org.apache.hadoop.mapreduce.JobID.java Source code

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Here is the source code for org.apache.hadoop.mapreduce.JobID.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 org.apache.hadoop.mapreduce;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.text.NumberFormat;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.io.Text;

/**
 * JobID represents the immutable and unique identifier for 
 * the job. JobID consists of two parts. First part 
 * represents the jobtracker identifier, so that jobID to jobtracker map 
 * is defined. For cluster setup this string is the jobtracker 
 * start time, for local setting, it is "local" and a random number.
 * Second part of the JobID is the job number. <br> 
 * An example JobID is : 
 * <code>job_200707121733_0003</code> , which represents the third job 
 * running at the jobtracker started at <code>200707121733</code>. 
 * <p>
 * Applications should never construct or parse JobID strings, but rather 
 * use appropriate constructors or {@link #forName(String)} method. 
 * 
 * @see TaskID
 * @see TaskAttemptID
 */
@InterfaceAudience.Public
@InterfaceStability.Stable
public class JobID extends org.apache.hadoop.mapred.ID implements Comparable<ID> {
    public static final String JOB = "job";

    // Jobid regex for various tools and framework components
    public static final String JOBID_REGEX = JOB + SEPARATOR + "[0-9]+" + SEPARATOR + "[0-9]+";

    private final Text jtIdentifier;

    protected static final NumberFormat idFormat = NumberFormat.getInstance();
    static {
        idFormat.setGroupingUsed(false);
        idFormat.setMinimumIntegerDigits(4);
    }

    /**
     * Constructs a JobID object 
     * @param jtIdentifier jobTracker identifier
     * @param id job number
     */
    public JobID(String jtIdentifier, int id) {
        super(id);
        this.jtIdentifier = new Text(jtIdentifier);
    }

    public JobID() {
        jtIdentifier = new Text();
    }

    public String getJtIdentifier() {
        return jtIdentifier.toString();
    }

    @Override
    public boolean equals(Object o) {
        if (!super.equals(o))
            return false;

        JobID that = (JobID) o;
        return this.jtIdentifier.equals(that.jtIdentifier);
    }

    /**Compare JobIds by first jtIdentifiers, then by job numbers*/
    @Override
    public int compareTo(ID o) {
        JobID that = (JobID) o;
        int jtComp = this.jtIdentifier.compareTo(that.jtIdentifier);
        if (jtComp == 0) {
            return this.id - that.id;
        } else
            return jtComp;
    }

    /**
     * Add the stuff after the "job" prefix to the given builder. This is useful,
     * because the sub-ids use this substring at the start of their string.
     * @param builder the builder to append to
     * @return the builder that was passed in
     */
    public StringBuilder appendTo(StringBuilder builder) {
        builder.append(SEPARATOR);
        builder.append(jtIdentifier);
        builder.append(SEPARATOR);
        builder.append(idFormat.format(id));
        return builder;
    }

    @Override
    public int hashCode() {
        return jtIdentifier.hashCode() + id;
    }

    @Override
    public String toString() {
        return appendTo(new StringBuilder(JOB)).toString();
    }

    @Override
    public void readFields(DataInput in) throws IOException {
        super.readFields(in);
        this.jtIdentifier.readFields(in);
    }

    @Override
    public void write(DataOutput out) throws IOException {
        super.write(out);
        jtIdentifier.write(out);
    }

    /** Construct a JobId object from given string 
     * @return constructed JobId object or null if the given String is null
     * @throws IllegalArgumentException if the given string is malformed
     */
    public static JobID forName(String str) throws IllegalArgumentException {
        if (str == null)
            return null;
        try {
            String[] parts = str.split("_");
            if (parts.length == 3) {
                if (parts[0].equals(JOB)) {
                    return new org.apache.hadoop.mapred.JobID(parts[1], Integer.parseInt(parts[2]));
                }
            }
        } catch (Exception ex) {//fall below
        }
        throw new IllegalArgumentException("JobId string : " + str + " is not properly formed");
    }

}