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GeneratedEdgeReader 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 java.io.IOException;
22  import org.apache.giraph.bsp.BspInputSplit;
23  import org.apache.giraph.conf.LongConfOption;
24  import org.apache.giraph.io.EdgeReader;
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  /**
31   * Used by GeneratedEdgeInputFormat
32   * to read some generated data
33   *
34   * @param <I> Vertex index value
35   * @param <E> Edge value
36   */
37  @SuppressWarnings("rawtypes")
38  public abstract class GeneratedEdgeReader<
39      I extends WritableComparable,
40      E extends Writable>
41      extends EdgeReader<I, E> {
42    /** Default edges produced by this reader */
43    public static final LongConfOption DEFAULT_READER_EDGES =
44      new LongConfOption("GeneratedEdgeReader.reader_edges", 10,
45          "Default edges produced by this reader");
46    /** Records read so far */
47    protected long recordsRead = 0;
48    /** Total records to read (on this split alone) */
49    protected long totalRecords = 0;
50    /** The input split from initialize(). */
51    protected BspInputSplit inputSplit = null;
52  
53    /**
54     * Default constructor for reflection.
55     */
56    public GeneratedEdgeReader() {
57    }
58  
59    @Override
60    public final void initialize(InputSplit inputSplit,
61        TaskAttemptContext context) throws IOException {
62      totalRecords = DEFAULT_READER_EDGES.get(getConf());
63      this.inputSplit = (BspInputSplit) inputSplit;
64    }
65  
66    @Override
67    public void close() throws IOException {
68    }
69  
70    @Override
71    public final float getProgress() throws IOException {
72      return recordsRead * 100.0f / totalRecords;
73    }
74  }