samer@0: /*
samer@0:  *	VFunction.java	
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.util.*;
samer@0: import  samer.maths.*;
samer@0: import  java.util.*;
samer@0: 
samer@0: import  samer.core.util.Tools;
samer@0: 
samer@0: /**
samer@0: 	A Viewable for a Function - provides a UI for getting
samer@0: 	a plot of the function and for looking at its derivative
samer@0: 	(would like to be able to switch the Function too)
samer@0:   */
samer@0: 
samer@0: public class VFunction extends Viewable implements Agent
samer@0: {
samer@0: 	Function	fn;
samer@0: 
samer@0: 	public VFunction(String name) { this(name,null); }
samer@0: 	public VFunction(String name, Function f) 
samer@0: 	{
samer@0: 		super(name); fn=f; setAgent(this);
samer@0: 		Shell.registerViewable(this);
samer@0: 	}
samer@0: 
samer@0: 	public void dispose() { Shell.deregisterViewable(this); super.dispose(); }
samer@0: 	public void setFunction(Function f) { fn=f; changed(); }
samer@0: 	public Function getFunction() { return fn; }
samer@0: 	public Viewer getViewer()
samer@0: 	{
samer@0: 		BaseViewer vwr = new BaseViewer(this) {
samer@0: 			{ update(VFunction.this,null); }
samer@0: 			public void update(Observable o, Object a) {
samer@0: 				setText( 
samer@0: 					getLabel() + ": "
samer@0: 					+ (fn==null ? "null" : fn.format("t")) 
samer@0: 				);
samer@0: 				super.update(o,a);
samer@0: 			}
samer@0: 		};
samer@0: 
samer@0: 		return vwr;
samer@0: 	}
samer@0: 
samer@0: 	public void getCommands(Agent.Registry r) { 
samer@0: 		r.add("plotter").add("derivative").add("inverse"); 
samer@0: 	}
samer@0: 
samer@0: 	public void execute(String cmd, Environment env) {
samer@0: 		if (cmd.equals("plotter")) {
samer@0: 			Shell.push(new Node("plotter",getNode()));
samer@0: 			FunctionPlotter plotter = new FunctionPlotter(this);
samer@0: 			Shell.expose((Viewer)plotter,"window");
samer@0: 			Shell.pop();
samer@0: 		} else if (cmd.equals("derivative")) {
samer@0: 			Shell.push(node);
samer@0: 			final VFunction dfn = new VFunction("derivative",fn.derivative());
samer@0: 			Shell.pop();
samer@0: 			addObserver( new Observer() {
samer@0: 				// this chains any update messages along to derivatives
samer@0: 				public void update(Observable o,Object arg) { dfn.changed(); }
samer@0: 			} );
samer@0: 			
samer@0: 		} else if (cmd.equals("inverse")) {
samer@0: 			Shell.push(node);
samer@0: 			final VFunction dfn = new VFunction("inverse",fn.inverse());
samer@0: 			Shell.pop();
samer@0: 		}
samer@0: 	}
samer@0: }