1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20 package org.apache.mina.core.future;
21
22 import java.util.concurrent.atomic.AtomicInteger;
23
24 import org.apache.mina.core.IoUtil;
25
26 /**
27 * An {@link IoFuture} of {@link IoFuture}s. It is useful when you want to
28 * get notified when all {@link IoFuture}s are complete. It is not recommended
29 * to use {@link CompositeIoFuture} if you just want to wait for all futures.
30 * In that case, please use {@link IoUtil#await(Iterable)} instead
31 * for better performance.
32 *
33 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
34 *
35 * @param <E> the type of the child futures.
36 */
37 public class CompositeIoFuture<E extends IoFuture> extends DefaultIoFuture {
38 /** A listener */
39 private final NotifyingListener listener = new NotifyingListener();
40
41 /** A thread safe counter that is used to keep a track of the notified futures */
42 private final AtomicInteger unnotified = new AtomicInteger();
43
44 /** A flag set to TRUE when all the future have been added to the list */
45 private volatile boolean constructionFinished;
46
47 /**
48 * Creates a new CompositeIoFuture instance
49 *
50 * @param children The list of internal futures
51 */
52 public CompositeIoFuture(Iterable<E> children) {
53 super(null);
54
55 for (E child : children) {
56 child.addListener(listener);
57 unnotified.incrementAndGet();
58 }
59
60 constructionFinished = true;
61
62 if (unnotified.get() == 0) {
63 setValue(true);
64 }
65 }
66
67 private class NotifyingListener implements IoFutureListener<IoFuture> {
68 /**
69 * {@inheritDoc}
70 */
71 @Override
72 public void operationComplete(IoFuture future) {
73 if (unnotified.decrementAndGet() == 0 && constructionFinished) {
74 setValue(true);
75 }
76 }
77 }
78 }