bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/ui/workbench/renderers/swt/SashRenderer.java

/*******************************************************************************
 * Copyright (c) 2009 IBM Corporation and others.
 * 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.e4.ui.workbench.renderers.swt;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.inject.Inject;
import org.eclipse.e4.core.services.events.IEventBroker;
import org.eclipse.e4.ui.model.application.ui.MElementContainer;
import org.eclipse.e4.ui.model.application.ui.MUIElement;
import org.eclipse.e4.ui.workbench.UIEvents;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Shell;
import org.osgi.service.event.Event;
import org.osgi.service.event.EventHandler;

public class SashRenderer extends SWTPartRenderer {

	@Inject
	private IEventBroker eventBroker;

	private static final int UNDEFINED_WEIGHT = -1;
	private static final int DEFAULT_WEIGHT = 5000;

	private EventHandler sashOrientationHandler;
	private EventHandler sashWeightHandler;

	public SashRenderer() {
		super();
	}

	@PostConstruct
	void postConstruct() {
		sashOrientationHandler = new EventHandler() {
			public void handleEvent(Event event) {
				// Ensure that this event is for a MPartSashContainer
				MUIElement element = (MUIElement) event
						.getProperty(UIEvents.EventTags.ELEMENT);
				if (element.getRenderer() != SashRenderer.this) {
					return;
				}
				forceLayout((MElementContainer<MUIElement>) element);
			}
		};

		eventBroker.subscribe(UIEvents.buildTopic(UIEvents.GenericTile.TOPIC,
				UIEvents.GenericTile.HORIZONTAL), sashOrientationHandler);

		sashWeightHandler = new EventHandler() {
			public void handleEvent(Event event) {
				// Ensure that this event is for a MPartSashContainer
				MUIElement element = (MUIElement) event
						.getProperty(UIEvents.EventTags.ELEMENT);
				MElementContainer<MUIElement> parent = element.getParent();
				if (parent.getRenderer() != SashRenderer.this)
					return;

				forceLayout(parent);
			}
		};

		eventBroker.subscribe(UIEvents.buildTopic(UIEvents.UIElement.TOPIC,
				UIEvents.UIElement.CONTAINERDATA), sashWeightHandler);
	}

	/**
	 * @param pscModel
	 */
	protected void forceLayout(MElementContainer<MUIElement> pscModel) {
		// layout the containing Composite
		while (!(pscModel.getWidget() instanceof Control))
			pscModel = pscModel.getParent();
		Control ctrl = (Control) pscModel.getWidget();
		if (ctrl instanceof Shell)
			((Shell) ctrl).layout(null, SWT.ALL | SWT.CHANGED | SWT.DEFER);
		else
			ctrl.getParent().layout(null, SWT.ALL | SWT.CHANGED | SWT.DEFER);
	}

	@PreDestroy
	void preDestroy() {
		eventBroker.unsubscribe(sashOrientationHandler);
		eventBroker.unsubscribe(sashWeightHandler);
	}

	public Object createWidget(final MUIElement element, Object parent) {
		MUIElement elementParent = element.getParent();
		if (elementParent.getRenderer() == this) {
			Rectangle newRect = new Rectangle(0, 0, 0, 0);

			// If my layout's container gets disposed 'unbind' the sash elements
			if (parent instanceof Composite) {
				((Composite) parent).addDisposeListener(new DisposeListener() {
					public void widgetDisposed(DisposeEvent e) {
						element.setWidget(null);
						element.setRenderer(null);
					}
				});
			}
			return newRect;
		}

		// This is a 'root' sash container, create a composite
		Composite sashComposite = new Composite((Composite) parent, SWT.NONE);
		sashComposite.setLayout(new SashLayout(sashComposite, element));

		return sashComposite;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.ui.workbench.renderers.swt.SWTPartRenderer#childAdded(
	 * org.eclipse.e4.ui.model.application.MPart,
	 * org.eclipse.e4.ui.model.application.MPart)
	 */
	@Override
	public void childRendered(MElementContainer<MUIElement> parentElement,
			MUIElement element) {
		super.childRendered(parentElement, element);

		// Ensure that the element's 'containerInfo' is initialized
		int weight = getWeight(element);
		if (weight == UNDEFINED_WEIGHT) {
			element.setContainerData(Integer.toString(DEFAULT_WEIGHT));
		}

		forceLayout(parentElement);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.ui.internal.workbench.swt.AbstractPartRenderer#hideChild
	 * (org.eclipse.e4.ui.model.application.ui.MElementContainer,
	 * org.eclipse.e4.ui.model.application.ui.MUIElement)
	 */
	@Override
	public void hideChild(MElementContainer<MUIElement> parentElement,
			MUIElement child) {
		super.hideChild(parentElement, child);

		forceLayout(parentElement);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.ui.internal.workbench.swt.AbstractPartRenderer#getUIContainer
	 * (org.eclipse.e4.ui.model.application.ui.MUIElement)
	 */
	@Override
	public Object getUIContainer(MUIElement element) {
		// OK, find the 'root' of the sash container
		MUIElement parentElement = element.getParent();
		while (parentElement.getRenderer() == this
				&& !(parentElement.getWidget() instanceof Composite))
			parentElement = parentElement.getParent();

		if (parentElement.getWidget() instanceof Composite)
			return parentElement.getWidget();

		return null;
	}

	/**
	 * @param element
	 * @return
	 */
	private static int getWeight(MUIElement element) {
		String info = element.getContainerData();
		if (info == null || info.length() == 0) {
			element.setContainerData(Integer.toString(10000));
			info = element.getContainerData();
		}

		try {
			int value = Integer.parseInt(info);
			return value;
		} catch (NumberFormatException e) {
			return UNDEFINED_WEIGHT;
		}
	}
}