--- jsr166/src/main/java/util/LinkedList.java 2005/05/25 14:05:06 1.34
+++ jsr166/src/main/java/util/LinkedList.java 2007/05/20 07:54:01 1.47
@@ -1,8 +1,26 @@
/*
- * %W% %E%
+ * Copyright 1997-2006 Sun Microsystems, Inc. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
- * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
- * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
*/
package java.util;
@@ -25,18 +43,20 @@ package java.util;
* list. Operations that index into the list will traverse the list from
* the beginning or the end, whichever is closer to the specified index.
*
- * Note that this implementation is not synchronized. If multiple
- * threads access a list concurrently, and at least one of the threads
- * modifies the list structurally, it must be synchronized
- * externally. (A structural modification is any operation that adds or
- * deletes one or more elements; merely setting the value of an element is not
- * a structural modification.) This is typically accomplished by
- * synchronizing on some object that naturally encapsulates the list. If no
- * such object exists, the list should be "wrapped" using the
- * Collections.synchronizedList method. This is best done at creation time,
- * to prevent accidental unsynchronized access to the list:
- * List list = Collections.synchronizedList(new LinkedList(...));
- *
+ * Note that this implementation is not synchronized.
+ * If multiple threads access a linked list concurrently, and at least
+ * one of the threads modifies the list structurally, it must be
+ * synchronized externally. (A structural modification is any operation
+ * that adds or deletes one or more elements; merely setting the value of
+ * an element is not a structural modification.) This is typically
+ * accomplished by synchronizing on some object that naturally
+ * encapsulates the list.
+ *
+ * If no such object exists, the list should be "wrapped" using the
+ * {@link Collections#synchronizedList Collections.synchronizedList}
+ * method. This is best done at creation time, to prevent accidental
+ * unsynchronized access to the list:
+ * List list = Collections.synchronizedList(new LinkedList(...));
*
* The iterators returned by this class's iterator and
* listIterator methods are fail-fast: if the list is
@@ -57,7 +77,7 @@ package java.util;
* should be used only to detect bugs.
*
*
This class is a member of the
- *
+ *
* Java Collections Framework.
*
* @author Josh Bloch
@@ -65,7 +85,6 @@ package java.util;
* @see List
* @see ArrayList
* @see Vector
- * @see Collections#synchronizedList(List)
* @since 1.2
* @param the type of elements held in this collection
*/
@@ -92,10 +111,10 @@ public class LinkedList
* @param c the collection whose elements are to be placed into this list
* @throws NullPointerException if the specified collection is null
*/
- public LinkedList(Collection c) {
- this();
- addAll(c);
- }
+ public LinkedList(Collection c) {
+ this();
+ addAll(c);
+ }
/**
* Returns the first element in this list.
@@ -144,19 +163,20 @@ public class LinkedList
}
/**
- * Inserts the given element at the beginning of this list.
+ * Inserts the specified element at the beginning of this list.
*
- * @param e the element to be inserted at the beginning of this list
+ * @param e the element to add
*/
public void addFirst(E e) {
addBefore(e, header.next);
}
/**
- * Appends the given element to the end of this list. (Identical in
- * function to the add method; included only for consistency.)
+ * Appends the specified element to the end of this list.
*
- * @param e the element to be inserted at the end of this list
+ * This method is equivalent to {@link #add}.
+ *
+ * @param e the element to add
*/
public void addLast(E e) {
addBefore(e, header);
@@ -187,8 +207,10 @@ public class LinkedList
/**
* Appends the specified element to the end of this list.
*
+ * This method is equivalent to {@link #addLast}.
+ *
* @param e element to be appended to this list
- * @return true (as per the spec for {@link Collection#add})
+ * @return true (as specified by {@link Collection#add})
*/
public boolean add(E e) {
addBefore(e, header);
@@ -481,7 +503,7 @@ public class LinkedList
* Adds the specified element as the tail (last element) of this list.
*
* @param e the element to add
- * @return true (as per the spec for {@link Queue#offer})
+ * @return true (as specified by {@link Queue#offer})
* @since 1.5
*/
public boolean offer(E e) {
@@ -493,7 +515,7 @@ public class LinkedList
* Inserts the specified element at the front of this list.
*
* @param e the element to insert
- * @return true (as per the spec for {@link Deque#offerFirst})
+ * @return true (as specified by {@link Deque#offerFirst})
* @since 1.6
*/
public boolean offerFirst(E e) {
@@ -505,7 +527,7 @@ public class LinkedList
* Inserts the specified element at the end of this list.
*
* @param e the element to insert
- * @return true (as per the spec for {@link Deque#offerLast})
+ * @return true (as specified by {@link Deque#offerLast})
* @since 1.6
*/
public boolean offerLast(E e) {
@@ -542,8 +564,8 @@ public class LinkedList
}
/**
- * Retrieves and removes the first element of this list, or
- * null if this list is empty.
+ * Retrieves and removes the first element of this list,
+ * or returns null if this list is empty.
*
* @return the first element of this list, or null if
* this list is empty
@@ -556,8 +578,8 @@ public class LinkedList
}
/**
- * Retrieves and removes the last element of this list, or
- * null if this list is empty.
+ * Retrieves and removes the last element of this list,
+ * or returns null if this list is empty.
*
* @return the last element of this list, or null if
* this list is empty
@@ -794,6 +816,27 @@ public class LinkedList
}
/**
+ * @since 1.6
+ */
+ public Iterator descendingIterator() {
+ return new DescendingIterator();
+ }
+
+ /** Adapter to provide descending iterators via ListItr.previous */
+ private class DescendingIterator implements Iterator {
+ final ListItr itr = new ListItr(size());
+ public boolean hasNext() {
+ return itr.hasPrevious();
+ }
+ public E next() {
+ return itr.previous();
+ }
+ public void remove() {
+ itr.remove();
+ }
+ }
+
+ /**
* Returns a shallow copy of this LinkedList. (The elements
* themselves are not cloned.)
*