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EdgeOutputFormat 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.io;
20  
21  import java.io.IOException;
22  
23  import org.apache.hadoop.io.Writable;
24  import org.apache.hadoop.io.WritableComparable;
25  import org.apache.hadoop.mapreduce.TaskAttemptContext;
26  
27  /**
28   * abstract class which can only write edges
29   *
30   * @param <I> Vertex id
31   * @param <V> Vertex value
32   * @param <E> Edge value
33   */
34  @SuppressWarnings("rawtypes")
35  public abstract class EdgeOutputFormat<
36      I extends WritableComparable, V extends Writable,
37      E extends Writable> extends
38      OutputFormat<I, V, E> {
39    /**
40     * Create an edge writer for a given split. The framework will call
41     * {@link EdgeWriter#initialize(TaskAttemptContext)} before
42     * the split is used.
43     *
44     * @param context the information about the task
45     * @return a new vertex writer
46     * @throws IOException
47     * @throws InterruptedException
48     */
49    public abstract EdgeWriter<I, V, E> createEdgeWriter(
50      TaskAttemptContext context) throws IOException, InterruptedException;
51  }