001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *     http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing, software
013     * distributed under the License is distributed on an "AS IS" BASIS,
014     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015     * See the License for the specific language governing permissions and
016     * limitations under the License.
017     */
018    
019    package org.apache.hadoop.mapreduce;
020    
021    import java.io.DataInput;
022    import java.io.DataOutput;
023    import java.io.IOException;
024    import java.text.NumberFormat;
025    
026    import org.apache.hadoop.classification.InterfaceAudience;
027    import org.apache.hadoop.classification.InterfaceStability;
028    import org.apache.hadoop.io.Text;
029    
030    /**
031     * JobID represents the immutable and unique identifier for 
032     * the job. JobID consists of two parts. First part 
033     * represents the jobtracker identifier, so that jobID to jobtracker map 
034     * is defined. For cluster setup this string is the jobtracker 
035     * start time, for local setting, it is "local".
036     * Second part of the JobID is the job number. <br> 
037     * An example JobID is : 
038     * <code>job_200707121733_0003</code> , which represents the third job 
039     * running at the jobtracker started at <code>200707121733</code>. 
040     * <p>
041     * Applications should never construct or parse JobID strings, but rather 
042     * use appropriate constructors or {@link #forName(String)} method. 
043     * 
044     * @see TaskID
045     * @see TaskAttemptID
046     */
047    @InterfaceAudience.Public
048    @InterfaceStability.Stable
049    public class JobID extends org.apache.hadoop.mapred.ID 
050                       implements Comparable<ID> {
051      protected static final String JOB = "job";
052      
053      // Jobid regex for various tools and framework components
054      public static final String JOBID_REGEX = 
055        JOB + SEPARATOR + "[0-9]+" + SEPARATOR + "[0-9]+";
056      
057      private final Text jtIdentifier;
058      
059      protected static final NumberFormat idFormat = NumberFormat.getInstance();
060      static {
061        idFormat.setGroupingUsed(false);
062        idFormat.setMinimumIntegerDigits(4);
063      }
064      
065      /**
066       * Constructs a JobID object 
067       * @param jtIdentifier jobTracker identifier
068       * @param id job number
069       */
070      public JobID(String jtIdentifier, int id) {
071        super(id);
072        this.jtIdentifier = new Text(jtIdentifier);
073      }
074      
075      public JobID() { 
076        jtIdentifier = new Text();
077      }
078      
079      public String getJtIdentifier() {
080        return jtIdentifier.toString();
081      }
082      
083      @Override
084      public boolean equals(Object o) {
085        if (!super.equals(o))
086          return false;
087    
088        JobID that = (JobID)o;
089        return this.jtIdentifier.equals(that.jtIdentifier);
090      }
091      
092      /**Compare JobIds by first jtIdentifiers, then by job numbers*/
093      @Override
094      public int compareTo(ID o) {
095        JobID that = (JobID)o;
096        int jtComp = this.jtIdentifier.compareTo(that.jtIdentifier);
097        if(jtComp == 0) {
098          return this.id - that.id;
099        }
100        else return jtComp;
101      }
102      
103      /**
104       * Add the stuff after the "job" prefix to the given builder. This is useful,
105       * because the sub-ids use this substring at the start of their string.
106       * @param builder the builder to append to
107       * @return the builder that was passed in
108       */
109      public StringBuilder appendTo(StringBuilder builder) {
110        builder.append(SEPARATOR);
111        builder.append(jtIdentifier);
112        builder.append(SEPARATOR);
113        builder.append(idFormat.format(id));
114        return builder;
115      }
116    
117      @Override
118      public int hashCode() {
119        return jtIdentifier.hashCode() + id;
120      }
121    
122      @Override
123      public String toString() {
124        return appendTo(new StringBuilder(JOB)).toString();
125      }
126    
127      @Override
128      public void readFields(DataInput in) throws IOException {
129        super.readFields(in);
130        this.jtIdentifier.readFields(in);
131      }
132    
133      @Override
134      public void write(DataOutput out) throws IOException {
135        super.write(out);
136        jtIdentifier.write(out);
137      }
138      
139      /** Construct a JobId object from given string 
140       * @return constructed JobId object or null if the given String is null
141       * @throws IllegalArgumentException if the given string is malformed
142       */
143      public static JobID forName(String str) throws IllegalArgumentException {
144        if(str == null)
145          return null;
146        try {
147          String[] parts = str.split("_");
148          if(parts.length == 3) {
149            if(parts[0].equals(JOB)) {
150              return new org.apache.hadoop.mapred.JobID(parts[1], 
151                                                        Integer.parseInt(parts[2]));
152            }
153          }
154        }catch (Exception ex) {//fall below
155        }
156        throw new IllegalArgumentException("JobId string : " + str 
157            + " is not properly formed");
158      }
159      
160    }