jdk/src/java.base/share/classes/java/util/LinkedList.java
author mchung
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8074431: Remove native2ascii tool Reviewed-by: erikj, alanb, okutsu, mfang, naoto
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/*
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 * Copyright (c) 1997, 2013, 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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import java.util.function.Consumer;
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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&nbsp;?&nbsp;e==null&nbsp;:&nbsp;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) >= 0;
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    }
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    /**
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     * Returns the number of elements in this list.
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     *
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     * @return the number of elements in this list
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     */
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    public int size() {
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        return size;
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    }
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    /**
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     * 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 #addLast}.
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     *
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     * @param e element to be appended to this list
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     * @return {@code true} (as specified by {@link Collection#add})
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     */
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    public boolean add(E e) {
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        linkLast(e);
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        return true;
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    }
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    /**
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     * Removes the first occurrence of the specified element from this list,
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     * if it is present.  If this list does not contain the element, it is
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     * unchanged.  More formally, removes the element with the lowest index
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     * {@code i} such that
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     * <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>
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     * (if such an element exists).  Returns {@code true} if this list
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     * contained the specified element (or equivalently, if this list
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     * changed as a result of the call).
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     *
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     * @param o element to be removed from this list, if present
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     * @return {@code true} if this list contained the specified element
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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 (Node<E> x = first; x != null; x = x.next) {
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                if (x.item == null) {
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                    unlink(x);
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                    return true;
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                }
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            }
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        } else {
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            for (Node<E> x = first; x != null; x = x.next) {
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                if (o.equals(x.item)) {
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                    unlink(x);
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                    return true;
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                }
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            }
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        }
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        return false;
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    }
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    /**
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     * Appends all of the elements in the specified collection to the end of
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     * this list, in the order that they are returned by the specified
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     * collection's iterator.  The behavior of this operation is undefined if
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     * the specified collection is modified while the operation is in
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     * progress.  (Note that this will occur if the specified collection is
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     * this list, and it's nonempty.)
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diff changeset
   381
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   382
     * @param c collection containing elements to be added to this list
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   383
     * @return {@code true} if this list changed as a result of the call
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   384
     * @throws NullPointerException if the specified collection is null
90ce3da70b43 Initial load
duke
parents:
diff changeset
   385
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   386
    public boolean addAll(Collection<? extends E> c) {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   387
        return addAll(size, c);
90ce3da70b43 Initial load
duke
parents:
diff changeset
   388
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   389
90ce3da70b43 Initial load
duke
parents:
diff changeset
   390
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   391
     * Inserts all of the elements in the specified collection into this
90ce3da70b43 Initial load
duke
parents:
diff changeset
   392
     * list, starting at the specified position.  Shifts the element
90ce3da70b43 Initial load
duke
parents:
diff changeset
   393
     * currently at that position (if any) and any subsequent elements to
90ce3da70b43 Initial load
duke
parents:
diff changeset
   394
     * the right (increases their indices).  The new elements will appear
90ce3da70b43 Initial load
duke
parents:
diff changeset
   395
     * in the list in the order that they are returned by the
90ce3da70b43 Initial load
duke
parents:
diff changeset
   396
     * specified collection's iterator.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   397
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   398
     * @param index index at which to insert the first element
90ce3da70b43 Initial load
duke
parents:
diff changeset
   399
     *              from the specified collection
90ce3da70b43 Initial load
duke
parents:
diff changeset
   400
     * @param c collection containing elements to be added to this list
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   401
     * @return {@code true} if this list changed as a result of the call
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   402
     * @throws IndexOutOfBoundsException {@inheritDoc}
90ce3da70b43 Initial load
duke
parents:
diff changeset
   403
     * @throws NullPointerException if the specified collection is null
90ce3da70b43 Initial load
duke
parents:
diff changeset
   404
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   405
    public boolean addAll(int index, Collection<? extends E> c) {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   406
        checkPositionIndex(index);
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   407
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   408
        Object[] a = c.toArray();
90ce3da70b43 Initial load
duke
parents:
diff changeset
   409
        int numNew = a.length;
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   410
        if (numNew == 0)
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   411
            return false;
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   412
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   413
        Node<E> pred, succ;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   414
        if (index == size) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   415
            succ = null;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   416
            pred = last;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   417
        } else {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   418
            succ = node(index);
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   419
            pred = succ.prev;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   420
        }
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   421
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   422
        for (Object o : a) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   423
            @SuppressWarnings("unchecked") E e = (E) o;
7803
56bc97d69d93 6880112: Project Coin: Port JDK core library code to use diamond operator
smarks
parents: 6124
diff changeset
   424
            Node<E> newNode = new Node<>(pred, e, null);
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   425
            if (pred == null)
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   426
                first = newNode;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   427
            else
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   428
                pred.next = newNode;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   429
            pred = newNode;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   430
        }
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   431
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   432
        if (succ == null) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   433
            last = pred;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   434
        } else {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   435
            pred.next = succ;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   436
            succ.prev = pred;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   437
        }
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   438
90ce3da70b43 Initial load
duke
parents:
diff changeset
   439
        size += numNew;
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   440
        modCount++;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   441
        return true;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   442
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   443
90ce3da70b43 Initial load
duke
parents:
diff changeset
   444
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   445
     * Removes all of the elements from this list.
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   446
     * The list will be empty after this call returns.
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   447
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   448
    public void clear() {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   449
        // Clearing all of the links between nodes is "unnecessary", but:
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   450
        // - helps a generational GC if the discarded nodes inhabit
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   451
        //   more than one generation
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   452
        // - is sure to free memory even if there is a reachable Iterator
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   453
        for (Node<E> x = first; x != null; ) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   454
            Node<E> next = x.next;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   455
            x.item = null;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   456
            x.next = null;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   457
            x.prev = null;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   458
            x = next;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   459
        }
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   460
        first = last = null;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   461
        size = 0;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   462
        modCount++;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   463
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   464
90ce3da70b43 Initial load
duke
parents:
diff changeset
   465
90ce3da70b43 Initial load
duke
parents:
diff changeset
   466
    // Positional Access Operations
90ce3da70b43 Initial load
duke
parents:
diff changeset
   467
90ce3da70b43 Initial load
duke
parents:
diff changeset
   468
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   469
     * Returns the element at the specified position in this list.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   470
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   471
     * @param index index of the element to return
90ce3da70b43 Initial load
duke
parents:
diff changeset
   472
     * @return the element at the specified position in this list
90ce3da70b43 Initial load
duke
parents:
diff changeset
   473
     * @throws IndexOutOfBoundsException {@inheritDoc}
90ce3da70b43 Initial load
duke
parents:
diff changeset
   474
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   475
    public E get(int index) {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   476
        checkElementIndex(index);
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   477
        return node(index).item;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   478
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   479
90ce3da70b43 Initial load
duke
parents:
diff changeset
   480
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   481
     * Replaces the element at the specified position in this list with the
90ce3da70b43 Initial load
duke
parents:
diff changeset
   482
     * specified element.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   483
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   484
     * @param index index of the element to replace
90ce3da70b43 Initial load
duke
parents:
diff changeset
   485
     * @param element element to be stored at the specified position
90ce3da70b43 Initial load
duke
parents:
diff changeset
   486
     * @return the element previously at the specified position
90ce3da70b43 Initial load
duke
parents:
diff changeset
   487
     * @throws IndexOutOfBoundsException {@inheritDoc}
90ce3da70b43 Initial load
duke
parents:
diff changeset
   488
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   489
    public E set(int index, E element) {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   490
        checkElementIndex(index);
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   491
        Node<E> x = node(index);
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   492
        E oldVal = x.item;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   493
        x.item = element;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   494
        return oldVal;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   495
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   496
90ce3da70b43 Initial load
duke
parents:
diff changeset
   497
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   498
     * Inserts the specified element at the specified position in this list.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   499
     * Shifts the element currently at that position (if any) and any
90ce3da70b43 Initial load
duke
parents:
diff changeset
   500
     * subsequent elements to the right (adds one to their indices).
90ce3da70b43 Initial load
duke
parents:
diff changeset
   501
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   502
     * @param index index at which the specified element is to be inserted
90ce3da70b43 Initial load
duke
parents:
diff changeset
   503
     * @param element element to be inserted
90ce3da70b43 Initial load
duke
parents:
diff changeset
   504
     * @throws IndexOutOfBoundsException {@inheritDoc}
90ce3da70b43 Initial load
duke
parents:
diff changeset
   505
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   506
    public void add(int index, E element) {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   507
        checkPositionIndex(index);
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   508
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   509
        if (index == size)
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   510
            linkLast(element);
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   511
        else
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   512
            linkBefore(element, node(index));
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   513
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   514
90ce3da70b43 Initial load
duke
parents:
diff changeset
   515
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   516
     * Removes the element at the specified position in this list.  Shifts any
90ce3da70b43 Initial load
duke
parents:
diff changeset
   517
     * subsequent elements to the left (subtracts one from their indices).
90ce3da70b43 Initial load
duke
parents:
diff changeset
   518
     * Returns the element that was removed from the list.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   519
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   520
     * @param index the index of the element to be removed
90ce3da70b43 Initial load
duke
parents:
diff changeset
   521
     * @return the element previously at the specified position
90ce3da70b43 Initial load
duke
parents:
diff changeset
   522
     * @throws IndexOutOfBoundsException {@inheritDoc}
90ce3da70b43 Initial load
duke
parents:
diff changeset
   523
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   524
    public E remove(int index) {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   525
        checkElementIndex(index);
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   526
        return unlink(node(index));
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   527
    }
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   528
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   529
    /**
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   530
     * Tells if the argument is the index of an existing element.
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   531
     */
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   532
    private boolean isElementIndex(int index) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   533
        return index >= 0 && index < size;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   534
    }
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   535
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   536
    /**
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   537
     * Tells if the argument is the index of a valid position for an
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   538
     * iterator or an add operation.
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   539
     */
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   540
    private boolean isPositionIndex(int index) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   541
        return index >= 0 && index <= size;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   542
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   543
90ce3da70b43 Initial load
duke
parents:
diff changeset
   544
    /**
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   545
     * Constructs an IndexOutOfBoundsException detail message.
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   546
     * Of the many possible refactorings of the error handling code,
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   547
     * this "outlining" performs best with both server and client VMs.
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   548
     */
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   549
    private String outOfBoundsMsg(int index) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   550
        return "Index: "+index+", Size: "+size;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   551
    }
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   552
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   553
    private void checkElementIndex(int index) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   554
        if (!isElementIndex(index))
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   555
            throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   556
    }
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   557
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   558
    private void checkPositionIndex(int index) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   559
        if (!isPositionIndex(index))
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   560
            throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   561
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   562
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   563
    /**
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   564
     * Returns the (non-null) Node at the specified element index.
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   565
     */
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   566
    Node<E> node(int index) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   567
        // assert isElementIndex(index);
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   568
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   569
        if (index < (size >> 1)) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   570
            Node<E> x = first;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   571
            for (int i = 0; i < index; i++)
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   572
                x = x.next;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   573
            return x;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   574
        } else {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   575
            Node<E> x = last;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   576
            for (int i = size - 1; i > index; i--)
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   577
                x = x.prev;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   578
            return x;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   579
        }
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   580
    }
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   581
90ce3da70b43 Initial load
duke
parents:
diff changeset
   582
    // Search Operations
90ce3da70b43 Initial load
duke
parents:
diff changeset
   583
90ce3da70b43 Initial load
duke
parents:
diff changeset
   584
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   585
     * Returns the index of the first occurrence of the specified element
90ce3da70b43 Initial load
duke
parents:
diff changeset
   586
     * in this list, or -1 if this list does not contain the element.
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   587
     * More formally, returns the lowest index {@code i} such that
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   588
     * <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>,
90ce3da70b43 Initial load
duke
parents:
diff changeset
   589
     * or -1 if there is no such index.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   590
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   591
     * @param o element to search for
90ce3da70b43 Initial load
duke
parents:
diff changeset
   592
     * @return the index of the first occurrence of the specified element in
90ce3da70b43 Initial load
duke
parents:
diff changeset
   593
     *         this list, or -1 if this list does not contain the element
90ce3da70b43 Initial load
duke
parents:
diff changeset
   594
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   595
    public int indexOf(Object o) {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   596
        int index = 0;
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   597
        if (o == null) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   598
            for (Node<E> x = first; x != null; x = x.next) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   599
                if (x.item == null)
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   600
                    return index;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   601
                index++;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   602
            }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   603
        } else {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   604
            for (Node<E> x = first; x != null; x = x.next) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   605
                if (o.equals(x.item))
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   606
                    return index;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   607
                index++;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   608
            }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   609
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   610
        return -1;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   611
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   612
90ce3da70b43 Initial load
duke
parents:
diff changeset
   613
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   614
     * Returns the index of the last occurrence of the specified element
90ce3da70b43 Initial load
duke
parents:
diff changeset
   615
     * in this list, or -1 if this list does not contain the element.
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   616
     * More formally, returns the highest index {@code i} such that
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   617
     * <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>,
90ce3da70b43 Initial load
duke
parents:
diff changeset
   618
     * or -1 if there is no such index.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   619
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   620
     * @param o element to search for
90ce3da70b43 Initial load
duke
parents:
diff changeset
   621
     * @return the index of the last occurrence of the specified element in
90ce3da70b43 Initial load
duke
parents:
diff changeset
   622
     *         this list, or -1 if this list does not contain the element
90ce3da70b43 Initial load
duke
parents:
diff changeset
   623
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   624
    public int lastIndexOf(Object o) {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   625
        int index = size;
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   626
        if (o == null) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   627
            for (Node<E> x = last; x != null; x = x.prev) {
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   628
                index--;
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   629
                if (x.item == null)
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   630
                    return index;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   631
            }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   632
        } else {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   633
            for (Node<E> x = last; x != null; x = x.prev) {
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   634
                index--;
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   635
                if (o.equals(x.item))
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   636
                    return index;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   637
            }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   638
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   639
        return -1;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   640
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   641
90ce3da70b43 Initial load
duke
parents:
diff changeset
   642
    // Queue operations.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   643
90ce3da70b43 Initial load
duke
parents:
diff changeset
   644
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   645
     * Retrieves, but does not remove, the head (first element) of this list.
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   646
     *
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   647
     * @return the head of this list, or {@code null} if this list is empty
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   648
     * @since 1.5
90ce3da70b43 Initial load
duke
parents:
diff changeset
   649
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   650
    public E peek() {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   651
        final Node<E> f = first;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   652
        return (f == null) ? null : f.item;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   653
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   654
90ce3da70b43 Initial load
duke
parents:
diff changeset
   655
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   656
     * Retrieves, but does not remove, the head (first element) of this list.
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   657
     *
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   658
     * @return the head of this list
90ce3da70b43 Initial load
duke
parents:
diff changeset
   659
     * @throws NoSuchElementException if this list is empty
90ce3da70b43 Initial load
duke
parents:
diff changeset
   660
     * @since 1.5
90ce3da70b43 Initial load
duke
parents:
diff changeset
   661
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   662
    public E element() {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   663
        return getFirst();
90ce3da70b43 Initial load
duke
parents:
diff changeset
   664
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   665
90ce3da70b43 Initial load
duke
parents:
diff changeset
   666
    /**
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   667
     * Retrieves and removes the head (first element) of this list.
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   668
     *
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   669
     * @return the head of this list, or {@code null} if this list is empty
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   670
     * @since 1.5
90ce3da70b43 Initial load
duke
parents:
diff changeset
   671
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   672
    public E poll() {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   673
        final Node<E> f = first;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   674
        return (f == null) ? null : unlinkFirst(f);
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   675
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   676
90ce3da70b43 Initial load
duke
parents:
diff changeset
   677
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   678
     * Retrieves and removes the head (first element) of this list.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   679
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   680
     * @return the head of this list
90ce3da70b43 Initial load
duke
parents:
diff changeset
   681
     * @throws NoSuchElementException if this list is empty
90ce3da70b43 Initial load
duke
parents:
diff changeset
   682
     * @since 1.5
90ce3da70b43 Initial load
duke
parents:
diff changeset
   683
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   684
    public E remove() {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   685
        return removeFirst();
90ce3da70b43 Initial load
duke
parents:
diff changeset
   686
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   687
90ce3da70b43 Initial load
duke
parents:
diff changeset
   688
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   689
     * Adds the specified element as the tail (last element) of this list.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   690
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   691
     * @param e the element to add
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   692
     * @return {@code true} (as specified by {@link Queue#offer})
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   693
     * @since 1.5
90ce3da70b43 Initial load
duke
parents:
diff changeset
   694
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   695
    public boolean offer(E e) {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   696
        return add(e);
90ce3da70b43 Initial load
duke
parents:
diff changeset
   697
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   698
90ce3da70b43 Initial load
duke
parents:
diff changeset
   699
    // Deque operations
90ce3da70b43 Initial load
duke
parents:
diff changeset
   700
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   701
     * Inserts the specified element at the front of this list.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   702
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   703
     * @param e the element to insert
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   704
     * @return {@code true} (as specified by {@link Deque#offerFirst})
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   705
     * @since 1.6
90ce3da70b43 Initial load
duke
parents:
diff changeset
   706
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   707
    public boolean offerFirst(E e) {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   708
        addFirst(e);
90ce3da70b43 Initial load
duke
parents:
diff changeset
   709
        return true;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   710
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   711
90ce3da70b43 Initial load
duke
parents:
diff changeset
   712
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   713
     * Inserts the specified element at the end of this list.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   714
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   715
     * @param e the element to insert
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   716
     * @return {@code true} (as specified by {@link Deque#offerLast})
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   717
     * @since 1.6
90ce3da70b43 Initial load
duke
parents:
diff changeset
   718
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   719
    public boolean offerLast(E e) {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   720
        addLast(e);
90ce3da70b43 Initial load
duke
parents:
diff changeset
   721
        return true;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   722
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   723
90ce3da70b43 Initial load
duke
parents:
diff changeset
   724
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   725
     * Retrieves, but does not remove, the first element of this list,
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   726
     * or returns {@code null} if this list is empty.
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   727
     *
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   728
     * @return the first element of this list, or {@code null}
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   729
     *         if this list is empty
90ce3da70b43 Initial load
duke
parents:
diff changeset
   730
     * @since 1.6
90ce3da70b43 Initial load
duke
parents:
diff changeset
   731
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   732
    public E peekFirst() {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   733
        final Node<E> f = first;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   734
        return (f == null) ? null : f.item;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   735
     }
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   736
90ce3da70b43 Initial load
duke
parents:
diff changeset
   737
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   738
     * Retrieves, but does not remove, the last element of this list,
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   739
     * or returns {@code null} if this list is empty.
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   740
     *
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   741
     * @return the last element of this list, or {@code null}
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   742
     *         if this list is empty
90ce3da70b43 Initial load
duke
parents:
diff changeset
   743
     * @since 1.6
90ce3da70b43 Initial load
duke
parents:
diff changeset
   744
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   745
    public E peekLast() {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   746
        final Node<E> l = last;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   747
        return (l == null) ? null : l.item;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   748
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   749
90ce3da70b43 Initial load
duke
parents:
diff changeset
   750
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   751
     * Retrieves and removes the first element of this list,
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   752
     * or returns {@code null} if this list is empty.
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   753
     *
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   754
     * @return the first element of this list, or {@code null} if
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   755
     *     this list is empty
90ce3da70b43 Initial load
duke
parents:
diff changeset
   756
     * @since 1.6
90ce3da70b43 Initial load
duke
parents:
diff changeset
   757
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   758
    public E pollFirst() {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   759
        final Node<E> f = first;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   760
        return (f == null) ? null : unlinkFirst(f);
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   761
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   762
90ce3da70b43 Initial load
duke
parents:
diff changeset
   763
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   764
     * Retrieves and removes the last element of this list,
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   765
     * or returns {@code null} if this list is empty.
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   766
     *
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   767
     * @return the last element of this list, or {@code null} if
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   768
     *     this list is empty
90ce3da70b43 Initial load
duke
parents:
diff changeset
   769
     * @since 1.6
90ce3da70b43 Initial load
duke
parents:
diff changeset
   770
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   771
    public E pollLast() {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   772
        final Node<E> l = last;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   773
        return (l == null) ? null : unlinkLast(l);
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   774
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   775
90ce3da70b43 Initial load
duke
parents:
diff changeset
   776
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   777
     * Pushes an element onto the stack represented by this list.  In other
90ce3da70b43 Initial load
duke
parents:
diff changeset
   778
     * words, inserts the element at the front of this list.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   779
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   780
     * <p>This method is equivalent to {@link #addFirst}.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   781
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   782
     * @param e the element to push
90ce3da70b43 Initial load
duke
parents:
diff changeset
   783
     * @since 1.6
90ce3da70b43 Initial load
duke
parents:
diff changeset
   784
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   785
    public void push(E e) {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   786
        addFirst(e);
90ce3da70b43 Initial load
duke
parents:
diff changeset
   787
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   788
90ce3da70b43 Initial load
duke
parents:
diff changeset
   789
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   790
     * Pops an element from the stack represented by this list.  In other
90ce3da70b43 Initial load
duke
parents:
diff changeset
   791
     * words, removes and returns the first element of this list.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   792
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   793
     * <p>This method is equivalent to {@link #removeFirst()}.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   794
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   795
     * @return the element at the front of this list (which is the top
90ce3da70b43 Initial load
duke
parents:
diff changeset
   796
     *         of the stack represented by this list)
90ce3da70b43 Initial load
duke
parents:
diff changeset
   797
     * @throws NoSuchElementException if this list is empty
90ce3da70b43 Initial load
duke
parents:
diff changeset
   798
     * @since 1.6
90ce3da70b43 Initial load
duke
parents:
diff changeset
   799
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   800
    public E pop() {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   801
        return removeFirst();
90ce3da70b43 Initial load
duke
parents:
diff changeset
   802
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   803
90ce3da70b43 Initial load
duke
parents:
diff changeset
   804
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   805
     * Removes the first occurrence of the specified element in this
90ce3da70b43 Initial load
duke
parents:
diff changeset
   806
     * list (when traversing the list from head to tail).  If the list
90ce3da70b43 Initial load
duke
parents:
diff changeset
   807
     * does not contain the element, it is unchanged.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   808
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   809
     * @param o element to be removed from this list, if present
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   810
     * @return {@code true} if the list contained the specified element
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   811
     * @since 1.6
90ce3da70b43 Initial load
duke
parents:
diff changeset
   812
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   813
    public boolean removeFirstOccurrence(Object o) {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   814
        return remove(o);
90ce3da70b43 Initial load
duke
parents:
diff changeset
   815
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   816
90ce3da70b43 Initial load
duke
parents:
diff changeset
   817
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   818
     * Removes the last occurrence of the specified element in this
90ce3da70b43 Initial load
duke
parents:
diff changeset
   819
     * list (when traversing the list from head to tail).  If the list
90ce3da70b43 Initial load
duke
parents:
diff changeset
   820
     * does not contain the element, it is unchanged.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   821
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   822
     * @param o element to be removed from this list, if present
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   823
     * @return {@code true} if the list contained the specified element
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   824
     * @since 1.6
90ce3da70b43 Initial load
duke
parents:
diff changeset
   825
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   826
    public boolean removeLastOccurrence(Object o) {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   827
        if (o == null) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   828
            for (Node<E> x = last; x != null; x = x.prev) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   829
                if (x.item == null) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   830
                    unlink(x);
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   831
                    return true;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   832
                }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   833
            }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   834
        } else {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   835
            for (Node<E> x = last; x != null; x = x.prev) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   836
                if (o.equals(x.item)) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   837
                    unlink(x);
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   838
                    return true;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   839
                }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   840
            }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   841
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   842
        return false;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   843
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   844
90ce3da70b43 Initial load
duke
parents:
diff changeset
   845
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   846
     * Returns a list-iterator of the elements in this list (in proper
90ce3da70b43 Initial load
duke
parents:
diff changeset
   847
     * sequence), starting at the specified position in the list.
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   848
     * Obeys the general contract of {@code List.listIterator(int)}.<p>
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   849
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   850
     * The list-iterator is <i>fail-fast</i>: if the list is structurally
90ce3da70b43 Initial load
duke
parents:
diff changeset
   851
     * modified at any time after the Iterator is created, in any way except
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   852
     * through the list-iterator's own {@code remove} or {@code add}
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   853
     * methods, the list-iterator will throw a
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   854
     * {@code ConcurrentModificationException}.  Thus, in the face of
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   855
     * concurrent modification, the iterator fails quickly and cleanly, rather
90ce3da70b43 Initial load
duke
parents:
diff changeset
   856
     * than risking arbitrary, non-deterministic behavior at an undetermined
90ce3da70b43 Initial load
duke
parents:
diff changeset
   857
     * time in the future.
90ce3da70b43 Initial load
duke
parents:
diff changeset
   858
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
   859
     * @param index index of the first element to be returned from the
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   860
     *              list-iterator (by a call to {@code next})
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   861
     * @return a ListIterator of the elements in this list (in proper
90ce3da70b43 Initial load
duke
parents:
diff changeset
   862
     *         sequence), starting at the specified position in the list
90ce3da70b43 Initial load
duke
parents:
diff changeset
   863
     * @throws IndexOutOfBoundsException {@inheritDoc}
90ce3da70b43 Initial load
duke
parents:
diff changeset
   864
     * @see List#listIterator(int)
90ce3da70b43 Initial load
duke
parents:
diff changeset
   865
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   866
    public ListIterator<E> listIterator(int index) {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   867
        checkPositionIndex(index);
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   868
        return new ListItr(index);
90ce3da70b43 Initial load
duke
parents:
diff changeset
   869
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   870
90ce3da70b43 Initial load
duke
parents:
diff changeset
   871
    private class ListItr implements ListIterator<E> {
23746
ce60f7b62312 8035284: Remove redundant null initialization
mduigou
parents: 22078
diff changeset
   872
        private Node<E> lastReturned;
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   873
        private Node<E> next;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   874
        private int nextIndex;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   875
        private int expectedModCount = modCount;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   876
90ce3da70b43 Initial load
duke
parents:
diff changeset
   877
        ListItr(int index) {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   878
            // assert isPositionIndex(index);
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   879
            next = (index == size) ? null : node(index);
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   880
            nextIndex = index;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   881
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   882
90ce3da70b43 Initial load
duke
parents:
diff changeset
   883
        public boolean hasNext() {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   884
            return nextIndex < size;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   885
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   886
90ce3da70b43 Initial load
duke
parents:
diff changeset
   887
        public E next() {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   888
            checkForComodification();
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   889
            if (!hasNext())
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   890
                throw new NoSuchElementException();
90ce3da70b43 Initial load
duke
parents:
diff changeset
   891
90ce3da70b43 Initial load
duke
parents:
diff changeset
   892
            lastReturned = next;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   893
            next = next.next;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   894
            nextIndex++;
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   895
            return lastReturned.item;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   896
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   897
90ce3da70b43 Initial load
duke
parents:
diff changeset
   898
        public boolean hasPrevious() {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   899
            return nextIndex > 0;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   900
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   901
90ce3da70b43 Initial load
duke
parents:
diff changeset
   902
        public E previous() {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   903
            checkForComodification();
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   904
            if (!hasPrevious())
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   905
                throw new NoSuchElementException();
90ce3da70b43 Initial load
duke
parents:
diff changeset
   906
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   907
            lastReturned = next = (next == null) ? last : next.prev;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   908
            nextIndex--;
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   909
            return lastReturned.item;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   910
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   911
90ce3da70b43 Initial load
duke
parents:
diff changeset
   912
        public int nextIndex() {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   913
            return nextIndex;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   914
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   915
90ce3da70b43 Initial load
duke
parents:
diff changeset
   916
        public int previousIndex() {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   917
            return nextIndex - 1;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   918
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   919
90ce3da70b43 Initial load
duke
parents:
diff changeset
   920
        public void remove() {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   921
            checkForComodification();
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   922
            if (lastReturned == null)
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   923
                throw new IllegalStateException();
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   924
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   925
            Node<E> lastNext = lastReturned.next;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   926
            unlink(lastReturned);
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   927
            if (next == lastReturned)
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   928
                next = lastNext;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   929
            else
90ce3da70b43 Initial load
duke
parents:
diff changeset
   930
                nextIndex--;
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   931
            lastReturned = null;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   932
            expectedModCount++;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   933
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   934
90ce3da70b43 Initial load
duke
parents:
diff changeset
   935
        public void set(E e) {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   936
            if (lastReturned == null)
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   937
                throw new IllegalStateException();
90ce3da70b43 Initial load
duke
parents:
diff changeset
   938
            checkForComodification();
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   939
            lastReturned.item = e;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   940
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   941
90ce3da70b43 Initial load
duke
parents:
diff changeset
   942
        public void add(E e) {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   943
            checkForComodification();
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   944
            lastReturned = null;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   945
            if (next == null)
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   946
                linkLast(e);
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   947
            else
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   948
                linkBefore(e, next);
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   949
            nextIndex++;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   950
            expectedModCount++;
90ce3da70b43 Initial load
duke
parents:
diff changeset
   951
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   952
17168
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
   953
        public void forEachRemaining(Consumer<? super E> action) {
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
   954
            Objects.requireNonNull(action);
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
   955
            while (modCount == expectedModCount && nextIndex < size) {
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
   956
                action.accept(next.item);
17432
efdf6eb85a17 8013150: Iterator.remove and forEachRemaining relationship not specified
mduigou
parents: 17180
diff changeset
   957
                lastReturned = next;
17168
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
   958
                next = next.next;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
   959
                nextIndex++;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
   960
            }
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
   961
            checkForComodification();
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
   962
        }
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
   963
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   964
        final void checkForComodification() {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   965
            if (modCount != expectedModCount)
90ce3da70b43 Initial load
duke
parents:
diff changeset
   966
                throw new ConcurrentModificationException();
90ce3da70b43 Initial load
duke
parents:
diff changeset
   967
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   968
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   969
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   970
    private static class Node<E> {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   971
        E item;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   972
        Node<E> next;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   973
        Node<E> prev;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   974
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   975
        Node(Node<E> prev, E element, Node<E> next) {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   976
            this.item = element;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   977
            this.next = next;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   978
            this.prev = prev;
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   979
        }
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   980
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   981
90ce3da70b43 Initial load
duke
parents:
diff changeset
   982
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
   983
     * @since 1.6
90ce3da70b43 Initial load
duke
parents:
diff changeset
   984
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
   985
    public Iterator<E> descendingIterator() {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   986
        return new DescendingIterator();
90ce3da70b43 Initial load
duke
parents:
diff changeset
   987
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   988
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   989
    /**
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   990
     * Adapter to provide descending iterators via ListItr.previous
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   991
     */
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   992
    private class DescendingIterator implements Iterator<E> {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
   993
        private final ListItr itr = new ListItr(size());
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
   994
        public boolean hasNext() {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   995
            return itr.hasPrevious();
90ce3da70b43 Initial load
duke
parents:
diff changeset
   996
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
   997
        public E next() {
90ce3da70b43 Initial load
duke
parents:
diff changeset
   998
            return itr.previous();
90ce3da70b43 Initial load
duke
parents:
diff changeset
   999
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1000
        public void remove() {
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1001
            itr.remove();
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1002
        }
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1003
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1004
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1005
    @SuppressWarnings("unchecked")
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1006
    private LinkedList<E> superClone() {
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1007
        try {
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1008
            return (LinkedList<E>) super.clone();
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1009
        } catch (CloneNotSupportedException e) {
10419
12c063b39232 7084245: Update usages of InternalError to use exception chaining
sherman
parents: 9035
diff changeset
  1010
            throw new InternalError(e);
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1011
        }
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1012
    }
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1013
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1014
    /**
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1015
     * Returns a shallow copy of this {@code LinkedList}. (The elements
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1016
     * themselves are not cloned.)
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1017
     *
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1018
     * @return a shallow copy of this {@code LinkedList} instance
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1019
     */
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1020
    public Object clone() {
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1021
        LinkedList<E> clone = superClone();
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1022
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1023
        // Put clone into "virgin" state
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1024
        clone.first = clone.last = null;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1025
        clone.size = 0;
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1026
        clone.modCount = 0;
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1027
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1028
        // Initialize clone with our elements
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1029
        for (Node<E> x = first; x != null; x = x.next)
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1030
            clone.add(x.item);
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1031
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1032
        return clone;
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1033
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1034
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1035
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1036
     * Returns an array containing all of the elements in this list
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1037
     * in proper sequence (from first to last element).
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1038
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1039
     * <p>The returned array will be "safe" in that no references to it are
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1040
     * maintained by this list.  (In other words, this method must allocate
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1041
     * a new array).  The caller is thus free to modify the returned array.
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1042
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1043
     * <p>This method acts as bridge between array-based and collection-based
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1044
     * APIs.
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1045
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1046
     * @return an array containing all of the elements in this list
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1047
     *         in proper sequence
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1048
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1049
    public Object[] toArray() {
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1050
        Object[] result = new Object[size];
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1051
        int i = 0;
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1052
        for (Node<E> x = first; x != null; x = x.next)
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1053
            result[i++] = x.item;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1054
        return result;
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1055
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1056
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1057
    /**
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1058
     * Returns an array containing all of the elements in this list in
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1059
     * proper sequence (from first to last element); the runtime type of
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1060
     * the returned array is that of the specified array.  If the list fits
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1061
     * in the specified array, it is returned therein.  Otherwise, a new
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1062
     * array is allocated with the runtime type of the specified array and
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1063
     * the size of this list.
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1064
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1065
     * <p>If the list fits in the specified array with room to spare (i.e.,
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1066
     * the array has more elements than the list), the element in the array
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1067
     * immediately following the end of the list is set to {@code null}.
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1068
     * (This is useful in determining the length of the list <i>only</i> if
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1069
     * the caller knows that the list does not contain any null elements.)
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1070
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1071
     * <p>Like the {@link #toArray()} method, this method acts as bridge between
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1072
     * array-based and collection-based APIs.  Further, this method allows
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1073
     * precise control over the runtime type of the output array, and may,
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1074
     * under certain circumstances, be used to save allocation costs.
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1075
     *
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1076
     * <p>Suppose {@code x} is a list known to contain only strings.
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1077
     * The following code can be used to dump the list into a newly
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1078
     * allocated array of {@code String}:
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1079
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1080
     * <pre>
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1081
     *     String[] y = x.toArray(new String[0]);</pre>
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1082
     *
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1083
     * Note that {@code toArray(new Object[0])} is identical in function to
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1084
     * {@code toArray()}.
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1085
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1086
     * @param a the array into which the elements of the list are to
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1087
     *          be stored, if it is big enough; otherwise, a new array of the
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1088
     *          same runtime type is allocated for this purpose.
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1089
     * @return an array containing the elements of the list
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1090
     * @throws ArrayStoreException if the runtime type of the specified array
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1091
     *         is not a supertype of the runtime type of every element in
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1092
     *         this list
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1093
     * @throws NullPointerException if the specified array is null
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1094
     */
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1095
    @SuppressWarnings("unchecked")
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1096
    public <T> T[] toArray(T[] a) {
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1097
        if (a.length < size)
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1098
            a = (T[])java.lang.reflect.Array.newInstance(
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1099
                                a.getClass().getComponentType(), size);
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1100
        int i = 0;
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1101
        Object[] result = a;
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1102
        for (Node<E> x = first; x != null; x = x.next)
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1103
            result[i++] = x.item;
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1104
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1105
        if (a.length > size)
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1106
            a[size] = null;
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1107
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1108
        return a;
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1109
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1110
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1111
    private static final long serialVersionUID = 876323262645176354L;
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1112
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1113
    /**
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1114
     * Saves the state of this {@code LinkedList} instance to a stream
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1115
     * (that is, serializes it).
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1116
     *
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1117
     * @serialData The size of the list (the number of elements it
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1118
     *             contains) is emitted (int), followed by all of its
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1119
     *             elements (each an Object) in the proper order.
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1120
     */
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1121
    private void writeObject(java.io.ObjectOutputStream s)
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1122
        throws java.io.IOException {
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1123
        // Write out any hidden serialization magic
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1124
        s.defaultWriteObject();
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1125
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1126
        // Write out size
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1127
        s.writeInt(size);
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1128
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1129
        // Write out all elements in the proper order.
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1130
        for (Node<E> x = first; x != null; x = x.next)
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1131
            s.writeObject(x.item);
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1132
    }
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1133
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1134
    /**
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1135
     * Reconstitutes this {@code LinkedList} instance from a stream
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1136
     * (that is, deserializes it).
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1137
     */
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1138
    @SuppressWarnings("unchecked")
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1139
    private void readObject(java.io.ObjectInputStream s)
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1140
        throws java.io.IOException, ClassNotFoundException {
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1141
        // Read in any hidden serialization magic
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1142
        s.defaultReadObject();
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1143
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1144
        // Read in size
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1145
        int size = s.readInt();
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1146
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1147
        // Read in all elements in the proper order.
4184
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1148
        for (int i = 0; i < size; i++)
66ef929d58f2 6897553: LinkedList performance improvements
martin
parents: 2
diff changeset
  1149
            linkLast((E)s.readObject());
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1150
    }
17168
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1151
19435
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1152
    /**
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1153
     * Creates a <em><a href="Spliterator.html#binding">late-binding</a></em>
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1154
     * and <em>fail-fast</em> {@link Spliterator} over the elements in this
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1155
     * list.
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1156
     *
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1157
     * <p>The {@code Spliterator} reports {@link Spliterator#SIZED} and
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1158
     * {@link Spliterator#ORDERED}.  Overriding implementations should document
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1159
     * the reporting of additional characteristic values.
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1160
     *
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1161
     * @implNote
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1162
     * The {@code Spliterator} additionally reports {@link Spliterator#SUBSIZED}
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1163
     * and implements {@code trySplit} to permit limited parallelism..
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1164
     *
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1165
     * @return a {@code Spliterator} over the elements in this list
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1166
     * @since 1.8
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1167
     */
9d7530ff42cb 8014824: Document Spliterator characteristics and binding policy of java util collection impls
psandoz
parents: 18788
diff changeset
  1168
    @Override
17168
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1169
    public Spliterator<E> spliterator() {
22078
bdec5d53e98c 8030851: Update code in java.util to use newer language features
psandoz
parents: 19435
diff changeset
  1170
        return new LLSpliterator<>(this, -1, 0);
17168
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1171
    }
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1172
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1173
    /** A customized variant of Spliterators.IteratorSpliterator */
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1174
    static final class LLSpliterator<E> implements Spliterator<E> {
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1175
        static final int BATCH_UNIT = 1 << 10;  // batch array size increment
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1176
        static final int MAX_BATCH = 1 << 25;  // max batch array size;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1177
        final LinkedList<E> list; // null OK unless traversed
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1178
        Node<E> current;      // current node; null until initialized
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1179
        int est;              // size estimate; -1 until first needed
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1180
        int expectedModCount; // initialized when est set
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1181
        int batch;            // batch size for splits
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1182
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1183
        LLSpliterator(LinkedList<E> list, int est, int expectedModCount) {
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1184
            this.list = list;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1185
            this.est = est;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1186
            this.expectedModCount = expectedModCount;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1187
        }
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1188
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1189
        final int getEst() {
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1190
            int s; // force initialization
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1191
            final LinkedList<E> lst;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1192
            if ((s = est) < 0) {
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1193
                if ((lst = list) == null)
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1194
                    s = est = 0;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1195
                else {
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1196
                    expectedModCount = lst.modCount;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1197
                    current = lst.first;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1198
                    s = est = lst.size;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1199
                }
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1200
            }
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1201
            return s;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1202
        }
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1203
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1204
        public long estimateSize() { return (long) getEst(); }
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1205
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1206
        public Spliterator<E> trySplit() {
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1207
            Node<E> p;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1208
            int s = getEst();
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1209
            if (s > 1 && (p = current) != null) {
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1210
                int n = batch + BATCH_UNIT;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1211
                if (n > s)
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1212
                    n = s;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1213
                if (n > MAX_BATCH)
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1214
                    n = MAX_BATCH;
18788
1bfd5f623662 8017141: java.util/stream Spliterators from sequential sources should not catch OOME
henryjen
parents: 17432
diff changeset
  1215
                Object[] a = new Object[n];
17168
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1216
                int j = 0;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1217
                do { a[j++] = p.item; } while ((p = p.next) != null && j < n);
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1218
                current = p;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1219
                batch = j;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1220
                est = s - j;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1221
                return Spliterators.spliterator(a, 0, j, Spliterator.ORDERED);
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1222
            }
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1223
            return null;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1224
        }
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1225
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1226
        public void forEachRemaining(Consumer<? super E> action) {
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1227
            Node<E> p; int n;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1228
            if (action == null) throw new NullPointerException();
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1229
            if ((n = getEst()) > 0 && (p = current) != null) {
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1230
                current = null;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1231
                est = 0;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1232
                do {
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1233
                    E e = p.item;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1234
                    p = p.next;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1235
                    action.accept(e);
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1236
                } while (p != null && --n > 0);
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1237
            }
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1238
            if (list.modCount != expectedModCount)
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1239
                throw new ConcurrentModificationException();
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1240
        }
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1241
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1242
        public boolean tryAdvance(Consumer<? super E> action) {
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1243
            Node<E> p;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1244
            if (action == null) throw new NullPointerException();
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1245
            if (getEst() > 0 && (p = current) != null) {
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1246
                --est;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1247
                E e = p.item;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1248
                current = p.next;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1249
                action.accept(e);
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1250
                if (list.modCount != expectedModCount)
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1251
                    throw new ConcurrentModificationException();
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1252
                return true;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1253
            }
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1254
            return false;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1255
        }
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1256
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1257
        public int characteristics() {
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1258
            return Spliterator.ORDERED | Spliterator.SIZED | Spliterator.SUBSIZED;
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1259
        }
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1260
    }
b7d3500f2516 8011426: java.util collection Spliterator implementations
psandoz
parents: 10419
diff changeset
  1261
2
90ce3da70b43 Initial load
duke
parents:
diff changeset
  1262
}