org.eclipse.fmc.blockdiagram.editor/src/org/eclipse/fmc/blockdiagram/editor/features/add/DotsConnectionAddFeature.java

/*******************************************************************************
 * <copyright>
 *
 * Copyright (c) 2013, 2013 SAP AG.
 * 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:
 *    SAP AG - initial API, implementation and documentation
 *
 * </copyright>
 *
 *******************************************************************************/
package org.eclipse.fmc.blockdiagram.editor.features.add;

import org.eclipse.fmc.blockdiagram.editor.model.ConnectionStyle;
import org.eclipse.fmc.blockdiagram.editor.model.FMCType;
import org.eclipse.graphiti.features.IFeatureProvider;
import org.eclipse.graphiti.features.context.IAddConnectionContext;
import org.eclipse.graphiti.features.context.IAddContext;
import org.eclipse.graphiti.mm.algorithms.Ellipse;
import org.eclipse.graphiti.mm.algorithms.Polyline;
import org.eclipse.graphiti.mm.pictograms.Connection;
import org.eclipse.graphiti.mm.pictograms.ConnectionDecorator;
import org.eclipse.graphiti.mm.pictograms.PictogramElement;
import org.eclipse.graphiti.services.Graphiti;
import org.eclipse.graphiti.services.IGaService;
import org.eclipse.graphiti.services.IPeService;

/**
 * This class is responsible for adding dots as a connection to the diagram.
 * Notice that dots connection can be drawn with no target (only source).
 * However, in the background, an invisible shape will be added.
 * 
 * @author Benjamin Schmeling
 * 
 */
public class DotsConnectionAddFeature extends ConnectionAddFeature {

	/**
	 * The diameter of a dots decorator.
	 */
	public static final int DOTS_SIZE = 6;

	/**
	 * The number of circles drawn when a dots connection is created.
	 */
	public static final int NO_OF_DOTS = 3;
	
	/**
	 * Specifies whether the graphical element is bound to a domain object.
	 */
	protected boolean linked = true;

	/**
	 * The main cosntructor.
	 * 
	 * @param featureProvider
	 *            The feature provider.
	 * @param style
	 *            The connection style.
	 */
	public DotsConnectionAddFeature(IFeatureProvider featureProvider, ConnectionStyle style) {
		super(featureProvider, style);
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.graphiti.func.IAdd#canAdd(org.eclipse.graphiti.features.context
	 * .IAddContext)
	 */
	@Override
	public boolean canAdd(IAddContext context) {
		return true;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.graphiti.func.IAdd#add(org.eclipse.graphiti.features.context
	 * .IAddContext)
	 */
	@Override
	public PictogramElement add(IAddContext context) {
		IPeService pe = Graphiti.getPeService();
		IGaService ga = Graphiti.getGaService();
		IAddConnectionContext cContext = (IAddConnectionContext) context;

		Connection cShape = super.createConnection();
		Polyline line = ga.createPolyline(cShape);
		line.setLineVisible(false);
		cShape.setStart(cContext.getSourceAnchor());
		cShape.setEnd(cContext.getTargetAnchor());
		line.setForeground(manageColor(0, 0, 0));

		for (int i = 0; i < NO_OF_DOTS; i++) {
			ConnectionDecorator deco = pe.createConnectionDecorator(cShape,
					false, (0.8 / NO_OF_DOTS) * (i + 1), true);
			Ellipse e = ga.createEllipse(deco);
			e.setBackground(manageColor(0, 0, 0));
			e.setForeground(manageColor(0, 0, 0));
			ga.setSize(e, DOTS_SIZE, DOTS_SIZE);
		}

		if (linked)
			link(cShape, ((FMCType) context.getNewObject()));
		return cShape;
	}

	/**
	 * Checks whether the given connection is a dots connection using the number
	 * of decorators and their type and size.
	 * 
	 * @param connection
	 *            The connection to be checked.
	 * @return True if it is a dots connection.
	 */
	public static boolean isDots(Connection connection) {
		for (ConnectionDecorator decorator : connection
				.getConnectionDecorators()) {
			if (decorator.getGraphicsAlgorithm() instanceof Ellipse) {
				Ellipse ellipse = (Ellipse) decorator.getGraphicsAlgorithm();
				if (ellipse.getWidth() != DOTS_SIZE
						|| ellipse.getHeight() != DOTS_SIZE) {
					return false;
				}
			}
		}
		return connection.getConnectionDecorators().size() == 3;
	}

}