/*

  * 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.edge.Edge;

 import org.apache.giraph.graph.Vertex;

 import org.apache.hadoop.io.Text;

 import org.apache.hadoop.io.Writable;

 import org.apache.hadoop.io.WritableComparable;

 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> {

   /** Split delimiter */

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

   /** Default split delimiter */

   public static final String LINE_TOKENIZE_VALUE_DEFAULT =

     AdjacencyListTextVertexInputFormat.LINE_TOKENIZE_VALUE_DEFAULT;

   @Override

   public AdjacencyListTextVertexWriter createVertexWriter(

       TaskAttemptContext context) {

     return new AdjacencyListTextVertexWriter();

   }

   /**

    * Vertex writer associated with {@link AdjacencyListTextVertexOutputFormat}.

    */

   protected class AdjacencyListTextVertexWriter extends

     TextVertexWriterToEachLine {

     /** Cached split delimeter */

     private String delimiter;

     @Override

     public void initialize(TaskAttemptContext context) throws IOException,

         InterruptedException {

       super.initialize(context);

       delimiter =

           getConf().get(LINE_TOKENIZE_VALUE, LINE_TOKENIZE_VALUE_DEFAULT);

     }

     @Override

     public Text convertVertexToLine(Vertex<I, V, E> vertex)

       throws IOException {

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

       sb.append(delimiter);

       sb.append(vertex.getValue());

       for (Edge<I, E> edge : vertex.getEdges()) {

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

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

       }

       return new Text(sb.toString());

     }

   }

 }