DragSourceEffect.java

/*******************************************************************************
 * Copyright (c) 2000, 2008, 2012 IBM Corporation, Gerhardt Informatics Kft. 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
 *     Gerhardt Informatics Kft. - GEFGWT port
 *******************************************************************************/
package org.eclipse.swt.dnd;

import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Control;

/**
 * This class provides default implementations to display a drag source effect
 * during a drag and drop operation. The current implementation does not provide
 * any visual feedback.
 * 
 * <p>
 * The drag source effect has the same API as the <code>DragSourceAdapter</code>
 * so that it can provide custom visual feedback when a
 * <code>DragSourceEvent</code> occurs.
 * </p>
 * 
 * <p>
 * Classes that wish to provide their own drag source effect such as displaying
 * a default source image during a drag can extend the
 * <code>DragSourceEffect</code> class, override the
 * <code>DragSourceAdapter.dragStart</code> method and set the field
 * <code>DragSourceEvent.image</code> with their own image. The image should be
 * disposed when <code>DragSourceAdapter.dragFinished</code> is called.
 * </p>
 * 
 * @see DragSourceAdapter
 * @see DragSourceEvent
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further
 *      information</a>
 * 
 * @since 3.3
 */
public class DragSourceEffect extends DragSourceAdapter {
	Control control = null;

	/**
	 * Creates a new <code>DragSourceEffect</code> to handle drag effect from
	 * the specified <code>Control</code>.
	 * 
	 * @param control
	 *            the <code>Control</code> that the user clicks on to initiate
	 *            the drag
	 * 
	 * @exception IllegalArgumentException
	 *                <ul>
	 *                <li>ERROR_NULL_ARGUMENT - if the control is null</li>
	 *                </ul>
	 */
	public DragSourceEffect(Control control) {
		if (control == null)
			SWT.error(SWT.ERROR_NULL_ARGUMENT);
		this.control = control;
	}

	/**
	 * Returns the Control which is registered for this DragSourceEffect. This
	 * is the control that the user clicks in to initiate dragging.
	 * 
	 * @return the Control which is registered for this DragSourceEffect
	 */
	public Control getControl() {
		return control;
	}
}