/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you under the Apache License, Version 2.0 (the

  * "License"); you may not use this file except in compliance

  * with the License.  You may obtain a copy of the License at

  *

  *     http://www.apache.org/licenses/LICENSE-2.0

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.apache.giraph.io.formats;

 import org.apache.giraph.bsp.ImmutableOutputCommitter;

 import org.apache.giraph.conf.GiraphConfiguration;

 import org.apache.giraph.graph.Vertex;

 import org.apache.giraph.io.VertexOutputFormat;

 import org.apache.giraph.io.VertexWriter;

 import org.apache.giraph.utils.TestGraph;

 import org.apache.hadoop.io.Writable;

 import org.apache.hadoop.io.WritableComparable;

 import org.apache.hadoop.mapreduce.JobContext;

 import org.apache.hadoop.mapreduce.OutputCommitter;

 import org.apache.hadoop.mapreduce.TaskAttemptContext;

 import java.io.IOException;

 /**

  * VertexOutputFormat which stores all vertices in memory

  *

  * @param <I> Vertex id

  * @param <V> Vertex data

  * @param <E> Edge data

  */

 public class InMemoryVertexOutputFormat<I extends WritableComparable,

     V extends Writable, E extends Writable> extends

     VertexOutputFormat<I, V, E> {

   /** Graph where we store all vertices */

   private static TestGraph OUTPUT_GRAPH;

   /**

    * Initialize this output format - needs to be called before running the

    * application. Creates new instance of TestGraph

    *

    * @param conf Configuration

    */

   public static void initializeOutputGraph(GiraphConfiguration conf) {

     OUTPUT_GRAPH = new TestGraph(conf);

   }

   /**

    * Get graph containing all the vertices

    *

    * @param <I> Vertex id

    * @param <V> Vertex data

    * @param <E> Edge data

    * @return Output graph

    */

   public static <I extends WritableComparable, V extends Writable,

       E extends Writable> TestGraph<I, V, E> getOutputGraph() {

     return OUTPUT_GRAPH;

   }

   @Override

   public VertexWriter<I, V, E> createVertexWriter(

       TaskAttemptContext context) throws IOException, InterruptedException {

     return new VertexWriter<I, V, E>() {

       @Override

       public void initialize(

           TaskAttemptContext context) throws IOException, InterruptedException {

       }

       @Override

       public void close(

           TaskAttemptContext context) throws IOException, InterruptedException {

       }

       @Override

       public void writeVertex(

           Vertex<I, V, E> vertex) throws IOException, InterruptedException {

         synchronized (OUTPUT_GRAPH) {

           OUTPUT_GRAPH.addVertex(vertex);

         }

       }

     };

   }

   @Override

   public void checkOutputSpecs(

       JobContext context) throws IOException, InterruptedException {

   }

   @Override

   public OutputCommitter getOutputCommitter(

       TaskAttemptContext context) throws IOException, InterruptedException {

     return new ImmutableOutputCommitter();

   }

 }