SimpleSliderSizePostProcessor.java

package org.csstudio.sds.components.model.eventing;

import org.csstudio.sds.components.model.SimpleSliderModel;
import org.csstudio.sds.eventhandling.AbstractWidgetPropertyPostProcessor;
import org.csstudio.sds.model.commands.SetPropertyCommand;
import org.eclipse.gef.commands.Command;
import org.eclipse.gef.commands.CompoundCommand;

/**
 * Post Processor that switches {@link SimpleSliderModel#PROP_ORIENTATION} depending
 * on widget size.
 * 
 * @author Sven Wende
 * 
 */
public class SimpleSliderSizePostProcessor extends AbstractWidgetPropertyPostProcessor<SimpleSliderModel> {

	@Override
	protected Command doCreateCommand(SimpleSliderModel widget) {
		assert widget != null : "widget != null";
		return new EnsureInvariantsCommand(widget);
	}

	private static final class EnsureInvariantsCommand extends Command {
		private final SimpleSliderModel widget;
		private CompoundCommand chain;

		private EnsureInvariantsCommand(SimpleSliderModel widget) {
			this.widget = widget;
		}

		@Override
		public void execute() {
			if (chain == null) {
				chain = new CompoundCommand();
				chain.add(new SetPropertyCommand(widget, SimpleSliderModel.PROP_ORIENTATION, widget.getWidth()>=widget.getHeight()));
			}

			chain.execute();
		}

		@Override
		public void undo() {
			chain.undo();
		}
	}

}