SkeletonWorkerManager

A plugin for the manager which handles both worker resource requirements and their life cycle events.

package org.jtrix.project.skeleton2.plugins;

import org.jtrix.project.libjtrix.debug.*;
import org.jtrix.project.beatrix.handle.*;
import org.jtrix.project.beatrix.plugins.*;
import org.jtrix.project.beatrix.plugins.hooks.*;
import org.jtrix.project.beatrix.plugins.util.*;

/**
 * Plugin that manages start up and shutdown of workers.
 * 
 * @author  ulf@jtrix.org
 * @author  nadia@jtrix.org
 * @version $Revision: 1.17 $
 */

public class SkeletonWorkerManager extends AbstractPlugin  
    implements IWorkerLifeCycle, IWorkerResourceRequester
{ 
    /** Respond to a new worker starting by inserting plugins remotely.
     */
    public void workerStarted(IWorkerHandle worker)
    {
        try
        {
            Debug.msg(Debug.INFO, this, "workerStarted()");
            IInternalFacetCache ifc = (IInternalFacetCache) pluginManager()
                .lookup(IInternalFacetCache.class)[0];
        
            // Add a service manager plugin to the worker.
            // Add a plugin for the worker's basic functionality.
            // Add a plugin to the service manager which provides the skeleton gservice.

            IRemotePluginManager pm = (IRemotePluginManager)ifc
                .getInternalFacet(worker, IRemotePluginManager.class.getName(), null, true);
            pm.remoteAdd(RemoteServiceManager.class, false);
            pm.remoteAdd(SkeletonWorker.class, true);

            Debug.msg(Debug.INFO, this, "workerStarted, looking up service manager");
            IRemoteServiceManager sm = (IRemoteServiceManager)pm
                .remoteLookup(IRemoteServiceManager.class)[0];
            Debug.msg(Debug.INFO, this, "Got service manager");
            sm.remoteAdd("skeleton",SkeletonServiceProvider.class, null, false);
        }
        catch(Exception e)
        {
            Debug.exc(this, e, "workerStarted() failed.");
        }
    }

    /** Respond to a worker dying.
     */
    public void workerDied(IWorkerHandle worker)
    {}
    
    /** Demand particular resources for a worker. We only do this as a demonstration
     * of how to demand resources. We demand filesystem resources easily
     * with FileSystemLocator.LocatorInfo in the LifeCyclePlugin. Here we demand
     * a socket factory and set our requirements by hand.
     */
    public void configureResourceHandle(IResourceHandle resource)
            throws IWorkerResourceRequester.ResourceUnavailableException
    {
        ISocketFactoryLocator sfl
            = (ISocketFactoryLocator)pluginManager().lookup(ISocketFactoryLocator.class)[0];
        IResourceClassHandle[] net_classes = sfl.locateByCount(1, 1);

        if(net_classes.length == 0)
        {
            throw new IWorkerResourceRequester.ResourceUnavailableException(
                "No resource classes");
        }

        try
        {
            resource.addBinding("net", 10, net_classes, null);
        }
        catch (Exception e)
        {
            Debug.exc(this,e,"Resource creation failed");
            throw new IWorkerResourceRequester.ResourceUnavailableException(
                "Resource creation failed");
        }
    }
}

A worker starting is a prompt to add plugins remotely; a worker dying requires no action. Meanwhile, the plugin also sets worker resource requirements for networking; worker disk requirements are handled entirely by the FileSystemLocator.

See Section  on internal facets, Section  on remote plugin management and Section  on resources.