Difference between revisions of "BundleProxyClassLoader recipe"

Revision as of 17:09, 12 June 2006

import java.io.IOException;
import java.net.URL;
import java.util.Enumeration;

import org.osgi.framework.Bundle;

public class BundleProxyClassLoader extends ClassLoader {
	private Bundle bundle;
	private ClassLoader parent;
		
	public BundleProxyClassLoader(Bundle bundle) {
		this.bundle = bundle;
	}
	
	public BundleProxyClassLoader(Bundle bundle, ClassLoader parent) {
		super(parent);
		this.parent = parent;
	    this.bundle = bundle;
	}

	// Note: Both ClassLoader.getResources(...) and bundle.getResources(...) consult 
	// the boot classloader. As a result, BundleProxyClassLoader.getResources(...) 
	// might return duplicate results from the boot classloader. Prior to Java 5 
	// Classloader.getResources was marked final. If your target environment requires
	// at least Java 5 you can prevent the occurence of duplicate boot classloader 
	// resources by overriding ClassLoader.getResources(...) instead of 
	// ClassLoader.findResources(...).   
	public Enumeration findResources(String name) throws IOException {
	    return bundle.getResources(name);
	}
	
	public URL findResource(String name) {
	    return bundle.getResource(name);
	}

	public Class findClass(String name) throws ClassNotFoundException {
	    return bundle.loadClass(name);
	}
	
	public URL getResource(String name) {
		return (parent == null) ? findResource(name) : super.getResource(name);
	}

	public Class loadClass(String name) throws ClassNotFoundException {
		return (parent == null) ? findClass(name) : super.loadClass(name);
	}
}