/*

  * 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.lib;

 import org.apache.giraph.graph.BasicVertex;

 import org.apache.giraph.graph.VertexWriter;

 import org.apache.hadoop.io.Text;

 import org.apache.hadoop.io.Writable;

 import org.apache.hadoop.io.WritableComparable;

 import org.apache.hadoop.mapreduce.RecordWriter;

 import org.apache.hadoop.mapreduce.TaskAttemptContext;

 import java.io.IOException;

 /**

  * OutputFormat to write out the graph nodes as text, value-separated (by

  * tabs, by default).  With the default delimiter, a vertex is written out as:

  *

  * <VertexId><tab><Vertex Value><tab>[<EdgeId><tab><EdgeValue>]+

  *

  * @param <I> Vertex index value

  * @param <V> Vertex value

  * @param <E> Edge value

  */

 @SuppressWarnings("rawtypes")

 public class AdjacencyListTextVertexOutputFormat<I extends WritableComparable,

     V extends Writable, E extends Writable>

     extends TextVertexOutputFormat<I, V, E> {

   /**

    * Vertex writer associated wtih {@link AdjacencyListTextVertexOutputFormat}.

    *

    * @param <I> Vertex id

    * @param <V> Vertex data

    * @param <E> Edge data

    */

   static class AdjacencyListVertexWriter<I extends WritableComparable, V extends

       Writable, E extends Writable> extends TextVertexWriter<I, V, E> {

     /** Split delimiter */

     public static final String LINE_TOKENIZE_VALUE = "output.delimiter";

     /** Default split delimiter */

     public static final String LINE_TOKENIZE_VALUE_DEFAULT = "\t";

     /** Cached split delimeter */

     private String delimiter;

     /**

      * Constructor with writer.

      *

      * @param recordWriter Record writer used for writing.

      */

     public AdjacencyListVertexWriter(RecordWriter<Text, Text> recordWriter) {

       super(recordWriter);

     }

     @Override

     public void writeVertex(BasicVertex<I, V, E, ?> vertex) throws IOException,

     InterruptedException {

       if (delimiter == null) {

         delimiter = getContext().getConfiguration()

             .get(LINE_TOKENIZE_VALUE, LINE_TOKENIZE_VALUE_DEFAULT);

       }

       StringBuffer sb = new StringBuffer(vertex.getVertexId().toString());

       sb.append(delimiter);

       sb.append(vertex.getVertexValue().toString());

       for (I edge : vertex) {

         sb.append(delimiter).append(edge);

         sb.append(delimiter).append(vertex.getEdgeValue(edge));

       }

       getRecordWriter().write(new Text(sb.toString()), null);

     }

   }

   @Override

   public VertexWriter<I, V, E> createVertexWriter(TaskAttemptContext context)

     throws IOException, InterruptedException {

     return new AdjacencyListVertexWriter<I, V, E>

     (textOutputFormat.getRecordWriter(context));

   }

 }