From 97b8365cafc3a344a22d3980b8ed885f5c6d8357 Mon Sep 17 00:00:00 2001
From: Tom Tromey <tromey@gcc.gnu.org>
Date: Tue, 9 Jan 2007 19:58:05 +0000
Subject: Merged gcj-eclipse branch to trunk.

From-SVN: r120621
---
 .../jsr166/java/util/concurrent/Executor.java      | 112 +++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 libjava/classpath/external/jsr166/java/util/concurrent/Executor.java

(limited to 'libjava/classpath/external/jsr166/java/util/concurrent/Executor.java')

diff --git a/libjava/classpath/external/jsr166/java/util/concurrent/Executor.java b/libjava/classpath/external/jsr166/java/util/concurrent/Executor.java
new file mode 100644
index 00000000000..a61e9215291
--- /dev/null
+++ b/libjava/classpath/external/jsr166/java/util/concurrent/Executor.java
@@ -0,0 +1,112 @@
+/*
+ * 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;
+
+/**
+ * An object that executes submitted {@link Runnable} tasks. This
+ * interface provides a way of decoupling task submission from the
+ * mechanics of how each task will be run, including details of thread
+ * use, scheduling, etc.  An <tt>Executor</tt> is normally used
+ * instead of explicitly creating threads. For example, rather than
+ * invoking <tt>new Thread(new(RunnableTask())).start()</tt> for each
+ * of a set of tasks, you might use:
+ *
+ * <pre>
+ * Executor executor = <em>anExecutor</em>;
+ * executor.execute(new RunnableTask1());
+ * executor.execute(new RunnableTask2());
+ * ...
+ * </pre>
+ *
+ * However, the <tt>Executor</tt> interface does not strictly
+ * require that execution be asynchronous. In the simplest case, an
+ * executor can run the submitted task immediately in the caller's
+ * thread:
+ *
+ * <pre>
+ * class DirectExecutor implements Executor {
+ *     public void execute(Runnable r) {
+ *         r.run();
+ *     }
+ * }</pre>
+ *
+ * More typically, tasks are executed in some thread other
+ * than the caller's thread.  The executor below spawns a new thread
+ * for each task.
+ *
+ * <pre>
+ * class ThreadPerTaskExecutor implements Executor {
+ *     public void execute(Runnable r) {
+ *         new Thread(r).start();
+ *     }
+ * }</pre>
+ *
+ * Many <tt>Executor</tt> implementations impose some sort of
+ * limitation on how and when tasks are scheduled.  The executor below
+ * serializes the submission of tasks to a second executor,
+ * illustrating a composite executor.
+ *
+ * <pre>
+ * class SerialExecutor implements Executor {
+ *     final Queue&lt;Runnable&gt; tasks = new ArrayDeque&lt;Runnable&gt;();
+ *     final Executor executor;
+ *     Runnable active;
+ *
+ *     SerialExecutor(Executor executor) {
+ *         this.executor = executor;
+ *     }
+ *
+ *     public synchronized void execute(final Runnable r) {
+ *         tasks.offer(new Runnable() {
+ *             public void run() {
+ *                 try {
+ *                     r.run();
+ *                 } finally {
+ *                     scheduleNext();
+ *                 }
+ *             }
+ *         });
+ *         if (active == null) {
+ *             scheduleNext();
+ *         }
+ *     }
+ *
+ *     protected synchronized void scheduleNext() {
+ *         if ((active = tasks.poll()) != null) {
+ *             executor.execute(active);
+ *         }
+ *     }
+ * }</pre>
+ *
+ * The <tt>Executor</tt> implementations provided in this package
+ * implement {@link ExecutorService}, which is a more extensive
+ * interface.  The {@link ThreadPoolExecutor} class provides an
+ * extensible thread pool implementation. The {@link Executors} class
+ * provides convenient factory methods for these Executors.
+ *
+ * <p>Memory consistency effects: Actions in a thread prior to
+ * submitting a {@code Runnable} object to an {@code Executor}
+ * <a href="package-summary.html#MemoryVisibility"><i>happen-before</i></a>
+ * its execution begins, perhaps in another thread.
+ *
+ * @since 1.5
+ * @author Doug Lea
+ */
+public interface Executor {
+
+    /**
+     * Executes the given command at some time in the future.  The command
+     * may execute in a new thread, in a pooled thread, or in the calling
+     * thread, at the discretion of the <tt>Executor</tt> implementation.
+     *
+     * @param command the runnable task
+     * @throws RejectedExecutionException if this task cannot be
+     * accepted for execution.
+     * @throws NullPointerException if command is null
+     */
+    void execute(Runnable command);
+}
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