SimpleJob


1   package org.oddjob.framework;
2   
3   
4   import org.apache.log4j.MDC;
5   import org.oddjob.Resetable;
6   import org.oddjob.Stateful;
7   import org.oddjob.images.IconHelper;
8   import org.oddjob.logging.Log4jArchiver;
9   import org.oddjob.state.JobState;
10  import org.oddjob.util.OddjobLockedException;
11  
12  /**
13   * An abstract implementation of a job which provides commen functionality to
14   * concrete sub classes.
15   * 
16   * @author Rob Gordon
17   */
18  
19  public abstract class SimpleJob extends BasePrimary
20  implements  Runnable  , Resetable, Stateful {
21  
22      /*
23       *  (non-Javadoc)
24       * @see org.oddjob.framework.BaseComponent#independant()
25       */
26      protected boolean independant() {
27          return true;
28      }
29      
30      /**
31       * Execute this job.
32       * 
33       * @return 0 if the job is complete, anything else otherwise.
34       * @throws Exception If the unexpected occurs.
35       */
36      abstract protected int execute() throws Throwable  ;
37  
38      /**
39       * Implement the main execute method for a job. This surrounds the 
40       * doExecute method of the sub class and sets state for the job.
41       */
42      public final void run() throws OddjobLockedException {
43          lock.accquire("Job executing.");
44          String   oldMDC = (String  )MDC.get(Log4jArchiver.MDC);
45          try {
46              MDC.put(Log4jArchiver.MDC, getLogger());
47              if (!stateHandler.requestJobStateExecuting()) { 
48                  logger().debug("Can't execute job [" + this + "] because state is ["
49                          + stateHandler.getJobState() + "]");
50                  return;
51              }
52              iconHelper.changeIcon(IconHelper.EXECUTING);
53      
54              // runtime configuration.
55              if (!configure()) {
56                  return;
57              }
58              logger().info("Executing job [" + this + "]");
59          
60              int result = -1;
61              try {           
62                  result = execute();
63              }
64              catch (Throwable   e) {
65                  logger().warn("Job Exception in [" + this + "]", e);
66                  setJobStateException(e);
67                  return;
68              }
69      
70              logger().info("Finished job [" + this + "], result " + result);
71          
72              if (result == 0) {
73                  setJobStateComplete();
74              }
75              else {                      
76                  setJobStateNotComplete();
77              }
78          }
79          finally {
80              if (oldMDC != null) {
81                  MDC.put(Log4jArchiver.MDC, oldMDC);
82              }
83              else {
84                  MDC.remove(Log4jArchiver.MDC);
85              }
86              lock.release();
87          }
88      }
89      
90      /**
91       * Allow subclasses to indicate they are 
92       * stopping. The subclass must still implement 
93       * Stoppable.
94       */
95      public final void stop() {
96          if (destroyed) {
97              throw new IllegalStateException  ("[" + this + "] destroyed");
98          }
99          if (stateHandler.getJobState() != JobState.EXECUTING) {
100             return;
101         }
102         logger().debug("Thread [" + Thread.currentThread().getName() 
103                 + "] requested [" + getName() + "] stop.");
104         iconHelper.changeIcon(IconHelper.STOPPING);
105         try {
106             onStop();
107         } catch (RuntimeException   e) {
108             iconHelper.changeIcon(IconHelper.EXECUTING);
109             throw e;
110         }
111         stop = true;
112         synchronized (this) {
113             notifyAll();
114         }
115     }
116     
117     public void onStop() { }
118     
119     /**
120      * Perform a soft reset on the job.
121      */
122     public void softReset() {
123         lock.accquire("Soft reset in progress.");
124         try {
125             logger().debug("Thread [" + Thread.currentThread().getName() 
126                     + "] soft reset for [" + this + "].");
127             if (canSoftReset()) {
128                 setJobStateReady();
129                 logger().info("Reset job [" + this + "]");
130             }
131         }
132         finally {
133             lock.release();
134         }
135     }
136     
137     /**
138      * Perform a hard reset on the job.
139      */
140     public void hardReset() {
141         lock.accquire("Hard reset in progress.");
142         try {
143             logger().debug("Thread [" + Thread.currentThread().getName() 
144                     + "] hard reset for [" + this + "].");
145             if (canHardReset()) {
146                 setJobStateReady();
147                 logger().info("Reset job [" + this + "]");
148             }
149         }
150         finally {
151             lock.release();
152         }
153     }
154 
155 }
156
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