/*

  * 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.utils;

 import org.apache.giraph.bsp.BspInputSplit;

 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.TaskAttemptContext;

 import java.io.IOException;

 import java.util.ArrayList;

 import java.util.Iterator;

 import java.util.List;

 /**

  * An input format that reads the input graph in memory. Used for unit tests.

  *

  * @param <I> The Input

  * @param <V> The vertex type

  * @param <E> The edge type

  */

 public class InMemoryVertexInputFormat<I extends WritableComparable,

     V extends Writable, E extends Writable>

     extends VertexInputFormat<I, V, E> {

   /** The graph */

   private static TestGraph GRAPH;

   public static void setGraph(TestGraph graph) {

     InMemoryVertexInputFormat.GRAPH = graph;

   }

   public static TestGraph getGraph() {

     return GRAPH;

   }

   @Override public void checkInputSpecs(Configuration conf) { }

   @Override

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

     throws IOException, InterruptedException {

     // This is meaningless, the VertexReader will generate all the test

     // data.

     List<InputSplit> inputSplitList = new ArrayList<InputSplit>();

     for (int i = 0; i < minSplitCountHint; ++i) {

       inputSplitList.add(new BspInputSplit(i, minSplitCountHint));

     }

     return inputSplitList;

   }

   @Override

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

       TaskAttemptContext context) throws IOException {

     return new InMemoryVertexReader();

   }

   /**

    * Simple in memory reader

    */

   private class InMemoryVertexReader extends VertexReader<I, V, E> {

     /** The iterator */

     private Iterator<Vertex<I, V, E>> vertexIterator;

     /** Current vertex */

     private Vertex<I, V, E> currentVertex;

     @Override

     public void initialize(InputSplit inputSplit,

                            TaskAttemptContext context) {

       vertexIterator = GRAPH.iterator();

     }

     @Override

     public boolean nextVertex() {

       if (vertexIterator.hasNext()) {

         currentVertex = vertexIterator.next();

         return true;

       }

       return false;

     }

     @Override

     public Vertex<I, V, E> getCurrentVertex() {

       return currentVertex;

     }

     @Override

     public void close() {

     }

     @Override

     public float getProgress() {

       return 0;

     }

   }

 }