SchedulerTraker


1   /*
2    * (c) Rob Gordon 2005
3    */
4   package org.oddjob.monitor.model;
5   
6   import java.util.ArrayList  ;
7   import java.util.List  ;
8   
9   import org.apache.log4j.Logger;
10  import org.oddjob.framework.Transportable;
11  import org.oddjob.scheduling.OddjobScheduler;
12  import org.oddjob.scheduling.ScheduleSummary;
13  
14  /**
15   * Tracks schedulers as they are added and removed from a job tree. Used
16   * by Explorer to build the schedule/unshedule actions.
17   * 
18   * @author Rob Gordon.
19   */
20  public class SchedulerTraker {
21      private static final Logger logger = Logger.getLogger(SchedulerTraker.class);
22      
23      /** Available schedulers */
24      private List   schedulers/*<OddjobScheduler>*/ = new ArrayList  ();
25  
26      /**
27       * Add a scheduler to the list of those available.
28       * 
29       * @param scheduler The scheduler.
30       */
31      synchronized public void addScheduler(OddjobScheduler scheduler) {
32          schedulers.add(scheduler);
33      }
34      
35      /**
36       * Remove a scheduler from the list of available schedulers.
37       * 
38       * @param scheduler The scheduler.
39       */
40      synchronized public void removeSchedule(OddjobScheduler scheduler) {
41          schedulers.remove(scheduler);
42      }
43      
44      /**
45       * Get a the JobSchedulerSummary objects for the given jobs.
46       * 
47       * @param component The job which might be scheduled.
48       * @return An array of scheduler summary objects. Might be empty
49       * but never null.
50       */
51      public JobSchedulerSummary[] getSchedulerSummaries(Object   component) {
52          List   results = new ArrayList  ();
53          OddjobScheduler[] sa = getSchedulers();
54          for (int i = 0; i < sa.length; ++i) {
55              ScheduleSummary[] summaries = null; 
56              try {
57                  OddjobScheduler scheduler = sa[i]; 
58                  // if job isn't a proxy, then don't attempt to send
59                  // accross network
60                  if (scheduler instanceof Transportable 
61                          && ! (component instanceof Transportable)) {
62                      continue;
63                  }
64                  summaries = scheduler.summariesFor(component);
65                  if (summaries == null) {
66                      throw new IllegalStateException  ("An OddjobScheduler should never provide null summaries.");
67                  }
68              } catch (Exception   e) {
69                  // most likely a lost network connection.
70                  logger.warn("Failed to retrieve scheduler summaries.", e);
71                  continue;
72              }
73              for (int j = 0; j < summaries.length; ++j) {
74                  results.add(new JobSchedulerSummary(sa[i], summaries[j]));              
75              }
76          }
77          return (JobSchedulerSummary[]) results.toArray(new JobSchedulerSummary[0]);
78      }
79      
80      /**
81       * Get a list of the available schedulers.
82       * 
83       * @return An array of available schedulers. Never null.
84       */
85      synchronized public OddjobScheduler[] getSchedulers() {
86          return (OddjobScheduler[]) schedulers.toArray(new OddjobScheduler[0]);
87      }
88  }
89
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