diagrampart.java

GEF基础源码

package com.jixy.study.gef.control;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.util.List;

import org.eclipse.draw2d.IFigure;
import org.eclipse.gef.EditPolicy;
import org.eclipse.gef.editparts.AbstractGraphicalEditPart;

import com.jixy.study.gef.model.Diagram;
import com.jixy.study.gef.util.DiagramLayoutEditPolicy;
import com.jixy.study.gef.view.DiagramFigure;

//在GEF里，模型的监听器就是EditPart，所以都要实现PropertyChangeListener接口。
public class DiagramPart extends AbstractGraphicalEditPart implements
		PropertyChangeListener {

	protected IFigure createFigure() {

		return new DiagramFigure();

	}

	// 对于含有子元素的EditPart，必须覆盖getModelChildren()方法返回子对象列表，
	// 例如DiagramPart里这个方法返回的是Diagram对象包含的Ellipse对象列表。
	protected List getModelChildren() {

		List children = ((Diagram) getModel()).getChildren();

		return children;

	}

	public void activate() {
		if (isActive()) {
			return;
		}
		super.activate();
		((Diagram) getModel()).addPropertyChangeListener(this);
	}

	public void deactivate() {
		if (!isActive()) {
			return;
		}
		super.deactivate();
		((Diagram) getModel()).removePropertyChangeListener(this);
	}

	public void propertyChange(PropertyChangeEvent event) {
		String propertyName = event.getPropertyName();
		if ("children".equals(propertyName)) {
			refreshChildren();
		}
	}

	protected void createEditPolicies() {
		installEditPolicy(EditPolicy.LAYOUT_ROLE, new DiagramLayoutEditPolicy());
	}

}