com.ebay.erl.mobius.core.builder.TSVDataset.java Source code

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Here is the source code for com.ebay.erl.mobius.core.builder.TSVDataset.java

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package com.ebay.erl.mobius.core.builder;

import java.io.IOException;

import org.apache.hadoop.mapred.InputFormat;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.TextInputFormat;

import com.ebay.erl.mobius.core.MobiusJob;
import com.ebay.erl.mobius.core.mapred.AbstractMobiusMapper;
import com.ebay.erl.mobius.core.mapred.TSVMapper;
import com.ebay.erl.mobius.util.SerializableUtil;

/**
 * Represents a dataset backed with the Hadoop text format.
 * 
 * 
 * 
 * <p>
 * This product is licensed under the Apache License,  Version 2.0, 
 * available at http://www.apache.org/licenses/LICENSE-2.0.
 * 
 * This product contains portions derived from Apache hadoop which is 
 * licensed under the Apache License, Version 2.0, available at 
 * http://hadoop.apache.org.
 * 
 *  2007  2012 eBay Inc., Evan Chiu, Woody Zhou, Neel Sundaresan
 * 
 * @see TSVDatasetBuilder
 * @see TSVMapper
 */
@SuppressWarnings({ "deprecation", "unchecked" })
public class TSVDataset extends Dataset {
    private static final long serialVersionUID = -4596104689783253807L;
    private String delimiter = "\t";

    /**
     * Create an instance of dataset with {@link TextInputFormat}
     * and {@link TSVMapper} as default.
     * <p>
     * 
     * User should not create instance of this class
     * directly through constructor, but to use 
     * {@link TSVDatasetBuilder} to build one.
     * 
     * @param job a Mobius job contains an analysis flow.
     * @param name the name of this dataset.
     */
    protected TSVDataset(MobiusJob job, String name) {
        super(job, name);
        this.input_format = TextInputFormat.class;
        this.mapper = TSVMapper.class;
    }

    TSVDataset setDelimiter(String delimiter) {
        this.delimiter = delimiter;
        return this;
    }

    /**
     * Always throw {@link UnsupportedOperationException} as one cannot change 
     * the input format, the input format is fixed to {@link TextInputFormat}.
     */
    @Override
    protected void setInputFormat(Class<? extends InputFormat> input_format) {
        throw new UnsupportedOperationException("Cannot set different inputformat to TSV dataset");
    }

    /**
     * only accept a mapper which is the subclass of {@link TSVMapper}
     */
    @Override
    protected void setMapper(Class<? extends AbstractMobiusMapper> mapper) {
        if (TSVMapper.class.isAssignableFrom(mapper)) {
            // mapper extends TSVMapper
            this.mapper = mapper;
        } else {
            throw new IllegalArgumentException(
                    "Only class which extends " + TSVMapper.class.getCanonicalName() + " is accepted.");
        }
    }

    @Override
    public JobConf createJobConf(byte jobSequenceNumber) throws IOException {
        JobConf conf = super.createJobConf(jobSequenceNumber);
        if (!this.delimiter.equals("\t")) {
            conf.set(this.getID() + ".delimiter", SerializableUtil.serializeToBase64(delimiter));
        }
        return conf;
    }
}