eu.edisonproject.utility.commons.WholeFileRecordReader.java Source code

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Here is the source code for eu.edisonproject.utility.commons.WholeFileRecordReader.java

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/*
 * Copyright 2017 alogo.
 *
 * Licensed 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 eu.edisonproject.utility.commons;

import java.io.IOException;

import org.apache.hadoop.io.NullWritable;
import org.apache.hadoop.io.BytesWritable;

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;
import org.apache.hadoop.io.Text;

/**
 *
 * From https://gist.github.com/sritchie/808035
 */
public class WholeFileRecordReader extends RecordReader<NullWritable, Text> {

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

    private final NullWritable key = NullWritable.get();
    private final Text value = new Text();

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

    @Override
    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);
                value.set(new String(contents));
            } finally {
                IOUtils.closeStream(in);
            }
            processed = true;
            return true;
        }
        return false;
    }

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

    @Override
    public Text 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
    }
}