trunk/proposal/embed/src/java/org/apache/tools/ant/taskdefs/optional/TaskDiscovery.java

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package org.apache.tools.ant.taskdefs.optional;
import org.apache.tools.ant.*;

import java.util.*;

import org.apache.commons.discovery.*;
import org.apache.commons.discovery.jdk.JDKHooks;
import org.apache.commons.discovery.resource.*;


/**
 * Default implementation for discovery and (lazy) creation of tasks.
 *
 * Several mechanisms will be used:
 * - properties files found in the classpath ( META-INF/ant.tasks ).
 * - resources named after the task name: META-INF/ant/[TASK_NAME].task
 *
 */
public class TaskDiscovery extends Task implements ProjectComponentFactory
{
    String RESOURCE_NAME="META-INF/ant.tasks";

    // Also discovery the 'legacy' names - in ant1.6 the initial preloaded tasks
    // should be deprecated.
    
    Resource[] discoveredTasks = null;

    Hashtable taskDefs=new Hashtable();

    public Object createProjectComponent( Project project,
                                          String ns,
                                          String taskName )
        throws BuildException
    {
        //        System.out.println("Try create " + taskName);
        // 
        return null;
    }

    public String toString() {
        StringBuffer sb=new StringBuffer();
        sb.append( "DiscoveredTasks[" );
        if( discoveredTasks != null ) {
            for( int i=0; i<discoveredTasks.length; i++ ) {
                if( i>0) sb.append( ", ");
                sb.append( discoveredTasks[i] );
            }
            sb.append( "]");
        }
        return sb.toString();
    }


    Properties taskClassNames=new Properties();

    /** @TODO: Register itself as ProjectComponentHelper.
     */
    public void execute() throws BuildException
    {
        ProjectComponentHelper pcHelper=ProjectComponentHelper.getProjectComponentHelper();
        pcHelper.addComponentFactory( this );
        
        // We'll read all 'ant.tasks' at startup, and every time an unknown task
        // is found ( the classloader may be different from last time ). Not the best
        // solution, just a start.
        DiscoverResources disc = new DiscoverResources();
        disc.addClassLoader( JDKHooks.getJDKHooks().getThreadContextClassLoader() );
        disc.addClassLoader( this.getClass().getClassLoader() );
        
        ResourceIterator ri = disc.findResources(RESOURCE_NAME);
        
        Vector vector = new Vector();
        while (ri.hasNext()) {
            Resource resourceInfo = ri.nextResource();
            vector.add(resourceInfo);
            System.out.println("Found " + resourceInfo);

            
        }
        
        discoveredTasks = new Resource[vector.size()];
        vector.copyInto(discoveredTasks);
    }
        
}