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ChunkQueue xref
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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.hadoop.chukwa.datacollection;
20  
21  
22  import java.util.List;
23  import org.apache.hadoop.chukwa.Chunk;
24  
25  /**
26   * A generic interface for queues of Chunks.
27   * 
28   * Differs from a normal queue interface primarily by having collect().
29   */
30  public interface ChunkQueue extends ChunkReceiver {
31    /**
32     * Add a chunk to the queue, blocking if queue is full.
33     * 
34     * @param chunk
35     * @throws InterruptedException if thread is interrupted while blocking
36     */
37    public void add(Chunk chunk) throws InterruptedException;
38  
39    /**
40     * Return at least one, and no more than count, Chunks into chunks. Blocks if
41     * queue is empty.
42     * @param chunks 
43     * @param count 
44     * @throws InterruptedException 
45     */
46    public void collect(List<Chunk> chunks, int count)
47        throws InterruptedException;
48  
49    /**
50     * Return an approximation of the number of chunks in the queue currently. No
51     * guarantees are made about the accuracy of this number.
52     * @return 
53     */
54    public int size();
55  }