/*

  * 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.edge.EdgeFactory;

 import org.apache.giraph.graph.Vertex;

 import org.apache.hadoop.io.DoubleWritable;

 import org.apache.hadoop.io.FloatWritable;

 import org.apache.hadoop.io.LongWritable;

 import org.apache.hadoop.io.Text;

 import org.apache.hadoop.mapreduce.InputSplit;

 import org.apache.hadoop.mapreduce.TaskAttemptContext;

 import org.json.JSONArray;

 import org.json.JSONException;

 import com.google.common.collect.Lists;

 import java.io.IOException;

 import java.util.List;

 /**

   * VertexInputFormat that features <code>long</code> vertex ID's,

   * <code>double</code> vertex values and <code>float</code>

   * out-edge weights, and <code>double</code> message types,

   *  specified in JSON format.

   */

 public class JsonLongDoubleFloatDoubleVertexInputFormat extends

   TextVertexInputFormat<LongWritable, DoubleWritable, FloatWritable> {

   @Override

   public TextVertexReader createVertexReader(InputSplit split,

       TaskAttemptContext context) {

     return new JsonLongDoubleFloatDoubleVertexReader();

   }

  /**

   * VertexReader that features <code>double</code> vertex

   * values and <code>float</code> out-edge weights. The

   * files should be in the following JSON format:

   * JSONArray(<vertex id>, <vertex value>,

   *   JSONArray(JSONArray(<dest vertex id>, <edge value>), ...))

   * Here is an example with vertex id 1, vertex value 4.3, and two edges.

   * First edge has a destination vertex 2, edge value 2.1.

   * Second edge has a destination vertex 3, edge value 0.7.

   * [1,4.3,[[2,2.1],[3,0.7]]]

   */

   class JsonLongDoubleFloatDoubleVertexReader extends

     TextVertexReaderFromEachLineProcessedHandlingExceptions<JSONArray,

     JSONException> {

     @Override

     protected JSONArray preprocessLine(Text line) throws JSONException {

       return new JSONArray(line.toString());

     }

     @Override

     protected LongWritable getId(JSONArray jsonVertex) throws JSONException,

               IOException {

       return new LongWritable(jsonVertex.getLong(0));

     }

     @Override

     protected DoubleWritable getValue(JSONArray jsonVertex) throws

       JSONException, IOException {

       return new DoubleWritable(jsonVertex.getDouble(1));

     }

     @Override

     protected Iterable<Edge<LongWritable, FloatWritable>> getEdges(

         JSONArray jsonVertex) throws JSONException, IOException {

       JSONArray jsonEdgeArray = jsonVertex.getJSONArray(2);

       List<Edge<LongWritable, FloatWritable>> edges =

           Lists.newArrayListWithCapacity(jsonEdgeArray.length());

       for (int i = 0; i < jsonEdgeArray.length(); ++i) {

         JSONArray jsonEdge = jsonEdgeArray.getJSONArray(i);

         edges.add(EdgeFactory.create(new LongWritable(jsonEdge.getLong(0)),

             new FloatWritable((float) jsonEdge.getDouble(1))));

       }

       return edges;

     }

     @Override

     protected Vertex<LongWritable, DoubleWritable, FloatWritable>

     handleException(Text line, JSONArray jsonVertex, JSONException e) {

       throw new IllegalArgumentException(

           "Couldn't get vertex from line " + line, e);

     }

   }

 }