; |
| 874 |
< |
for (Entry e = header.next; e != header; e = e.next) |
| 875 |
< |
a[i++] = e.element; |
| 874 |
> |
Object[] result = a; |
| 875 |
> |
for (Entry<E> e = header.next; e != header; e = e.next) |
| 876 |
> |
result[i++] = e.element; |
| 877 |
|
|
| 878 |
|
if (a.length > size) |
| 879 |
|
a[size] = null; |
| 888 |
|
* is, serialize it). |
| 889 |
|
* |
| 890 |
|
* @serialData The size of the list (the number of elements it |
| 891 |
< |
* contains) is emitted (int), followed by all of its |
| 892 |
< |
* elements (each an Object) in the proper order. |
| 891 |
> |
* contains) is emitted (int), followed by all of its |
| 892 |
> |
* elements (each an Object) in the proper order. |
| 893 |
|
*/ |
| 894 |
< |
private synchronized void writeObject(java.io.ObjectOutputStream s) |
| 894 |
> |
private void writeObject(java.io.ObjectOutputStream s) |
| 895 |
|
throws java.io.IOException { |
| 896 |
< |
// Write out any hidden serialization magic |
| 897 |
< |
s.defaultWriteObject(); |
| 896 |
> |
// Write out any hidden serialization magic |
| 897 |
> |
s.defaultWriteObject(); |
| 898 |
|
|
| 899 |
|
// Write out size |
| 900 |
|
s.writeInt(size); |
| 901 |
|
|
| 902 |
< |
// Write out all elements in the proper order. |
| 902 |
> |
// Write out all elements in the proper order. |
| 903 |
|
for (Entry e = header.next; e != header; e = e.next) |
| 904 |
|
s.writeObject(e.element); |
| 905 |
|
} |
| 908 |
|
* Reconstitute this <tt>LinkedList</tt> instance from a stream (that is |
| 909 |
|
* deserialize it). |
| 910 |
|
*/ |
| 911 |
< |
private synchronized void readObject(java.io.ObjectInputStream s) |
| 911 |
> |
private void readObject(java.io.ObjectInputStream s) |
| 912 |
|
throws java.io.IOException, ClassNotFoundException { |
| 913 |
< |
// Read in any hidden serialization magic |
| 914 |
< |
s.defaultReadObject(); |
| 913 |
> |
// Read in any hidden serialization magic |
| 914 |
> |
s.defaultReadObject(); |
| 915 |
|
|
| 916 |
|
// Read in size |
| 917 |
|
int size = s.readInt(); |
| 918 |
|
|
| 919 |
|
// Initialize header |
| 920 |
< |
header = new Entry(null, null, null); |
| 920 |
> |
header = new Entry<E>(null, null, null); |
| 921 |
|
header.next = header.previous = header; |
| 922 |
|
|
| 923 |
< |
// Read in all elements in the proper order. |
| 924 |
< |
for (int i=0; i<size; i++) |
| 925 |
< |
add(s.readObject()); |
| 708 |
< |
} |
| 709 |
< |
|
| 710 |
< |
public Object peek() { |
| 711 |
< |
if (size==0) |
| 712 |
< |
return null; |
| 713 |
< |
return getFirst(); |
| 714 |
< |
} |
| 715 |
< |
|
| 716 |
< |
public Object element() { |
| 717 |
< |
return getFirst(); |
| 923 |
> |
// Read in all elements in the proper order. |
| 924 |
> |
for (int i=0; i<size; i++) |
| 925 |
> |
addBefore((E)s.readObject(), header); |
| 926 |
|
} |
| 719 |
– |
|
| 720 |
– |
public Object poll() { |
| 721 |
– |
if (size==0) |
| 722 |
– |
return null; |
| 723 |
– |
return removeFirst(); |
| 724 |
– |
} |
| 725 |
– |
|
| 726 |
– |
public Object remove() { |
| 727 |
– |
return removeFirst(); |
| 728 |
– |
} |
| 729 |
– |
|
| 730 |
– |
public boolean offer(Object x) { |
| 731 |
– |
return add(x); |
| 732 |
– |
} |
| 733 |
– |
|
| 927 |
|
} |
