[jboss-dev-forums] [Design the new POJO MicroContainer] - Missing element in WeakRefVFSCache

[alesj]

Just something I noticed, which I didn't expect.

I'm running JBossAS with WeakRefVFSCache: -Djboss.vfs.cache=org.jboss.virtual.plugins.cache.WeakRefVFSCache
Hence every VFSContext that doesn't have strong ref should be GCed.

In order to prevent some of them from being GCed too soon,
I've added the following bean:

  | public class PreInitializeVFSContexts
  | {
  |    private Logger log = Logger.getLogger(PreInitializeVFSContexts.class);
  |    private List<URL> initializedVFSContexts;
  |    private boolean holdReference;
  |    private List<VFS> references;
  | 
  |    /**
  |     * Start initializer.
  |     *
  |     * @throws Exception for any exception
  |     */
  |    public void start() throws Exception
  |    {
  |       if (initializedVFSContexts != null && initializedVFSContexts.isEmpty() == false)
  |       {
  |          if (holdReference)
  |             references = new ArrayList<VFS>();
  | 
  |          for (URL url : initializedVFSContexts)
  |          {
  |             VFS vfs = VFS.getVFS(url);
  |             log.debug("Initialized Virtual File: " + vfs.getRoot());
  |             if (holdReference)
  |             {
  |                references.add(vfs);
  |             }
  |          }
  |       }
  |    }
  | 
  |    /**
  |     * Clear possible references.
  |     */
  |    public void stop()
  |    {
  |       if (references != null)
  |          references.clear();
  |    }
  | 
  |    /**
  |     * Get VFS references.
  |     *
  |     * @return the VFS references
  |     */
  |    public List<VFS> getReferences()
  |    {
  |       return references;
  |    }
  | 
  |    /**
  |     * Set URLs that need to be initialized before anything else.
  |     *
  |     * @param initializedVFSContexts the URLs to be initialized
  |     */
  |    public void setInitializedVFSContexts(List<URL> initializedVFSContexts)
  |    {
  |       this.initializedVFSContexts = initializedVFSContexts;
  |    }
  | 
  |    /**
  |     * Should we hold the reference to initialized VFSs.
  |     *
  |     * @param holdReference the hold reference flag
  |     */
  |    public void setHoldReference(boolean holdReference)
  |    {
  |       this.holdReference = holdReference;
  |    }
  | }
  | 
So, if you mark this bean as holdReference, it's gonna put VFS into List,
hence keeping the strong ref; VFS --> VFSContext

See JBossAS/initialize.xml:

  |   <bean name="JBossVFSInitializer" class="org.jboss.virtual.plugins.cache.PreInitializeVFSContexts">
  |     <property name="initializedVFSContexts">
  |       <list elementClass="java.net.URL">
  |         <value>${jboss.lib.url}</value>
  |         <value>${jboss.shared.lib.url}</value>
  |         <value>${jboss.server.lib.url}</value>
  |       </list>
  |     </property>
  |     <property name="holdReference">true</property>
  |   </bean>
  | 
But when inspecting jmx-console VFSCacheStatistics,
I'm missing jboss.server.lib.url (it's real value) in VFSContext list.

Where did I go wrong? :-)

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