JobID.java
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上传日期:2018-01-08
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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.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".
- * 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
- * @see org.apache.hadoop.mapred.JobTracker#getNewJobId()
- * @see org.apache.hadoop.mapred.JobTracker#getStartTime()
- */
- public class JobID extends org.apache.hadoop.mapred.ID
- implements Comparable<ID> {
- protected static final String JOB = "job";
- 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");
- }
-
- }