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.yarn.api.records;
020    
021    import java.text.NumberFormat;
022    
023    import org.apache.hadoop.classification.InterfaceAudience.Private;
024    import org.apache.hadoop.classification.InterfaceAudience.Public;
025    import org.apache.hadoop.classification.InterfaceStability.Stable;
026    import org.apache.hadoop.classification.InterfaceStability.Unstable;
027    
028    /**
029     * <p><code>ApplicationId</code> represents the <em>globally unique</em> 
030     * identifier for an application.</p>
031     * 
032     * <p>The globally unique nature of the identifier is achieved by using the 
033     * <em>cluster timestamp</em> i.e. start-time of the 
034     * <code>ResourceManager</code> along with a monotonically increasing counter
035     * for the application.</p>
036     */
037    @Public
038    @Stable
039    public abstract class ApplicationId implements Comparable<ApplicationId> {
040      
041      /**
042       * Get the short integer identifier of the <code>ApplicationId</code>
043       * which is unique for all applications started by a particular instance
044       * of the <code>ResourceManager</code>.
045       * @return short integer identifier of the <code>ApplicationId</code>
046       */
047      @Public
048      @Stable
049      public abstract int getId();
050      
051      @Private
052      @Unstable
053      public abstract void setId(int id);
054      
055      /**
056       * Get the <em>start time</em> of the <code>ResourceManager</code> which is 
057       * used to generate globally unique <code>ApplicationId</code>.
058       * @return <em>start time</em> of the <code>ResourceManager</code>
059       */
060      public abstract long getClusterTimestamp();
061      
062      @Private
063      @Unstable
064      public abstract void setClusterTimestamp(long clusterTimestamp);
065    
066      
067      
068      static final ThreadLocal<NumberFormat> appIdFormat =
069        new ThreadLocal<NumberFormat>() {
070          @Override
071          public NumberFormat initialValue() {
072            NumberFormat fmt = NumberFormat.getInstance();
073            fmt.setGroupingUsed(false);
074            fmt.setMinimumIntegerDigits(4);
075            return fmt;
076          }
077        };
078    
079      @Override
080      public int compareTo(ApplicationId other) {
081        if (this.getClusterTimestamp() - other.getClusterTimestamp() == 0) {
082          return this.getId() - other.getId();
083        } else {
084          return this.getClusterTimestamp() > other.getClusterTimestamp() ? 1 : 
085            this.getClusterTimestamp() < other.getClusterTimestamp() ? -1 : 0;
086        }
087      }
088    
089      @Override
090      public String toString() {
091        return "application_" + this.getClusterTimestamp() + "_"
092            + appIdFormat.get().format(getId());
093      }
094    
095      @Override
096      public int hashCode() {
097        // Generated by eclipse.
098        final int prime = 31;
099        int result = 1;
100        long clusterTimestamp = getClusterTimestamp();
101        result = prime * result
102            + (int) (clusterTimestamp ^ (clusterTimestamp >>> 32));
103        result = prime * result + getId();
104        return result;
105      }
106    
107      @Override
108      public boolean equals(Object obj) {
109        if (this == obj)
110          return true;
111        if (obj == null)
112          return false;
113        if (getClass() != obj.getClass())
114          return false;
115        ApplicationId other = (ApplicationId) obj;
116        if (this.getClusterTimestamp() != other.getClusterTimestamp())
117          return false;
118        if (this.getId() != other.getId())
119          return false;
120        return true;
121      }
122    }