ConnectionRouter.java

/*******************************************************************************
 * Copyright (c) 2000, 2005 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.draw2d;

import org.eclipse.draw2d.geometry.Point;
import org.eclipse.draw2d.geometry.PointList;

/**
 * Routes a {@link Connection}, possibly using a constraint.
 */
public interface ConnectionRouter {

/**
 * The default router for Connections.
 */
ConnectionRouter NULL = new NullConnectionRouter();

/**
 * Returns the constraint for the Connection.
 * @param connection The connection
 * @return The constraint
 */
Object getConstraint(Connection connection);

/**
 * Invalidates the given Connection.
 * @param connection The connection to be invalidated
 */
void invalidate(Connection connection);

/**
 * Routes the Connection.
 * @param connection The Connection to route
 */
void route(Connection connection);

/**
 * Removes the Connection from this router.
 * @param connection The Connection to remove
 */
void remove(Connection connection);

/**
 * Maps the given constraint to the given Connection.
 * @param connection The Connection
 * @param constraint The constraint
 */
void setConstraint(Connection connection, Object constraint);

/**
 * Routes Connections directly from the source anchor to the target anchor with no
 * bendpoints in between.
 */
class NullConnectionRouter
	extends AbstractRouter
{

	/**
	 * Constructs a new NullConnectionRouter.
	 */
	NullConnectionRouter() { }

	/**
	 * Routes the given Connection directly between the source and target anchors.
	 * @param conn the connection to be routed
	 */
	public void route(Connection conn) {
		PointList points = conn.getPoints();
		points.removeAllPoints();
		Point p;
		conn.translateToRelative(p = getStartPoint(conn));
		points.addPoint(p);
		conn.translateToRelative(p = getEndPoint(conn));
		points.addPoint(p);
		conn.setPoints(points);
	}

}

}