[120] | 1 | /** |
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| 2 | * Licensed to the Apache Software Foundation (ASF) under one |
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| 3 | * or more contributor license agreements. See the NOTICE file |
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| 4 | * distributed with this work for additional information |
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| 5 | * regarding copyright ownership. The ASF licenses this file |
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| 6 | * to you under the Apache License, Version 2.0 (the |
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| 7 | * "License"); you may not use this file except in compliance |
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| 8 | * with the License. You may obtain a copy of the License at |
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| 9 | * |
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| 10 | * http://www.apache.org/licenses/LICENSE-2.0 |
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| 11 | * |
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| 12 | * Unless required by applicable law or agreed to in writing, software |
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| 13 | * distributed under the License is distributed on an "AS IS" BASIS, |
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| 14 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 15 | * See the License for the specific language governing permissions and |
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| 16 | * limitations under the License. |
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| 17 | */ |
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| 18 | |
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| 19 | package org.apache.hadoop.mapreduce; |
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| 20 | |
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| 21 | import java.io.DataInput; |
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| 22 | import java.io.DataOutput; |
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| 23 | import java.io.IOException; |
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| 24 | import java.text.NumberFormat; |
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| 25 | |
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| 26 | /** |
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| 27 | * TaskID represents the immutable and unique identifier for |
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| 28 | * a Map or Reduce Task. Each TaskID encompasses multiple attempts made to |
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| 29 | * execute the Map or Reduce Task, each of which are uniquely indentified by |
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| 30 | * their TaskAttemptID. |
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| 31 | * |
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| 32 | * TaskID consists of 3 parts. First part is the {@link JobID}, that this |
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| 33 | * TaskInProgress belongs to. Second part of the TaskID is either 'm' or 'r' |
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| 34 | * representing whether the task is a map task or a reduce task. |
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| 35 | * And the third part is the task number. <br> |
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| 36 | * An example TaskID is : |
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| 37 | * <code>task_200707121733_0003_m_000005</code> , which represents the |
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| 38 | * fifth map task in the third job running at the jobtracker |
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| 39 | * started at <code>200707121733</code>. |
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| 40 | * <p> |
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| 41 | * Applications should never construct or parse TaskID strings |
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| 42 | * , but rather use appropriate constructors or {@link #forName(String)} |
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| 43 | * method. |
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| 44 | * |
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| 45 | * @see JobID |
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| 46 | * @see TaskAttemptID |
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| 47 | */ |
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| 48 | public class TaskID extends org.apache.hadoop.mapred.ID { |
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| 49 | protected static final String TASK = "task"; |
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| 50 | protected static final NumberFormat idFormat = NumberFormat.getInstance(); |
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| 51 | static { |
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| 52 | idFormat.setGroupingUsed(false); |
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| 53 | idFormat.setMinimumIntegerDigits(6); |
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| 54 | } |
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| 55 | |
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| 56 | private JobID jobId; |
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| 57 | private boolean isMap; |
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| 58 | |
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| 59 | /** |
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| 60 | * Constructs a TaskID object from given {@link JobID}. |
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| 61 | * @param jobId JobID that this tip belongs to |
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| 62 | * @param isMap whether the tip is a map |
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| 63 | * @param id the tip number |
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| 64 | */ |
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| 65 | public TaskID(JobID jobId, boolean isMap, int id) { |
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| 66 | super(id); |
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| 67 | if(jobId == null) { |
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| 68 | throw new IllegalArgumentException("jobId cannot be null"); |
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| 69 | } |
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| 70 | this.jobId = jobId; |
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| 71 | this.isMap = isMap; |
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| 72 | } |
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| 73 | |
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| 74 | /** |
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| 75 | * Constructs a TaskInProgressId object from given parts. |
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| 76 | * @param jtIdentifier jobTracker identifier |
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| 77 | * @param jobId job number |
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| 78 | * @param isMap whether the tip is a map |
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| 79 | * @param id the tip number |
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| 80 | */ |
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| 81 | public TaskID(String jtIdentifier, int jobId, boolean isMap, int id) { |
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| 82 | this(new JobID(jtIdentifier, jobId), isMap, id); |
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| 83 | } |
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| 84 | |
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| 85 | public TaskID() { |
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| 86 | jobId = new JobID(); |
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| 87 | } |
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| 88 | |
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| 89 | /** Returns the {@link JobID} object that this tip belongs to */ |
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| 90 | public JobID getJobID() { |
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| 91 | return jobId; |
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| 92 | } |
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| 93 | |
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| 94 | /**Returns whether this TaskID is a map ID */ |
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| 95 | public boolean isMap() { |
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| 96 | return isMap; |
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| 97 | } |
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| 98 | |
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| 99 | @Override |
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| 100 | public boolean equals(Object o) { |
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| 101 | if (!super.equals(o)) |
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| 102 | return false; |
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| 103 | |
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| 104 | TaskID that = (TaskID)o; |
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| 105 | return this.isMap == that.isMap && this.jobId.equals(that.jobId); |
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| 106 | } |
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| 107 | |
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| 108 | /**Compare TaskInProgressIds by first jobIds, then by tip numbers. Reduces are |
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| 109 | * defined as greater then maps.*/ |
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| 110 | @Override |
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| 111 | public int compareTo(ID o) { |
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| 112 | TaskID that = (TaskID)o; |
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| 113 | int jobComp = this.jobId.compareTo(that.jobId); |
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| 114 | if(jobComp == 0) { |
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| 115 | if(this.isMap == that.isMap) { |
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| 116 | return this.id - that.id; |
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| 117 | } |
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| 118 | else return this.isMap ? -1 : 1; |
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| 119 | } |
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| 120 | else return jobComp; |
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| 121 | } |
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| 122 | @Override |
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| 123 | public String toString() { |
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| 124 | return appendTo(new StringBuilder(TASK)).toString(); |
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| 125 | } |
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| 126 | |
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| 127 | /** |
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| 128 | * Add the unique string to the given builder. |
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| 129 | * @param builder the builder to append to |
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| 130 | * @return the builder that was passed in |
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| 131 | */ |
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| 132 | protected StringBuilder appendTo(StringBuilder builder) { |
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| 133 | return jobId.appendTo(builder). |
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| 134 | append(SEPARATOR). |
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| 135 | append(isMap ? 'm' : 'r'). |
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| 136 | append(SEPARATOR). |
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| 137 | append(idFormat.format(id)); |
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| 138 | } |
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| 139 | |
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| 140 | @Override |
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| 141 | public int hashCode() { |
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| 142 | return jobId.hashCode() * 524287 + id; |
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| 143 | } |
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| 144 | |
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| 145 | @Override |
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| 146 | public void readFields(DataInput in) throws IOException { |
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| 147 | super.readFields(in); |
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| 148 | jobId.readFields(in); |
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| 149 | isMap = in.readBoolean(); |
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| 150 | } |
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| 151 | |
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| 152 | @Override |
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| 153 | public void write(DataOutput out) throws IOException { |
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| 154 | super.write(out); |
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| 155 | jobId.write(out); |
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| 156 | out.writeBoolean(isMap); |
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| 157 | } |
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| 158 | |
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| 159 | /** Construct a TaskID object from given string |
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| 160 | * @return constructed TaskID object or null if the given String is null |
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| 161 | * @throws IllegalArgumentException if the given string is malformed |
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| 162 | */ |
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| 163 | public static TaskID forName(String str) |
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| 164 | throws IllegalArgumentException { |
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| 165 | if(str == null) |
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| 166 | return null; |
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| 167 | try { |
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| 168 | String[] parts = str.split("_"); |
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| 169 | if(parts.length == 5) { |
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| 170 | if(parts[0].equals(TASK)) { |
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| 171 | boolean isMap = false; |
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| 172 | if(parts[3].equals("m")) isMap = true; |
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| 173 | else if(parts[3].equals("r")) isMap = false; |
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| 174 | else throw new Exception(); |
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| 175 | return new org.apache.hadoop.mapred.TaskID(parts[1], |
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| 176 | Integer.parseInt(parts[2]), |
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| 177 | isMap, |
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| 178 | Integer.parseInt(parts[4])); |
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| 179 | } |
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| 180 | } |
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| 181 | }catch (Exception ex) {//fall below |
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| 182 | } |
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| 183 | throw new IllegalArgumentException("TaskId string : " + str |
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| 184 | + " is not properly formed"); |
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| 185 | } |
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| 186 | |
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| 187 | } |
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