com.cloudera.bigdata.analysis.dataload.io.SplitableInputFormat.java Source code

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Here is the source code for com.cloudera.bigdata.analysis.dataload.io.SplitableInputFormat.java

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/**
 * 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.cloudera.bigdata.analysis.dataload.io;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.compress.CompressionCodec;
import org.apache.hadoop.io.compress.CompressionCodecFactory;
import org.apache.hadoop.io.compress.SplittableCompressionCodec;
import org.apache.hadoop.mapreduce.InputFormat;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.mapreduce.Job;
import org.apache.hadoop.mapreduce.JobContext;
import org.apache.hadoop.mapreduce.RecordReader;
import org.apache.hadoop.mapreduce.TaskAttemptContext;
import org.apache.hadoop.mapreduce.lib.input.FileInputFormat;
import org.apache.hadoop.mapreduce.lib.input.LineRecordReader;

import com.cloudera.bigdata.analysis.dataload.mapreduce.SplitableRecordReader;

/**
 * An {@link InputFormat} for plain text files. Files are broken into lines.
 * Either linefeed or carriage-return are used to signal end of line. Keys are
 * the position in the file, and values are the line of text..
 */
public class SplitableInputFormat extends FileInputFormat<LongWritable, Text> {
    private static final Log LOG = LogFactory.getLog(SplitableInputFormat.class);
    private static String DELIMITER = "mapreduce.input.splitableInputFormat.delimiter";
    private static String RECORD_READER = "mapreduce.input.splitableInputFormat.recordReader";
    private static String ENCODING = "mapreduce.input.splitableInputFormat.encoding";

    public static void setReaderClass(Job job, String className) {
        job.getConfiguration().set(RECORD_READER, className);
    }

    public static void setEncoding(Job job, String encoding) {
        job.getConfiguration().set(ENCODING, encoding);
    }

    public static void setDelimiter(Job job, String delimiter) {
        job.getConfiguration().set(DELIMITER, delimiter);
    }

    @Override
    public RecordReader<LongWritable, Text> createRecordReader(InputSplit split, TaskAttemptContext context) {
        String delimiter = context.getConfiguration().get(DELIMITER);
        String encoding = context.getConfiguration().get(ENCODING);
        String className = context.getConfiguration().get(RECORD_READER,
                "org.apache.hadoop.mapreduce.lib.input.LineRecordReader");

        byte[] recordDelimiterBytes = null;
        if (null != delimiter)
            recordDelimiterBytes = delimiter.getBytes();
        // Here is the reader to do the real split.

        SplitableRecordReader recorder;
        try {
            Class<? extends SplitableRecordReader> recordClass = (Class<? extends SplitableRecordReader>) Class
                    .forName(className);
            recorder = recordClass.newInstance();
        } catch (Exception e) {
            LOG.error("Unable to create instance of class " + className.toString(), e);
            return new LineRecordReader(recordDelimiterBytes);
        }
        if (encoding != null) {
            recorder.setEncoding(encoding);
        }
        if (delimiter != null) {
            recorder.setRecordDelimiterBytes(recordDelimiterBytes);
        }
        return recorder;
    }

    @Override
    protected boolean isSplitable(JobContext context, Path file) {
        CompressionCodec codec = new CompressionCodecFactory(context.getConfiguration()).getCodec(file);
        if (null == codec) {
            return true;
        }
        return codec instanceof SplittableCompressionCodec;
    }

}