/*
    * Created on May 12, 2004
    *
    */
   package org.neo.swarm.services.classloader;
   
   import java.util.Collection;
   import java.util.Iterator;
   
  import org.neo.swarm.SwarmContainer;
  
  /***
   * Performs distributed class loading on classes matching the wildcard. Must be installed on Containers wanting to pool
   * class definitions, Install using -Djava.system.class.loader=org.neo.swarm.service.classloader.DistributedClassLoader
   * 
   * @author navery
   */
  public class DistributedClassLoader extends ClassLoader implements RemoteClassLoader {
  
  	public static int hits = 0;
  	public static String applicationClassmatching = ".*agent.*";
  	public static SwarmContainer container = null;
  
  	/***
  	 * Provide delegation constructor use to chain classloader heirarchy
  	 *  
  	 */
  	public DistributedClassLoader(ClassLoader parent) {
  		super(parent);
  	}
  
  	/***
  	 * Standard ctor which uses the getSystemClassLoader() as the parent
  	 *  
  	 */
  	public DistributedClassLoader() {
  		super();
  	}
  	
  	protected Class findClass(String name) throws ClassNotFoundException {
  		return super.findClass(name);
  	}
  
  	protected Class loadClass(String name, boolean arg1) throws ClassNotFoundException {
  		if (!name.matches(applicationClassmatching)) {
  			//		System.out.println("load class x deferring:" + serviceName);
  			return super.loadClass(name, arg1);
  		}
  		try {
  			hits++;
  
  			System.out.println("xxxxxxxxxxxxxxxxxxxxxxxxx locating class in system class loader:" + name);
  			//			// ask the bootstrapper to locate it... if it fails then we query the remote classloaders
  			return super.loadClass(name, arg1);
  		} catch (ClassNotFoundException ex) {
  			try {
  				System.out.println("xxxxxxxxxxxxxxxxxxxxxxxxx FAILED - querying remote containers for:" + name);
  
  				// we search the remote app contexts, if we get a response then put it into the local class cache and
  				// return the defined class
  				Collection remoteClassLoaders = container.getComponentsOfType(RemoteClassLoader.class);
  				Iterator iter = remoteClassLoaders.iterator();
  				while (iter.hasNext()) {
  					RemoteClassLoader remoteClassLoader = (RemoteClassLoader) iter.next();
  					try {
  						Class remoteClass = remoteClassLoader.loadApplicationClass(name);
  						System.out.println("xxxxxxxxxxxxxxxxxxxxxxxxx FOUND - querying remote containers for:" + name);
  
  						return remoteClass;
  					} catch (ClassNotFoundException ex2) {
  						System.out.println("xxxxxxxxxxxxxxxxxxxxxxxxx FAILED- carry on searching for:" + name);
  						// this remote instance failed for some reason
  					} catch (Exception ex2) {
  						ex.printStackTrace();
  					}
  				}
  			} catch (Exception ex3) {
  				ex.printStackTrace();
  			}
  		}
  		throw new ClassNotFoundException(name);
  	}
  
  	/***
  	 * Remoted call that remote containers call to load foreign classes.
  	 */
  	public Class loadApplicationClass(String name) throws ClassNotFoundException {
  		// searches the local class cache, if it doesnt find it then return null;
  		try {
  			System.out.println("loadApploicationClass called..........");
  			// we immediately defer to the bootstrapper which would have loaded the user application
  			return super.loadClass(name);
  		} catch (ClassNotFoundException ex) {
  			return Class.forName(null);
  		}
  	}
  }