/*

  * 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.graph.Vertex;

 import org.apache.giraph.io.VertexInputFormat;

 import org.apache.giraph.io.VertexReader;

 import org.apache.hadoop.conf.Configuration;

 import org.apache.hadoop.io.Writable;

 import org.apache.hadoop.io.WritableComparable;

 import org.apache.hadoop.mapreduce.InputSplit;

 import org.apache.hadoop.mapreduce.JobContext;

 import org.apache.hadoop.mapreduce.RecordReader;

 import org.apache.hadoop.mapreduce.TaskAttemptContext;

 import org.apache.hadoop.mapreduce.lib.input.SequenceFileInputFormat;

 import java.io.IOException;

 import java.util.List;

 /**

  * Sequence file vertex input format based on {@link SequenceFileInputFormat}.

  *

  * @param <I> Vertex id

  * @param <V> Vertex data

  * @param <E> Edge data

  * @param <X> Value type

  */

 @SuppressWarnings("rawtypes")

 public class SequenceFileVertexInputFormat<I extends WritableComparable,

     V extends Writable, E extends Writable, X extends Vertex<I, V, E>>

     extends VertexInputFormat<I, V, E> {

   /** Internal input format */

   protected SequenceFileInputFormat<I, X> sequenceFileInputFormat =

     new SequenceFileInputFormat<I, X>();

   @Override public void checkInputSpecs(Configuration conf) { }

   @Override

   public List<InputSplit> getSplits(JobContext context, int minSplitCountHint)

     throws IOException, InterruptedException {

     return sequenceFileInputFormat.getSplits(context);

   }

   @Override

   public VertexReader<I, V, E> createVertexReader(InputSplit split,

       TaskAttemptContext context) throws IOException {

     return new SequenceFileVertexReader<I, V, E, X>(

         sequenceFileInputFormat.createRecordReader(split, context));

   }

   /**

    * Vertex reader used with {@link SequenceFileVertexInputFormat}.

    *

    * @param <I> Vertex id

    * @param <V> Vertex data

    * @param <E> Edge data

    * @param <X> Value type

    */

   public static class SequenceFileVertexReader<I extends WritableComparable,

       V extends Writable, E extends Writable, X extends Vertex<I, V, E>>

       extends VertexReader<I, V, E> {

     /** Internal record reader from {@link SequenceFileInputFormat} */

     private final RecordReader<I, X> recordReader;

     /**

      * Constructor with record reader.

      *

      * @param recordReader Reader from {@link SequenceFileInputFormat}.

      */

     public SequenceFileVertexReader(RecordReader<I, X> recordReader) {

       this.recordReader = recordReader;

     }

     @Override public void initialize(InputSplit inputSplit,

         TaskAttemptContext context) throws IOException, InterruptedException {

       recordReader.initialize(inputSplit, context);

     }

     @Override public boolean nextVertex() throws IOException,

         InterruptedException {

       return recordReader.nextKeyValue();

     }

     @Override public Vertex<I, V, E> getCurrentVertex()

       throws IOException, InterruptedException {

       return recordReader.getCurrentValue();

     }

     @Override public void close() throws IOException {

       recordReader.close();

     }

     @Override public float getProgress() throws IOException,

         InterruptedException {

       return recordReader.getProgress();

     }

   }

 }