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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, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  
19  package org.apache.giraph.zk;
20  
21  /**
22   * Synchronize on waiting for an event to have happened.  This is a one-time
23   * event.
24   */
25  public interface BspEvent {
26    /**
27     * Reset the permanent signal.
28     */
29    void reset();
30  
31    /**
32     * The event occurred and the occurrence has been logged for future
33     * waiters.
34     */
35    void signal();
36  
37    /**
38     * Wait until the event occurred or waiting timed out.
39     * @param msecs Milliseconds to wait until the event occurred. 0 indicates
40     *        check immediately.  -1 indicates wait forever.
41     * @return true if event occurred, false if timed out while waiting
42     */
43    boolean waitMsecs(int msecs);
44  
45    /**
46     * Wait indefinitely until the event occurs.
47     */
48    void waitForever();
49  }