samer@0: /*
samer@0:  *	Copyright (c) 2000, Samer Abdallah, King's College London.
samer@0:  *	All rights reserved.
samer@0:  *
samer@0:  *	This software is provided AS iS and WITHOUT ANY WARRANTY; 
samer@0:  *	without even the implied warranty of MERCHANTABILITY or 
samer@0:  *	FITNESS FOR A PARTICULAR PURPOSE.
samer@0:  */
samer@0: 
samer@0: package	samer.maths;
samer@0: import	samer.core.*;
samer@0: import	samer.core.types.*;
samer@0: import	samer.core.util.*;
samer@0: import	java.awt.*;
samer@0: import	java.util.*;
samer@0: 
samer@0: /**
samer@0: 	A Viewable random number generator.
samer@0: 	The Generator itself must expose any parameters
samer@0: 	it has, but this object allows the user to
samer@0: 	control what class of generator to use. 
samer@0:   */
samer@0: 
samer@0: public class VGenerator extends Viewable implements Agent, Generator
samer@0: {
samer@0: 	Generator	gen;
samer@0: 	String		desc;		// description of the current generator
samer@0: 
samer@0: 	public VGenerator(String nm) throws Exception { this(nm,new Zero()); }
samer@0: 	public VGenerator(String nm, Generator g) throws Exception {
samer@0: 		super(nm); setAgent(this);	gen = g;
samer@0: 		Shell.registerViewable(this);
samer@0: 	}
samer@0: 	
samer@0: 	public double next() { return gen.next(); }
samer@0: 	public void   next(double[] x) { gen.next(x); }
samer@0: 
samer@0: 	public void dispose() 
samer@0: 	{
samer@0: 		Shell.deregisterViewable(this);
samer@0: 		gen.dispose();
samer@0: 		super.dispose();
samer@0: 	}
samer@0: 
samer@0: 	public Generator getGenerator() { return gen; }
samer@0: 	public void setGenerator(Generator g) {
samer@0: 		gen.dispose(); gen=g; changed();
samer@0: 	}
samer@0: 
samer@0: 	public Viewer getViewer() { return new UI(); }
samer@0: 
samer@0: 	private class UI extends BaseViewer {
samer@0: 		UI() {
samer@0: 			super(VGenerator.this);
samer@0: 			update(VGenerator.this,null);
samer@0: 		}
samer@0: 
samer@0: 		public void update(Observable o, Object arg) {
samer@0: 			super.update(o,arg);
samer@0: 			Shell.trace("VGenerator update to "+gen.toString());
samer@0: 			setText(getLabel()+": "+gen.toString());
samer@0: 		}
samer@0: 	}
samer@0: 
samer@0: 	public void getCommands(Registry r)	{ r.add("set").add("next"); }	
samer@0: 
samer@0: 	public void execute(String cmd, Environment env) throws Exception
samer@0: 	{
samer@0: 		if (cmd.equals("set")) {
samer@0: 			Shell.push(getNode());
samer@0: 			setGenerator((Generator)X.object(env.datum()));
samer@0: 			Shell.pop();
samer@0: 		} else if (cmd.equals("next")) {
samer@0: 			env.add(new Double(gen.next()));
samer@0: 		}
samer@0: 	}
samer@0: }
samer@0: