bundles/org.eclipse.e4.ui.workbench.addons.swt/src/org/eclipse/e4/ui/workbench/addons/dndaddon/PartDragAgent.java

/*******************************************************************************
 * Copyright (c) 2010 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.addons.dndaddon;

import org.eclipse.e4.ui.model.application.ui.MUIElement;
import org.eclipse.e4.ui.model.application.ui.basic.MPart;
import org.eclipse.e4.ui.model.application.ui.basic.MPartStack;
import org.eclipse.e4.ui.model.application.ui.basic.MStackElement;
import org.eclipse.e4.ui.widgets.CTabFolder;
import org.eclipse.e4.ui.workbench.IPresentationEngine;
import org.eclipse.e4.ui.workbench.modeling.EPartService;
import org.eclipse.swt.graphics.Point;

/**
 *
 */
public class PartDragAgent extends DragAgent {
	public PartDragAgent(DnDManager manager) {
		super(manager);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.e4.ui.workbench.addons.dndaddon.DragAgent#getElementToDrag(org.eclipse.e4.ui.
	 * workbench.addons.dndaddon.CursorInfo)
	 */
	@Override
	public MUIElement getElementToDrag(DnDInfo info) {
		if (!(info.curElement instanceof MPartStack))
			return null;

		MPartStack stack = (MPartStack) info.curElement;

		// Drag a part that is in a stack
		if (info.itemElement instanceof MStackElement) {
			// Prevent dragging 'No Move' parts
			if (info.itemElement.getTags().contains(IPresentationEngine.NO_MOVE))
				return null;

			int tbrCount = dndManager.getModelService().countRenderableChildren(stack);
			if (tbrCount > 1 || dndManager.getModelService().isLastEditorStack(stack)) {
				dragElement = info.itemElement;
				return info.itemElement;
			}
		}

		// Drag a complete stack
		// Only allow a drag to start if we're a CTabFolder
		if (!(stack.getWidget() instanceof CTabFolder))
			return null;

		// Only allow a drag to start if we're inside the 'tab area' of the CTF
		CTabFolder ctf = (CTabFolder) stack.getWidget();
		Point ctfPos = ctf.getDisplay().map(null, ctf, info.cursorPos);
		if (ctfPos.y > ctf.getTabHeight())
			return null;

		// Prevent dragging 'No Move' stacks
		if (stack.getTags().contains(IPresentationEngine.NO_MOVE))
			return null;

		// Prevent dragging the last stack out of the shared area
		if (dndManager.getModelService().isLastEditorStack(stack))
			return null;

		dragElement = info.curElement;
		return info.curElement;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.e4.ui.workbench.addons.dndaddon.DragAgent#dragStart(org.eclipse.e4.ui.model.
	 * application.ui.MUIElement)
	 */
	@Override
	public void dragStart(MUIElement element, DnDInfo info) {
		super.dragStart(element, info);
		if (dndManager.getFeedbackStyle() != DnDManager.SIMPLE)
			dndManager.hostElement(element, 16, 10);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.e4.ui.workbench.addons.dndaddon.DragAgent#dragFinished()
	 */
	@Override
	public void dragFinished() {
		if (dragElement instanceof MPart) {
			EPartService ps = dndManager.getDragWindow().getContext().get(EPartService.class);
			ps.activate((MPart) dragElement);
		}
		super.dragFinished();
	}
}