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/*
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* Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package java.util;
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/**
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* Doubly-linked list implementation of the {@code List} and {@code Deque}
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* interfaces. Implements all optional list operations, and permits all
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* elements (including {@code null}).
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*
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* <p>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 beginning or the end, whichever is closer to the specified index.
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*
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* <p><strong>Note that this implementation is not synchronized.</strong>
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* If multiple threads access a linked list concurrently, and at least
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* one of the threads modifies the list structurally, it <i>must</i> be
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* synchronized externally. (A structural modification is any operation
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* that adds or deletes one or more elements; merely setting the value of
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* an element is not a structural modification.) This is typically
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* accomplished by synchronizing on some object that naturally
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* encapsulates the list.
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*
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* If no such object exists, the list should be "wrapped" using the
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* {@link Collections#synchronizedList Collections.synchronizedList}
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* method. This is best done at creation time, to prevent accidental
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* unsynchronized access to the list:<pre>
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* List list = Collections.synchronizedList(new LinkedList(...));</pre>
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*
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* <p>The iterators returned by this class's {@code iterator} and
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* {@code listIterator} 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
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* any way except through the Iterator's own {@code remove} or
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* {@code add} 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 {@code ConcurrentModificationException} on a best-effort basis.
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* Therefore, it would be wrong to write a program that depended on this
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* exception for its correctness: <i>the fail-fast behavior of iterators
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* should be used only to detect bugs.</i>
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*
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* <p>This class is a member of the
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* <a href="{@docRoot}/../technotes/guides/collections/index.html">
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* Java Collections Framework</a>.
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*
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* @author Josh Bloch
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* @see List
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* @see ArrayList
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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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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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transient int size = 0;
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/**
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* Pointer to first node.
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* Invariant: (first == null && last == null) ||
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* (first.prev == null && first.item != null)
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*/
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transient Node<E> first;
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/**
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* Pointer to last node.
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* Invariant: (first == null && last == null) ||
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* (last.next == null && last.item != null)
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*/
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transient Node<E> last;
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/**
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* Constructs an empty list.
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*/
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public LinkedList() {
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}
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/**
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* Constructs a list containing the elements of the specified
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* collection, in the order they are returned by the collection's
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* iterator.
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*
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* @param c the collection whose elements are to be placed into this list
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* @throws NullPointerException if the specified collection is null
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*/
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public 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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* Links e as first element.
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*/
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private void linkFirst(E e) {
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final Node<E> f = first;
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final Node<E> newNode = new Node<>(null, e, f);
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first = newNode;
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if (f == null)
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last = newNode;
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else
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f.prev = newNode;
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size++;
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modCount++;
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}
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/**
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* Links e as last element.
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*/
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void linkLast(E e) {
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final Node<E> l = last;
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final Node<E> newNode = new Node<>(l, e, null);
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last = newNode;
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if (l == null)
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first = newNode;
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else
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l.next = newNode;
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size++;
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modCount++;
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}
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/**
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* Inserts element e before non-null Node succ.
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*/
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void linkBefore(E e, Node<E> succ) {
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// assert succ != null;
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final Node<E> pred = succ.prev;
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final Node<E> newNode = new Node<>(pred, e, succ);
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succ.prev = newNode;
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if (pred == null)
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first = newNode;
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else
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pred.next = newNode;
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size++;
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modCount++;
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}
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/**
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* Unlinks non-null first node f.
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*/
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private E unlinkFirst(Node<E> f) {
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// assert f == first && f != null;
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final E element = f.item;
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final Node<E> next = f.next;
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f.item = null;
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f.next = null; // help GC
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first = next;
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if (next == null)
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last = null;
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else
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next.prev = null;
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size--;
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modCount++;
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return element;
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}
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/**
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* Unlinks non-null last node l.
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*/
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private E unlinkLast(Node<E> l) {
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// assert l == last && l != null;
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final E element = l.item;
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final Node<E> prev = l.prev;
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l.item = null;
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l.prev = null; // help GC
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last = prev;
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if (prev == null)
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first = null;
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else
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prev.next = null;
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size--;
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modCount++;
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return element;
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}
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/**
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* Unlinks non-null node x.
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*/
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E unlink(Node<E> x) {
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// assert x != null;
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final E element = x.item;
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final Node<E> next = x.next;
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final Node<E> prev = x.prev;
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if (prev == null) {
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first = next;
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} else {
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prev.next = next;
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x.prev = null;
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}
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if (next == null) {
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last = prev;
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} else {
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next.prev = prev;
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x.next = null;
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}
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x.item = null;
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size--;
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modCount++;
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return element;
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}
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/**
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* Returns the first element in this list.
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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 E getFirst() {
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final Node<E> f = first;
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if (f == null)
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throw new NoSuchElementException();
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return f.item;
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}
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/**
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* Returns the last element in this list.
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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 E getLast() {
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final Node<E> l = last;
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if (l == null)
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throw new NoSuchElementException();
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return l.item;
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}
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/**
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* Removes and returns the first element from this list.
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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 E removeFirst() {
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final Node<E> f = first;
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if (f == null)
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throw new NoSuchElementException();
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return unlinkFirst(f);
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}
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/**
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* Removes and returns the last element from this list.
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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 E removeLast() {
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final Node<E> l = last;
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if (l == null)
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throw new NoSuchElementException();
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return unlinkLast(l);
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}
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/**
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* Inserts the specified element at the beginning of this list.
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*
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* @param e the element to add
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*/
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public void addFirst(E e) {
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linkFirst(e);
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}
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/**
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* Appends the specified element to the end of this list.
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*
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* <p>This method is equivalent to {@link #add}.
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*
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* @param e the element to add
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*/
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public void addLast(E e) {
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linkLast(e);
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}
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/**
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* Returns {@code true} if this list contains the specified element.
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* More formally, returns {@code true} if and only if this list contains
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* at least one element {@code e} such that
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* <tt>(o==null ? e==null : o.equals(e))</tt>.
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*
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* @param o element whose presence in this list is to be tested
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* @return {@code true} if this list contains the specified element
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*/
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public boolean contains(Object o) {
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return indexOf(o) != -1;
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}
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/**
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* Returns the number of elements in this list.
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*
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* @return the number of elements in this list
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*/
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jaroslav@597
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public int size() {
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return size;
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jaroslav@597
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}
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jaroslav@597
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jaroslav@597
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/**
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* Appends the specified element to the end of this list.
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*
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jaroslav@597
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* <p>This method is equivalent to {@link #addLast}.
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*
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jaroslav@597
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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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*/
|
jaroslav@597
|
335 |
public boolean add(E e) {
|
jaroslav@597
|
336 |
linkLast(e);
|
jaroslav@597
|
337 |
return true;
|
jaroslav@597
|
338 |
}
|
jaroslav@597
|
339 |
|
jaroslav@597
|
340 |
/**
|
jaroslav@597
|
341 |
* Removes the first occurrence of the specified element from this list,
|
jaroslav@597
|
342 |
* if it is present. If this list does not contain the element, it is
|
jaroslav@597
|
343 |
* unchanged. More formally, removes the element with the lowest index
|
jaroslav@597
|
344 |
* {@code i} such that
|
jaroslav@597
|
345 |
* <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>
|
jaroslav@597
|
346 |
* (if such an element exists). Returns {@code true} if this list
|
jaroslav@597
|
347 |
* contained the specified element (or equivalently, if this list
|
jaroslav@597
|
348 |
* changed as a result of the call).
|
jaroslav@597
|
349 |
*
|
jaroslav@597
|
350 |
* @param o element to be removed from this list, if present
|
jaroslav@597
|
351 |
* @return {@code true} if this list contained the specified element
|
jaroslav@597
|
352 |
*/
|
jaroslav@597
|
353 |
public boolean remove(Object o) {
|
jaroslav@597
|
354 |
if (o == null) {
|
jaroslav@597
|
355 |
for (Node<E> x = first; x != null; x = x.next) {
|
jaroslav@597
|
356 |
if (x.item == null) {
|
jaroslav@597
|
357 |
unlink(x);
|
jaroslav@597
|
358 |
return true;
|
jaroslav@597
|
359 |
}
|
jaroslav@597
|
360 |
}
|
jaroslav@597
|
361 |
} else {
|
jaroslav@597
|
362 |
for (Node<E> x = first; x != null; x = x.next) {
|
jaroslav@597
|
363 |
if (o.equals(x.item)) {
|
jaroslav@597
|
364 |
unlink(x);
|
jaroslav@597
|
365 |
return true;
|
jaroslav@597
|
366 |
}
|
jaroslav@597
|
367 |
}
|
jaroslav@597
|
368 |
}
|
jaroslav@597
|
369 |
return false;
|
jaroslav@597
|
370 |
}
|
jaroslav@597
|
371 |
|
jaroslav@597
|
372 |
/**
|
jaroslav@597
|
373 |
* Appends all of the elements in the specified collection to the end of
|
jaroslav@597
|
374 |
* this list, in the order that they are returned by the specified
|
jaroslav@597
|
375 |
* collection's iterator. The behavior of this operation is undefined if
|
jaroslav@597
|
376 |
* the specified collection is modified while the operation is in
|
jaroslav@597
|
377 |
* progress. (Note that this will occur if the specified collection is
|
jaroslav@597
|
378 |
* this list, and it's nonempty.)
|
jaroslav@597
|
379 |
*
|
jaroslav@597
|
380 |
* @param c collection containing elements to be added to this list
|
jaroslav@597
|
381 |
* @return {@code true} if this list changed as a result of the call
|
jaroslav@597
|
382 |
* @throws NullPointerException if the specified collection is null
|
jaroslav@597
|
383 |
*/
|
jaroslav@597
|
384 |
public boolean addAll(Collection<? extends E> c) {
|
jaroslav@597
|
385 |
return addAll(size, c);
|
jaroslav@597
|
386 |
}
|
jaroslav@597
|
387 |
|
jaroslav@597
|
388 |
/**
|
jaroslav@597
|
389 |
* Inserts all of the elements in the specified collection into this
|
jaroslav@597
|
390 |
* list, starting at the specified position. Shifts the element
|
jaroslav@597
|
391 |
* currently at that position (if any) and any subsequent elements to
|
jaroslav@597
|
392 |
* the right (increases their indices). The new elements will appear
|
jaroslav@597
|
393 |
* in the list in the order that they are returned by the
|
jaroslav@597
|
394 |
* specified collection's iterator.
|
jaroslav@597
|
395 |
*
|
jaroslav@597
|
396 |
* @param index index at which to insert the first element
|
jaroslav@597
|
397 |
* from the specified collection
|
jaroslav@597
|
398 |
* @param c collection containing elements to be added to this list
|
jaroslav@597
|
399 |
* @return {@code true} if this list changed as a result of the call
|
jaroslav@597
|
400 |
* @throws IndexOutOfBoundsException {@inheritDoc}
|
jaroslav@597
|
401 |
* @throws NullPointerException if the specified collection is null
|
jaroslav@597
|
402 |
*/
|
jaroslav@597
|
403 |
public boolean addAll(int index, Collection<? extends E> c) {
|
jaroslav@597
|
404 |
checkPositionIndex(index);
|
jaroslav@597
|
405 |
|
jaroslav@597
|
406 |
Object[] a = c.toArray();
|
jaroslav@597
|
407 |
int numNew = a.length;
|
jaroslav@597
|
408 |
if (numNew == 0)
|
jaroslav@597
|
409 |
return false;
|
jaroslav@597
|
410 |
|
jaroslav@597
|
411 |
Node<E> pred, succ;
|
jaroslav@597
|
412 |
if (index == size) {
|
jaroslav@597
|
413 |
succ = null;
|
jaroslav@597
|
414 |
pred = last;
|
jaroslav@597
|
415 |
} else {
|
jaroslav@597
|
416 |
succ = node(index);
|
jaroslav@597
|
417 |
pred = succ.prev;
|
jaroslav@597
|
418 |
}
|
jaroslav@597
|
419 |
|
jaroslav@597
|
420 |
for (Object o : a) {
|
jaroslav@597
|
421 |
@SuppressWarnings("unchecked") E e = (E) o;
|
jaroslav@597
|
422 |
Node<E> newNode = new Node<>(pred, e, null);
|
jaroslav@597
|
423 |
if (pred == null)
|
jaroslav@597
|
424 |
first = newNode;
|
jaroslav@597
|
425 |
else
|
jaroslav@597
|
426 |
pred.next = newNode;
|
jaroslav@597
|
427 |
pred = newNode;
|
jaroslav@597
|
428 |
}
|
jaroslav@597
|
429 |
|
jaroslav@597
|
430 |
if (succ == null) {
|
jaroslav@597
|
431 |
last = pred;
|
jaroslav@597
|
432 |
} else {
|
jaroslav@597
|
433 |
pred.next = succ;
|
jaroslav@597
|
434 |
succ.prev = pred;
|
jaroslav@597
|
435 |
}
|
jaroslav@597
|
436 |
|
jaroslav@597
|
437 |
size += numNew;
|
jaroslav@597
|
438 |
modCount++;
|
jaroslav@597
|
439 |
return true;
|
jaroslav@597
|
440 |
}
|
jaroslav@597
|
441 |
|
jaroslav@597
|
442 |
/**
|
jaroslav@597
|
443 |
* Removes all of the elements from this list.
|
jaroslav@597
|
444 |
* The list will be empty after this call returns.
|
jaroslav@597
|
445 |
*/
|
jaroslav@597
|
446 |
public void clear() {
|
jaroslav@597
|
447 |
// Clearing all of the links between nodes is "unnecessary", but:
|
jaroslav@597
|
448 |
// - helps a generational GC if the discarded nodes inhabit
|
jaroslav@597
|
449 |
// more than one generation
|
jaroslav@597
|
450 |
// - is sure to free memory even if there is a reachable Iterator
|
jaroslav@597
|
451 |
for (Node<E> x = first; x != null; ) {
|
jaroslav@597
|
452 |
Node<E> next = x.next;
|
jaroslav@597
|
453 |
x.item = null;
|
jaroslav@597
|
454 |
x.next = null;
|
jaroslav@597
|
455 |
x.prev = null;
|
jaroslav@597
|
456 |
x = next;
|
jaroslav@597
|
457 |
}
|
jaroslav@597
|
458 |
first = last = null;
|
jaroslav@597
|
459 |
size = 0;
|
jaroslav@597
|
460 |
modCount++;
|
jaroslav@597
|
461 |
}
|
jaroslav@597
|
462 |
|
jaroslav@597
|
463 |
|
jaroslav@597
|
464 |
// Positional Access Operations
|
jaroslav@597
|
465 |
|
jaroslav@597
|
466 |
/**
|
jaroslav@597
|
467 |
* Returns the element at the specified position in this list.
|
jaroslav@597
|
468 |
*
|
jaroslav@597
|
469 |
* @param index index of the element to return
|
jaroslav@597
|
470 |
* @return the element at the specified position in this list
|
jaroslav@597
|
471 |
* @throws IndexOutOfBoundsException {@inheritDoc}
|
jaroslav@597
|
472 |
*/
|
jaroslav@597
|
473 |
public E get(int index) {
|
jaroslav@597
|
474 |
checkElementIndex(index);
|
jaroslav@597
|
475 |
return node(index).item;
|
jaroslav@597
|
476 |
}
|
jaroslav@597
|
477 |
|
jaroslav@597
|
478 |
/**
|
jaroslav@597
|
479 |
* Replaces the element at the specified position in this list with the
|
jaroslav@597
|
480 |
* specified element.
|
jaroslav@597
|
481 |
*
|
jaroslav@597
|
482 |
* @param index index of the element to replace
|
jaroslav@597
|
483 |
* @param element element to be stored at the specified position
|
jaroslav@597
|
484 |
* @return the element previously at the specified position
|
jaroslav@597
|
485 |
* @throws IndexOutOfBoundsException {@inheritDoc}
|
jaroslav@597
|
486 |
*/
|
jaroslav@597
|
487 |
public E set(int index, E element) {
|
jaroslav@597
|
488 |
checkElementIndex(index);
|
jaroslav@597
|
489 |
Node<E> x = node(index);
|
jaroslav@597
|
490 |
E oldVal = x.item;
|
jaroslav@597
|
491 |
x.item = element;
|
jaroslav@597
|
492 |
return oldVal;
|
jaroslav@597
|
493 |
}
|
jaroslav@597
|
494 |
|
jaroslav@597
|
495 |
/**
|
jaroslav@597
|
496 |
* Inserts the specified element at the specified position in this list.
|
jaroslav@597
|
497 |
* Shifts the element currently at that position (if any) and any
|
jaroslav@597
|
498 |
* subsequent elements to the right (adds one to their indices).
|
jaroslav@597
|
499 |
*
|
jaroslav@597
|
500 |
* @param index index at which the specified element is to be inserted
|
jaroslav@597
|
501 |
* @param element element to be inserted
|
jaroslav@597
|
502 |
* @throws IndexOutOfBoundsException {@inheritDoc}
|
jaroslav@597
|
503 |
*/
|
jaroslav@597
|
504 |
public void add(int index, E element) {
|
jaroslav@597
|
505 |
checkPositionIndex(index);
|
jaroslav@597
|
506 |
|
jaroslav@597
|
507 |
if (index == size)
|
jaroslav@597
|
508 |
linkLast(element);
|
jaroslav@597
|
509 |
else
|
jaroslav@597
|
510 |
linkBefore(element, node(index));
|
jaroslav@597
|
511 |
}
|
jaroslav@597
|
512 |
|
jaroslav@597
|
513 |
/**
|
jaroslav@597
|
514 |
* Removes the element at the specified position in this list. Shifts any
|
jaroslav@597
|
515 |
* subsequent elements to the left (subtracts one from their indices).
|
jaroslav@597
|
516 |
* Returns the element that was removed from the list.
|
jaroslav@597
|
517 |
*
|
jaroslav@597
|
518 |
* @param index the index of the element to be removed
|
jaroslav@597
|
519 |
* @return the element previously at the specified position
|
jaroslav@597
|
520 |
* @throws IndexOutOfBoundsException {@inheritDoc}
|
jaroslav@597
|
521 |
*/
|
jaroslav@597
|
522 |
public E remove(int index) {
|
jaroslav@597
|
523 |
checkElementIndex(index);
|
jaroslav@597
|
524 |
return unlink(node(index));
|
jaroslav@597
|
525 |
}
|
jaroslav@597
|
526 |
|
jaroslav@597
|
527 |
/**
|
jaroslav@597
|
528 |
* Tells if the argument is the index of an existing element.
|
jaroslav@597
|
529 |
*/
|
jaroslav@597
|
530 |
private boolean isElementIndex(int index) {
|
jaroslav@597
|
531 |
return index >= 0 && index < size;
|
jaroslav@597
|
532 |
}
|
jaroslav@597
|
533 |
|
jaroslav@597
|
534 |
/**
|
jaroslav@597
|
535 |
* Tells if the argument is the index of a valid position for an
|
jaroslav@597
|
536 |
* iterator or an add operation.
|
jaroslav@597
|
537 |
*/
|
jaroslav@597
|
538 |
private boolean isPositionIndex(int index) {
|
jaroslav@597
|
539 |
return index >= 0 && index <= size;
|
jaroslav@597
|
540 |
}
|
jaroslav@597
|
541 |
|
jaroslav@597
|
542 |
/**
|
jaroslav@597
|
543 |
* Constructs an IndexOutOfBoundsException detail message.
|
jaroslav@597
|
544 |
* Of the many possible refactorings of the error handling code,
|
jaroslav@597
|
545 |
* this "outlining" performs best with both server and client VMs.
|
jaroslav@597
|
546 |
*/
|
jaroslav@597
|
547 |
private String outOfBoundsMsg(int index) {
|
jaroslav@597
|
548 |
return "Index: "+index+", Size: "+size;
|
jaroslav@597
|
549 |
}
|
jaroslav@597
|
550 |
|
jaroslav@597
|
551 |
private void checkElementIndex(int index) {
|
jaroslav@597
|
552 |
if (!isElementIndex(index))
|
jaroslav@597
|
553 |
throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
|
jaroslav@597
|
554 |
}
|
jaroslav@597
|
555 |
|
jaroslav@597
|
556 |
private void checkPositionIndex(int index) {
|
jaroslav@597
|
557 |
if (!isPositionIndex(index))
|
jaroslav@597
|
558 |
throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
|
jaroslav@597
|
559 |
}
|
jaroslav@597
|
560 |
|
jaroslav@597
|
561 |
/**
|
jaroslav@597
|
562 |
* Returns the (non-null) Node at the specified element index.
|
jaroslav@597
|
563 |
*/
|
jaroslav@597
|
564 |
Node<E> node(int index) {
|
jaroslav@597
|
565 |
// assert isElementIndex(index);
|
jaroslav@597
|
566 |
|
jaroslav@597
|
567 |
if (index < (size >> 1)) {
|
jaroslav@597
|
568 |
Node<E> x = first;
|
jaroslav@597
|
569 |
for (int i = 0; i < index; i++)
|
jaroslav@597
|
570 |
x = x.next;
|
jaroslav@597
|
571 |
return x;
|
jaroslav@597
|
572 |
} else {
|
jaroslav@597
|
573 |
Node<E> x = last;
|
jaroslav@597
|
574 |
for (int i = size - 1; i > index; i--)
|
jaroslav@597
|
575 |
x = x.prev;
|
jaroslav@597
|
576 |
return x;
|
jaroslav@597
|
577 |
}
|
jaroslav@597
|
578 |
}
|
jaroslav@597
|
579 |
|
jaroslav@597
|
580 |
// Search Operations
|
jaroslav@597
|
581 |
|
jaroslav@597
|
582 |
/**
|
jaroslav@597
|
583 |
* Returns the index of the first occurrence of the specified element
|
jaroslav@597
|
584 |
* in this list, or -1 if this list does not contain the element.
|
jaroslav@597
|
585 |
* More formally, returns the lowest index {@code i} such that
|
jaroslav@597
|
586 |
* <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>,
|
jaroslav@597
|
587 |
* or -1 if there is no such index.
|
jaroslav@597
|
588 |
*
|
jaroslav@597
|
589 |
* @param o element to search for
|
jaroslav@597
|
590 |
* @return the index of the first occurrence of the specified element in
|
jaroslav@597
|
591 |
* this list, or -1 if this list does not contain the element
|
jaroslav@597
|
592 |
*/
|
jaroslav@597
|
593 |
public int indexOf(Object o) {
|
jaroslav@597
|
594 |
int index = 0;
|
jaroslav@597
|
595 |
if (o == null) {
|
jaroslav@597
|
596 |
for (Node<E> x = first; x != null; x = x.next) {
|
jaroslav@597
|
597 |
if (x.item == null)
|
jaroslav@597
|
598 |
return index;
|
jaroslav@597
|
599 |
index++;
|
jaroslav@597
|
600 |
}
|
jaroslav@597
|
601 |
} else {
|
jaroslav@597
|
602 |
for (Node<E> x = first; x != null; x = x.next) {
|
jaroslav@597
|
603 |
if (o.equals(x.item))
|
jaroslav@597
|
604 |
return index;
|
jaroslav@597
|
605 |
index++;
|
jaroslav@597
|
606 |
}
|
jaroslav@597
|
607 |
}
|
jaroslav@597
|
608 |
return -1;
|
jaroslav@597
|
609 |
}
|
jaroslav@597
|
610 |
|
jaroslav@597
|
611 |
/**
|
jaroslav@597
|
612 |
* Returns the index of the last occurrence of the specified element
|
jaroslav@597
|
613 |
* in this list, or -1 if this list does not contain the element.
|
jaroslav@597
|
614 |
* More formally, returns the highest index {@code i} such that
|
jaroslav@597
|
615 |
* <tt>(o==null ? get(i)==null : o.equals(get(i)))</tt>,
|
jaroslav@597
|
616 |
* or -1 if there is no such index.
|
jaroslav@597
|
617 |
*
|
jaroslav@597
|
618 |
* @param o element to search for
|
jaroslav@597
|
619 |
* @return the index of the last occurrence of the specified element in
|
jaroslav@597
|
620 |
* this list, or -1 if this list does not contain the element
|
jaroslav@597
|
621 |
*/
|
jaroslav@597
|
622 |
public int lastIndexOf(Object o) {
|
jaroslav@597
|
623 |
int index = size;
|
jaroslav@597
|
624 |
if (o == null) {
|
jaroslav@597
|
625 |
for (Node<E> x = last; x != null; x = x.prev) {
|
jaroslav@597
|
626 |
index--;
|
jaroslav@597
|
627 |
if (x.item == null)
|
jaroslav@597
|
628 |
return index;
|
jaroslav@597
|
629 |
}
|
jaroslav@597
|
630 |
} else {
|
jaroslav@597
|
631 |
for (Node<E> x = last; x != null; x = x.prev) {
|
jaroslav@597
|
632 |
index--;
|
jaroslav@597
|
633 |
if (o.equals(x.item))
|
jaroslav@597
|
634 |
return index;
|
jaroslav@597
|
635 |
}
|
jaroslav@597
|
636 |
}
|
jaroslav@597
|
637 |
return -1;
|
jaroslav@597
|
638 |
}
|
jaroslav@597
|
639 |
|
jaroslav@597
|
640 |
// Queue operations.
|
jaroslav@597
|
641 |
|
jaroslav@597
|
642 |
/**
|
jaroslav@597
|
643 |
* Retrieves, but does not remove, the head (first element) of this list.
|
jaroslav@597
|
644 |
*
|
jaroslav@597
|
645 |
* @return the head of this list, or {@code null} if this list is empty
|
jaroslav@597
|
646 |
* @since 1.5
|
jaroslav@597
|
647 |
*/
|
jaroslav@597
|
648 |
public E peek() {
|
jaroslav@597
|
649 |
final Node<E> f = first;
|
jaroslav@597
|
650 |
return (f == null) ? null : f.item;
|
jaroslav@597
|
651 |
}
|
jaroslav@597
|
652 |
|
jaroslav@597
|
653 |
/**
|
jaroslav@597
|
654 |
* Retrieves, but does not remove, the head (first element) of this list.
|
jaroslav@597
|
655 |
*
|
jaroslav@597
|
656 |
* @return the head of this list
|
jaroslav@597
|
657 |
* @throws NoSuchElementException if this list is empty
|
jaroslav@597
|
658 |
* @since 1.5
|
jaroslav@597
|
659 |
*/
|
jaroslav@597
|
660 |
public E element() {
|
jaroslav@597
|
661 |
return getFirst();
|
jaroslav@597
|
662 |
}
|
jaroslav@597
|
663 |
|
jaroslav@597
|
664 |
/**
|
jaroslav@597
|
665 |
* Retrieves and removes the head (first element) of this list.
|
jaroslav@597
|
666 |
*
|
jaroslav@597
|
667 |
* @return the head of this list, or {@code null} if this list is empty
|
jaroslav@597
|
668 |
* @since 1.5
|
jaroslav@597
|
669 |
*/
|
jaroslav@597
|
670 |
public E poll() {
|
jaroslav@597
|
671 |
final Node<E> f = first;
|
jaroslav@597
|
672 |
return (f == null) ? null : unlinkFirst(f);
|
jaroslav@597
|
673 |
}
|
jaroslav@597
|
674 |
|
jaroslav@597
|
675 |
/**
|
jaroslav@597
|
676 |
* Retrieves and removes the head (first element) of this list.
|
jaroslav@597
|
677 |
*
|
jaroslav@597
|
678 |
* @return the head of this list
|
jaroslav@597
|
679 |
* @throws NoSuchElementException if this list is empty
|
jaroslav@597
|
680 |
* @since 1.5
|
jaroslav@597
|
681 |
*/
|
jaroslav@597
|
682 |
public E remove() {
|
jaroslav@597
|
683 |
return removeFirst();
|
jaroslav@597
|
684 |
}
|
jaroslav@597
|
685 |
|
jaroslav@597
|
686 |
/**
|
jaroslav@597
|
687 |
* Adds the specified element as the tail (last element) of this list.
|
jaroslav@597
|
688 |
*
|
jaroslav@597
|
689 |
* @param e the element to add
|
jaroslav@597
|
690 |
* @return {@code true} (as specified by {@link Queue#offer})
|
jaroslav@597
|
691 |
* @since 1.5
|
jaroslav@597
|
692 |
*/
|
jaroslav@597
|
693 |
public boolean offer(E e) {
|
jaroslav@597
|
694 |
return add(e);
|
jaroslav@597
|
695 |
}
|
jaroslav@597
|
696 |
|
jaroslav@597
|
697 |
// Deque operations
|
jaroslav@597
|
698 |
/**
|
jaroslav@597
|
699 |
* Inserts the specified element at the front of this list.
|
jaroslav@597
|
700 |
*
|
jaroslav@597
|
701 |
* @param e the element to insert
|
jaroslav@597
|
702 |
* @return {@code true} (as specified by {@link Deque#offerFirst})
|
jaroslav@597
|
703 |
* @since 1.6
|
jaroslav@597
|
704 |
*/
|
jaroslav@597
|
705 |
public boolean offerFirst(E e) {
|
jaroslav@597
|
706 |
addFirst(e);
|
jaroslav@597
|
707 |
return true;
|
jaroslav@597
|
708 |
}
|
jaroslav@597
|
709 |
|
jaroslav@597
|
710 |
/**
|
jaroslav@597
|
711 |
* Inserts the specified element at the end of this list.
|
jaroslav@597
|
712 |
*
|
jaroslav@597
|
713 |
* @param e the element to insert
|
jaroslav@597
|
714 |
* @return {@code true} (as specified by {@link Deque#offerLast})
|
jaroslav@597
|
715 |
* @since 1.6
|
jaroslav@597
|
716 |
*/
|
jaroslav@597
|
717 |
public boolean offerLast(E e) {
|
jaroslav@597
|
718 |
addLast(e);
|
jaroslav@597
|
719 |
return true;
|
jaroslav@597
|
720 |
}
|
jaroslav@597
|
721 |
|
jaroslav@597
|
722 |
/**
|
jaroslav@597
|
723 |
* Retrieves, but does not remove, the first element of this list,
|
jaroslav@597
|
724 |
* or returns {@code null} if this list is empty.
|
jaroslav@597
|
725 |
*
|
jaroslav@597
|
726 |
* @return the first element of this list, or {@code null}
|
jaroslav@597
|
727 |
* if this list is empty
|
jaroslav@597
|
728 |
* @since 1.6
|
jaroslav@597
|
729 |
*/
|
jaroslav@597
|
730 |
public E peekFirst() {
|
jaroslav@597
|
731 |
final Node<E> f = first;
|
jaroslav@597
|
732 |
return (f == null) ? null : f.item;
|
jaroslav@597
|
733 |
}
|
jaroslav@597
|
734 |
|
jaroslav@597
|
735 |
/**
|
jaroslav@597
|
736 |
* Retrieves, but does not remove, the last element of this list,
|
jaroslav@597
|
737 |
* or returns {@code null} if this list is empty.
|
jaroslav@597
|
738 |
*
|
jaroslav@597
|
739 |
* @return the last element of this list, or {@code null}
|
jaroslav@597
|
740 |
* if this list is empty
|
jaroslav@597
|
741 |
* @since 1.6
|
jaroslav@597
|
742 |
*/
|
jaroslav@597
|
743 |
public E peekLast() {
|
jaroslav@597
|
744 |
final Node<E> l = last;
|
jaroslav@597
|
745 |
return (l == null) ? null : l.item;
|
jaroslav@597
|
746 |
}
|
jaroslav@597
|
747 |
|
jaroslav@597
|
748 |
/**
|
jaroslav@597
|
749 |
* Retrieves and removes the first element of this list,
|
jaroslav@597
|
750 |
* or returns {@code null} if this list is empty.
|
jaroslav@597
|
751 |
*
|
jaroslav@597
|
752 |
* @return the first element of this list, or {@code null} if
|
jaroslav@597
|
753 |
* this list is empty
|
jaroslav@597
|
754 |
* @since 1.6
|
jaroslav@597
|
755 |
*/
|
jaroslav@597
|
756 |
public E pollFirst() {
|
jaroslav@597
|
757 |
final Node<E> f = first;
|
jaroslav@597
|
758 |
return (f == null) ? null : unlinkFirst(f);
|
jaroslav@597
|
759 |
}
|
jaroslav@597
|
760 |
|
jaroslav@597
|
761 |
/**
|
jaroslav@597
|
762 |
* Retrieves and removes the last element of this list,
|
jaroslav@597
|
763 |
* or returns {@code null} if this list is empty.
|
jaroslav@597
|
764 |
*
|
jaroslav@597
|
765 |
* @return the last element of this list, or {@code null} if
|
jaroslav@597
|
766 |
* this list is empty
|
jaroslav@597
|
767 |
* @since 1.6
|
jaroslav@597
|
768 |
*/
|
jaroslav@597
|
769 |
public E pollLast() {
|
jaroslav@597
|
770 |
final Node<E> l = last;
|
jaroslav@597
|
771 |
return (l == null) ? null : unlinkLast(l);
|
jaroslav@597
|
772 |
}
|
jaroslav@597
|
773 |
|
jaroslav@597
|
774 |
/**
|
jaroslav@597
|
775 |
* Pushes an element onto the stack represented by this list. In other
|
jaroslav@597
|
776 |
* words, inserts the element at the front of this list.
|
jaroslav@597
|
777 |
*
|
jaroslav@597
|
778 |
* <p>This method is equivalent to {@link #addFirst}.
|
jaroslav@597
|
779 |
*
|
jaroslav@597
|
780 |
* @param e the element to push
|
jaroslav@597
|
781 |
* @since 1.6
|
jaroslav@597
|
782 |
*/
|
jaroslav@597
|
783 |
public void push(E e) {
|
jaroslav@597
|
784 |
addFirst(e);
|
jaroslav@597
|
785 |
}
|
jaroslav@597
|
786 |
|
jaroslav@597
|
787 |
/**
|
jaroslav@597
|
788 |
* Pops an element from the stack represented by this list. In other
|
jaroslav@597
|
789 |
* words, removes and returns the first element of this list.
|
jaroslav@597
|
790 |
*
|
jaroslav@597
|
791 |
* <p>This method is equivalent to {@link #removeFirst()}.
|
jaroslav@597
|
792 |
*
|
jaroslav@597
|
793 |
* @return the element at the front of this list (which is the top
|
jaroslav@597
|
794 |
* of the stack represented by this list)
|
jaroslav@597
|
795 |
* @throws NoSuchElementException if this list is empty
|
jaroslav@597
|
796 |
* @since 1.6
|
jaroslav@597
|
797 |
*/
|
jaroslav@597
|
798 |
public E pop() {
|
jaroslav@597
|
799 |
return removeFirst();
|
jaroslav@597
|
800 |
}
|
jaroslav@597
|
801 |
|
jaroslav@597
|
802 |
/**
|
jaroslav@597
|
803 |
* Removes the first occurrence of the specified element in this
|
jaroslav@597
|
804 |
* list (when traversing the list from head to tail). If the list
|
jaroslav@597
|
805 |
* does not contain the element, it is unchanged.
|
jaroslav@597
|
806 |
*
|
jaroslav@597
|
807 |
* @param o element to be removed from this list, if present
|
jaroslav@597
|
808 |
* @return {@code true} if the list contained the specified element
|
jaroslav@597
|
809 |
* @since 1.6
|
jaroslav@597
|
810 |
*/
|
jaroslav@597
|
811 |
public boolean removeFirstOccurrence(Object o) {
|
jaroslav@597
|
812 |
return remove(o);
|
jaroslav@597
|
813 |
}
|
jaroslav@597
|
814 |
|
jaroslav@597
|
815 |
/**
|
jaroslav@597
|
816 |
* Removes the last occurrence of the specified element in this
|
jaroslav@597
|
817 |
* list (when traversing the list from head to tail). If the list
|
jaroslav@597
|
818 |
* does not contain the element, it is unchanged.
|
jaroslav@597
|
819 |
*
|
jaroslav@597
|
820 |
* @param o element to be removed from this list, if present
|
jaroslav@597
|
821 |
* @return {@code true} if the list contained the specified element
|
jaroslav@597
|
822 |
* @since 1.6
|
jaroslav@597
|
823 |
*/
|
jaroslav@597
|
824 |
public boolean removeLastOccurrence(Object o) {
|
jaroslav@597
|
825 |
if (o == null) {
|
jaroslav@597
|
826 |
for (Node<E> x = last; x != null; x = x.prev) {
|
jaroslav@597
|
827 |
if (x.item == null) {
|
jaroslav@597
|
828 |
unlink(x);
|
jaroslav@597
|
829 |
return true;
|
jaroslav@597
|
830 |
}
|
jaroslav@597
|
831 |
}
|
jaroslav@597
|
832 |
} else {
|
jaroslav@597
|
833 |
for (Node<E> x = last; x != null; x = x.prev) {
|
jaroslav@597
|
834 |
if (o.equals(x.item)) {
|
jaroslav@597
|
835 |
unlink(x);
|
jaroslav@597
|
836 |
return true;
|
jaroslav@597
|
837 |
}
|
jaroslav@597
|
838 |
}
|
jaroslav@597
|
839 |
}
|
jaroslav@597
|
840 |
return false;
|
jaroslav@597
|
841 |
}
|
jaroslav@597
|
842 |
|
jaroslav@597
|
843 |
/**
|
jaroslav@597
|
844 |
* Returns a list-iterator of the elements in this list (in proper
|
jaroslav@597
|
845 |
* sequence), starting at the specified position in the list.
|
jaroslav@597
|
846 |
* Obeys the general contract of {@code List.listIterator(int)}.<p>
|
jaroslav@597
|
847 |
*
|
jaroslav@597
|
848 |
* The list-iterator is <i>fail-fast</i>: if the list is structurally
|
jaroslav@597
|
849 |
* modified at any time after the Iterator is created, in any way except
|
jaroslav@597
|
850 |
* through the list-iterator's own {@code remove} or {@code add}
|
jaroslav@597
|
851 |
* methods, the list-iterator will throw a
|
jaroslav@597
|
852 |
* {@code ConcurrentModificationException}. Thus, in the face of
|
jaroslav@597
|
853 |
* concurrent modification, the iterator fails quickly and cleanly, rather
|
jaroslav@597
|
854 |
* than risking arbitrary, non-deterministic behavior at an undetermined
|
jaroslav@597
|
855 |
* time in the future.
|
jaroslav@597
|
856 |
*
|
jaroslav@597
|
857 |
* @param index index of the first element to be returned from the
|
jaroslav@597
|
858 |
* list-iterator (by a call to {@code next})
|
jaroslav@597
|
859 |
* @return a ListIterator of the elements in this list (in proper
|
jaroslav@597
|
860 |
* sequence), starting at the specified position in the list
|
jaroslav@597
|
861 |
* @throws IndexOutOfBoundsException {@inheritDoc}
|
jaroslav@597
|
862 |
* @see List#listIterator(int)
|
jaroslav@597
|
863 |
*/
|
jaroslav@597
|
864 |
public ListIterator<E> listIterator(int index) {
|
jaroslav@597
|
865 |
checkPositionIndex(index);
|
jaroslav@597
|
866 |
return new ListItr(index);
|
jaroslav@597
|
867 |
}
|
jaroslav@597
|
868 |
|
jaroslav@597
|
869 |
private class ListItr implements ListIterator<E> {
|
jaroslav@597
|
870 |
private Node<E> lastReturned = null;
|
jaroslav@597
|
871 |
private Node<E> next;
|
jaroslav@597
|
872 |
private int nextIndex;
|
jaroslav@597
|
873 |
private int expectedModCount = modCount;
|
jaroslav@597
|
874 |
|
jaroslav@597
|
875 |
ListItr(int index) {
|
jaroslav@597
|
876 |
// assert isPositionIndex(index);
|
jaroslav@597
|
877 |
next = (index == size) ? null : node(index);
|
jaroslav@597
|
878 |
nextIndex = index;
|
jaroslav@597
|
879 |
}
|
jaroslav@597
|
880 |
|
jaroslav@597
|
881 |
public boolean hasNext() {
|
jaroslav@597
|
882 |
return nextIndex < size;
|
jaroslav@597
|
883 |
}
|
jaroslav@597
|
884 |
|
jaroslav@597
|
885 |
public E next() {
|
jaroslav@597
|
886 |
checkForComodification();
|
jaroslav@597
|
887 |
if (!hasNext())
|
jaroslav@597
|
888 |
throw new NoSuchElementException();
|
jaroslav@597
|
889 |
|
jaroslav@597
|
890 |
lastReturned = next;
|
jaroslav@597
|
891 |
next = next.next;
|
jaroslav@597
|
892 |
nextIndex++;
|
jaroslav@597
|
893 |
return lastReturned.item;
|
jaroslav@597
|
894 |
}
|
jaroslav@597
|
895 |
|
jaroslav@597
|
896 |
public boolean hasPrevious() {
|
jaroslav@597
|
897 |
return nextIndex > 0;
|
jaroslav@597
|
898 |
}
|
jaroslav@597
|
899 |
|
jaroslav@597
|
900 |
public E previous() {
|
jaroslav@597
|
901 |
checkForComodification();
|
jaroslav@597
|
902 |
if (!hasPrevious())
|
jaroslav@597
|
903 |
throw new NoSuchElementException();
|
jaroslav@597
|
904 |
|
jaroslav@597
|
905 |
lastReturned = next = (next == null) ? last : next.prev;
|
jaroslav@597
|
906 |
nextIndex--;
|
jaroslav@597
|
907 |
return lastReturned.item;
|
jaroslav@597
|
908 |
}
|
jaroslav@597
|
909 |
|
jaroslav@597
|
910 |
public int nextIndex() {
|
jaroslav@597
|
911 |
return nextIndex;
|
jaroslav@597
|
912 |
}
|
jaroslav@597
|
913 |
|
jaroslav@597
|
914 |
public int previousIndex() {
|
jaroslav@597
|
915 |
return nextIndex - 1;
|
jaroslav@597
|
916 |
}
|
jaroslav@597
|
917 |
|
jaroslav@597
|
918 |
public void remove() {
|
jaroslav@597
|
919 |
checkForComodification();
|
jaroslav@597
|
920 |
if (lastReturned == null)
|
jaroslav@597
|
921 |
throw new IllegalStateException();
|
jaroslav@597
|
922 |
|
jaroslav@597
|
923 |
Node<E> lastNext = lastReturned.next;
|
jaroslav@597
|
924 |
unlink(lastReturned);
|
jaroslav@597
|
925 |
if (next == lastReturned)
|
jaroslav@597
|
926 |
next = lastNext;
|
jaroslav@597
|
927 |
else
|
jaroslav@597
|
928 |
nextIndex--;
|
jaroslav@597
|
929 |
lastReturned = null;
|
jaroslav@597
|
930 |
expectedModCount++;
|
jaroslav@597
|
931 |
}
|
jaroslav@597
|
932 |
|
jaroslav@597
|
933 |
public void set(E e) {
|
jaroslav@597
|
934 |
if (lastReturned == null)
|
jaroslav@597
|
935 |
throw new IllegalStateException();
|
jaroslav@597
|
936 |
checkForComodification();
|
jaroslav@597
|
937 |
lastReturned.item = e;
|
jaroslav@597
|
938 |
}
|
jaroslav@597
|
939 |
|
jaroslav@597
|
940 |
public void add(E e) {
|
jaroslav@597
|
941 |
checkForComodification();
|
jaroslav@597
|
942 |
lastReturned = null;
|
jaroslav@597
|
943 |
if (next == null)
|
jaroslav@597
|
944 |
linkLast(e);
|
jaroslav@597
|
945 |
else
|
jaroslav@597
|
946 |
linkBefore(e, next);
|
jaroslav@597
|
947 |
nextIndex++;
|
jaroslav@597
|
948 |
expectedModCount++;
|
jaroslav@597
|
949 |
}
|
jaroslav@597
|
950 |
|
jaroslav@597
|
951 |
final void checkForComodification() {
|
jaroslav@597
|
952 |
if (modCount != expectedModCount)
|
jaroslav@597
|
953 |
throw new ConcurrentModificationException();
|
jaroslav@597
|
954 |
}
|
jaroslav@597
|
955 |
}
|
jaroslav@597
|
956 |
|
jaroslav@597
|
957 |
private static class Node<E> {
|
jaroslav@597
|
958 |
E item;
|
jaroslav@597
|
959 |
Node<E> next;
|
jaroslav@597
|
960 |
Node<E> prev;
|
jaroslav@597
|
961 |
|
jaroslav@597
|
962 |
Node(Node<E> prev, E element, Node<E> next) {
|
jaroslav@597
|
963 |
this.item = element;
|
jaroslav@597
|
964 |
this.next = next;
|
jaroslav@597
|
965 |
this.prev = prev;
|
jaroslav@597
|
966 |
}
|
jaroslav@597
|
967 |
}
|
jaroslav@597
|
968 |
|
jaroslav@597
|
969 |
/**
|
jaroslav@597
|
970 |
* @since 1.6
|
jaroslav@597
|
971 |
*/
|
jaroslav@597
|
972 |
public Iterator<E> descendingIterator() {
|
jaroslav@597
|
973 |
return new DescendingIterator();
|
jaroslav@597
|
974 |
}
|
jaroslav@597
|
975 |
|
jaroslav@597
|
976 |
/**
|
jaroslav@597
|
977 |
* Adapter to provide descending iterators via ListItr.previous
|
jaroslav@597
|
978 |
*/
|
jaroslav@597
|
979 |
private class DescendingIterator implements Iterator<E> {
|
jaroslav@597
|
980 |
private final ListItr itr = new ListItr(size());
|
jaroslav@597
|
981 |
public boolean hasNext() {
|
jaroslav@597
|
982 |
return itr.hasPrevious();
|
jaroslav@597
|
983 |
}
|
jaroslav@597
|
984 |
public E next() {
|
jaroslav@597
|
985 |
return itr.previous();
|
jaroslav@597
|
986 |
}
|
jaroslav@597
|
987 |
public void remove() {
|
jaroslav@597
|
988 |
itr.remove();
|
jaroslav@597
|
989 |
}
|
jaroslav@597
|
990 |
}
|
jaroslav@597
|
991 |
|
jaroslav@597
|
992 |
@SuppressWarnings("unchecked")
|
jaroslav@597
|
993 |
private LinkedList<E> superClone() {
|
jaroslav@597
|
994 |
try {
|
jaroslav@597
|
995 |
return (LinkedList<E>) super.clone();
|
jaroslav@597
|
996 |
} catch (CloneNotSupportedException e) {
|
jaroslav@597
|
997 |
throw new InternalError();
|
jaroslav@597
|
998 |
}
|
jaroslav@597
|
999 |
}
|
jaroslav@597
|
1000 |
|
jaroslav@597
|
1001 |
/**
|
jaroslav@597
|
1002 |
* Returns a shallow copy of this {@code LinkedList}. (The elements
|
jaroslav@597
|
1003 |
* themselves are not cloned.)
|
jaroslav@597
|
1004 |
*
|
jaroslav@597
|
1005 |
* @return a shallow copy of this {@code LinkedList} instance
|
jaroslav@597
|
1006 |
*/
|
jaroslav@597
|
1007 |
public Object clone() {
|
jaroslav@597
|
1008 |
LinkedList<E> clone = superClone();
|
jaroslav@597
|
1009 |
|
jaroslav@597
|
1010 |
// Put clone into "virgin" state
|
jaroslav@597
|
1011 |
clone.first = clone.last = null;
|
jaroslav@597
|
1012 |
clone.size = 0;
|
jaroslav@597
|
1013 |
clone.modCount = 0;
|
jaroslav@597
|
1014 |
|
jaroslav@597
|
1015 |
// Initialize clone with our elements
|
jaroslav@597
|
1016 |
for (Node<E> x = first; x != null; x = x.next)
|
jaroslav@597
|
1017 |
clone.add(x.item);
|
jaroslav@597
|
1018 |
|
jaroslav@597
|
1019 |
return clone;
|
jaroslav@597
|
1020 |
}
|
jaroslav@597
|
1021 |
|
jaroslav@597
|
1022 |
/**
|
jaroslav@597
|
1023 |
* Returns an array containing all of the elements in this list
|
jaroslav@597
|
1024 |
* in proper sequence (from first to last element).
|
jaroslav@597
|
1025 |
*
|
jaroslav@597
|
1026 |
* <p>The returned array will be "safe" in that no references to it are
|
jaroslav@597
|
1027 |
* maintained by this list. (In other words, this method must allocate
|
jaroslav@597
|
1028 |
* a new array). The caller is thus free to modify the returned array.
|
jaroslav@597
|
1029 |
*
|
jaroslav@597
|
1030 |
* <p>This method acts as bridge between array-based and collection-based
|
jaroslav@597
|
1031 |
* APIs.
|
jaroslav@597
|
1032 |
*
|
jaroslav@597
|
1033 |
* @return an array containing all of the elements in this list
|
jaroslav@597
|
1034 |
* in proper sequence
|
jaroslav@597
|
1035 |
*/
|
jaroslav@597
|
1036 |
public Object[] toArray() {
|
jaroslav@597
|
1037 |
Object[] result = new Object[size];
|
jaroslav@597
|
1038 |
int i = 0;
|
jaroslav@597
|
1039 |
for (Node<E> x = first; x != null; x = x.next)
|
jaroslav@597
|
1040 |
result[i++] = x.item;
|
jaroslav@597
|
1041 |
return result;
|
jaroslav@597
|
1042 |
}
|
jaroslav@597
|
1043 |
|
jaroslav@597
|
1044 |
/**
|
jaroslav@597
|
1045 |
* Returns an array containing all of the elements in this list in
|
jaroslav@597
|
1046 |
* proper sequence (from first to last element); the runtime type of
|
jaroslav@597
|
1047 |
* the returned array is that of the specified array. If the list fits
|
jaroslav@597
|
1048 |
* in the specified array, it is returned therein. Otherwise, a new
|
jaroslav@597
|
1049 |
* array is allocated with the runtime type of the specified array and
|
jaroslav@597
|
1050 |
* the size of this list.
|
jaroslav@597
|
1051 |
*
|
jaroslav@597
|
1052 |
* <p>If the list fits in the specified array with room to spare (i.e.,
|
jaroslav@597
|
1053 |
* the array has more elements than the list), the element in the array
|
jaroslav@597
|
1054 |
* immediately following the end of the list is set to {@code null}.
|
jaroslav@597
|
1055 |
* (This is useful in determining the length of the list <i>only</i> if
|
jaroslav@597
|
1056 |
* the caller knows that the list does not contain any null elements.)
|
jaroslav@597
|
1057 |
*
|
jaroslav@597
|
1058 |
* <p>Like the {@link #toArray()} method, this method acts as bridge between
|
jaroslav@597
|
1059 |
* array-based and collection-based APIs. Further, this method allows
|
jaroslav@597
|
1060 |
* precise control over the runtime type of the output array, and may,
|
jaroslav@597
|
1061 |
* under certain circumstances, be used to save allocation costs.
|
jaroslav@597
|
1062 |
*
|
jaroslav@597
|
1063 |
* <p>Suppose {@code x} is a list known to contain only strings.
|
jaroslav@597
|
1064 |
* The following code can be used to dump the list into a newly
|
jaroslav@597
|
1065 |
* allocated array of {@code String}:
|
jaroslav@597
|
1066 |
*
|
jaroslav@597
|
1067 |
* <pre>
|
jaroslav@597
|
1068 |
* String[] y = x.toArray(new String[0]);</pre>
|
jaroslav@597
|
1069 |
*
|
jaroslav@597
|
1070 |
* Note that {@code toArray(new Object[0])} is identical in function to
|
jaroslav@597
|
1071 |
* {@code toArray()}.
|
jaroslav@597
|
1072 |
*
|
jaroslav@597
|
1073 |
* @param a the array into which the elements of the list are to
|
jaroslav@597
|
1074 |
* be stored, if it is big enough; otherwise, a new array of the
|
jaroslav@597
|
1075 |
* same runtime type is allocated for this purpose.
|
jaroslav@597
|
1076 |
* @return an array containing the elements of the list
|
jaroslav@597
|
1077 |
* @throws ArrayStoreException if the runtime type of the specified array
|
jaroslav@597
|
1078 |
* is not a supertype of the runtime type of every element in
|
jaroslav@597
|
1079 |
* this list
|
jaroslav@597
|
1080 |
* @throws NullPointerException if the specified array is null
|
jaroslav@597
|
1081 |
*/
|
jaroslav@597
|
1082 |
@SuppressWarnings("unchecked")
|
jaroslav@597
|
1083 |
public <T> T[] toArray(T[] a) {
|
jaroslav@597
|
1084 |
if (a.length < size)
|
jaroslav@597
|
1085 |
a = (T[])java.lang.reflect.Array.newInstance(
|
jaroslav@597
|
1086 |
a.getClass().getComponentType(), size);
|
jaroslav@597
|
1087 |
int i = 0;
|
jaroslav@597
|
1088 |
Object[] result = a;
|
jaroslav@597
|
1089 |
for (Node<E> x = first; x != null; x = x.next)
|
jaroslav@597
|
1090 |
result[i++] = x.item;
|
jaroslav@597
|
1091 |
|
jaroslav@597
|
1092 |
if (a.length > size)
|
jaroslav@597
|
1093 |
a[size] = null;
|
jaroslav@597
|
1094 |
|
jaroslav@597
|
1095 |
return a;
|
jaroslav@597
|
1096 |
}
|
jaroslav@597
|
1097 |
|
jaroslav@597
|
1098 |
private static final long serialVersionUID = 876323262645176354L;
|
jaroslav@597
|
1099 |
|
jaroslav@597
|
1100 |
}
|