RHTestBotCanvas.java

/*******************************************************************************
 * This file is protected by Copyright. 
 * Please refer to the COPYRIGHT file distributed with this source distribution.
 *
 * This file is part of REDHAWK IDE.
 *
 * 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
 *******************************************************************************/
package gov.redhawk.ide.swtbot.diagram;

import org.eclipse.draw2d.FigureCanvas;
import org.eclipse.draw2d.LightweightSystem;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swtbot.eclipse.gef.finder.widgets.SWTBotGefFigureCanvas;
import org.eclipse.swtbot.swt.finder.exceptions.WidgetNotFoundException;
import org.eclipse.swtbot.swt.finder.finders.UIThreadRunnable;
import org.eclipse.swtbot.swt.finder.results.VoidResult;

/**
 * This class exists to help make dragging connections in the Graphiti diagram
 * work properly.
 */
public class RHTestBotCanvas extends SWTBotGefFigureCanvas {

	/**
	 * @param canvas
	 * @throws WidgetNotFoundException
	 */
	public RHTestBotCanvas(FigureCanvas canvas) throws WidgetNotFoundException {
		super(canvas);
	}

	/**
	 * @param canvas
	 * @param lightweightSystem
	 * @throws WidgetNotFoundException
	 */
	public RHTestBotCanvas(Canvas canvas, LightweightSystem lightweightSystem) throws WidgetNotFoundException {
		super(canvas, lightweightSystem);
	}

	/**
	 * Simulate a drag-drop. For Graphiti, it's important that there be an intermediate mouse movement event. In the
	 * original SWTBot drag code it performs 4 actions:
	 * <ol>
	 * <li>mouse-down source</li>
	 * <li>mouse-move source</li>
	 * <li>mouse-move target</li>
	 * <li>mouse-up target</li>
	 * </ol>
	 * Graphiti's code double-checks that the mouse has moved far enough away from the original mouse-down point that
	 * it can be considered a drag operation (see {@link AbstractTool#movedPastThreshold()}). However, Graphiti doesn't
	 * update the 'current location' of the mouse until AFTER it checks the threshold during a drag (see
	 * {@link AbstractTool#mouseDrag(MouseEvent, EditPartViewer)}). If Graphiti doesn't think the mouse has moved far
	 * enough, it never sets the drag-drop target, and essentially it's like the drag-drop didn't happen. We solve this
	 * by issuing a mouse movement event halfway to the target.
	 *
	 * @see org.eclipse.swtbot.eclipse.gef.finder.widgets.SWTBotGefFigureCanvas#mouseDrag(int, int, int, int)
	 */
	@Override
	public void mouseDrag(final int fromXPosition, final int fromYPosition, final int toXPosition, final int toYPosition) {
		final int middleXPosition = (fromXPosition + toXPosition) / 2;
		final int middleYPosition = (fromYPosition + toYPosition) / 2;
		UIThreadRunnable.asyncExec(new VoidResult() {
			public void run() {
				org.eclipse.swt.events.MouseEvent meMove = new MouseEvent(createMouseEvent(fromXPosition, fromYPosition, 0, 0, 0));
				eventDispatcher.dispatchMouseMoved(meMove);
				org.eclipse.swt.events.MouseEvent meDown = new MouseEvent(createMouseEvent(fromXPosition, fromYPosition, 1, SWT.BUTTON1, 1));
				eventDispatcher.dispatchMousePressed(meDown);

				// The half-way mouse drag event
				org.eclipse.swt.events.MouseEvent meMoveMiddle = new MouseEvent(createMouseEvent(middleXPosition, middleYPosition, 1, SWT.BUTTON1, 0));
				eventDispatcher.dispatchMouseMoved(meMoveMiddle);

				org.eclipse.swt.events.MouseEvent meMoveTarget = new MouseEvent(createMouseEvent(toXPosition, toYPosition, 1, SWT.BUTTON1, 0));
				eventDispatcher.dispatchMouseMoved(meMoveTarget);
				org.eclipse.swt.events.MouseEvent meUp = new MouseEvent(createMouseEvent(toXPosition, toYPosition, 1, SWT.BUTTON1, 1));
				eventDispatcher.dispatchMouseReleased(meUp);
			}
		});
	}

	/**
	 * Cause a mouse-down event. Don't forget to call {@link #mouseUp(int, int)}.
	 */
	public void mouseDown(final int xPosition, final int yPosition) {
		UIThreadRunnable.asyncExec(new VoidResult() {
			public void run() {
				org.eclipse.swt.events.MouseEvent meMove = new MouseEvent(createMouseEvent(xPosition, yPosition, 0, 0, 0));
				eventDispatcher.dispatchMouseMoved(meMove);
				org.eclipse.swt.events.MouseEvent meDown = new MouseEvent(createMouseEvent(xPosition, yPosition, 1, SWT.BUTTON1, 1));
				eventDispatcher.dispatchMousePressed(meDown);
			}
		});
	}

	/**
	 * Cause a mouse-up event.
	 */
	public void mouseUp(final int xPosition, final int yPosition) {
		UIThreadRunnable.asyncExec(new VoidResult() {
			public void run() {
				org.eclipse.swt.events.MouseEvent meMoveTarget = new MouseEvent(createMouseEvent(xPosition, yPosition, 1, SWT.BUTTON1, 0));
				eventDispatcher.dispatchMouseMoved(meMoveTarget);
				org.eclipse.swt.events.MouseEvent meUp = new MouseEvent(createMouseEvent(xPosition, yPosition, 1, SWT.BUTTON1, 1));
				eventDispatcher.dispatchMouseReleased(meUp);
			}
		});
	}
}