CursorHelper.java

package org.csstudio.sds.ui.cursors.internal;

import org.csstudio.sds.cursorservice.AbstractCursor;
import org.csstudio.sds.cursorservice.ContributedCursor;
import org.csstudio.sds.cursorservice.CursorService;
import org.csstudio.sds.cursorservice.ICursorService;
import org.csstudio.sds.cursorservice.SWTCursor;
import org.csstudio.sds.cursorservice.WorkspaceCursor;
import org.csstudio.ui.util.ImageUtil;
import org.eclipse.draw2d.IFigure;
import org.eclipse.swt.graphics.Cursor;
import org.eclipse.swt.graphics.ImageData;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Cursor helper methods.
 * 
 * @author swende
 * 
 */
public class CursorHelper {

    private static final Logger LOG = LoggerFactory.getLogger(CursorHelper.class);

	/**
	 * Private to prevent instantiation of this class.
	 */
	private CursorHelper() {

	}

	/**
	 * Tries to find a cursor for the specified id.
	 * 
	 * @param cursorId
	 *            the cursor id
	 * @return a cursor or null if none was found
	 */
	public static Cursor getCursor(String cursorId) {
		// find the descriptor for the specified cursor id
		AbstractCursor d = CursorService.getInstance().findCursor(
				cursorId);

		Cursor cursor = null;

		if (d != null) {
			if (d == ICursorService.SYSTEM_DEFAULT_CURSOR) {
				cursor = null;
			} else if (d instanceof SWTCursor) {
				cursor = new Cursor(Display.getCurrent(),
						((SWTCursor) d).getSWTCursor());
			} else if (d instanceof ContributedCursor) {
				ContributedCursor cc = (ContributedCursor) d;
				ImageData imageData = ImageUtil.getInstance()
						.getImage(cc.getBundle(),
								cc.getImage()).getImageData();
				cursor = new Cursor(Display.getCurrent(), imageData, 1, 1);
			} else if (d instanceof WorkspaceCursor) {
				WorkspaceCursor wc = (WorkspaceCursor) d;
				ImageData imageData = ImageUtil.getInstance()
						.getImageDescriptorFromFile(
								wc.getGraphicsFile()).getImageData();
				cursor = new Cursor(Display.getCurrent(), imageData, 1, 1);
			} else {
				LOG.warn("Unknown cursor type: " + d.getClass());
				cursor = null;
			}
		}

		return cursor;
	}

	/**
	 * Applies a cursor to the specified Draw2d figure. If no cursor is found
	 * for the specified id, no cursor is applied.
	 * 
	 * @param figure
	 *            the Draw2d figure
	 * @param cursorId
	 *            the cursor id
	 */
	public static void applyCursor(IFigure figure, String cursorId) {
		Cursor cursor = getCursor(cursorId);

		// a null value sets the cursor back to the system default
		figure.setCursor(cursor);
	}

	/**
	 * Applies a cursor to the specified SWT control. If no cursor is found for
	 * the specified id, no cursor is applied.
	 * 
	 * @param control
	 *            the SWT control
	 * @param cursorId
	 *            the cursor id
	 */
	public static void applyCursor(Control control, String cursorId) {
		Cursor cursor = getCursor(cursorId);

		// a null value sets the cursor back to the system default
		control.setCursor(cursor);
	}

}