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SuperstepOutput 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.superstep_output;
20  
21  import org.apache.giraph.io.SimpleVertexWriter;
22  import org.apache.hadoop.io.Writable;
23  import org.apache.hadoop.io.WritableComparable;
24  
25  import java.io.IOException;
26  
27  /**
28   * Interface for outputing data during the computation.
29   *
30   * @param <I> Vertex id
31   * @param <V> Vertex value
32   * @param <E> Edge value
33   */
34  public interface SuperstepOutput<I extends WritableComparable,
35      V extends Writable, E extends Writable> {
36  
37    /**
38     * Get the Writer. You have to return it after usage in order for it to be
39     * properly closed.
40     *
41     * @return SimpleVertexWriter
42     */
43    SimpleVertexWriter<I, V, E> getVertexWriter();
44  
45    /**
46     * Return the Writer after usage, which you got by calling
47     * {@link #getVertexWriter()}
48     *
49     * @param vertexWriter SimpleVertexWriter which you are returning
50     */
51    void returnVertexWriter(SimpleVertexWriter<I, V, E> vertexWriter);
52  
53    /**
54     * Finalize this output in the end of the application
55     */
56    void postApplication() throws IOException, InterruptedException;
57  }