Importing upstream Jetty jetty-9.2.1.v20140609

[gigi.git] / lib / jetty / org / eclipse / jetty / util / thread / ScheduledExecutorScheduler.java

diff --git a/lib/jetty/org/eclipse/jetty/util/thread/ScheduledExecutorScheduler.java b/lib/jetty/org/eclipse/jetty/util/thread/ScheduledExecutorScheduler.java
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+++ b/lib/jetty/org/eclipse/jetty/util/thread/ScheduledExecutorScheduler.java
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+//
+//  ========================================================================
+//  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
+//  ------------------------------------------------------------------------
+//  All rights reserved. This program and the accompanying materials
+//  are made available under the terms of the Eclipse Public License v1.0
+//  and Apache License v2.0 which accompanies this distribution.
+//
+//      The Eclipse Public License is available at
+//      http://www.eclipse.org/legal/epl-v10.html
+//
+//      The Apache License v2.0 is available at
+//      http://www.opensource.org/licenses/apache2.0.php
+//
+//  You may elect to redistribute this code under either of these licenses.
+//  ========================================================================
+//
+
+package org.eclipse.jetty.util.thread;
+
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.TimeUnit;
+
+import org.eclipse.jetty.util.component.AbstractLifeCycle;
+
+/**
+ * Implementation of {@link Scheduler} based on JDK's {@link ScheduledThreadPoolExecutor}.
+ * <p />
+ * While use of {@link ScheduledThreadPoolExecutor} creates futures that will not be used,
+ * it has the advantage of allowing to set a property to remove cancelled tasks from its
+ * queue even if the task did not fire, which provides a huge benefit in the performance
+ * of garbage collection in young generation.
+ */
+public class ScheduledExecutorScheduler extends AbstractLifeCycle implements Scheduler
+{
+    private final String name;
+    private final boolean daemon;
+    private volatile ScheduledThreadPoolExecutor scheduler;
+
+    public ScheduledExecutorScheduler()
+    {
+        this(null, false);
+    }
+
+    public ScheduledExecutorScheduler(String name, boolean daemon)
+    {
+        this.name = name == null ? "Scheduler-" + hashCode() : name;
+        this.daemon = daemon;
+    }
+
+    @Override
+    protected void doStart() throws Exception
+    {
+        scheduler = new ScheduledThreadPoolExecutor(1, new ThreadFactory()
+        {
+            @Override
+            public Thread newThread(Runnable r)
+            {
+                Thread thread = new Thread(r, name);
+                thread.setDaemon(daemon);
+                return thread;
+            }
+        });
+        scheduler.setRemoveOnCancelPolicy(true);
+        super.doStart();
+    }
+
+    @Override
+    protected void doStop() throws Exception
+    {
+        scheduler.shutdownNow();
+        super.doStop();
+        scheduler = null;
+    }
+
+    @Override
+    public Task schedule(Runnable task, long delay, TimeUnit unit)
+    {
+        ScheduledFuture<?> result = scheduler.schedule(task, delay, unit);
+        return new ScheduledFutureTask(result);
+    }
+
+    private class ScheduledFutureTask implements Task
+    {
+        private final ScheduledFuture<?> scheduledFuture;
+
+        public ScheduledFutureTask(ScheduledFuture<?> scheduledFuture)
+        {
+            this.scheduledFuture = scheduledFuture;
+        }
+
+        @Override
+        public boolean cancel()
+        {
+            return scheduledFuture.cancel(false);
+        }
+    }
+}