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GeneratedVertexReader 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.examples;
20  
21  import org.apache.giraph.bsp.BspInputSplit;
22  import org.apache.giraph.conf.BooleanConfOption;
23  import org.apache.giraph.conf.LongConfOption;
24  import org.apache.giraph.io.VertexReader;
25  import org.apache.hadoop.io.Writable;
26  import org.apache.hadoop.io.WritableComparable;
27  import org.apache.hadoop.mapreduce.InputSplit;
28  import org.apache.hadoop.mapreduce.TaskAttemptContext;
29  
30  import java.io.IOException;
31  
32  /**
33   * Used by GeneratedVertexInputFormat to read some generated data
34   *
35   * @param <I> Vertex index value
36   * @param <V> Vertex value
37   * @param <E> Edge value
38   */
39  @SuppressWarnings("rawtypes")
40  public abstract class GeneratedVertexReader<
41      I extends WritableComparable, V extends Writable,
42      E extends Writable>
43      extends VertexReader<I, V, E> {
44    /** Vertices produced by this reader */
45    public static final LongConfOption READER_VERTICES =
46        new LongConfOption("GeneratedVertexReader.reader_vertices", 10,
47            "Vertices produced by this reader");
48    /** Reverse the order of the vertices? */
49    public static final BooleanConfOption REVERSE_ID_ORDER =
50        new BooleanConfOption("GeneratedVertexReader.reverseIdOrder", false,
51            "Reverse the order of the vertices?");
52    /** Records read so far */
53    protected long recordsRead = 0;
54    /** Total records to read (on this split alone) */
55    protected long totalRecords = 0;
56    /** The input split from initialize(). */
57    protected BspInputSplit inputSplit = null;
58    /** Reverse the id order? */
59    protected boolean reverseIdOrder;
60  
61    /**
62     * Default constructor for reflection.
63     */
64    public GeneratedVertexReader() {
65    }
66  
67    @Override
68    public final void initialize(InputSplit inputSplit,
69        TaskAttemptContext context) throws IOException {
70      totalRecords = GeneratedVertexReader.READER_VERTICES.get(getConf());
71      reverseIdOrder = GeneratedVertexReader.REVERSE_ID_ORDER.get(getConf());
72      this.inputSplit = (BspInputSplit) inputSplit;
73    }
74  
75    @Override
76    public void close() throws IOException {
77    }
78  
79    @Override
80    public final float getProgress() throws IOException {
81      return recordsRead * 100.0f / totalRecords;
82    }
83  }