harmony-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From ndbe...@apache.org
Subject svn commit: r421111 [5/11] - in /incubator/harmony/enhanced/classlib/trunk/sandbox: ./ juc-proposal/ juc-proposal/concurrent/ juc-proposal/concurrent/.settings/ juc-proposal/concurrent/META-INF/ juc-proposal/concurrent/src/ juc-proposal/concurrent/src/...
Date Wed, 12 Jul 2006 04:12:08 GMT
Added: incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/LinkedBlockingQueue.java
URL: http://svn.apache.org/viewvc/incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/LinkedBlockingQueue.java?rev=421111&view=auto
==============================================================================
--- incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/LinkedBlockingQueue.java (added)
+++ incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/LinkedBlockingQueue.java Tue Jul 11 21:12:04 2006
@@ -0,0 +1,720 @@
+/*
+ * Written by Doug Lea 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.concurrent;
+import java.util.concurrent.atomic.*;
+import java.util.concurrent.locks.*;
+import java.util.*;
+
+/**
+ * An optionally-bounded {@linkplain BlockingQueue blocking queue} based on
+ * linked nodes.
+ * This queue orders elements FIFO (first-in-first-out).
+ * The <em>head</em> of the queue is that element that has been on the
+ * queue the longest time.
+ * The <em>tail</em> of the queue is that element that has been on the
+ * queue the shortest time. New elements
+ * are inserted at the tail of the queue, and the queue retrieval
+ * operations obtain elements at the head of the queue.
+ * Linked queues typically have higher throughput than array-based queues but
+ * less predictable performance in most concurrent applications.
+ *
+ * <p> The optional capacity bound constructor argument serves as a
+ * way to prevent excessive queue expansion. The capacity, if unspecified,
+ * is equal to {@link Integer#MAX_VALUE}.  Linked nodes are
+ * dynamically created upon each insertion unless this would bring the
+ * queue above capacity.
+ *
+ * <p>This class implements 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}/../guide/collections/index.html">
+ * Java Collections Framework</a>.
+ *
+ * @since 1.5
+ * @author Doug Lea
+ * @param <E> the type of elements held in this collection
+ *
+ **/
+public class LinkedBlockingQueue<E> extends AbstractQueue<E>
+        implements BlockingQueue<E>, java.io.Serializable {
+    private static final long serialVersionUID = -6903933977591709194L;
+
+    /*
+     * A variant of the "two lock queue" algorithm.  The putLock gates
+     * entry to put (and offer), and has an associated condition for
+     * waiting puts.  Similarly for the takeLock.  The "count" field
+     * that they both rely on is maintained as an atomic to avoid
+     * needing to get both locks in most cases. Also, to minimize need
+     * for puts to get takeLock and vice-versa, cascading notifies are
+     * used. When a put notices that it has enabled at least one take,
+     * it signals taker. That taker in turn signals others if more
+     * items have been entered since the signal. And symmetrically for
+     * takes signalling puts. Operations such as remove(Object) and
+     * iterators acquire both locks.
+    */
+
+    /**
+     * Linked list node class
+     */
+    static class Node<E> {
+        /** The item, volatile to ensure barrier separating write and read */
+        volatile E item;
+        Node<E> next;
+        Node(E x) { item = x; }
+    }
+
+    /** The capacity bound, or Integer.MAX_VALUE if none */
+    private final int capacity;
+
+    /** Current number of elements */
+    private final AtomicInteger count = new AtomicInteger(0);
+
+    /** Head of linked list */
+    private transient Node<E> head;
+
+    /** Tail of linked list */
+    private transient Node<E> last;
+
+    /** Lock held by take, poll, etc */
+    private final ReentrantLock takeLock = new ReentrantLock();
+
+    /** Wait queue for waiting takes */
+    private final Condition notEmpty = takeLock.newCondition();
+
+    /** Lock held by put, offer, etc */
+    private final ReentrantLock putLock = new ReentrantLock();
+
+    /** Wait queue for waiting puts */
+    private final Condition notFull = putLock.newCondition();
+
+    /**
+     * Signal a waiting take. Called only from put/offer (which do not
+     * otherwise ordinarily lock takeLock.)
+     */
+    private void signalNotEmpty() {
+        final ReentrantLock takeLock = this.takeLock;
+        takeLock.lock();
+        try {
+            notEmpty.signal();
+        } finally {
+            takeLock.unlock();
+        }
+    }
+
+    /**
+     * Signal a waiting put. Called only from take/poll.
+     */
+    private void signalNotFull() {
+        final ReentrantLock putLock = this.putLock;
+        putLock.lock();
+        try {
+            notFull.signal();
+        } finally {
+            putLock.unlock();
+        }
+    }
+
+    /**
+     * Create a node and link it at end of queue
+     * @param x the item
+     */
+    private void insert(E x) {
+        last = last.next = new Node<E>(x);
+    }
+
+    /**
+     * Remove a node from head of queue,
+     * @return the node
+     */
+    private E extract() {
+        Node<E> first = head.next;
+        head = first;
+        E x = first.item;
+        first.item = null;
+        return x;
+    }
+
+    /**
+     * Lock to prevent both puts and takes.
+     */
+    private void fullyLock() {
+        putLock.lock();
+        takeLock.lock();
+    }
+
+    /**
+     * Unlock to allow both puts and takes.
+     */
+    private void fullyUnlock() {
+        takeLock.unlock();
+        putLock.unlock();
+    }
+
+
+    /**
+     * Creates a <tt>LinkedBlockingQueue</tt> with a capacity of
+     * {@link Integer#MAX_VALUE}.
+     */
+    public LinkedBlockingQueue() {
+        this(Integer.MAX_VALUE);
+    }
+
+    /**
+     * Creates a <tt>LinkedBlockingQueue</tt> with the given (fixed) capacity.
+     *
+     * @param capacity the capacity of this queue.
+     * @throws IllegalArgumentException if <tt>capacity</tt> is not greater
+     *         than zero.
+     */
+    public LinkedBlockingQueue(int capacity) {
+        if (capacity <= 0) throw new IllegalArgumentException();
+        this.capacity = capacity;
+        last = head = new Node<E>(null);
+    }
+
+    /**
+     * Creates a <tt>LinkedBlockingQueue</tt> with a capacity of
+     * {@link Integer#MAX_VALUE}, initially containing the elements of the
+     * given collection,
+     * added in traversal order of the collection's iterator.
+     * @param c the collection of elements to initially contain
+     * @throws NullPointerException if <tt>c</tt> or any element within it
+     * is <tt>null</tt>
+     */
+    public LinkedBlockingQueue(Collection<? extends E> c) {
+        this(Integer.MAX_VALUE);
+        for (Iterator<? extends E> it = c.iterator(); it.hasNext();)
+            add(it.next());
+    }
+
+
+    // this doc comment is overridden to remove the reference to collections
+    // greater in size than Integer.MAX_VALUE
+    /**
+     * Returns the number of elements in this queue.
+     *
+     * @return  the number of elements in this queue.
+     */
+    public int size() {
+        return count.get();
+    }
+
+    // this doc comment is a modified copy of the inherited doc comment,
+    // without the reference to unlimited queues.
+    /**
+     * Returns the number of elements that this queue can ideally (in
+     * the absence of memory or resource constraints) accept without
+     * blocking. This is always equal to the initial capacity of this queue
+     * less the current <tt>size</tt> of this queue.
+     * <p>Note that you <em>cannot</em> always tell if
+     * an attempt to <tt>add</tt> an element will succeed by
+     * inspecting <tt>remainingCapacity</tt> because it may be the
+     * case that a waiting consumer is ready to <tt>take</tt> an
+     * element out of an otherwise full queue.
+     */
+    public int remainingCapacity() {
+        return capacity - count.get();
+    }
+
+    /**
+     * Adds the specified element to the tail of this queue, waiting if
+     * necessary for space to become available.
+     * @param o the element to add
+     * @throws InterruptedException if interrupted while waiting.
+     * @throws NullPointerException if the specified element is <tt>null</tt>.
+     */
+    public void put(E o) throws InterruptedException {
+        if (o == null) throw new NullPointerException();
+        // Note: convention in all put/take/etc is to preset
+        // local var holding count  negative to indicate failure unless set.
+        int c = -1;
+        final ReentrantLock putLock = this.putLock;
+        final AtomicInteger count = this.count;
+        putLock.lockInterruptibly();
+        try {
+            /*
+             * Note that count is used in wait guard even though it is
+             * not protected by lock. This works because count can
+             * only decrease at this point (all other puts are shut
+             * out by lock), and we (or some other waiting put) are
+             * signalled if it ever changes from
+             * capacity. Similarly for all other uses of count in
+             * other wait guards.
+             */
+            try {
+                while (count.get() == capacity)
+                    notFull.await();
+            } catch (InterruptedException ie) {
+                notFull.signal(); // propagate to a non-interrupted thread
+                throw ie;
+            }
+            insert(o);
+            c = count.getAndIncrement();
+            if (c + 1 < capacity)
+                notFull.signal();
+        } finally {
+            putLock.unlock();
+        }
+        if (c == 0)
+            signalNotEmpty();
+    }
+
+    /**
+     * Inserts the specified element at the tail of this queue, waiting if
+     * necessary up to the specified wait time for space to become available.
+     * @param o the element to add
+     * @param timeout how long to wait before giving up, in units of
+     * <tt>unit</tt>
+     * @param unit a <tt>TimeUnit</tt> determining how to interpret the
+     * <tt>timeout</tt> parameter
+     * @return <tt>true</tt> if successful, or <tt>false</tt> if
+     * the specified waiting time elapses before space is available.
+     * @throws InterruptedException if interrupted while waiting.
+     * @throws NullPointerException if the specified element is <tt>null</tt>.
+     */
+    public boolean offer(E o, long timeout, TimeUnit unit)
+        throws InterruptedException {
+
+        if (o == null) throw new NullPointerException();
+        long nanos = unit.toNanos(timeout);
+        int c = -1;
+        final ReentrantLock putLock = this.putLock;
+        final AtomicInteger count = this.count;
+        putLock.lockInterruptibly();
+        try {
+            for (;;) {
+                if (count.get() < capacity) {
+                    insert(o);
+                    c = count.getAndIncrement();
+                    if (c + 1 < capacity)
+                        notFull.signal();
+                    break;
+                }
+                if (nanos <= 0)
+                    return false;
+                try {
+                    nanos = notFull.awaitNanos(nanos);
+                } catch (InterruptedException ie) {
+                    notFull.signal(); // propagate to a non-interrupted thread
+                    throw ie;
+                }
+            }
+        } finally {
+            putLock.unlock();
+        }
+        if (c == 0)
+            signalNotEmpty();
+        return true;
+    }
+
+    /**
+     * Inserts the specified element at the tail of this queue if possible,
+     * returning immediately if this queue is full.
+     *
+     * @param o the element to add.
+     * @return <tt>true</tt> if it was possible to add the element to
+     *         this queue, else <tt>false</tt>
+     * @throws NullPointerException if the specified element is <tt>null</tt>
+     */
+    public boolean offer(E o) {
+        if (o == null) throw new NullPointerException();
+        final AtomicInteger count = this.count;
+        if (count.get() == capacity)
+            return false;
+        int c = -1;
+        final ReentrantLock putLock = this.putLock;
+        putLock.lock();
+        try {
+            if (count.get() < capacity) {
+                insert(o);
+                c = count.getAndIncrement();
+                if (c + 1 < capacity)
+                    notFull.signal();
+            }
+        } finally {
+            putLock.unlock();
+        }
+        if (c == 0)
+            signalNotEmpty();
+        return c >= 0;
+    }
+
+
+    public E take() throws InterruptedException {
+        E x;
+        int c = -1;
+        final AtomicInteger count = this.count;
+        final ReentrantLock takeLock = this.takeLock;
+        takeLock.lockInterruptibly();
+        try {
+            try {
+                while (count.get() == 0)
+                    notEmpty.await();
+            } catch (InterruptedException ie) {
+                notEmpty.signal(); // propagate to a non-interrupted thread
+                throw ie;
+            }
+
+            x = extract();
+            c = count.getAndDecrement();
+            if (c > 1)
+                notEmpty.signal();
+        } finally {
+            takeLock.unlock();
+        }
+        if (c == capacity)
+            signalNotFull();
+        return x;
+    }
+
+    public E poll(long timeout, TimeUnit unit) throws InterruptedException {
+        E x = null;
+        int c = -1;
+        long nanos = unit.toNanos(timeout);
+        final AtomicInteger count = this.count;
+        final ReentrantLock takeLock = this.takeLock;
+        takeLock.lockInterruptibly();
+        try {
+            for (;;) {
+                if (count.get() > 0) {
+                    x = extract();
+                    c = count.getAndDecrement();
+                    if (c > 1)
+                        notEmpty.signal();
+                    break;
+                }
+                if (nanos <= 0)
+                    return null;
+                try {
+                    nanos = notEmpty.awaitNanos(nanos);
+                } catch (InterruptedException ie) {
+                    notEmpty.signal(); // propagate to a non-interrupted thread
+                    throw ie;
+                }
+            }
+        } finally {
+            takeLock.unlock();
+        }
+        if (c == capacity)
+            signalNotFull();
+        return x;
+    }
+
+    public E poll() {
+        final AtomicInteger count = this.count;
+        if (count.get() == 0)
+            return null;
+        E x = null;
+        int c = -1;
+        final ReentrantLock takeLock = this.takeLock;
+        takeLock.lock();
+        try {
+            if (count.get() > 0) {
+                x = extract();
+                c = count.getAndDecrement();
+                if (c > 1)
+                    notEmpty.signal();
+            }
+        } finally {
+            takeLock.unlock();
+        }
+        if (c == capacity)
+            signalNotFull();
+        return x;
+    }
+
+
+    public E peek() {
+        if (count.get() == 0)
+            return null;
+        final ReentrantLock takeLock = this.takeLock;
+        takeLock.lock();
+        try {
+            Node<E> first = head.next;
+            if (first == null)
+                return null;
+            else
+                return first.item;
+        } finally {
+            takeLock.unlock();
+        }
+    }
+
+    public boolean remove(Object o) {
+        if (o == null) return false;
+        boolean removed = false;
+        fullyLock();
+        try {
+            Node<E> trail = head;
+            Node<E> p = head.next;
+            while (p != null) {
+                if (o.equals(p.item)) {
+                    removed = true;
+                    break;
+                }
+                trail = p;
+                p = p.next;
+            }
+            if (removed) {
+                p.item = null;
+                trail.next = p.next;
+                if (count.getAndDecrement() == capacity)
+                    notFull.signalAll();
+            }
+        } finally {
+            fullyUnlock();
+        }
+        return removed;
+    }
+
+    public Object[] toArray() {
+        fullyLock();
+        try {
+            int size = count.get();
+            Object[] a = new Object[size];
+            int k = 0;
+            for (Node<E> p = head.next; p != null; p = p.next)
+                a[k++] = p.item;
+            return a;
+        } finally {
+            fullyUnlock();
+        }
+    }
+
+    public <T> T[] toArray(T[] a) {
+        fullyLock();
+        try {
+            int size = count.get();
+            if (a.length < size)
+                a = (T[])java.lang.reflect.Array.newInstance
+                    (a.getClass().getComponentType(), size);
+
+            int k = 0;
+            for (Node p = head.next; p != null; p = p.next)
+                a[k++] = (T)p.item;
+            return a;
+        } finally {
+            fullyUnlock();
+        }
+    }
+
+    public String toString() {
+        fullyLock();
+        try {
+            return super.toString();
+        } finally {
+            fullyUnlock();
+        }
+    }
+
+    public void clear() {
+        fullyLock();
+        try {
+            head.next = null;
+            if (count.getAndSet(0) == capacity)
+                notFull.signalAll();
+        } finally {
+            fullyUnlock();
+        }
+    }
+
+    public int drainTo(Collection<? super E> c) {
+        if (c == null)
+            throw new NullPointerException();
+        if (c == this)
+            throw new IllegalArgumentException();
+        Node first;
+        fullyLock();
+        try {
+            first = head.next;
+            head.next = null;
+            if (count.getAndSet(0) == capacity)
+                notFull.signalAll();
+        } finally {
+            fullyUnlock();
+        }
+        // Transfer the elements outside of locks
+        int n = 0;
+        for (Node<E> p = first; p != null; p = p.next) {
+            c.add(p.item);
+            p.item = null;
+            ++n;
+        }
+        return n;
+    }
+        
+    public int drainTo(Collection<? super E> c, int maxElements) {
+        if (c == null)
+            throw new NullPointerException();
+        if (c == this)
+            throw new IllegalArgumentException();
+        if (maxElements <= 0)
+            return 0;
+        fullyLock();
+        try {
+            int n = 0;
+            Node<E> p = head.next;
+            while (p != null && n < maxElements) {
+                c.add(p.item);
+                p.item = null;
+                p = p.next;
+                ++n;
+            }
+            if (n != 0) {
+                head.next = p;
+                if (count.getAndAdd(-n) == capacity)
+                    notFull.signalAll();
+            }
+            return n;
+        } finally {
+            fullyUnlock();
+        }
+    }
+
+    /**
+     * Returns an iterator over the elements in this queue in proper sequence.
+     * The returned <tt>Iterator</tt> is a "weakly consistent" iterator that
+     * will never throw {@link java.util.ConcurrentModificationException},
+     * and guarantees to traverse elements as they existed upon
+     * construction of the iterator, and may (but is not guaranteed to)
+     * reflect any modifications subsequent to construction.
+     *
+     * @return an iterator over the elements in this queue in proper sequence.
+     */
+    public Iterator<E> iterator() {
+      return new Itr();
+    }
+
+    private class Itr implements Iterator<E> {
+        /*
+         * Basic weak-consistent iterator.  At all times hold the next
+         * item to hand out so that if hasNext() reports true, we will
+         * still have it to return even if lost race with a take etc.
+         */
+        private Node<E> current;
+        private Node<E> lastRet;
+        private E currentElement;
+
+        Itr() {
+            final ReentrantLock putLock = LinkedBlockingQueue.this.putLock;
+            final ReentrantLock takeLock = LinkedBlockingQueue.this.takeLock;
+            putLock.lock();
+            takeLock.lock();
+            try {
+                current = head.next;
+                if (current != null)
+                    currentElement = current.item;
+            } finally {
+                takeLock.unlock();
+                putLock.unlock();
+            }
+        }
+
+        public boolean hasNext() {
+            return current != null;
+        }
+
+        public E next() {
+            final ReentrantLock putLock = LinkedBlockingQueue.this.putLock;
+            final ReentrantLock takeLock = LinkedBlockingQueue.this.takeLock;
+            putLock.lock();
+            takeLock.lock();
+            try {
+                if (current == null)
+                    throw new NoSuchElementException();
+                E x = currentElement;
+                lastRet = current;
+                current = current.next;
+                if (current != null)
+                    currentElement = current.item;
+                return x;
+            } finally {
+                takeLock.unlock();
+                putLock.unlock();
+            }
+        }
+
+        public void remove() {
+            if (lastRet == null)
+                throw new IllegalStateException();
+            final ReentrantLock putLock = LinkedBlockingQueue.this.putLock;
+            final ReentrantLock takeLock = LinkedBlockingQueue.this.takeLock;
+            putLock.lock();
+            takeLock.lock();
+            try {
+                Node<E> node = lastRet;
+                lastRet = null;
+                Node<E> trail = head;
+                Node<E> p = head.next;
+                while (p != null && p != node) {
+                    trail = p;
+                    p = p.next;
+                }
+                if (p == node) {
+                    p.item = null;
+                    trail.next = p.next;
+                    int c = count.getAndDecrement();
+                    if (c == capacity)
+                        notFull.signalAll();
+                }
+            } finally {
+                takeLock.unlock();
+                putLock.unlock();
+            }
+        }
+    }
+
+    /**
+     * Save the state to a stream (that is, serialize it).
+     *
+     * @serialData The capacity is emitted (int), followed by all of
+     * its elements (each an <tt>Object</tt>) in the proper order,
+     * followed by a null
+     * @param s the stream
+     */
+    private void writeObject(java.io.ObjectOutputStream s)
+        throws java.io.IOException {
+
+        fullyLock();
+        try {
+            // Write out any hidden stuff, plus capacity
+            s.defaultWriteObject();
+
+            // Write out all elements in the proper order.
+            for (Node<E> p = head.next; p != null; p = p.next)
+                s.writeObject(p.item);
+
+            // Use trailing null as sentinel
+            s.writeObject(null);
+        } finally {
+            fullyUnlock();
+        }
+    }
+
+    /**
+     * Reconstitute this queue instance from a stream (that is,
+     * deserialize it).
+     * @param s the stream
+     */
+    private void readObject(java.io.ObjectInputStream s)
+        throws java.io.IOException, ClassNotFoundException {
+        // Read in capacity, and any hidden stuff
+        s.defaultReadObject();
+
+        count.set(0);
+        last = head = new Node<E>(null);
+
+        // Read in all elements and place in queue
+        for (;;) {
+            E item = (E)s.readObject();
+            if (item == null)
+                break;
+            add(item);
+        }
+    }
+}

Propchange: incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/LinkedBlockingQueue.java
------------------------------------------------------------------------------
    svn:eol-style = native

Added: incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/PriorityBlockingQueue.java
URL: http://svn.apache.org/viewvc/incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/PriorityBlockingQueue.java?rev=421111&view=auto
==============================================================================
--- incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/PriorityBlockingQueue.java (added)
+++ incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/PriorityBlockingQueue.java Tue Jul 11 21:12:04 2006
@@ -0,0 +1,455 @@
+/*
+ * Written by Doug Lea 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.concurrent;
+
+import java.util.concurrent.locks.*;
+import java.util.*;
+
+/**
+ * An unbounded {@linkplain BlockingQueue blocking queue} that uses
+ * the same ordering rules as class {@link PriorityQueue} and supplies
+ * blocking retrieval operations.  While this queue is logically
+ * unbounded, attempted additions may fail due to resource exhaustion
+ * (causing <tt>OutOfMemoryError</tt>). This class does not permit
+ * <tt>null</tt> elements.  A priority queue relying on natural
+ * ordering also does not permit insertion of non-comparable objects
+ * (doing so results in <tt>ClassCastException</tt>).
+ *
+ * <p>This class implements all of the <em>optional</em> methods
+ * of the {@link Collection} and {@link Iterator} interfaces.
+ * <p>The Iterator provided in method {@link #iterator()} is
+ * <em>not</em> guaranteed to traverse the elements of the
+ * PriorityBlockingQueue in any particular order. If you need ordered
+ * traversal, consider using <tt>Arrays.sort(pq.toArray())</tt>.
+ *
+ * <p>This class is a member of the
+ * <a href="{@docRoot}/../guide/collections/index.html">
+ * Java Collections Framework</a>.
+ *
+ * @since 1.5
+ * @author Doug Lea
+ * @param <E> the type of elements held in this collection
+ */
+public class PriorityBlockingQueue<E> extends AbstractQueue<E>
+    implements BlockingQueue<E>, java.io.Serializable {
+    private static final long serialVersionUID = 5595510919245408276L;
+
+    private final PriorityQueue<E> q;
+    private final ReentrantLock lock = new ReentrantLock(true);
+    private final Condition notEmpty = lock.newCondition();
+
+    /**
+     * Creates a <tt>PriorityBlockingQueue</tt> with the default initial 
+     * capacity
+     * (11) that orders its elements according to their natural
+     * ordering (using <tt>Comparable</tt>).
+     */
+    public PriorityBlockingQueue() {
+        q = new PriorityQueue<E>();
+    }
+
+    /**
+     * Creates a <tt>PriorityBlockingQueue</tt> with the specified initial
+     * capacity
+     * that orders its elements according to their natural ordering
+     * (using <tt>Comparable</tt>).
+     *
+     * @param initialCapacity the initial capacity for this priority queue.
+     * @throws IllegalArgumentException if <tt>initialCapacity</tt> is less
+     * than 1
+     */
+    public PriorityBlockingQueue(int initialCapacity) {
+        q = new PriorityQueue<E>(initialCapacity, null);
+    }
+
+    /**
+     * Creates a <tt>PriorityBlockingQueue</tt> with the specified initial
+     * capacity
+     * that orders its elements according to the specified comparator.
+     *
+     * @param initialCapacity the initial capacity for this priority queue.
+     * @param comparator the comparator used to order this priority queue.
+     * If <tt>null</tt> then the order depends on the elements' natural
+     * ordering.
+     * @throws IllegalArgumentException if <tt>initialCapacity</tt> is less
+     * than 1
+     */
+    public PriorityBlockingQueue(int initialCapacity,
+                                 Comparator<? super E> comparator) {
+        q = new PriorityQueue<E>(initialCapacity, comparator);
+    }
+
+    /**
+     * Creates a <tt>PriorityBlockingQueue</tt> containing the elements
+     * in the specified collection.  The priority queue has an initial
+     * capacity of 110% of the size of the specified collection. If
+     * the specified collection is a {@link SortedSet} or a {@link
+     * PriorityQueue}, this priority queue will be sorted according to
+     * the same comparator, or according to its elements' natural
+     * order if the collection is sorted according to its elements'
+     * natural order.  Otherwise, this priority queue is ordered
+     * according to its elements' natural order.
+     *
+     * @param c the collection whose elements are to be placed
+     *        into this priority queue.
+     * @throws ClassCastException if elements of the specified collection
+     *         cannot be compared to one another according to the priority
+     *         queue's ordering.
+     * @throws NullPointerException if <tt>c</tt> or any element within it
+     * is <tt>null</tt>
+     */
+    public PriorityBlockingQueue(Collection<? extends E> c) {
+        q = new PriorityQueue<E>(c);
+    }
+
+
+    // these first few override just to update doc comments
+
+    /**
+     * Adds the specified element to this queue.
+     * @param o the element to add
+     * @return <tt>true</tt> (as per the general contract of
+     * <tt>Collection.add</tt>).
+     *
+     * @throws NullPointerException if the specified element is <tt>null</tt>.
+     * @throws ClassCastException if the specified element cannot be compared
+     * with elements currently in the priority queue according
+     * to the priority queue's ordering.
+     */
+    public boolean add(E o) {
+        return super.add(o);
+    }
+
+    /**
+     * Returns the comparator used to order this collection, or <tt>null</tt>
+     * if this collection is sorted according to its elements natural ordering
+     * (using <tt>Comparable</tt>).
+     *
+     * @return the comparator used to order this collection, or <tt>null</tt>
+     * if this collection is sorted according to its elements natural ordering.
+     */
+    public Comparator comparator() {
+        return q.comparator();
+    }
+
+    /**
+     * Inserts the specified element into this priority queue.
+     *
+     * @param o the element to add
+     * @return <tt>true</tt>
+     * @throws ClassCastException if the specified element cannot be compared
+     * with elements currently in the priority queue according
+     * to the priority queue's ordering.
+     * @throws NullPointerException if the specified element is <tt>null</tt>.
+     */
+    public boolean offer(E o) {
+        if (o == null) throw new NullPointerException();
+        final ReentrantLock lock = this.lock;
+        lock.lock();
+        try {
+            boolean ok = q.offer(o);
+            assert ok;
+            notEmpty.signal();
+            return true;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Adds the specified element to this priority queue. As the queue is
+     * unbounded this method will never block.
+     * @param o the element to add
+     * @throws ClassCastException if the element cannot be compared
+     * with elements currently in the priority queue according
+     * to the priority queue's ordering.
+     * @throws NullPointerException if the specified element is <tt>null</tt>.
+     */
+    public void put(E o) {
+        offer(o); // never need to block
+    }
+
+    /**
+     * Inserts the specified element into this priority queue. As the queue is
+     * unbounded this method will never block.
+     * @param o the element to add
+     * @param timeout This parameter is ignored as the method never blocks
+     * @param unit This parameter is ignored as the method never blocks
+     * @return <tt>true</tt>
+     * @throws ClassCastException if the element cannot be compared
+     * with elements currently in the priority queue according
+     * to the priority queue's ordering.
+     * @throws NullPointerException if the specified element is <tt>null</tt>.
+     */
+    public boolean offer(E o, long timeout, TimeUnit unit) {
+        return offer(o); // never need to block
+    }
+
+    public E take() throws InterruptedException {
+        final ReentrantLock lock = this.lock;
+        lock.lockInterruptibly();
+        try {
+            try {
+                while (q.size() == 0)
+                    notEmpty.await();
+            } catch (InterruptedException ie) {
+                notEmpty.signal(); // propagate to non-interrupted thread
+                throw ie;
+            }
+            E x = q.poll();
+            assert x != null;
+            return x;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+
+    public E poll() {
+        final ReentrantLock lock = this.lock;
+        lock.lock();
+        try {
+            return q.poll();
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    public E poll(long timeout, TimeUnit unit) throws InterruptedException {
+        long nanos = unit.toNanos(timeout);
+        final ReentrantLock lock = this.lock;
+        lock.lockInterruptibly();
+        try {
+            for (;;) {
+                E x = q.poll();
+                if (x != null)
+                    return x;
+                if (nanos <= 0)
+                    return null;
+                try {
+                    nanos = notEmpty.awaitNanos(nanos);
+                } catch (InterruptedException ie) {
+                    notEmpty.signal(); // propagate to non-interrupted thread
+                    throw ie;
+                }
+            }
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    public E peek() {
+        final ReentrantLock lock = this.lock;
+        lock.lock();
+        try {
+            return q.peek();
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    public int size() {
+        final ReentrantLock lock = this.lock;
+        lock.lock();
+        try {
+            return q.size();
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Always returns <tt>Integer.MAX_VALUE</tt> because
+     * a <tt>PriorityBlockingQueue</tt> is not capacity constrained.
+     * @return <tt>Integer.MAX_VALUE</tt>
+     */
+    public int remainingCapacity() {
+        return Integer.MAX_VALUE;
+    }
+
+    public boolean remove(Object o) {
+        final ReentrantLock lock = this.lock;
+        lock.lock();
+        try {
+            return q.remove(o);
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    public boolean contains(Object o) {
+        final ReentrantLock lock = this.lock;
+        lock.lock();
+        try {
+            return q.contains(o);
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    public Object[] toArray() {
+        final ReentrantLock lock = this.lock;
+        lock.lock();
+        try {
+            return q.toArray();
+        } finally {
+            lock.unlock();
+        }
+    }
+
+
+    public String toString() {
+        final ReentrantLock lock = this.lock;
+        lock.lock();
+        try {
+            return q.toString();
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    public int drainTo(Collection<? super E> c) {
+        if (c == null)
+            throw new NullPointerException();
+        if (c == this)
+            throw new IllegalArgumentException();
+        final ReentrantLock lock = this.lock;
+        lock.lock();
+        try {
+            int n = 0;
+            E e;
+            while ( (e = q.poll()) != null) {
+                c.add(e);
+                ++n;
+            }
+            return n;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    public int drainTo(Collection<? super E> c, int maxElements) {
+        if (c == null)
+            throw new NullPointerException();
+        if (c == this)
+            throw new IllegalArgumentException();
+        if (maxElements <= 0)
+            return 0;
+        final ReentrantLock lock = this.lock;
+        lock.lock();
+        try {
+            int n = 0;
+            E e;
+            while (n < maxElements && (e = q.poll()) != null) {
+                c.add(e);
+                ++n;
+            }
+            return n;
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Atomically removes all of the elements from this delay queue.
+     * The queue will be empty after this call returns.
+     */
+    public void clear() {
+        final ReentrantLock lock = this.lock;
+        lock.lock();
+        try {
+            q.clear();
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    public <T> T[] toArray(T[] a) {
+        final ReentrantLock lock = this.lock;
+        lock.lock();
+        try {
+            return q.toArray(a);
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    /**
+     * Returns an iterator over the elements in this queue. The
+     * iterator does not return the elements in any particular order.
+     * The returned iterator is a thread-safe "fast-fail" iterator
+     * that will throw {@link
+     * java.util.ConcurrentModificationException} upon detected
+     * interference.
+     *
+     * @return an iterator over the elements in this queue.
+     */
+    public Iterator<E> iterator() {
+        final ReentrantLock lock = this.lock;
+        lock.lock();
+        try {
+            return new Itr(q.iterator());
+        } finally {
+            lock.unlock();
+        }
+    }
+
+    private class Itr<E> implements Iterator<E> {
+        private final Iterator<E> iter;
+        Itr(Iterator<E> i) {
+            iter = i;
+        }
+
+        public boolean hasNext() {
+            /*
+             * No sync -- we rely on underlying hasNext to be
+             * stateless, in which case we can return true by mistake
+             * only when next() will subsequently throw
+             * ConcurrentModificationException.
+             */
+            return iter.hasNext();
+        }
+
+        public E next() {
+            ReentrantLock lock = PriorityBlockingQueue.this.lock;
+            lock.lock();
+            try {
+                return iter.next();
+            } finally {
+                lock.unlock();
+            }
+        }
+
+        public void remove() {
+            ReentrantLock lock = PriorityBlockingQueue.this.lock;
+            lock.lock();
+            try {
+                iter.remove();
+            } finally {
+                lock.unlock();
+            }
+        }
+    }
+
+    /**
+     * Save the state to a stream (that is, serialize it).  This
+     * merely wraps default serialization within lock.  The
+     * serialization strategy for items is left to underlying
+     * Queue. Note that locking is not needed on deserialization, so
+     * readObject is not defined, just relying on default.
+     */
+    private void writeObject(java.io.ObjectOutputStream s)
+        throws java.io.IOException {
+        lock.lock();
+        try {
+            s.defaultWriteObject();
+        } finally {
+            lock.unlock();
+        }
+    }
+
+}

Propchange: incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/PriorityBlockingQueue.java
------------------------------------------------------------------------------
    svn:eol-style = native

Added: incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/RejectedExecutionException.java
URL: http://svn.apache.org/viewvc/incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/RejectedExecutionException.java?rev=421111&view=auto
==============================================================================
--- incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/RejectedExecutionException.java (added)
+++ incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/RejectedExecutionException.java Tue Jul 11 21:12:04 2006
@@ -0,0 +1,62 @@
+/*
+ * Written by Doug Lea 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.concurrent;
+
+/**
+ * Exception thrown by an {@link Executor} when a task cannot be
+ * accepted for execution.
+ * 
+ * @since 1.5
+ * @author Doug Lea
+ */
+public class RejectedExecutionException extends RuntimeException {
+    private static final long serialVersionUID = -375805702767069545L;
+
+    /**
+     * Constructs a <tt>RejectedExecutionException</tt> with no detail message.
+     * The cause is not initialized, and may subsequently be
+     * initialized by a call to {@link #initCause(Throwable) initCause}.
+     */
+    public RejectedExecutionException() { }
+
+    /**
+     * Constructs a <tt>RejectedExecutionException</tt> with the
+     * specified detail message. The cause is not initialized, and may
+     * subsequently be initialized by a call to {@link
+     * #initCause(Throwable) initCause}.
+     *
+     * @param message the detail message
+     */
+    public RejectedExecutionException(String message) {
+        super(message);
+    }
+
+    /**
+     * Constructs a <tt>RejectedExecutionException</tt> with the
+     * specified detail message and cause.
+     *
+     * @param  message the detail message
+     * @param  cause the cause (which is saved for later retrieval by the
+     *         {@link #getCause()} method)
+     */
+    public RejectedExecutionException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    /**
+     * Constructs a <tt>RejectedExecutionException</tt> with the
+     * specified cause.  The detail message is set to: <pre> (cause ==
+     * null ? null : cause.toString())</pre> (which typically contains
+     * the class and detail message of <tt>cause</tt>).
+     *
+     * @param  cause the cause (which is saved for later retrieval by the
+     *         {@link #getCause()} method)
+     */
+    public RejectedExecutionException(Throwable cause) {
+        super(cause);
+    }
+}

Propchange: incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/RejectedExecutionException.java
------------------------------------------------------------------------------
    svn:eol-style = native

Added: incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/RejectedExecutionHandler.java
URL: http://svn.apache.org/viewvc/incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/RejectedExecutionHandler.java?rev=421111&view=auto
==============================================================================
--- incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/RejectedExecutionHandler.java (added)
+++ incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/RejectedExecutionHandler.java Tue Jul 11 21:12:04 2006
@@ -0,0 +1,33 @@
+/*
+ * Written by Doug Lea 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.concurrent;
+
+/**
+ * A handler for tasks that cannot be executed by a {@link
+ * ThreadPoolExecutor}.
+ *
+ * @since 1.5
+ * @author Doug Lea
+ */
+public interface RejectedExecutionHandler {
+
+    /**
+     * Method that may be invoked by a {@link ThreadPoolExecutor} when
+     * <tt>execute</tt> cannot accept a task. This may occur when no
+     * more threads or queue slots are available because their bounds
+     * would be exceeded, or upon shutdown of the Executor.
+     *
+     * In the absence other alternatives, the method may throw an
+     * unchecked {@link RejectedExecutionException}, which will be
+     * propagated to the caller of <tt>execute</tt>.
+     *
+     * @param r the runnable task requested to be executed
+     * @param executor the executor attempting to execute this task
+     * @throws RejectedExecutionException if there is no remedy
+     */
+    void rejectedExecution(Runnable r, ThreadPoolExecutor executor);
+}

Propchange: incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/RejectedExecutionHandler.java
------------------------------------------------------------------------------
    svn:eol-style = native

Added: incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/ScheduledExecutorService.java
URL: http://svn.apache.org/viewvc/incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/ScheduledExecutorService.java?rev=421111&view=auto
==============================================================================
--- incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/ScheduledExecutorService.java (added)
+++ incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/ScheduledExecutorService.java Tue Jul 11 21:12:04 2006
@@ -0,0 +1,145 @@
+/*
+ * Written by Doug Lea 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.concurrent;
+import java.util.concurrent.atomic.*;
+import java.util.*;
+
+/**
+ * An {@link ExecutorService} that can schedule commands to run after a given
+ * delay, or to execute periodically. 
+ *
+ * <p> The <tt>schedule</tt> methods create tasks with various delays
+ * and return a task object that can be used to cancel or check
+ * execution. The <tt>scheduleAtFixedRate</tt> and
+ * <tt>scheduleWithFixedDelay</tt> methods create and execute tasks
+ * that run periodically until cancelled.  
+ *
+ * <p> Commands submitted using the {@link Executor#execute} and
+ * {@link ExecutorService} <tt>submit</tt> methods are scheduled with
+ * a requested delay of zero. Zero and negative delays (but not
+ * periods) are also allowed in <tt>schedule</tt> methods, and are
+ * treated as requests for immediate execution.
+ *
+ * <p>All <tt>schedule</tt> methods accept <em>relative</em> delays and
+ * periods as arguments, not absolute times or dates. It is a simple
+ * matter to transform an absolute time represented as a {@link
+ * java.util.Date} to the required form. For example, to schedule at
+ * a certain future <tt>date</tt>, you can use: <tt>schedule(task,
+ * date.getTime() - System.currentTimeMillis(),
+ * TimeUnit.MILLISECONDS)</tt>. Beware however that expiration of a
+ * relative delay need not coincide with the current <tt>Date</tt> at
+ * which the task is enabled due to network time synchronization
+ * protocols, clock drift, or other factors. 
+ *
+ * The {@link Executors} class provides convenient factory methods for
+ * the ScheduledExecutorService implementations provided in this package.
+ *
+ * <h3>Usage Example</h3>
+ * 
+ * Here is a class with a method that sets up a ScheduledExecutorService
+ * to beep every ten seconds for an hour:
+ *
+ * <pre>
+ * import static java.util.concurrent.TimeUnit;
+ * class BeeperControl {
+ *    private final ScheduledExecutorService scheduler = 
+ *       Executors.newScheduledThreadPool(1);
+ *
+ *    public void beepForAnHour() {
+ *        final Runnable beeper = new Runnable() {
+ *                public void run() { System.out.println("beep"); }
+ *            };
+ *        final ScheduledFuture&lt;?&gt; beeperHandle = 
+ *            scheduler.scheduleAtFixedRate(beeper, 10, 10, SECONDS);
+ *        scheduler.schedule(new Runnable() {
+ *                public void run() { beeperHandle.cancel(true); }
+ *            }, 60 * 60, SECONDS);
+ *    }
+ * }
+ * </pre>
+ *
+ * @since 1.5
+ * @author Doug Lea
+ */
+public interface ScheduledExecutorService extends ExecutorService {
+
+    /**
+     * Creates and executes a one-shot action that becomes enabled
+     * after the given delay.
+     * @param command the task to execute.
+     * @param delay the time from now to delay execution.
+     * @param unit the time unit of the delay parameter.
+     * @return a Future representing pending completion of the task,
+     * and whose <tt>get()</tt> method will return <tt>null</tt>
+     * upon completion.
+     * @throws RejectedExecutionException if task cannot be scheduled
+     * for execution.
+     * @throws NullPointerException if command is null
+     */
+    public ScheduledFuture<?> schedule(Runnable command, long delay,  TimeUnit unit);
+
+    /**
+     * Creates and executes a ScheduledFuture that becomes enabled after the
+     * given delay.
+     * @param callable the function to execute.
+     * @param delay the time from now to delay execution.
+     * @param unit the time unit of the delay parameter.
+     * @return a ScheduledFuture that can be used to extract result or cancel.
+     * @throws RejectedExecutionException if task cannot be scheduled
+     * for execution.
+     * @throws NullPointerException if callable is null
+     */
+    public <V> ScheduledFuture<V> schedule(Callable<V> callable, long delay, TimeUnit unit);
+
+    /**
+     * Creates and executes a periodic action that becomes enabled first
+     * after the given initial delay, and subsequently with the given
+     * period; that is executions will commence after
+     * <tt>initialDelay</tt> then <tt>initialDelay+period</tt>, then
+     * <tt>initialDelay + 2 * period</tt>, and so on.  
+     * If any execution of the task
+     * encounters an exception, subsequent executions are suppressed.
+     * Otherwise, the task will only terminate via cancellation or
+     * termination of the executor.
+     * @param command the task to execute.
+     * @param initialDelay the time to delay first execution.
+     * @param period the period between successive executions.
+     * @param unit the time unit of the initialDelay and period parameters
+     * @return a Future representing pending completion of the task,
+     * and whose <tt>get()</tt> method will throw an exception upon
+     * cancellation.
+     * @throws RejectedExecutionException if task cannot be scheduled
+     * for execution.
+     * @throws NullPointerException if command is null
+     * @throws IllegalArgumentException if period less than or equal to zero.
+     */
+    public ScheduledFuture<?> scheduleAtFixedRate(Runnable command, long initialDelay,  long period, TimeUnit unit);
+    
+    /**
+     * Creates and executes a periodic action that becomes enabled first
+     * after the given initial delay, and subsequently with the
+     * given delay between the termination of one execution and the
+     * commencement of the next. If any execution of the task
+     * encounters an exception, subsequent executions are suppressed.
+     * Otherwise, the task will only terminate via cancellation or
+     * termination of the executor.
+     * @param command the task to execute.
+     * @param initialDelay the time to delay first execution.
+     * @param delay the delay between the termination of one
+     * execution and the commencement of the next.
+     * @param unit the time unit of the initialDelay and delay parameters
+     * @return a Future representing pending completion of the task,
+     * and whose <tt>get()</tt> method will throw an exception upon
+     * cancellation.
+     * @throws RejectedExecutionException if task cannot be scheduled
+     * for execution.
+     * @throws NullPointerException if command is null
+     * @throws IllegalArgumentException if delay less than or equal to zero.
+     */
+    public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, long initialDelay,  long delay, TimeUnit unit);
+
+}

Propchange: incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/ScheduledExecutorService.java
------------------------------------------------------------------------------
    svn:eol-style = native

Added: incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/ScheduledFuture.java
URL: http://svn.apache.org/viewvc/incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/ScheduledFuture.java?rev=421111&view=auto
==============================================================================
--- incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/ScheduledFuture.java (added)
+++ incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/ScheduledFuture.java Tue Jul 11 21:12:04 2006
@@ -0,0 +1,19 @@
+/*
+ * Written by Doug Lea 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.concurrent;
+
+/**
+ * A delayed result-bearing action that can be cancelled.
+ * Usually a scheduled future is the result of scheduling
+ * a task with a {@link ScheduledExecutorService}.
+ *
+ * @since 1.5
+ * @author Doug Lea
+ * @param <V> The result type returned by this Future
+ */
+public interface ScheduledFuture<V> extends Delayed, Future<V> {
+}

Propchange: incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/ScheduledFuture.java
------------------------------------------------------------------------------
    svn:eol-style = native

Added: incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/ScheduledThreadPoolExecutor.java
URL: http://svn.apache.org/viewvc/incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/ScheduledThreadPoolExecutor.java?rev=421111&view=auto
==============================================================================
--- incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/ScheduledThreadPoolExecutor.java (added)
+++ incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/ScheduledThreadPoolExecutor.java Tue Jul 11 21:12:04 2006
@@ -0,0 +1,541 @@
+/*
+ * Written by Doug Lea 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.concurrent;
+import java.util.concurrent.atomic.*;
+import java.util.*;
+
+/**
+ * A {@link ThreadPoolExecutor} that can additionally schedule
+ * commands to run after a given delay, or to execute
+ * periodically. This class is preferable to {@link java.util.Timer}
+ * when multiple worker threads are needed, or when the additional
+ * flexibility or capabilities of {@link ThreadPoolExecutor} (which
+ * this class extends) are required.
+ *
+ * <p> Delayed tasks execute no sooner than they are enabled, but
+ * without any real-time guarantees about when, after they are
+ * enabled, they will commence. Tasks scheduled for exactly the same
+ * execution time are enabled in first-in-first-out (FIFO) order of
+ * submission.
+ *
+ * <p>While this class inherits from {@link ThreadPoolExecutor}, a few
+ * of the inherited tuning methods are not useful for it. In
+ * particular, because it acts as a fixed-sized pool using
+ * <tt>corePoolSize</tt> threads and an unbounded queue, adjustments
+ * to <tt>maximumPoolSize</tt> have no useful effect.
+ *
+ * @since 1.5
+ * @author Doug Lea
+ */
+public class ScheduledThreadPoolExecutor 
+        extends ThreadPoolExecutor 
+        implements ScheduledExecutorService {
+
+    /**
+     * False if should cancel/suppress periodic tasks on shutdown.
+     */
+    private volatile boolean continueExistingPeriodicTasksAfterShutdown;
+
+    /**
+     * False if should cancel non-periodic tasks on shutdown.
+     */
+    private volatile boolean executeExistingDelayedTasksAfterShutdown = true;
+
+    /**
+     * Sequence number to break scheduling ties, and in turn to
+     * guarantee FIFO order among tied entries.
+     */
+    private static final AtomicLong sequencer = new AtomicLong(0);
+
+    /** Base of nanosecond timings, to avoid wrapping */
+    private static final long NANO_ORIGIN = System.nanoTime();
+
+    /**
+     * Returns nanosecond time offset by origin
+     */
+    final long now() {
+	return System.nanoTime() - NANO_ORIGIN;
+    }
+
+    private class ScheduledFutureTask<V> 
+            extends FutureTask<V> implements ScheduledFuture<V> {
+        
+        /** Sequence number to break ties FIFO */
+        private final long sequenceNumber;
+        /** The time the task is enabled to execute in nanoTime units */
+        private long time;
+        /**
+         * Period in nanoseconds for repeating tasks.  A positive
+         * value indicates fixed-rate execution.  A negative value
+         * indicates fixed-delay execution.  A value of 0 indicates a
+         * non-repeating task.
+         */
+        private final long period;
+
+        /**
+         * Creates a one-shot action with given nanoTime-based trigger time
+         */
+        ScheduledFutureTask(Runnable r, V result, long ns) {
+            super(r, result);
+            this.time = ns;
+            this.period = 0;
+            this.sequenceNumber = sequencer.getAndIncrement();
+        }
+
+        /**
+         * Creates a periodic action with given nano time and period
+         */
+        ScheduledFutureTask(Runnable r, V result, long ns,  long period) {
+            super(r, result);
+            this.time = ns;
+            this.period = period;
+            this.sequenceNumber = sequencer.getAndIncrement();
+        }
+
+        /**
+         * Creates a one-shot action with given nanoTime-based trigger
+         */
+        ScheduledFutureTask(Callable<V> callable, long ns) {
+            super(callable);
+            this.time = ns;
+            this.period = 0;
+            this.sequenceNumber = sequencer.getAndIncrement();
+        }
+
+        public long getDelay(TimeUnit unit) {
+            long d = unit.convert(time - now(), TimeUnit.NANOSECONDS);
+            return d;
+        }
+
+        public int compareTo(Object other) {
+            if (other == this) // compare zero ONLY if same object
+                return 0;
+            ScheduledFutureTask<?> x = (ScheduledFutureTask<?>)other;
+            long diff = time - x.time;
+            if (diff < 0)
+                return -1;
+            else if (diff > 0)
+                return 1;
+            else if (sequenceNumber < x.sequenceNumber)
+                return -1;
+            else
+                return 1;
+        }
+
+        /**
+         * Returns true if this is a periodic (not a one-shot) action.
+         * @return true if periodic
+         */
+        boolean isPeriodic() {
+            return period != 0;
+        }
+
+        /**
+         * Run a periodic task
+         */
+        private void runPeriodic() {
+            boolean ok = ScheduledFutureTask.super.runAndReset();
+            boolean down = isShutdown();
+            // Reschedule if not cancelled and not shutdown or policy allows
+            if (ok && (!down ||
+                       (getContinueExistingPeriodicTasksAfterShutdownPolicy() && 
+                        !isTerminating()))) {
+                long p = period;
+                if (p > 0)
+                    time += p;
+                else
+                    time = now() - p;
+                ScheduledThreadPoolExecutor.super.getQueue().add(this);
+            }
+            // This might have been the final executed delayed
+            // task.  Wake up threads to check.
+            else if (down) 
+                interruptIdleWorkers();
+        }
+
+        /**
+         * Overrides FutureTask version so as to reset/requeue if periodic.
+         */ 
+        public void run() {
+            if (isPeriodic())
+                runPeriodic();
+            else 
+                ScheduledFutureTask.super.run();
+        }
+    }
+
+    /**
+     * Specialized variant of ThreadPoolExecutor.execute for delayed tasks.
+     */
+    private void delayedExecute(Runnable command) {
+        if (isShutdown()) {
+            reject(command);
+            return;
+        }
+        // Prestart a thread if necessary. We cannot prestart it
+        // running the task because the task (probably) shouldn't be
+        // run yet, so thread will just idle until delay elapses.
+        if (getPoolSize() < getCorePoolSize())
+            prestartCoreThread();
+            
+        super.getQueue().add(command);
+    }
+
+    /**
+     * Cancel and clear the queue of all tasks that should not be run
+     * due to shutdown policy.
+     */
+    private void cancelUnwantedTasks() {
+        boolean keepDelayed = getExecuteExistingDelayedTasksAfterShutdownPolicy();
+        boolean keepPeriodic = getContinueExistingPeriodicTasksAfterShutdownPolicy();
+        if (!keepDelayed && !keepPeriodic) 
+            super.getQueue().clear();
+        else if (keepDelayed || keepPeriodic) {
+            Object[] entries = super.getQueue().toArray();
+            for (int i = 0; i < entries.length; ++i) {
+                Object e = entries[i];
+                if (e instanceof ScheduledFutureTask) {
+                    ScheduledFutureTask<?> t = (ScheduledFutureTask<?>)e;
+                    if (t.isPeriodic()? !keepPeriodic : !keepDelayed)
+                        t.cancel(false);
+                }
+            }
+            entries = null;
+            purge();
+        }
+    }
+
+    public boolean remove(Runnable task) {
+        if (!(task instanceof ScheduledFutureTask))
+            return false;
+        return getQueue().remove(task);
+    }
+
+    /**
+     * Creates a new ScheduledThreadPoolExecutor with the given core
+     * pool size.
+     * 
+     * @param corePoolSize the number of threads to keep in the pool,
+     * even if they are idle.
+     * @throws IllegalArgumentException if corePoolSize less than or
+     * equal to zero
+     */
+    public ScheduledThreadPoolExecutor(int corePoolSize) {
+        super(corePoolSize, Integer.MAX_VALUE, 0, TimeUnit.NANOSECONDS,
+              new DelayedWorkQueue());
+    }
+
+    /**
+     * Creates a new ScheduledThreadPoolExecutor with the given
+     * initial parameters.
+     * 
+     * @param corePoolSize the number of threads to keep in the pool,
+     * even if they are idle.
+     * @param threadFactory the factory to use when the executor
+     * creates a new thread. 
+     * @throws NullPointerException if threadFactory is null
+     */
+    public ScheduledThreadPoolExecutor(int corePoolSize,
+                             ThreadFactory threadFactory) {
+        super(corePoolSize, Integer.MAX_VALUE, 0, TimeUnit.NANOSECONDS,
+              new DelayedWorkQueue(), threadFactory);
+    }
+
+    /**
+     * Creates a new ScheduledThreadPoolExecutor with the given
+     * initial parameters.
+     * 
+     * @param corePoolSize the number of threads to keep in the pool,
+     * even if they are idle.
+     * @param handler the handler to use when execution is blocked
+     * because the thread bounds and queue capacities are reached.
+     * @throws NullPointerException if handler is null
+     */
+    public ScheduledThreadPoolExecutor(int corePoolSize,
+                              RejectedExecutionHandler handler) {
+        super(corePoolSize, Integer.MAX_VALUE, 0, TimeUnit.NANOSECONDS,
+              new DelayedWorkQueue(), handler);
+    }
+
+    /**
+     * Creates a new ScheduledThreadPoolExecutor with the given
+     * initial parameters.
+     * 
+     * @param corePoolSize the number of threads to keep in the pool,
+     * even if they are idle.
+     * @param threadFactory the factory to use when the executor
+     * creates a new thread. 
+     * @param handler the handler to use when execution is blocked
+     * because the thread bounds and queue capacities are reached.
+     * @throws NullPointerException if threadFactory or handler is null
+     */
+    public ScheduledThreadPoolExecutor(int corePoolSize,
+                              ThreadFactory threadFactory,
+                              RejectedExecutionHandler handler) {
+        super(corePoolSize, Integer.MAX_VALUE, 0, TimeUnit.NANOSECONDS,
+              new DelayedWorkQueue(), threadFactory, handler);
+    }
+
+    public ScheduledFuture<?> schedule(Runnable command, 
+                                       long delay, 
+                                       TimeUnit unit) {
+        if (command == null || unit == null)
+            throw new NullPointerException();
+        long triggerTime = now() + unit.toNanos(delay);
+        ScheduledFutureTask<?> t = 
+            new ScheduledFutureTask<Boolean>(command, null, triggerTime);
+        delayedExecute(t);
+        return t;
+    }
+
+    public <V> ScheduledFuture<V> schedule(Callable<V> callable, 
+                                           long delay, 
+                                           TimeUnit unit) {
+        if (callable == null || unit == null)
+            throw new NullPointerException();
+        if (delay < 0) delay = 0;
+        long triggerTime = now() + unit.toNanos(delay);
+        ScheduledFutureTask<V> t = 
+            new ScheduledFutureTask<V>(callable, triggerTime);
+        delayedExecute(t);
+        return t;
+    }
+
+    public ScheduledFuture<?> scheduleAtFixedRate(Runnable command, 
+                                                  long initialDelay,  
+                                                  long period, 
+                                                  TimeUnit unit) {
+        if (command == null || unit == null)
+            throw new NullPointerException();
+        if (period <= 0)
+            throw new IllegalArgumentException();
+        if (initialDelay < 0) initialDelay = 0;
+        long triggerTime = now() + unit.toNanos(initialDelay);
+        ScheduledFutureTask<?> t = 
+            new ScheduledFutureTask<Object>(command, 
+                                            null,
+                                            triggerTime,
+                                            unit.toNanos(period));
+        delayedExecute(t);
+        return t;
+    }
+    
+    public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, 
+                                                     long initialDelay,  
+                                                     long delay, 
+                                                     TimeUnit unit) {
+        if (command == null || unit == null)
+            throw new NullPointerException();
+        if (delay <= 0)
+            throw new IllegalArgumentException();
+        if (initialDelay < 0) initialDelay = 0;
+        long triggerTime = now() + unit.toNanos(initialDelay);
+        ScheduledFutureTask<?> t = 
+            new ScheduledFutureTask<Boolean>(command, 
+                                             null,
+                                             triggerTime,
+                                             unit.toNanos(-delay));
+        delayedExecute(t);
+        return t;
+    }
+    
+
+    /**
+     * Execute command with zero required delay. This has effect
+     * equivalent to <tt>schedule(command, 0, anyUnit)</tt>.  Note
+     * that inspections of the queue and of the list returned by
+     * <tt>shutdownNow</tt> will access the zero-delayed
+     * {@link ScheduledFuture}, not the <tt>command</tt> itself.
+     *
+     * @param command the task to execute
+     * @throws RejectedExecutionException at discretion of
+     * <tt>RejectedExecutionHandler</tt>, if task cannot be accepted
+     * for execution because the executor has been shut down.
+     * @throws NullPointerException if command is null
+     */
+    public void execute(Runnable command) {
+        if (command == null)
+            throw new NullPointerException();
+        schedule(command, 0, TimeUnit.NANOSECONDS);
+    }
+
+    // Override AbstractExecutorService methods
+
+    public Future<?> submit(Runnable task) {
+        return schedule(task, 0, TimeUnit.NANOSECONDS);
+    }
+
+    public <T> Future<T> submit(Runnable task, T result) {
+        return schedule(Executors.callable(task, result), 
+                        0, TimeUnit.NANOSECONDS);
+    }
+
+    public <T> Future<T> submit(Callable<T> task) {
+        return schedule(task, 0, TimeUnit.NANOSECONDS);
+    }
+
+    /**
+     * Set policy on whether to continue executing existing periodic
+     * tasks even when this executor has been <tt>shutdown</tt>. In
+     * this case, these tasks will only terminate upon
+     * <tt>shutdownNow</tt>, or after setting the policy to
+     * <tt>false</tt> when already shutdown. This value is by default
+     * false.
+     * @param value if true, continue after shutdown, else don't.
+     * @see #getExecuteExistingDelayedTasksAfterShutdownPolicy
+     */
+    public void setContinueExistingPeriodicTasksAfterShutdownPolicy(boolean value) {
+        continueExistingPeriodicTasksAfterShutdown = value;
+        if (!value && isShutdown())
+            cancelUnwantedTasks();
+    }
+
+    /**
+     * Get the policy on whether to continue executing existing
+     * periodic tasks even when this executor has been
+     * <tt>shutdown</tt>. In this case, these tasks will only
+     * terminate upon <tt>shutdownNow</tt> or after setting the policy
+     * to <tt>false</tt> when already shutdown. This value is by
+     * default false.
+     * @return true if will continue after shutdown.
+     * @see #setContinueExistingPeriodicTasksAfterShutdownPolicy
+     */
+    public boolean getContinueExistingPeriodicTasksAfterShutdownPolicy() {
+        return continueExistingPeriodicTasksAfterShutdown;
+    }
+
+    /**
+     * Set policy on whether to execute existing delayed
+     * tasks even when this executor has been <tt>shutdown</tt>. In
+     * this case, these tasks will only terminate upon
+     * <tt>shutdownNow</tt>, or after setting the policy to
+     * <tt>false</tt> when already shutdown. This value is by default
+     * true.
+     * @param value if true, execute after shutdown, else don't.
+     * @see #getExecuteExistingDelayedTasksAfterShutdownPolicy
+     */
+    public void setExecuteExistingDelayedTasksAfterShutdownPolicy(boolean value) {
+        executeExistingDelayedTasksAfterShutdown = value;
+        if (!value && isShutdown())
+            cancelUnwantedTasks();
+    }
+
+    /**
+     * Get policy on whether to execute existing delayed
+     * tasks even when this executor has been <tt>shutdown</tt>. In
+     * this case, these tasks will only terminate upon
+     * <tt>shutdownNow</tt>, or after setting the policy to
+     * <tt>false</tt> when already shutdown. This value is by default
+     * true.
+     * @return true if will execute after shutdown.
+     * @see #setExecuteExistingDelayedTasksAfterShutdownPolicy
+     */
+    public boolean getExecuteExistingDelayedTasksAfterShutdownPolicy() {
+        return executeExistingDelayedTasksAfterShutdown;
+    }
+
+
+    /**
+     * Initiates an orderly shutdown in which previously submitted
+     * tasks are executed, but no new tasks will be accepted. If the
+     * <tt>ExecuteExistingDelayedTasksAfterShutdownPolicy</tt> has
+     * been set <tt>false</tt>, existing delayed tasks whose delays
+     * have not yet elapsed are cancelled. And unless the
+     * <tt>ContinueExistingPeriodicTasksAfterShutdownPolicy</tt> has
+     * been set <tt>true</tt>, future executions of existing periodic
+     * tasks will be cancelled.
+     */
+    public void shutdown() {
+        cancelUnwantedTasks();
+        super.shutdown();
+    }
+
+    /**
+     * Attempts to stop all actively executing tasks, halts the
+     * processing of waiting tasks, and returns a list of the tasks that were
+     * awaiting execution. 
+     *  
+     * <p>There are no guarantees beyond best-effort attempts to stop
+     * processing actively executing tasks.  This implementation
+     * cancels tasks via {@link Thread#interrupt}, so if any tasks mask or
+     * fail to respond to interrupts, they may never terminate.
+     *
+     * @return list of tasks that never commenced execution.  Each
+     * element of this list is a {@link ScheduledFuture},
+     * including those tasks submitted using <tt>execute</tt>, which
+     * are for scheduling purposes used as the basis of a zero-delay
+     * <tt>ScheduledFuture</tt>.
+     */
+    public List<Runnable> shutdownNow() {
+        return super.shutdownNow();
+    }
+
+    /**
+     * Returns the task queue used by this executor.  Each element of
+     * this queue is a {@link ScheduledFuture}, including those
+     * tasks submitted using <tt>execute</tt> which are for scheduling
+     * purposes used as the basis of a zero-delay
+     * <tt>ScheduledFuture</tt>. Iteration over this queue is
+     * <em>not</em> guaranteed to traverse tasks in the order in
+     * which they will execute.
+     *
+     * @return the task queue
+     */
+    public BlockingQueue<Runnable> getQueue() {
+        return super.getQueue();
+    }
+
+    /**
+     * An annoying wrapper class to convince generics compiler to
+     * use a DelayQueue<ScheduledFutureTask> as a BlockingQueue<Runnable>
+     */ 
+    private static class DelayedWorkQueue 
+        extends AbstractCollection<Runnable> 
+        implements BlockingQueue<Runnable> {
+        
+        private final DelayQueue<ScheduledFutureTask> dq = new DelayQueue<ScheduledFutureTask>();
+        public Runnable poll() { return dq.poll(); }
+        public Runnable peek() { return dq.peek(); }
+        public Runnable take() throws InterruptedException { return dq.take(); }
+        public Runnable poll(long timeout, TimeUnit unit) throws InterruptedException {
+            return dq.poll(timeout, unit);
+        }
+
+        public boolean add(Runnable x) { return dq.add((ScheduledFutureTask)x); }
+        public boolean offer(Runnable x) { return dq.offer((ScheduledFutureTask)x); }
+        public void put(Runnable x)  {
+            dq.put((ScheduledFutureTask)x); 
+        }
+        public boolean offer(Runnable x, long timeout, TimeUnit unit) {
+            return dq.offer((ScheduledFutureTask)x, timeout, unit);
+        }
+
+        public Runnable remove() { return dq.remove(); }
+        public Runnable element() { return dq.element(); }
+        public void clear() { dq.clear(); }
+        public int drainTo(Collection<? super Runnable> c) { return dq.drainTo(c); }
+        public int drainTo(Collection<? super Runnable> c, int maxElements) { 
+            return dq.drainTo(c, maxElements); 
+        }
+
+        public int remainingCapacity() { return dq.remainingCapacity(); }
+        public boolean remove(Object x) { return dq.remove(x); }
+        public boolean contains(Object x) { return dq.contains(x); }
+        public int size() { return dq.size(); }
+        public boolean isEmpty() { return dq.isEmpty(); }
+        public Object[] toArray() { return dq.toArray(); }
+        public <T> T[] toArray(T[] array) { return dq.toArray(array); }
+        public Iterator<Runnable> iterator() { 
+            return new Iterator<Runnable>() {
+                private Iterator<ScheduledFutureTask> it = dq.iterator();
+                public boolean hasNext() { return it.hasNext(); }
+                public Runnable next() { return it.next(); }
+                public void remove() {  it.remove(); }
+            };
+        }
+    }
+}

Propchange: incubator/harmony/enhanced/classlib/trunk/sandbox/juc-proposal/concurrent/src/main/java/java/util/concurrent/ScheduledThreadPoolExecutor.java
------------------------------------------------------------------------------
    svn:eol-style = native



Mime
View raw message