cascading.tap.hadoop.io.MultiInputSplit.java Source code

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Here is the source code for cascading.tap.hadoop.io.MultiInputSplit.java

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/*
 * Copyright (c) 2007-2015 Concurrent, Inc. All Rights Reserved.
 *
 * Project and contact information: http://www.cascading.org/
 *
 * This file is part of the Cascading project.
 *
 * 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 cascading.tap.hadoop.io;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import cascading.flow.hadoop.util.HadoopUtil;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.WritableUtils;
import org.apache.hadoop.mapred.FileSplit;
import org.apache.hadoop.mapred.InputSplit;
import org.apache.hadoop.mapred.JobConf;
import org.apache.hadoop.mapred.JobConfigurable;
import org.apache.hadoop.util.ReflectionUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/** Class MultiInputSplit is used by MultiInputFormat */
public class MultiInputSplit implements InputSplit, JobConfigurable {
    public static final String CASCADING_SOURCE_PATH = "cascading.source.path";
    private static final Logger LOG = LoggerFactory.getLogger(MultiInputSplit.class);

    /** Field jobConf */
    private transient JobConf jobConf;
    /** Field inputSplit */
    InputSplit inputSplit;
    /** Field config */
    Map<String, String> config;

    /**
     * Method getCurrentTapSourcePath finds and returns the current source Tap filename path, if any.
     * <p/>
     * Use this method inside an Operation to find the current file being processed.
     *
     * @param jobConf
     * @return a String
     */
    public static String getCurrentTapSourcePath(JobConf jobConf) {
        return jobConf.get(CASCADING_SOURCE_PATH);
    }

    public MultiInputSplit(InputSplit inputSplit, Map<String, String> config) {
        if (inputSplit == null)
            throw new IllegalArgumentException("input split may not be null");

        if (config == null)
            throw new IllegalArgumentException("config may not be null");

        this.inputSplit = inputSplit;
        this.config = config;
    }

    /**
     * This constructor is used internally by Hadoop. it is expected {@link #configure(org.apache.hadoop.mapred.JobConf)}
     * and {@link #readFields(java.io.DataInput)} are called to properly initialize.
     */
    public MultiInputSplit() {
    }

    public void configure(JobConf jobConf) {
        this.jobConf = jobConf;
    }

    public long getLength() throws IOException {
        return inputSplit.getLength();
    }

    public String[] getLocations() throws IOException {
        return inputSplit.getLocations();
    }

    public InputSplit getWrappedInputSplit() {
        return inputSplit;
    }

    public void write(DataOutput out) throws IOException {
        out.writeUTF(inputSplit.getClass().getName());

        String[] keys = config.keySet().toArray(new String[config.size()]);
        String[] values = new String[keys.length];

        for (int i = 0; i < keys.length; i++)
            values[i] = config.get(keys[i]);

        WritableUtils.writeStringArray(out, keys);
        WritableUtils.writeStringArray(out, values);

        inputSplit.write(out);
    }

    public void readFields(DataInput in) throws IOException {
        String splitType = in.readUTF();
        config = new HashMap<String, String>();

        String[] keys = WritableUtils.readStringArray(in);
        String[] values = WritableUtils.readStringArray(in);

        for (int i = 0; i < keys.length; i++)
            config.put(keys[i], values[i]);

        if (LOG.isDebugEnabled()) {
            LOG.debug("current split config diff:");
            for (Map.Entry<String, String> entry : config.entrySet())
                LOG.debug("key: {}, value: {}", entry.getKey(), entry.getValue());
        }

        JobConf currentConf = HadoopUtil.mergeConf(jobConf, config, false);

        try {
            inputSplit = (InputSplit) ReflectionUtils.newInstance(currentConf.getClassByName(splitType),
                    currentConf);
        } catch (ClassNotFoundException exp) {
            throw new IOException("split class " + splitType + " not found");
        }

        inputSplit.readFields(in);

        if (inputSplit instanceof FileSplit) {
            Path path = ((FileSplit) inputSplit).getPath();

            if (path != null) {
                jobConf.set(CASCADING_SOURCE_PATH, path.toString());

                LOG.info("current split input path: {}", path);
            }
        }
    }
}