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[Jnode-svn-commits] SF.net SVN: jnode: [2991] trunk/core/src/classpath/java/java/util
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From: <ls...@us...> - 2007-01-07 05:38:17
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Revision: 2991
http://jnode.svn.sourceforge.net/jnode/?rev=2991&view=rev
Author: lsantha
Date: 2007-01-06 21:38:13 -0800 (Sat, 06 Jan 2007)
Log Message:
-----------
Classpath patches.
Added Paths:
-----------
trunk/core/src/classpath/java/java/util/ArrayDeque.java
trunk/core/src/classpath/java/java/util/Deque.java
trunk/core/src/classpath/java/java/util/NavigableMap.java
trunk/core/src/classpath/java/java/util/NavigableSet.java
trunk/core/src/classpath/java/java/util/concurrent/
trunk/core/src/classpath/java/java/util/concurrent/AbstractExecutorService.java
trunk/core/src/classpath/java/java/util/concurrent/ArrayBlockingQueue.java
trunk/core/src/classpath/java/java/util/concurrent/BlockingDeque.java
trunk/core/src/classpath/java/java/util/concurrent/BlockingQueue.java
trunk/core/src/classpath/java/java/util/concurrent/BrokenBarrierException.java
trunk/core/src/classpath/java/java/util/concurrent/Callable.java
trunk/core/src/classpath/java/java/util/concurrent/CancellationException.java
trunk/core/src/classpath/java/java/util/concurrent/CompletionService.java
trunk/core/src/classpath/java/java/util/concurrent/ConcurrentHashMap.java
trunk/core/src/classpath/java/java/util/concurrent/ConcurrentLinkedQueue.java
trunk/core/src/classpath/java/java/util/concurrent/ConcurrentMap.java
trunk/core/src/classpath/java/java/util/concurrent/ConcurrentNavigableMap.java
trunk/core/src/classpath/java/java/util/concurrent/ConcurrentSkipListMap.java
trunk/core/src/classpath/java/java/util/concurrent/ConcurrentSkipListSet.java
trunk/core/src/classpath/java/java/util/concurrent/CopyOnWriteArrayList.java
trunk/core/src/classpath/java/java/util/concurrent/CopyOnWriteArraySet.java
trunk/core/src/classpath/java/java/util/concurrent/CountDownLatch.java
trunk/core/src/classpath/java/java/util/concurrent/CyclicBarrier.java
trunk/core/src/classpath/java/java/util/concurrent/DelayQueue.java
trunk/core/src/classpath/java/java/util/concurrent/Delayed.java
trunk/core/src/classpath/java/java/util/concurrent/Exchanger.java
trunk/core/src/classpath/java/java/util/concurrent/ExecutionException.java
trunk/core/src/classpath/java/java/util/concurrent/Executor.java
trunk/core/src/classpath/java/java/util/concurrent/ExecutorCompletionService.java
trunk/core/src/classpath/java/java/util/concurrent/ExecutorService.java
trunk/core/src/classpath/java/java/util/concurrent/Executors.java
trunk/core/src/classpath/java/java/util/concurrent/Future.java
trunk/core/src/classpath/java/java/util/concurrent/FutureTask.java
trunk/core/src/classpath/java/java/util/concurrent/LinkedBlockingDeque.java
trunk/core/src/classpath/java/java/util/concurrent/LinkedBlockingQueue.java
trunk/core/src/classpath/java/java/util/concurrent/PriorityBlockingQueue.java
trunk/core/src/classpath/java/java/util/concurrent/RejectedExecutionException.java
trunk/core/src/classpath/java/java/util/concurrent/RejectedExecutionHandler.java
trunk/core/src/classpath/java/java/util/concurrent/RunnableFuture.java
trunk/core/src/classpath/java/java/util/concurrent/RunnableScheduledFuture.java
trunk/core/src/classpath/java/java/util/concurrent/ScheduledExecutorService.java
trunk/core/src/classpath/java/java/util/concurrent/ScheduledFuture.java
trunk/core/src/classpath/java/java/util/concurrent/ScheduledThreadPoolExecutor.java
trunk/core/src/classpath/java/java/util/concurrent/Semaphore.java
trunk/core/src/classpath/java/java/util/concurrent/SynchronousQueue.java
trunk/core/src/classpath/java/java/util/concurrent/ThreadFactory.java
trunk/core/src/classpath/java/java/util/concurrent/ThreadPoolExecutor.java
trunk/core/src/classpath/java/java/util/concurrent/TimeUnit.java
trunk/core/src/classpath/java/java/util/concurrent/TimeoutException.java
trunk/core/src/classpath/java/java/util/concurrent/atomic/
trunk/core/src/classpath/java/java/util/concurrent/atomic/AtomicBoolean.java
trunk/core/src/classpath/java/java/util/concurrent/atomic/AtomicInteger.java
trunk/core/src/classpath/java/java/util/concurrent/atomic/AtomicIntegerArray.java
trunk/core/src/classpath/java/java/util/concurrent/atomic/AtomicIntegerFieldUpdater.java
trunk/core/src/classpath/java/java/util/concurrent/atomic/AtomicLong.java
trunk/core/src/classpath/java/java/util/concurrent/atomic/AtomicLongArray.java
trunk/core/src/classpath/java/java/util/concurrent/atomic/AtomicLongFieldUpdater.java
trunk/core/src/classpath/java/java/util/concurrent/atomic/AtomicMarkableReference.java
trunk/core/src/classpath/java/java/util/concurrent/atomic/AtomicReference.java
trunk/core/src/classpath/java/java/util/concurrent/atomic/AtomicReferenceArray.java
trunk/core/src/classpath/java/java/util/concurrent/atomic/AtomicReferenceFieldUpdater.java
trunk/core/src/classpath/java/java/util/concurrent/atomic/AtomicStampedReference.java
trunk/core/src/classpath/java/java/util/concurrent/atomic/package.html
trunk/core/src/classpath/java/java/util/concurrent/locks/
trunk/core/src/classpath/java/java/util/concurrent/locks/AbstractOwnableSynchronizer.java
trunk/core/src/classpath/java/java/util/concurrent/locks/AbstractQueuedLongSynchronizer.java
trunk/core/src/classpath/java/java/util/concurrent/locks/AbstractQueuedSynchronizer.java
trunk/core/src/classpath/java/java/util/concurrent/locks/Condition.java
trunk/core/src/classpath/java/java/util/concurrent/locks/Lock.java
trunk/core/src/classpath/java/java/util/concurrent/locks/LockSupport.java
trunk/core/src/classpath/java/java/util/concurrent/locks/ReadWriteLock.java
trunk/core/src/classpath/java/java/util/concurrent/locks/ReentrantLock.java
trunk/core/src/classpath/java/java/util/concurrent/locks/package.html
trunk/core/src/classpath/java/java/util/concurrent/package.html
trunk/core/src/classpath/java/java/util/spi/
trunk/core/src/classpath/java/java/util/spi/CurrencyNameProvider.java
trunk/core/src/classpath/java/java/util/spi/LocaleNameProvider.java
trunk/core/src/classpath/java/java/util/spi/LocaleServiceProvider.java
trunk/core/src/classpath/java/java/util/spi/TimeZoneNameProvider.java
trunk/core/src/classpath/java/java/util/spi/package.html
Added: trunk/core/src/classpath/java/java/util/ArrayDeque.java
===================================================================
--- trunk/core/src/classpath/java/java/util/ArrayDeque.java (rev 0)
+++ trunk/core/src/classpath/java/java/util/ArrayDeque.java 2007-01-07 05:38:13 UTC (rev 2991)
@@ -0,0 +1,839 @@
+/*
+ * Written by Josh Bloch of Google Inc. and released to the public domain,
+ * as explained at http://creativecommons.org/licenses/publicdomain.
+ */
+
+package java.util;
+import java.io.*;
+
+/**
+ * Resizable-array implementation of the {@link Deque} interface. Array
+ * deques have no capacity restrictions; they grow as necessary to support
+ * usage. They are not thread-safe; in the absence of external
+ * synchronization, they do not support concurrent access by multiple threads.
+ * Null elements are prohibited. This class is likely to be faster than
+ * {@link Stack} when used as a stack, and faster than {@link LinkedList}
+ * when used as a queue.
+ *
+ * <p>Most <tt>ArrayDeque</tt> operations run in amortized constant time.
+ * Exceptions include {@link #remove(Object) remove}, {@link
+ * #removeFirstOccurrence removeFirstOccurrence}, {@link #removeLastOccurrence
+ * removeLastOccurrence}, {@link #contains contains}, {@link #iterator
+ * iterator.remove()}, and the bulk operations, all of which run in linear
+ * time.
+ *
+ * <p>The iterators returned by this class's <tt>iterator</tt> method are
+ * <i>fail-fast</i>: If the deque is modified at any time after the iterator
+ * is created, in any way except through the iterator's own <tt>remove</tt>
+ * method, the iterator will generally throw a {@link
+ * ConcurrentModificationException}. Thus, in the face of concurrent
+ * modification, the iterator fails quickly and cleanly, rather than risking
+ * arbitrary, non-deterministic behavior at an undetermined time in the
+ * future.
+ *
+ * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed
+ * as it is, generally speaking, impossible to make any hard guarantees in the
+ * presence of unsynchronized concurrent modification. Fail-fast iterators
+ * throw <tt>ConcurrentModificationException</tt> on a best-effort basis.
+ * Therefore, it would be wrong to write a program that depended on this
+ * exception for its correctness: <i>the fail-fast behavior of iterators
+ * should be used only to detect bugs.</i>
+ *
+ * <p>This class and its iterator implement all of the
+ * <em>optional</em> methods of the {@link Collection} and {@link
+ * Iterator} interfaces.
+ *
+ * <p>This class is a member of the
+ * <a href="{@docRoot}/../technotes/guides/collections/index.html">
+ * Java Collections Framework</a>.
+ *
+ * @author Josh Bloch and Doug Lea
+ * @since 1.6
+ * @param <E> the type of elements held in this collection
+ */
+public class ArrayDeque<E> extends AbstractCollection<E>
+ implements Deque<E>, Cloneable, Serializable
+{
+ /**
+ * The array in which the elements of the deque are stored.
+ * The capacity of the deque is the length of this array, which is
+ * always a power of two. The array is never allowed to become
+ * full, except transiently within an addX method where it is
+ * resized (see doubleCapacity) immediately upon becoming full,
+ * thus avoiding head and tail wrapping around to equal each
+ * other. We also guarantee that all array cells not holding
+ * deque elements are always null.
+ */
+ private transient E[] elements;
+
+ /**
+ * The index of the element at the head of the deque (which is the
+ * element that would be removed by remove() or pop()); or an
+ * arbitrary number equal to tail if the deque is empty.
+ */
+ private transient int head;
+
+ /**
+ * The index at which the next element would be added to the tail
+ * of the deque (via addLast(E), add(E), or push(E)).
+ */
+ private transient int tail;
+
+ /**
+ * The minimum capacity that we'll use for a newly created deque.
+ * Must be a power of 2.
+ */
+ private static final int MIN_INITIAL_CAPACITY = 8;
+
+ // ****** Array allocation and resizing utilities ******
+
+ /**
+ * Allocate empty array to hold the given number of elements.
+ *
+ * @param numElements the number of elements to hold
+ */
+ private void allocateElements(int numElements) {
+ int initialCapacity = MIN_INITIAL_CAPACITY;
+ // Find the best power of two to hold elements.
+ // Tests "<=" because arrays aren't kept full.
+ if (numElements >= initialCapacity) {
+ initialCapacity = numElements;
+ initialCapacity |= (initialCapacity >>> 1);
+ initialCapacity |= (initialCapacity >>> 2);
+ initialCapacity |= (initialCapacity >>> 4);
+ initialCapacity |= (initialCapacity >>> 8);
+ initialCapacity |= (initialCapacity >>> 16);
+ initialCapacity++;
+
+ if (initialCapacity < 0) // Too many elements, must back off
+ initialCapacity >>>= 1;// Good luck allocating 2 ^ 30 elements
+ }
+ elements = (E[]) new Object[initialCapacity];
+ }
+
+ /**
+ * Double the capacity of this deque. Call only when full, i.e.,
+ * when head and tail have wrapped around to become equal.
+ */
+ private void doubleCapacity() {
+ assert head == tail;
+ int p = head;
+ int n = elements.length;
+ int r = n - p; // number of elements to the right of p
+ int newCapacity = n << 1;
+ if (newCapacity < 0)
+ throw new IllegalStateException("Sorry, deque too big");
+ Object[] a = new Object[newCapacity];
+ System.arraycopy(elements, p, a, 0, r);
+ System.arraycopy(elements, 0, a, r, p);
+ elements = (E[])a;
+ head = 0;
+ tail = n;
+ }
+
+ /**
+ * Copies the elements from our element array into the specified array,
+ * in order (from first to last element in the deque). It is assumed
+ * that the array is large enough to hold all elements in the deque.
+ *
+ * @return its argument
+ */
+ private <T> T[] copyElements(T[] a) {
+ if (head < tail) {
+ System.arraycopy(elements, head, a, 0, size());
+ } else if (head > tail) {
+ int headPortionLen = elements.length - head;
+ System.arraycopy(elements, head, a, 0, headPortionLen);
+ System.arraycopy(elements, 0, a, headPortionLen, tail);
+ }
+ return a;
+ }
+
+ /**
+ * Constructs an empty array deque with an initial capacity
+ * sufficient to hold 16 elements.
+ */
+ public ArrayDeque() {
+ elements = (E[]) new Object[16];
+ }
+
+ /**
+ * Constructs an empty array deque with an initial capacity
+ * sufficient to hold the specified number of elements.
+ *
+ * @param numElements lower bound on initial capacity of the deque
+ */
+ public ArrayDeque(int numElements) {
+ allocateElements(numElements);
+ }
+
+ /**
+ * Constructs a deque containing the elements of the specified
+ * collection, in the order they are returned by the collection's
+ * iterator. (The first element returned by the collection's
+ * iterator becomes the first element, or <i>front</i> of the
+ * deque.)
+ *
+ * @param c the collection whose elements are to be placed into the deque
+ * @throws NullPointerException if the specified collection is null
+ */
+ public ArrayDeque(Collection<? extends E> c) {
+ allocateElements(c.size());
+ addAll(c);
+ }
+
+ // The main insertion and extraction methods are addFirst,
+ // addLast, pollFirst, pollLast. The other methods are defined in
+ // terms of these.
+
+ /**
+ * Inserts the specified element at the front of this deque.
+ *
+ * @param e the element to add
+ * @throws NullPointerException if the specified element is null
+ */
+ public void addFirst(E e) {
+ if (e == null)
+ throw new NullPointerException();
+ elements[head = (head - 1) & (elements.length - 1)] = e;
+ if (head == tail)
+ doubleCapacity();
+ }
+
+ /**
+ * Inserts the specified element at the end of this deque.
+ *
+ * <p>This method is equivalent to {@link #add}.
+ *
+ * @param e the element to add
+ * @throws NullPointerException if the specified element is null
+ */
+ public void addLast(E e) {
+ if (e == null)
+ throw new NullPointerException();
+ elements[tail] = e;
+ if ( (tail = (tail + 1) & (elements.length - 1)) == head)
+ doubleCapacity();
+ }
+
+ /**
+ * Inserts the specified element at the front of this deque.
+ *
+ * @param e the element to add
+ * @return <tt>true</tt> (as specified by {@link Deque#offerFirst})
+ * @throws NullPointerException if the specified element is null
+ */
+ public boolean offerFirst(E e) {
+ addFirst(e);
+ return true;
+ }
+
+ /**
+ * Inserts the specified element at the end of this deque.
+ *
+ * @param e the element to add
+ * @return <tt>true</tt> (as specified by {@link Deque#offerLast})
+ * @throws NullPointerException if the specified element is null
+ */
+ public boolean offerLast(E e) {
+ addLast(e);
+ return true;
+ }
+
+ /**
+ * @throws NoSuchElementException {@inheritDoc}
+ */
+ public E removeFirst() {
+ E x = pollFirst();
+ if (x == null)
+ throw new NoSuchElementException();
+ return x;
+ }
+
+ /**
+ * @throws NoSuchElementException {@inheritDoc}
+ */
+ public E removeLast() {
+ E x = pollLast();
+ if (x == null)
+ throw new NoSuchElementException();
+ return x;
+ }
+
+ public E pollFirst() {
+ int h = head;
+ E result = elements[h]; // Element is null if deque empty
+ if (result == null)
+ return null;
+ elements[h] = null; // Must null out slot
+ head = (h + 1) & (elements.length - 1);
+ return result;
+ }
+
+ public E pollLast() {
+ int t = (tail - 1) & (elements.length - 1);
+ E result = elements[t];
+ if (result == null)
+ return null;
+ elements[t] = null;
+ tail = t;
+ return result;
+ }
+
+ /**
+ * @throws NoSuchElementException {@inheritDoc}
+ */
+ public E getFirst() {
+ E x = elements[head];
+ if (x == null)
+ throw new NoSuchElementException();
+ return x;
+ }
+
+ /**
+ * @throws NoSuchElementException {@inheritDoc}
+ */
+ public E getLast() {
+ E x = elements[(tail - 1) & (elements.length - 1)];
+ if (x == null)
+ throw new NoSuchElementException();
+ return x;
+ }
+
+ public E peekFirst() {
+ return elements[head]; // elements[head] is null if deque empty
+ }
+
+ public E peekLast() {
+ return elements[(tail - 1) & (elements.length - 1)];
+ }
+
+ /**
+ * Removes the first occurrence of the specified element in this
+ * deque (when traversing the deque from head to tail).
+ * If the deque does not contain the element, it is unchanged.
+ * More formally, removes the first element <tt>e</tt> such that
+ * <tt>o.equals(e)</tt> (if such an element exists).
+ * Returns <tt>true</tt> if this deque contained the specified element
+ * (or equivalently, if this deque changed as a result of the call).
+ *
+ * @param o element to be removed from this deque, if present
+ * @return <tt>true</tt> if the deque contained the specified element
+ */
+ public boolean removeFirstOccurrence(Object o) {
+ if (o == null)
+ return false;
+ int mask = elements.length - 1;
+ int i = head;
+ E x;
+ while ( (x = elements[i]) != null) {
+ if (o.equals(x)) {
+ delete(i);
+ return true;
+ }
+ i = (i + 1) & mask;
+ }
+ return false;
+ }
+
+ /**
+ * Removes the last occurrence of the specified element in this
+ * deque (when traversing the deque from head to tail).
+ * If the deque does not contain the element, it is unchanged.
+ * More formally, removes the last element <tt>e</tt> such that
+ * <tt>o.equals(e)</tt> (if such an element exists).
+ * Returns <tt>true</tt> if this deque contained the specified element
+ * (or equivalently, if this deque changed as a result of the call).
+ *
+ * @param o element to be removed from this deque, if present
+ * @return <tt>true</tt> if the deque contained the specified element
+ */
+ public boolean removeLastOccurrence(Object o) {
+ if (o == null)
+ return false;
+ int mask = elements.length - 1;
+ int i = (tail - 1) & mask;
+ E x;
+ while ( (x = elements[i]) != null) {
+ if (o.equals(x)) {
+ delete(i);
+ return true;
+ }
+ i = (i - 1) & mask;
+ }
+ return false;
+ }
+
+ // *** Queue methods ***
+
+ /**
+ * Inserts the specified element at the end of this deque.
+ *
+ * <p>This method is equivalent to {@link #addLast}.
+ *
+ * @param e the element to add
+ * @return <tt>true</tt> (as specified by {@link Collection#add})
+ * @throws NullPointerException if the specified element is null
+ */
+ public boolean add(E e) {
+ addLast(e);
+ return true;
+ }
+
+ /**
+ * Inserts the specified element at the end of this deque.
+ *
+ * <p>This method is equivalent to {@link #offerLast}.
+ *
+ * @param e the element to add
+ * @return <tt>true</tt> (as specified by {@link Queue#offer})
+ * @throws NullPointerException if the specified element is null
+ */
+ public boolean offer(E e) {
+ return offerLast(e);
+ }
+
+ /**
+ * Retrieves and removes the head of the queue represented by this deque.
+ *
+ * This method differs from {@link #poll poll} only in that it throws an
+ * exception if this deque is empty.
+ *
+ * <p>This method is equivalent to {@link #removeFirst}.
+ *
+ * @return the head of the queue represented by this deque
+ * @throws NoSuchElementException {@inheritDoc}
+ */
+ public E remove() {
+ return removeFirst();
+ }
+
+ /**
+ * Retrieves and removes the head of the queue represented by this deque
+ * (in other words, the first element of this deque), or returns
+ * <tt>null</tt> if this deque is empty.
+ *
+ * <p>This method is equivalent to {@link #pollFirst}.
+ *
+ * @return the head of the queue represented by this deque, or
+ * <tt>null</tt> if this deque is empty
+ */
+ public E poll() {
+ return pollFirst();
+ }
+
+ /**
+ * Retrieves, but does not remove, the head of the queue represented by
+ * this deque. This method differs from {@link #peek peek} only in
+ * that it throws an exception if this deque is empty.
+ *
+ * <p>This method is equivalent to {@link #getFirst}.
+ *
+ * @return the head of the queue represented by this deque
+ * @throws NoSuchElementException {@inheritDoc}
+ */
+ public E element() {
+ return getFirst();
+ }
+
+ /**
+ * Retrieves, but does not remove, the head of the queue represented by
+ * this deque, or returns <tt>null</tt> if this deque is empty.
+ *
+ * <p>This method is equivalent to {@link #peekFirst}.
+ *
+ * @return the head of the queue represented by this deque, or
+ * <tt>null</tt> if this deque is empty
+ */
+ public E peek() {
+ return peekFirst();
+ }
+
+ // *** Stack methods ***
+
+ /**
+ * Pushes an element onto the stack represented by this deque. In other
+ * words, inserts the element at the front of this deque.
+ *
+ * <p>This method is equivalent to {@link #addFirst}.
+ *
+ * @param e the element to push
+ * @throws NullPointerException if the specified element is null
+ */
+ public void push(E e) {
+ addFirst(e);
+ }
+
+ /**
+ * Pops an element from the stack represented by this deque. In other
+ * words, removes and returns the first element of this deque.
+ *
+ * <p>This method is equivalent to {@link #removeFirst()}.
+ *
+ * @return the element at the front of this deque (which is the top
+ * of the stack represented by this deque)
+ * @throws NoSuchElementException {@inheritDoc}
+ */
+ public E pop() {
+ return removeFirst();
+ }
+
+ private void checkInvariants() {
+ assert elements[tail] == null;
+ assert head == tail ? elements[head] == null :
+ (elements[head] != null &&
+ elements[(tail - 1) & (elements.length - 1)] != null);
+ assert elements[(head - 1) & (elements.length - 1)] == null;
+ }
+
+ /**
+ * Removes the element at the specified position in the elements array,
+ * adjusting head and tail as necessary. This can result in motion of
+ * elements backwards or forwards in the array.
+ *
+ * <p>This method is called delete rather than remove to emphasize
+ * that its semantics differ from those of {@link List#remove(int)}.
+ *
+ * @return true if elements moved backwards
+ */
+ private boolean delete(int i) {
+ checkInvariants();
+ final E[] elements = this.elements;
+ final int mask = elements.length - 1;
+ final int h = head;
+ final int t = tail;
+ final int front = (i - h) & mask;
+ final int back = (t - i) & mask;
+
+ // Invariant: head <= i < tail mod circularity
+ if (front >= ((t - h) & mask))
+ throw new ConcurrentModificationException();
+
+ // Optimize for least element motion
+ if (front < back) {
+ if (h <= i) {
+ System.arraycopy(elements, h, elements, h + 1, front);
+ } else { // Wrap around
+ System.arraycopy(elements, 0, elements, 1, i);
+ elements[0] = elements[mask];
+ System.arraycopy(elements, h, elements, h + 1, mask - h);
+ }
+ elements[h] = null;
+ head = (h + 1) & mask;
+ return false;
+ } else {
+ if (i < t) { // Copy the null tail as well
+ System.arraycopy(elements, i + 1, elements, i, back);
+ tail = t - 1;
+ } else { // Wrap around
+ System.arraycopy(elements, i + 1, elements, i, mask - i);
+ elements[mask] = elements[0];
+ System.arraycopy(elements, 1, elements, 0, t);
+ tail = (t - 1) & mask;
+ }
+ return true;
+ }
+ }
+
+ // *** Collection Methods ***
+
+ /**
+ * Returns the number of elements in this deque.
+ *
+ * @return the number of elements in this deque
+ */
+ public int size() {
+ return (tail - head) & (elements.length - 1);
+ }
+
+ /**
+ * Returns <tt>true</tt> if this deque contains no elements.
+ *
+ * @return <tt>true</tt> if this deque contains no elements
+ */
+ public boolean isEmpty() {
+ return head == tail;
+ }
+
+ /**
+ * Returns an iterator over the elements in this deque. The elements
+ * will be ordered from first (head) to last (tail). This is the same
+ * order that elements would be dequeued (via successive calls to
+ * {@link #remove} or popped (via successive calls to {@link #pop}).
+ *
+ * @return an iterator over the elements in this deque
+ */
+ public Iterator<E> iterator() {
+ return new DeqIterator();
+ }
+
+ public Iterator<E> descendingIterator() {
+ return new DescendingIterator();
+ }
+
+ private class DeqIterator implements Iterator<E> {
+ /**
+ * Index of element to be returned by subsequent call to next.
+ */
+ private int cursor = head;
+
+ /**
+ * Tail recorded at construction (also in remove), to stop
+ * iterator and also to check for comodification.
+ */
+ private int fence = tail;
+
+ /**
+ * Index of element returned by most recent call to next.
+ * Reset to -1 if element is deleted by a call to remove.
+ */
+ private int lastRet = -1;
+
+ public boolean hasNext() {
+ return cursor != fence;
+ }
+
+ public E next() {
+ if (cursor == fence)
+ throw new NoSuchElementException();
+ E result = elements[cursor];
+ // This check doesn't catch all possible comodifications,
+ // but does catch the ones that corrupt traversal
+ if (tail != fence || result == null)
+ throw new ConcurrentModificationException();
+ lastRet = cursor;
+ cursor = (cursor + 1) & (elements.length - 1);
+ return result;
+ }
+
+ public void remove() {
+ if (lastRet < 0)
+ throw new IllegalStateException();
+ if (delete(lastRet)) { // if left-shifted, undo increment in next()
+ cursor = (cursor - 1) & (elements.length - 1);
+ fence = tail;
+ }
+ lastRet = -1;
+ }
+ }
+
+ private class DescendingIterator implements Iterator<E> {
+ /*
+ * This class is nearly a mirror-image of DeqIterator, using
+ * tail instead of head for initial cursor, and head instead of
+ * tail for fence.
+ */
+ private int cursor = tail;
+ private int fence = head;
+ private int lastRet = -1;
+
+ public boolean hasNext() {
+ return cursor != fence;
+ }
+
+ public E next() {
+ if (cursor == fence)
+ throw new NoSuchElementException();
+ cursor = (cursor - 1) & (elements.length - 1);
+ E result = elements[cursor];
+ if (head != fence || result == null)
+ throw new ConcurrentModificationException();
+ lastRet = cursor;
+ return result;
+ }
+
+ public void remove() {
+ if (lastRet < 0)
+ throw new IllegalStateException();
+ if (!delete(lastRet)) {
+ cursor = (cursor + 1) & (elements.length - 1);
+ fence = head;
+ }
+ lastRet = -1;
+ }
+ }
+
+ /**
+ * Returns <tt>true</tt> if this deque contains the specified element.
+ * More formally, returns <tt>true</tt> if and only if this deque contains
+ * at least one element <tt>e</tt> such that <tt>o.equals(e)</tt>.
+ *
+ * @param o object to be checked for containment in this deque
+ * @return <tt>true</tt> if this deque contains the specified element
+ */
+ public boolean contains(Object o) {
+ if (o == null)
+ return false;
+ int mask = elements.length - 1;
+ int i = head;
+ E x;
+ while ( (x = elements[i]) != null) {
+ if (o.equals(x))
+ return true;
+ i = (i + 1) & mask;
+ }
+ return false;
+ }
+
+ /**
+ * Removes a single instance of the specified element from this deque.
+ * If the deque does not contain the element, it is unchanged.
+ * More formally, removes the first element <tt>e</tt> such that
+ * <tt>o.equals(e)</tt> (if such an element exists).
+ * Returns <tt>true</tt> if this deque contained the specified element
+ * (or equivalently, if this deque changed as a result of the call).
+ *
+ * <p>This method is equivalent to {@link #removeFirstOccurrence}.
+ *
+ * @param o element to be removed from this deque, if present
+ * @return <tt>true</tt> if this deque contained the specified element
+ */
+ public boolean remove(Object o) {
+ return removeFirstOccurrence(o);
+ }
+
+ /**
+ * Removes all of the elements from this deque.
+ * The deque will be empty after this call returns.
+ */
+ public void clear() {
+ int h = head;
+ int t = tail;
+ if (h != t) { // clear all cells
+ head = tail = 0;
+ int i = h;
+ int mask = elements.length - 1;
+ do {
+ elements[i] = null;
+ i = (i + 1) & mask;
+ } while (i != t);
+ }
+ }
+
+ /**
+ * Returns an array containing all of the elements in this deque
+ * in proper sequence (from first to last element).
+ *
+ * <p>The returned array will be "safe" in that no references to it are
+ * maintained by this deque. (In other words, this method must allocate
+ * a new array). The caller is thus free to modify the returned array.
+ *
+ * <p>This method acts as bridge between array-based and collection-based
+ * APIs.
+ *
+ * @return an array containing all of the elements in this deque
+ */
+ public Object[] toArray() {
+ return copyElements(new Object[size()]);
+ }
+
+ /**
+ * Returns an array containing all of the elements in this deque in
+ * proper sequence (from first to last element); the runtime type of the
+ * returned array is that of the specified array. If the deque fits in
+ * the specified array, it is returned therein. Otherwise, a new array
+ * is allocated with the runtime type of the specified array and the
+ * size of this deque.
+ *
+ * <p>If this deque fits in the specified array with room to spare
+ * (i.e., the array has more elements than this deque), the element in
+ * the array immediately following the end of the deque is set to
+ * <tt>null</tt>.
+ *
+ * <p>Like the {@link #toArray()} method, this method acts as bridge between
+ * array-based and collection-based APIs. Further, this method allows
+ * precise control over the runtime type of the output array, and may,
+ * under certain circumstances, be used to save allocation costs.
+ *
+ * <p>Suppose <tt>x</tt> is a deque known to contain only strings.
+ * The following code can be used to dump the deque into a newly
+ * allocated array of <tt>String</tt>:
+ *
+ * <pre>
+ * String[] y = x.toArray(new String[0]);</pre>
+ *
+ * Note that <tt>toArray(new Object[0])</tt> is identical in function to
+ * <tt>toArray()</tt>.
+ *
+ * @param a the array into which the elements of the deque are to
+ * be stored, if it is big enough; otherwise, a new array of the
+ * same runtime type is allocated for this purpose
+ * @return an array containing all of the elements in this deque
+ * @throws ArrayStoreException if the runtime type of the specified array
+ * is not a supertype of the runtime type of every element in
+ * this deque
+ * @throws NullPointerException if the specified array is null
+ */
+ public <T> T[] toArray(T[] a) {
+ int size = size();
+ if (a.length < size)
+ a = (T[])java.lang.reflect.Array.newInstance(
+ a.getClass().getComponentType(), size);
+ copyElements(a);
+ if (a.length > size)
+ a[size] = null;
+ return a;
+ }
+
+ // *** Object methods ***
+
+ /**
+ * Returns a copy of this deque.
+ *
+ * @return a copy of this deque
+ */
+ public ArrayDeque<E> clone() {
+ try {
+ ArrayDeque<E> result = (ArrayDeque<E>) super.clone();
+ // Classpath local: we don't have Arrays.copyOf yet.
+ // result.elements = Arrays.copyOf(elements, elements.length);
+ result.elements = elements.clone();
+ return result;
+
+ } catch (CloneNotSupportedException e) {
+ throw new AssertionError();
+ }
+ }
+
+ /**
+ * Appease the serialization gods.
+ */
+ private static final long serialVersionUID = 2340985798034038923L;
+
+ /**
+ * Serialize this deque.
+ *
+ * @serialData The current size (<tt>int</tt>) of the deque,
+ * followed by all of its elements (each an object reference) in
+ * first-to-last order.
+ */
+ private void writeObject(ObjectOutputStream s) throws IOException {
+ s.defaultWriteObject();
+
+ // Write out size
+ s.writeInt(size());
+
+ // Write out elements in order.
+ int mask = elements.length - 1;
+ for (int i = head; i != tail; i = (i + 1) & mask)
+ s.writeObject(elements[i]);
+ }
+
+ /**
+ * Deserialize this deque.
+ */
+ private void readObject(ObjectInputStream s)
+ throws IOException, ClassNotFoundException {
+ s.defaultReadObject();
+
+ // Read in size and allocate array
+ int size = s.readInt();
+ allocateElements(size);
+ head = 0;
+ tail = size;
+
+ // Read in all elements in the proper order.
+ for (int i = 0; i < size; i++)
+ elements[i] = (E)s.readObject();
+ }
+}
Added: trunk/core/src/classpath/java/java/util/Deque.java
===================================================================
--- trunk/core/src/classpath/java/java/util/Deque.java (rev 0)
+++ trunk/core/src/classpath/java/java/util/Deque.java 2007-01-07 05:38:13 UTC (rev 2991)
@@ -0,0 +1,547 @@
+/*
+ * Written by Doug Lea and Josh Bloch with assistance from members of
+ * JCP JSR-166 Expert Group and released to the public domain, as explained
+ * at http://creativecommons.org/licenses/publicdomain
+ */
+
+package java.util;
+
+/**
+ * A linear collection that supports element insertion and removal at
+ * both ends. The name <i>deque</i> is short for "double ended queue"
+ * and is usually pronounced "deck". Most <tt>Deque</tt>
+ * implementations place no fixed limits on the number of elements
+ * they may contain, but this interface supports capacity-restricted
+ * deques as well as those with no fixed size limit.
+ *
+ * <p>This interface defines methods to access the elements at both
+ * ends of the deque. Methods are provided to insert, remove, and
+ * examine the element. Each of these methods exists in two forms:
+ * one throws an exception if the operation fails, the other returns a
+ * special value (either <tt>null</tt> or <tt>false</tt>, depending on
+ * the operation). The latter form of the insert operation is
+ * designed specifically for use with capacity-restricted
+ * <tt>Deque</tt> implementations; in most implementations, insert
+ * operations cannot fail.
+ *
+ * <p>The twelve methods described above are summarized in the
+ * following table:
+ *
+ * <p>
+ * <table BORDER CELLPADDING=3 CELLSPACING=1>
+ * <tr>
+ * <td></td>
+ * <td ALIGN=CENTER COLSPAN = 2> <b>First Element (Head)</b></td>
+ * <td ALIGN=CENTER COLSPAN = 2> <b>Last Element (Tail)</b></td>
+ * </tr>
+ * <tr>
+ * <td></td>
+ * <td ALIGN=CENTER><em>Throws exception</em></td>
+ * <td ALIGN=CENTER><em>Special value</em></td>
+ * <td ALIGN=CENTER><em>Throws exception</em></td>
+ * <td ALIGN=CENTER><em>Special value</em></td>
+ * </tr>
+ * <tr>
+ * <td><b>Insert</b></td>
+ * <td>{@link #addFirst addFirst(e)}</td>
+ * <td>{@link #offerFirst offerFirst(e)}</td>
+ * <td>{@link #addLast addLast(e)}</td>
+ * <td>{@link #offerLast offerLast(e)}</td>
+ * </tr>
+ * <tr>
+ * <td><b>Remove</b></td>
+ * <td>{@link #removeFirst removeFirst()}</td>
+ * <td>{@link #pollFirst pollFirst()}</td>
+ * <td>{@link #removeLast removeLast()}</td>
+ * <td>{@link #pollLast pollLast()}</td>
+ * </tr>
+ * <tr>
+ * <td><b>Examine</b></td>
+ * <td>{@link #getFirst getFirst()}</td>
+ * <td>{@link #peekFirst peekFirst()}</td>
+ * <td>{@link #getLast getLast()}</td>
+ * <td>{@link #peekLast peekLast()}</td>
+ * </tr>
+ * </table>
+ *
+ * <p>This interface extends the {@link Queue} interface. When a deque is
+ * used as a queue, FIFO (First-In-First-Out) behavior results. Elements are
+ * added at the end of the deque and removed from the beginning. The methods
+ * inherited from the <tt>Queue</tt> interface are precisely equivalent to
+ * <tt>Deque</tt> methods as indicated in the following table:
+ *
+ * <p>
+ * <table BORDER CELLPADDING=3 CELLSPACING=1>
+ * <tr>
+ * <td ALIGN=CENTER> <b><tt>Queue</tt> Method</b></td>
+ * <td ALIGN=CENTER> <b>Equivalent <tt>Deque</tt> Method</b></td>
+ * </tr>
+ * <tr>
+ * <td>{@link java.util.Queue#add add(e)}</td>
+ * <td>{@link #addLast addLast(e)}</td>
+ * </tr>
+ * <tr>
+ * <td>{@link java.util.Queue#offer offer(e)}</td>
+ * <td>{@link #offerLast offerLast(e)}</td>
+ * </tr>
+ * <tr>
+ * <td>{@link java.util.Queue#remove remove()}</td>
+ * <td>{@link #removeFirst removeFirst()}</td>
+ * </tr>
+ * <tr>
+ * <td>{@link java.util.Queue#poll poll()}</td>
+ * <td>{@link #pollFirst pollFirst()}</td>
+ * </tr>
+ * <tr>
+ * <td>{@link java.util.Queue#element element()}</td>
+ * <td>{@link #getFirst getFirst()}</td>
+ * </tr>
+ * <tr>
+ * <td>{@link java.util.Queue#peek peek()}</td>
+ * <td>{@link #peek peekFirst()}</td>
+ * </tr>
+ * </table>
+ *
+ * <p>Deques can also be used as LIFO (Last-In-First-Out) stacks. This
+ * interface should be used in preference to the legacy {@link Stack} class.
+ * When a deque is used as a stack, elements are pushed and popped from the
+ * beginning of the deque. Stack methods are precisely equivalent to
+ * <tt>Deque</tt> methods as indicated in the table below:
+ *
+ * <p>
+ * <table BORDER CELLPADDING=3 CELLSPACING=1>
+ * <tr>
+ * <td ALIGN=CENTER> <b>Stack Method</b></td>
+ * <td ALIGN=CENTER> <b>Equivalent <tt>Deque</tt> Method</b></td>
+ * </tr>
+ * <tr>
+ * <td>{@link #push push(e)}</td>
+ * <td>{@link #addFirst addFirst(e)}</td>
+ * </tr>
+ * <tr>
+ * <td>{@link #pop pop()}</td>
+ * <td>{@link #removeFirst removeFirst()}</td>
+ * </tr>
+ * <tr>
+ * <td>{@link #peek peek()}</td>
+ * <td>{@link #peekFirst peekFirst()}</td>
+ * </tr>
+ * </table>
+ *
+ * <p>Note that the {@link #peek peek} method works equally well when
+ * a deque is used as a queue or a stack; in either case, elements are
+ * drawn from the beginning of the deque.
+ *
+ * <p>This interface provides two methods to remove interior
+ * elements, {@link #removeFirstOccurrence removeFirstOccurrence} and
+ * {@link #removeLastOccurrence removeLastOccurrence}.
+ *
+ * <p>Unlike the {@link List} interface, this interface does not
+ * provide support for indexed access to elements.
+ *
+ * <p>While <tt>Deque</tt> implementations are not strictly required
+ * to prohibit the insertion of null elements, they are strongly
+ * encouraged to do so. Users of any <tt>Deque</tt> implementations
+ * that do allow null elements are strongly encouraged <i>not</i> to
+ * take advantage of the ability to insert nulls. This is so because
+ * <tt>null</tt> is used as a special return value by various methods
+ * to indicated that the deque is empty.
+ *
+ * <p><tt>Deque</tt> implementations generally do not define
+ * element-based versions of the <tt>equals</tt> and <tt>hashCode</tt>
+ * methods, but instead inherit the identity-based versions from class
+ * <tt>Object</tt>.
+ *
+ * <p>This interface is a member of the <a
+ * href="{@docRoot}/../technotes/guides/collections/index.html"> Java Collections
+ * Framework</a>.
+ *
+ * @author Doug Lea
+ * @author Josh Bloch
+ * @since 1.6
+ * @param <E> the type of elements held in this collection
+ */
+
+public interface Deque<E> extends Queue<E> {
+ /**
+ * Inserts the specified element at the front of this deque if it is
+ * possible to do so immediately without violating capacity restrictions.
+ * When using a capacity-restricted deque, it is generally preferable to
+ * use method {@link #offerFirst}.
+ *
+ * @param e the element to add
+ * @throws IllegalStateException if the element cannot be added at this
+ * time due to capacity restrictions
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this deque
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * @throws IllegalArgumentException if some property of the specified
+ * element prevents it from being added to this deque
+ */
+ void addFirst(E e);
+
+ /**
+ * Inserts the specified element at the end of this deque if it is
+ * possible to do so immediately without violating capacity restrictions.
+ * When using a capacity-restricted deque, it is generally preferable to
+ * use method {@link #offerLast}.
+ *
+ * <p>This method is equivalent to {@link #add}.
+ *
+ * @param e the element to add
+ * @throws IllegalStateException if the element cannot be added at this
+ * time due to capacity restrictions
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this deque
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * @throws IllegalArgumentException if some property of the specified
+ * element prevents it from being added to this deque
+ */
+ void addLast(E e);
+
+ /**
+ * Inserts the specified element at the front of this deque unless it would
+ * violate capacity restrictions. When using a capacity-restricted deque,
+ * this method is generally preferable to the {@link #addFirst} method,
+ * which can fail to insert an element only by throwing an exception.
+ *
+ * @param e the element to add
+ * @return <tt>true</tt> if the element was added to this deque, else
+ * <tt>false</tt>
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this deque
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * @throws IllegalArgumentException if some property of the specified
+ * element prevents it from being added to this deque
+ */
+ boolean offerFirst(E e);
+
+ /**
+ * Inserts the specified element at the end of this deque unless it would
+ * violate capacity restrictions. When using a capacity-restricted deque,
+ * this method is generally preferable to the {@link #addLast} method,
+ * which can fail to insert an element only by throwing an exception.
+ *
+ * @param e the element to add
+ * @return <tt>true</tt> if the element was added to this deque, else
+ * <tt>false</tt>
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this deque
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * @throws IllegalArgumentException if some property of the specified
+ * element prevents it from being added to this deque
+ */
+ boolean offerLast(E e);
+
+ /**
+ * Retrieves and removes the first element of this deque. This method
+ * differs from {@link #pollFirst pollFirst} only in that it throws an
+ * exception if this deque is empty.
+ *
+ * @return the head of this deque
+ * @throws NoSuchElementException if this deque is empty
+ */
+ E removeFirst();
+
+ /**
+ * Retrieves and removes the last element of this deque. This method
+ * differs from {@link #pollLast pollLast} only in that it throws an
+ * exception if this deque is empty.
+ *
+ * @return the tail of this deque
+ * @throws NoSuchElementException if this deque is empty
+ */
+ E removeLast();
+
+ /**
+ * Retrieves and removes the first element of this deque,
+ * or returns <tt>null</tt> if this deque is empty.
+ *
+ * @return the head of this deque, or <tt>null</tt> if this deque is empty
+ */
+ E pollFirst();
+
+ /**
+ * Retrieves and removes the last element of this deque,
+ * or returns <tt>null</tt> if this deque is empty.
+ *
+ * @return the tail of this deque, or <tt>null</tt> if this deque is empty
+ */
+ E pollLast();
+
+ /**
+ * Retrieves, but does not remove, the first element of this deque.
+ *
+ * This method differs from {@link #peekFirst peekFirst} only in that it
+ * throws an exception if this deque is empty.
+ *
+ * @return the head of this deque
+ * @throws NoSuchElementException if this deque is empty
+ */
+ E getFirst();
+
+ /**
+ * Retrieves, but does not remove, the last element of this deque.
+ * This method differs from {@link #peekLast peekLast} only in that it
+ * throws an exception if this deque is empty.
+ *
+ * @return the tail of this deque
+ * @throws NoSuchElementException if this deque is empty
+ */
+ E getLast();
+
+ /**
+ * Retrieves, but does not remove, the first element of this deque,
+ * or returns <tt>null</tt> if this deque is empty.
+ *
+ * @return the head of this deque, or <tt>null</tt> if this deque is empty
+ */
+ E peekFirst();
+
+ /**
+ * Retrieves, but does not remove, the last element of this deque,
+ * or returns <tt>null</tt> if this deque is empty.
+ *
+ * @return the tail of this deque, or <tt>null</tt> if this deque is empty
+ */
+ E peekLast();
+
+ /**
+ * Removes the first occurrence of the specified element from this deque.
+ * If the deque does not contain the element, it is unchanged.
+ * More formally, removes the first element <tt>e</tt> such that
+ * <tt>(o==null ? e==null : o.equals(e))</tt>
+ * (if such an element exists).
+ * Returns <tt>true</tt> if this deque contained the specified element
+ * (or equivalently, if this deque changed as a result of the call).
+ *
+ * @param o element to be removed from this deque, if present
+ * @return <tt>true</tt> if an element was removed as a result of this call
+ * @throws ClassCastException if the class of the specified element
+ * is incompatible with this deque (optional)
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements (optional)
+ */
+ boolean removeFirstOccurrence(Object o);
+
+ /**
+ * Removes the last occurrence of the specified element from this deque.
+ * If the deque does not contain the element, it is unchanged.
+ * More formally, removes the last element <tt>e</tt> such that
+ * <tt>(o==null ? e==null : o.equals(e))</tt>
+ * (if such an element exists).
+ * Returns <tt>true</tt> if this deque contained the specified element
+ * (or equivalently, if this deque changed as a result of the call).
+ *
+ * @param o element to be removed from this deque, if present
+ * @return <tt>true</tt> if an element was removed as a result of this call
+ * @throws ClassCastException if the class of the specified element
+ * is incompatible with this deque (optional)
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements (optional)
+ */
+ boolean removeLastOccurrence(Object o);
+
+ // *** Queue methods ***
+
+ /**
+ * Inserts the specified element into the queue represented by this deque
+ * (in other words, at the tail of this deque) if it is possible to do so
+ * immediately without violating capacity restrictions, returning
+ * <tt>true</tt> upon success and throwing an
+ * <tt>IllegalStateException</tt> if no space is currently available.
+ * When using a capacity-restricted deque, it is generally preferable to
+ * use {@link #offer(Object) offer}.
+ *
+ * <p>This method is equivalent to {@link #addLast}.
+ *
+ * @param e the element to add
+ * @return <tt>true</tt> (as specified by {@link Collection#add})
+ * @throws IllegalStateException if the element cannot be added at this
+ * time due to capacity restrictions
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this deque
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * @throws IllegalArgumentException if some property of the specified
+ * element prevents it from being added to this deque
+ */
+ boolean add(E e);
+
+ /**
+ * Inserts the specified element into the queue represented by this deque
+ * (in other words, at the tail of this deque) if it is possible to do so
+ * immediately without violating capacity restrictions, returning
+ * <tt>true</tt> upon success and <tt>false</tt> if no space is currently
+ * available. When using a capacity-restricted deque, this method is
+ * generally preferable to the {@link #add} method, which can fail to
+ * insert an element only by throwing an exception.
+ *
+ * <p>This method is equivalent to {@link #offerLast}.
+ *
+ * @param e the element to add
+ * @return <tt>true</tt> if the element was added to this deque, else
+ * <tt>false</tt>
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this deque
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * @throws IllegalArgumentException if some property of the specified
+ * element prevents it from being added to this deque
+ */
+ boolean offer(E e);
+
+ /**
+ * Retrieves and removes the head of the queue represented by this deque
+ * (in other words, the first element of this deque).
+ * This method differs from {@link #poll poll} only in that it throws an
+ * exception if this deque is empty.
+ *
+ * <p>This method is equivalent to {@link #removeFirst()}.
+ *
+ * @return the head of the queue represented by this deque
+ * @throws NoSuchElementException if this deque is empty
+ */
+ E remove();
+
+ /**
+ * Retrieves and removes the head of the queue represented by this deque
+ * (in other words, the first element of this deque), or returns
+ * <tt>null</tt> if this deque is empty.
+ *
+ * <p>This method is equivalent to {@link #pollFirst()}.
+ *
+ * @return the first element of this deque, or <tt>null</tt> if
+ * this deque is empty
+ */
+ E poll();
+
+ /**
+ * Retrieves, but does not remove, the head of the queue represented by
+ * this deque (in other words, the first element of this deque).
+ * This method differs from {@link #peek peek} only in that it throws an
+ * exception if this deque is empty.
+ *
+ * <p>This method is equivalent to {@link #getFirst()}.
+ *
+ * @return the head of the queue represented by this deque
+ * @throws NoSuchElementException if this deque is empty
+ */
+ E element();
+
+ /**
+ * Retrieves, but does not remove, the head of the queue represented by
+ * this deque (in other words, the first element of this deque), or
+ * returns <tt>null</tt> if this deque is empty.
+ *
+ * <p>This method is equivalent to {@link #peekFirst()}.
+ *
+ * @return the head of the queue represented by this deque, or
+ * <tt>null</tt> if this deque is empty
+ */
+ E peek();
+
+
+ // *** Stack methods ***
+
+ /**
+ * Pushes an element onto the stack represented by this deque (in other
+ * words, at the head of this deque) if it is possible to do so
+ * immediately without violating capacity restrictions, returning
+ * <tt>true</tt> upon success and throwing an
+ * <tt>IllegalStateException</tt> if no space is currently available.
+ *
+ * <p>This method is equivalent to {@link #addFirst}.
+ *
+ * @param e the element to push
+ * @throws IllegalStateException if the element cannot be added at this
+ * time due to capacity restrictions
+ * @throws ClassCastException if the class of the specified element
+ * prevents it from being added to this deque
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements
+ * @throws IllegalArgumentException if some property of the specified
+ * element prevents it from being added to this deque
+ */
+ void push(E e);
+
+ /**
+ * Pops an element from the stack represented by this deque. In other
+ * words, removes and returns the first element of this deque.
+ *
+ * <p>This method is equivalent to {@link #removeFirst()}.
+ *
+ * @return the element at the front of this deque (which is the top
+ * of the stack represented by this deque)
+ * @throws NoSuchElementException if this deque is empty
+ */
+ E pop();
+
+
+ // *** Collection methods ***
+
+ /**
+ * Removes the first occurrence of the specified element from this deque.
+ * If the deque does not contain the element, it is unchanged.
+ * More formally, removes the first element <tt>e</tt> such that
+ * <tt>(o==null ? e==null : o.equals(e))</tt>
+ * (if such an element exists).
+ * Returns <tt>true</tt> if this deque contained the specified element
+ * (or equivalently, if this deque changed as a result of the call).
+ *
+ * <p>This method is equivalent to {@link #removeFirstOccurrence}.
+ *
+ * @param o element to be removed from this deque, if present
+ * @return <tt>true</tt> if an element was removed as a result of this call
+ * @throws ClassCastException if the class of the specified element
+ * is incompatible with this deque (optional)
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements (optional)
+ */
+ boolean remove(Object o);
+
+ /**
+ * Returns <tt>true</tt> if this deque contains the specified element.
+ * More formally, returns <tt>true</tt> if and only if this deque contains
+ * at least one element <tt>e</tt> such that
+ * <tt>(o==null ? e==null : o.equals(e))</tt>.
+ *
+ * @param o element whose presence in this deque is to be tested
+ * @return <tt>true</tt> if this deque contains the specified element
+ * @throws ClassCastException if the type of the specified element
+ * is incompatible with this deque (optional)
+ * @throws NullPointerException if the specified element is null and this
+ * deque does not permit null elements (optional)
+ */
+ boolean contains(Object o);
+
+ /**
+ * Returns the number of elements in this deque.
+ *
+ * @return the number of elements in this deque
+ */
+ public int size();
+
+ /**
+ * Returns an iterator over the elements in this deque in proper sequence.
+ * The elements will be returned in order from first (head) to last (tail).
+ *
+ * @return an iterator over the elements in this deque in proper sequence
+ */
+ Iterator<E> iterator();
+
+ /**
+ * Returns an iterator over the elements in this deque in reverse
+ * sequential order. The elements will be returned in order from
+ * last (tail) to first (head).
+ *
+ * @return an iterator over the elements in this deque in reverse
+ * sequence
+ */
+ Iterator<E> descendingIterator();
+
+}
Added: trunk/core/src/classpath/java/java/util/NavigableMap.java
===================================================================
--- trunk/core/src/classpath/java/java/util/NavigableMap.java (rev 0)
+++ trunk/core/src/classpath/java/java/util/NavigableMap.java 2007-01-07 05:38:13 UTC (rev 2991)
@@ -0,0 +1,395 @@
+/*
+ * Written by Doug Lea and Josh Bloch with assistance from members of JCP
+ * JSR-166 Expert Group and released to the public domain, as explained at
+ * http://creativecommons.org/licenses/publicdomain
+ */
+
+package java.util;
+
+/**
+ * A {@link SortedMap} extended with navigation methods returning the
+ * closest matches for given search targets. Methods
+ * {@code lowerEntry}, {@code floorEntry}, {@code ceilingEntry},
+ * and {@code higherEntry} return {@code Map.Entry} objects
+ * associated with keys respectively less than, less than or equal,
+ * greater than or equal, and greater than a given key, returning
+ * {@code null} if there is no such key. Similarly, methods
+ * {@code lowerKey}, {@code floorKey}, {@code ceilingKey}, and
+ * {@code higherKey} return only the associated keys. All of these
+ * methods are designed for locating, not traversing entries.
+ *
+ * <p>A {@code NavigableMap} may be accessed and traversed in either
+ * ascending or descending key order. The {@code descendingMap}
+ * method returns a view of the map with the senses of all relational
+ * and directional methods inverted. The performance of ascending
+ * operations and views is likely to be faster than that of descending
+ * ones. Methods {@code subMap}, {@code headMap},
+ * and {@code tailMap} differ from the like-named {@code
+ * SortedMap} methods in accepting additional arguments describing
+ * whether lower and upper bounds are inclusive versus exclusive.
+ * Submaps of any {@code NavigableMap} must implement the {@code
+ * NavigableMap} interface.
+ *
+ * <p>This interface additionally defines methods {@code firstEntry},
+ * {@code pollFirstEntry}, {@code lastEnt...
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