/*
    * 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.gora;
  
  import java.io.IOException;
  
  import org.apache.giraph.edge.Edge;
  import org.apache.giraph.edge.EdgeFactory;
  import org.apache.giraph.io.gora.generated.GEdge;
  import org.apache.hadoop.io.FloatWritable;
  import org.apache.hadoop.io.LongWritable;
  import org.apache.hadoop.mapreduce.InputSplit;
  import org.apache.hadoop.mapreduce.TaskAttemptContext;
  
  /**
   * Example implementation of a specific reader for a generated data bean.
   */
  public class GoraGEdgeEdgeInputFormat
    extends GoraEdgeInputFormat<LongWritable, FloatWritable> {
  
    /**
     * Default constructor
     */
    public GoraGEdgeEdgeInputFormat() {
    }
  
    /**
     * Creates specific vertex reader to be used inside Hadoop.
     * @param split split to be read.
     * @param context JobContext to be used.
     * @return GoraEdgeReader Edge reader to be used by Hadoop.
     */
    @Override
    public GoraEdgeReader createEdgeReader(
        InputSplit split, TaskAttemptContext context) throws IOException {
      return new GoraGEdgeEdgeReader();
    }
  
    /**
     * Gora edge reader
     */
    protected class GoraGEdgeEdgeReader extends GoraEdgeReader {
  
      /** source vertex of the edge */
      private LongWritable sourceId;
  
      /**
       * Transforms a GoraObject into an Edge object.
       * @param goraObject Object from Gora to be translated.
       * @return Edge Result from transforming the gora object.
       */
      @Override
      protected Edge<LongWritable, FloatWritable> transformEdge
      (Object goraObject) {
        Edge<LongWritable, FloatWritable> edge = null;
        GEdge goraEdge = (GEdge) goraObject;
        this.sourceId = new LongWritable();
        this.sourceId.set(Long.parseLong(goraEdge.getVertexInId().toString()));
        edge = EdgeFactory.create(
            new LongWritable(
                Long.parseLong(goraEdge.getVertexOutId().toString())),
            new FloatWritable(goraEdge.getEdgeWeight()));
        return edge;
      }
  
      /**
       * Gets the currentSourceId for the edge.
       * @return LongWritable currentSourceId for the edge.
       */
      @Override
      public LongWritable getCurrentSourceId() throws IOException,
          InterruptedException {
        return this.sourceId;
      }
    }
  }