content: /*
   * 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 com.manning.hip.ch11;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.apache.hadoop.io.Writable;
  import org.apache.hadoop.mapreduce.InputFormat;
  import org.apache.hadoop.mapreduce.Job;
  import org.apache.hadoop.mapreduce.RecordReader;
  import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
  import org.apache.hadoop.mapreduce.lib.input.SequenceFileInputFormat;
  import org.apache.hadoop.mapreduce.lib.input.SequenceFileRecordReader;
  import org.apache.pig.FileInputLoadFunc;
  import org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigSplit;
  import org.apache.pig.data.Tuple;
  import org.apache.pig.data.TupleFactory;
  
  import java.io.IOException;
  
  public class SequenceFileTupleLoader extends FileInputLoadFunc {
    
    private SequenceFileRecordReader<Writable, Writable> reader;
   
    protected static final Log LOG = LogFactory.getLog(
      SequenceFileTupleLoader.class);
    protected TupleFactory mTupleFactory = TupleFactory.getInstance();
  
    @Override
    public Tuple getNext() throws IOException {
      boolean next;
      try {
        next = reader.nextKeyValue();
      } catch (InterruptedException e) {
        throw new IOException(e);
      }
      
      if (!next) return null;
      
      Object value = reader.getCurrentValue();
      
      if (value == null) {
        return null;
      }
      if(!(value instanceof Tuple)) {
        return null;
      }
  
      return (Tuple) value;
    }
  
    @SuppressWarnings("unchecked")
    @Override
    public InputFormat getInputFormat() throws IOException {
      return new SequenceFileInputFormat<Writable, Writable>();
    }
  
    @SuppressWarnings("unchecked")
    @Override
    public void prepareToRead(RecordReader reader, PigSplit split)
          throws IOException {
      this.reader = (SequenceFileRecordReader) reader;
    }
  
    @Override
    public void setLocation(String location, Job job) throws IOException {
      FileInputFormat.setInputPaths(job, location);    
    }
  }
  