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    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
    39      private final NotifyingListener listener = new NotifyingListener();
    40
    41      private final AtomicInteger unnotified = new AtomicInteger();
    42
    43      private volatile boolean constructionFinished;
    44
    45      public CompositeIoFuture(Iterable<E> children) {
    46          super(null);
    47
    48          for (E f : children) {
    49              f.addListener(listener);
    50              unnotified.incrementAndGet();
    51          }
    52
    53          constructionFinished = true;
    54          if (unnotified.get() == 0) {
    55              setValue(true);
    56          }
    57      }
    58
    59      private class NotifyingListener implements IoFutureListener<IoFuture> {
    60          public void operationComplete(IoFuture future) {
    61              if (unnotified.decrementAndGet() == 0 && constructionFinished) {
    62                  setValue(true);
    63              }
    64          }
    65      }
    66  }