import java.awt.*;
import java.awt.event.*;
import java.util.Hashtable;
import java.lang.reflect.Method;

public class DynamicHookupTest extends java.applet.Applet { 
	DynamicActionAdapter actionAdapter = new DynamicActionAdapter();

	public void init() {
		Button launchButton = new Button("Launch!");
		actionAdapter.hookup( launchButton, this, "launchTheMissiles" );
		add( launchButton );
	}

	public void launchTheMissiles() {  
		System.out.println("Fire...");
	}
}

class DynamicActionAdapter implements ActionListener {
	Hashtable actions = new Hashtable();
	
	public void hookup( Object sourceObject, Object targetObject, String targetMethod ) {
		actions.put( sourceObject, new Target( targetObject, targetMethod ) );
		invokeReflectedMethod( sourceObject, "addActionListener", 
			new Object [] { this }, new Class [] { ActionListener.class } );
	}

	public void actionPerformed(ActionEvent e) {
		Target target = (Target)actions.get( e.getSource() );
		if ( target == null )
			throw new RuntimeException("unknown source");
		invokeReflectedMethod( target.object, target.methodName, null, null );
	}

	private void invokeReflectedMethod( 
		Object target, String methodName, Object [] args, Class [] argTypes ) {

		try {
			Method method = target.getClass().getMethod( methodName, argTypes );
			method.invoke( target, args );
		} catch ( Exception e ) {
			throw new RuntimeException("invocation problem: "+e);
		}
	}

	class Target {
		Object object;
		String methodName;

		Target( Object object, String methodName ) {
			this.object = object;
			this.methodName = methodName;
		}
	}
}