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PartitionExchange 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.giraph.partition;
20  
21  import java.util.List;
22  import java.util.Map;
23  import java.util.Set;
24  
25  import org.apache.giraph.worker.WorkerInfo;
26  
27  /**
28   * Describes what is required to send and wait for in a potential partition
29   * exchange between workers.
30   */
31  public class PartitionExchange {
32    /** Workers that I am dependent on before I can continue */
33    private final Set<WorkerInfo> myDependencyWorkerSet;
34    /** Workers that I need to sent partitions to */
35    private final Map<WorkerInfo, List<Integer>> sendWorkerPartitionMap;
36  
37    /**
38     * Only constructor.
39     *
40     * @param myDependencyWorkerSet All the workers I must wait for
41     * @param sendWorkerPartitionMap Partitions I need to send to other workers
42     */
43    public PartitionExchange(
44        Set<WorkerInfo> myDependencyWorkerSet,
45        Map<WorkerInfo, List<Integer>> sendWorkerPartitionMap) {
46      this.myDependencyWorkerSet = myDependencyWorkerSet;
47      this.sendWorkerPartitionMap = sendWorkerPartitionMap;
48    }
49  
50    /**
51     * Get the workers that I must wait for
52     *
53     * @return Set of workers I must wait for
54     */
55    public Set<WorkerInfo> getMyDependencyWorkerSet() {
56      return myDependencyWorkerSet;
57    }
58  
59    /**
60     * Get a mapping of worker to list of partition ids I need to send to.
61     *
62     * @return Mapping of worker to partition id list I will send to.
63     */
64    public Map<WorkerInfo, List<Integer>> getSendWorkerPartitionMap() {
65      return sendWorkerPartitionMap;
66    }
67  
68    /**
69     * Is this worker involved in a partition exchange?  Receiving or sending?
70     *
71     * @return True if needs to be involved in the exchange, false otherwise.
72     */
73    public boolean doExchange() {
74      return !myDependencyWorkerSet.isEmpty() ||
75          !sendWorkerPartitionMap.isEmpty();
76    }
77  }