/*

  * 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.bsp;

 import java.io.IOException;

 import org.apache.hadoop.mapreduce.InputSplit;

 import org.apache.hadoop.mapreduce.RecordReader;

 import org.apache.hadoop.mapreduce.TaskAttemptContext;

 import org.apache.hadoop.io.Text;

 /**

  * Only returns a single key-value pair so that the map() can run.

  */

 class BspRecordReader extends RecordReader<Text, Text> {

   /** Singular key object */

   private static final Text ONLY_KEY = new Text("only key");

   /** Single value object */

   private static final Text ONLY_VALUE = new Text("only value");

   /** Has the one record been seen? */

   private boolean seenRecord = false;

   @Override

   public void close() throws IOException {

     return;

   }

   @Override

   public float getProgress() throws IOException {

     return seenRecord ? 1f : 0f;

   }

   @Override

   public Text getCurrentKey() throws IOException, InterruptedException {

     return ONLY_KEY;

   }

   @Override

   public Text getCurrentValue() throws IOException, InterruptedException {

     return ONLY_VALUE;

   }

   @Override

   public void initialize(InputSplit inputSplit, TaskAttemptContext context)

     throws IOException, InterruptedException {

   }

   @Override

   public boolean nextKeyValue() throws IOException, InterruptedException {

     if (!seenRecord) {

       seenRecord = true;

       return true;

     }

     return false;

   }

 }