ComputeFigure.java

/*******************************************************************************
 * Copyright (c) 2009-2013 CWI
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:

 *   * Paul Klint - Paul.Klint@cwi.nl - CWI
*******************************************************************************/
package org.rascalmpl.eclipse.library.vis.figure.interaction;


import org.rascalmpl.eclipse.library.vis.figure.FigureFactory;
import org.rascalmpl.eclipse.library.vis.figure.combine.LayoutProxy;
import org.rascalmpl.eclipse.library.vis.properties.PropertyManager;
import org.rascalmpl.eclipse.library.vis.properties.PropertyValue;
import org.rascalmpl.eclipse.library.vis.swt.IFigureConstructionEnv;
import org.rascalmpl.eclipse.library.vis.util.NameResolver;
import io.usethesource.vallang.IConstructor;
import io.usethesource.vallang.IList;
import io.usethesource.vallang.IValue;

public class ComputeFigure extends LayoutProxy {
	
	final private IValue callback;
	private IConstructor prevValue; // TODO: remove this when nullary closures are memoed
	PropertyValue<Boolean> recompute;
	private IList childProps;

	public ComputeFigure(IFigureConstructionEnv env, PropertyManager properties, PropertyValue<Boolean> recompute, IValue fun, IList childProps) {
		super(null,properties);
		this.childProps = childProps;
		env.getCallBackEnv().checkIfIsCallBack(fun);
		this.callback = fun;
		this.recompute = recompute;
		prevValue = null;
	}

	public void setChildren(IFigureConstructionEnv env, NameResolver resolver){
		if(prevValue == null || recompute.getValue()){
			IConstructor figureCons =
				(IConstructor) env.getCallBackEnv().executeRascalFigureCallBack(callback, noTypes, noArgs);
			if(figureCons == null){
				return;
			}
			if(prevValue == null || !figureCons.isEqual(prevValue)){
				if(innerFig != null){
					innerFig.destroy(env);
				}
				setInnerFig( FigureFactory.make(env, figureCons, prop, childProps));
				prop.stealExternalPropertiesFrom(innerFig.prop);
				prevValue = figureCons;
			}
		}
	}
}