WholeFileRecordReader.java

package com.caseystella.util.common.hadoop.input.whole;

import java.io.IOException;

import org.apache.hadoop.io.BytesWritable;

import org.apache.hadoop.io.Text;
import org.apache.hadoop.mapreduce.lib.input.FileSplit;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.conf.Configuration;

import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IOUtils;

/**
 * This is pretty much just from Tom White's book.  I needed it so I could wrap it in a
 * Pig Loader.
 */
class WholeFileRecordReader extends RecordReader<Text, BytesWritable> {

    private FileSplit fileSplit;
    private Configuration conf;
    private boolean processed = false;

    private Text key = new Text();
    private BytesWritable value = new BytesWritable();

    public void initialize(InputSplit inputSplit, TaskAttemptContext taskAttemptContext) throws IOException, InterruptedException {
        this.fileSplit = (FileSplit) inputSplit;
        this.conf = taskAttemptContext.getConfiguration();
    }

    public boolean nextKeyValue() throws IOException {
        if (!processed) {
            byte[] contents = new byte[(int) fileSplit.getLength()];

            Path file = fileSplit.getPath();
            FileSystem fs = file.getFileSystem(conf);

            FSDataInputStream in = null;
            try {
                in = fs.open(file);
                IOUtils.readFully(in, contents, 0, contents.length);
                value.set(contents, 0, contents.length);
                key.set(file.toString());
            } finally {
                IOUtils.closeStream(in);
            }
            processed = true;
            return true;
        }
        return false;
    }

    @Override
    public Text getCurrentKey() throws IOException, InterruptedException {
        return key;
    }

    @Override
    public BytesWritable getCurrentValue() throws IOException, InterruptedException {
        return value;
    }

    @Override
    public float getProgress() throws IOException, InterruptedException  {
        return processed ? 1.0f : 0.0f;
    }

    @Override
    public void close() throws IOException {
        // do nothing
    }
}