lib/jetty/org/eclipse/jetty/util/FutureCallback.java

   1 //
   2 //  ========================================================================
   3 //  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
   4 //  ------------------------------------------------------------------------
   5 //  All rights reserved. This program and the accompanying materials
   6 //  are made available under the terms of the Eclipse Public License v1.0
   7 //  and Apache License v2.0 which accompanies this distribution.
   8 //
   9 //      The Eclipse Public License is available at
  10 //      http://www.eclipse.org/legal/epl-v10.html
  11 //
  12 //      The Apache License v2.0 is available at
  13 //      http://www.opensource.org/licenses/apache2.0.php
  14 //
  15 //  You may elect to redistribute this code under either of these licenses.
  16 //  ========================================================================
  17 //
  18
  19 package org.eclipse.jetty.util;
  20
  21 import java.io.IOException;
  22 import java.util.concurrent.CancellationException;
  23 import java.util.concurrent.CountDownLatch;
  24 import java.util.concurrent.ExecutionException;
  25 import java.util.concurrent.Future;
  26 import java.util.concurrent.TimeUnit;
  27 import java.util.concurrent.TimeoutException;
  28 import java.util.concurrent.atomic.AtomicBoolean;
  29
  30 public class FutureCallback implements Future<Void>,Callback
  31 {
  32     private static Throwable COMPLETED=new Throwable();
  33     private final AtomicBoolean _done=new AtomicBoolean(false);
  34     private final CountDownLatch _latch=new CountDownLatch(1);
  35     private Throwable _cause;
  36
  37     public FutureCallback()
  38     {}
  39
  40     public FutureCallback(boolean completed)
  41     {
  42         if (completed)
  43         {
  44             _cause=COMPLETED;
  45             _done.set(true);
  46             _latch.countDown();
  47         }
  48     }
  49
  50     public FutureCallback(Throwable failed)
  51     {
  52         _cause=failed;
  53         _done.set(true);
  54         _latch.countDown();
  55     }
  56
  57     @Override
  58     public void succeeded()
  59     {
  60         if (_done.compareAndSet(false,true))
  61         {
  62             _cause=COMPLETED;
  63             _latch.countDown();
  64         }
  65     }
  66
  67     @Override
  68     public void failed(Throwable cause)
  69     {
  70         if (_done.compareAndSet(false,true))
  71         {
  72             _cause=cause;
  73             _latch.countDown();
  74         }
  75     }
  76
  77     @Override
  78     public boolean cancel(boolean mayInterruptIfRunning)
  79     {
  80         if (_done.compareAndSet(false,true))
  81         {
  82             _cause=new CancellationException();
  83             _latch.countDown();
  84             return true;
  85         }
  86         return false;
  87     }
  88
  89     @Override
  90     public boolean isCancelled()
  91     {
  92         if (_done.get())
  93         {
  94             try
  95             {
  96                 _latch.await();
  97             }
  98             catch (InterruptedException e)
  99             {
 100                 throw new RuntimeException(e);
 101             }
 102             return _cause instanceof CancellationException;
 103         }
 104         return false;
 105     }
 106
 107     @Override
 108     public boolean isDone()
 109     {
 110         return _done.get() && _latch.getCount()==0;
 111     }
 112
 113     @Override
 114     public Void get() throws InterruptedException, ExecutionException
 115     {
 116         _latch.await();
 117         if (_cause==COMPLETED)
 118             return null;
 119         if (_cause instanceof CancellationException)
 120             throw (CancellationException) new CancellationException().initCause(_cause);
 121         throw new ExecutionException(_cause);
 122     }
 123
 124     @Override
 125     public Void get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException
 126     {
 127         if (!_latch.await(timeout,unit))
 128             throw new TimeoutException();
 129
 130         if (_cause==COMPLETED)
 131             return null;
 132         if (_cause instanceof TimeoutException)
 133             throw (TimeoutException)_cause;
 134         if (_cause instanceof CancellationException)
 135             throw (CancellationException) new CancellationException().initCause(_cause);
 136         throw new ExecutionException(_cause);
 137     }
 138
 139     public static void rethrow(ExecutionException e) throws IOException
 140     {
 141         Throwable cause=e.getCause();
 142         if (cause instanceof IOException)
 143             throw (IOException)cause;
 144         if (cause instanceof Error)
 145             throw (Error)cause;
 146         if (cause instanceof RuntimeException)
 147             throw (RuntimeException)cause;
 148         throw new RuntimeException(cause);
 149     }
 150
 151     @Override
 152     public String toString()
 153     {
 154         return String.format("FutureCallback@%x{%b,%b}",hashCode(),_done,_cause==COMPLETED);
 155     }
 156
 157 }