/*

  * 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.iterables;

 import org.apache.giraph.conf.ImmutableClassesGiraphConfiguration;

 import org.apache.giraph.graph.Vertex;

 import org.apache.giraph.io.VertexReader;

 import org.apache.hadoop.io.Writable;

 import org.apache.hadoop.io.WritableComparable;

 import org.apache.hadoop.mapreduce.InputSplit;

 import org.apache.hadoop.mapreduce.TaskAttemptContext;

 import java.io.IOException;

 /**

  * Wraps {@link GiraphReader} for vertices into {@link VertexReader}

  *

  * @param <I> Vertex id

  * @param <V> Vertex data

  * @param <E> Edge data

  */

 public class VertexReaderWrapper<I extends WritableComparable,

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

   /** Wrapped vertex reader */

   private GiraphReader<Vertex<I, V, E>> vertexReader;

   /** {@link VertexReader}-like wrapper of {@link #vertexReader} */

   private IteratorToReaderWrapper<Vertex<I, V, E>> iterator;

   /**

    * Constructor

    *

    * @param vertexReader GiraphReader for vertices to wrap

    */

   public VertexReaderWrapper(GiraphReader<Vertex<I, V, E>> vertexReader) {

     this.vertexReader = vertexReader;

     iterator = new IteratorToReaderWrapper<Vertex<I, V, E>>(vertexReader);

   }

   @Override

   public void setConf(

       ImmutableClassesGiraphConfiguration<I, V, E> conf) {

     super.setConf(conf);

     conf.configureIfPossible(vertexReader);

   }

   @Override

   public boolean nextVertex() throws IOException, InterruptedException {

     return iterator.nextObject();

   }

   @Override

   public Vertex<I, V, E> getCurrentVertex() throws IOException,

       InterruptedException {

     return iterator.getCurrentObject();

   }

   @Override

   public void initialize(InputSplit inputSplit,

       TaskAttemptContext context) throws IOException, InterruptedException {

     vertexReader.initialize(inputSplit, context);

   }

   @Override

   public void close() throws IOException {

     vertexReader.close();

   }

   @Override

   public float getProgress() throws IOException, InterruptedException {

     return vertexReader.getProgress();

   }

 }