bundles/org.eclipse.draw2d/src/org/eclipse/draw2d/ConnectionLayer.java

/*******************************************************************************
 * Copyright (c) 2000, 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
 *     Research Group Software Construction,
 *     RWTH Aachen University, Germany - Contribution for Bugzilla 195527
 *******************************************************************************/
package org.eclipse.draw2d;

import org.eclipse.swt.SWT;

/**
 * Layer designed specifically to handle the presence of connections. This is
 * done due to the necessity of having a router for the connections added.
 */
public class ConnectionLayer extends FreeformLayer {

	int antialias = SWT.DEFAULT;

	/**
	 * The ConnectionRouter used to route all connections on this layer.
	 */
	protected ConnectionRouter connectionRouter;

	/**
	 * Adds the given figure with the given contraint at the given index. If the
	 * figure is a {@link Connection}, its {@link ConnectionRouter} is set.
	 * 
	 * @param figure
	 *            Figure being added
	 * @param constraint
	 *            Constraint of the figure being added
	 * @param index
	 *            Index where the figure is to be added
	 * @since 2.0
	 */
	public void add(IFigure figure, Object constraint, int index) {
		super.add(figure, constraint, index);

		// If the connection layout manager is set, then every
		// figure added should use this layout manager.
		if (figure instanceof Connection && getConnectionRouter() != null)
			((Connection) figure).setConnectionRouter(getConnectionRouter());
	}

	/**
	 * Returns the ConnectionRouter being used by this layer.
	 * 
	 * @return ConnectionRouter being used by this layer
	 * @since 2.0
	 */
	public ConnectionRouter getConnectionRouter() {
		return connectionRouter;
	}

	/**
	 * @see IFigure#paint(Graphics)
	 */
	public void paint(Graphics graphics) {
		if (antialias != SWT.DEFAULT)
			graphics.setAntialias(antialias);
		super.paint(graphics);
	}

	/**
	 * Removes the figure from this Layer. If the figure is a {@link Connection}
	 * , that Connection's {@link ConnectionRouter} is set to <code>null</code>.
	 * 
	 * @param figure
	 *            The figure to remove
	 */
	public void remove(IFigure figure) {
		if (figure instanceof Connection)
			((Connection) figure).setConnectionRouter(null);
		super.remove(figure);
	}

	/**
	 * Sets the ConnectionRouter for this layer. This router is set as the
	 * ConnectionRouter for all the child connections of this Layer.
	 * 
	 * @param router
	 *            The ConnectionRouter to set for this Layer
	 * @since 2.0
	 */
	public void setConnectionRouter(ConnectionRouter router) {
		connectionRouter = router;
		FigureIterator iter = new FigureIterator(this);
		IFigure figure;
		while (iter.hasNext()) {
			figure = iter.nextFigure();
			if (figure instanceof Connection)
				((Connection) figure).setConnectionRouter(router);
		}
	}

	/**
	 * Sets whether antialiasing should be enabled for the connection layer. If
	 * this value is set to something other than {@link SWT#DEFAULT},
	 * {@link Graphics#setAntialias(int)} will be called with the given value
	 * when painting this layer.
	 * 
	 * @param antialias
	 *            the antialias setting
	 * @since 3.1
	 */
	public void setAntialias(int antialias) {
		this.antialias = antialias;
	}

}