ConsoleArchiverCache


1   /*
2    * (c) Rob Gordon 2005
3    */
4   package org.oddjob.logging;
5   
6   import java.util.ArrayList  ;
7   import java.util.List  ;
8   
9   import org.apache.log4j.Logger;
10  import org.oddjob.Structural;
11  import org.oddjob.structural.StructuralEvent;
12  import org.oddjob.structural.StructuralListener;
13  
14  /**
15   * A cache for ConsoleArchiver archivers.
16   * <p>
17   */
18  public class ConsoleArchiverCache extends AbstractArchiverCache {
19      private static final Logger logger = Logger.getLogger(ConsoleArchiverCache.class);
20      
21      /** List of nodes we're listening to so we can tidy up. */
22      private final List   listeningTo = new ArrayList  ();
23  
24      /** Structural listener */
25      private final StructuralListener structuralListener = new StructuralListener() {
26          public void childAdded(StructuralEvent event) {
27              Object   node = event.getChild();
28              addChild(node);
29          }
30          public void childRemoved(StructuralEvent event) {
31              Object   node = event.getChild();
32              removeChild(node);
33          }
34      };
35  
36      private final Resolver resolver;
37      
38      public ConsoleArchiverCache(Object   root, Resolver resolver) {
39          this(root, LogArchiver.MAX_HISTORY, resolver);
40      }
41      
42      public ConsoleArchiverCache(Object   root, int maxHistory, Resolver resolver) {
43          super(maxHistory);
44          this.resolver = resolver;
45          addChild(root);
46      }
47          
48      /**
49       * Add a child node to this Log Archiver.
50       * 
51       * @param node The child node.
52       */
53      void addChild(Object   node) {
54          LogArchive consoleArchive = resolver.archiveFor(node);
55          if (consoleArchive == null) {
56              throw new IllegalStateException  ("Console must not be null");
57          }
58          addArchive(consoleArchive);
59          
60          if (node instanceof ConsoleArchiver) {
61              return;
62          }
63          
64          if (node instanceof Structural) {
65              ((Structural) node).addStructuralListener(structuralListener);
66              listeningTo.add(node);
67          }
68      }   
69  
70      void removeChild(Object   node) {
71          String   archive = resolver.idFor(node);
72          removeArchive(archive);
73          
74          if (node instanceof Structural) {
75              ((Structural) node).removeStructuralListener(structuralListener);
76              listeningTo.remove(node);
77          }
78      }
79      
80      public void destroy() {
81          while (listeningTo.size() > 0) {
82              removeChild(listeningTo.get(0));
83          }
84      }
85          
86      /**
87       * Resolves the LogArchive and Id for a ConsoleArchiver.
88       *
89       */
90      public static interface Resolver {
91          public LogArchive archiveFor(Object   component);
92          
93          public String   idFor(Object   component);
94      }
95  
96  }
97
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags