Fix issue #343 Restrict message end movement

plugins/org.eclipse.papyrus.uml.diagram.sequence.contribution/plugin.xml

@@ -124,4 +124,22 @@
     <!-- when integrated with Papyrus, we should avoid applying this context by default -->   
     <context appliedByDefault="true" contextModel="context/lightweight-seqd.contexts" isCustomizable="true"/>
  </extension>
+
+ <extension
+       point="org.eclipse.gmf.runtime.diagram.ui.paletteProviders">
+    <paletteProvider
+          class="org.eclipse.papyrus.uml.diagram.sequence.runtime.internal.providers.SequencePaletteProvider">
+       <Priority
+             name="Highest">
+       </Priority>
+       <!-- For some reason, Papyrus ignores the <content> object descriptor. -->
+       <editor>
+          <!-- the <method> is understood by the extension point. It's an oversight in the exsd. -->
+          <method
+                name="getContributorId()"
+                value="org.eclipse.papyrus.uml.diagram.sequence.runtime">
+          </method>
+       </editor>
+    </paletteProvider>
+ </extension>
 </plugin>

plugins/org.eclipse.papyrus.uml.diagram.sequence.figure/META-INF/MANIFEST.MF

@@ -9,7 +9,8 @@ Bundle-Activator: org.eclipse.papyrus.uml.diagram.sequence.figure.internal.Activ
 Export-Package: org.eclipse.papyrus.uml.diagram.sequence.figure,
  org.eclipse.papyrus.uml.diagram.sequence.figure.anchors,
  org.eclipse.papyrus.uml.diagram.sequence.figure.border,
- org.eclipse.papyrus.uml.diagram.sequence.figure.internal;x-internal:=true
+ org.eclipse.papyrus.uml.diagram.sequence.figure.internal;x-internal:=true,
+ org.eclipse.papyrus.uml.diagram.sequence.figure.magnets
 Require-Bundle: org.eclipse.core.runtime;bundle-version="[3.13.0,4.0.0)",
  org.eclipse.draw2d;bundle-version="[3.10.0,4.0.0)",
  org.eclipse.gmf.runtime.draw2d.ui;bundle-version="[1.9.0,2.0.0)",

plugins/org.eclipse.papyrus.uml.diagram.sequence.figure/src/org/eclipse/papyrus/uml/diagram/sequence/figure/magnets/DefaultMagnet.java

@@ -0,0 +1,64 @@
+/*****************************************************************************
+ * Copyright (c) 2018 Christian W. Damus 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:
+ *   Christian W. Damus - Initial API and implementation
+ *****************************************************************************/
+
+package org.eclipse.papyrus.uml.diagram.sequence.figure.magnets;
+
+import org.eclipse.draw2d.geometry.Point;
+
+/**
+ * A simple implementation of the {@linkplain IMagnet magnet} protocol.
+ */
+public class DefaultMagnet implements IMagnet {
+
+	private final int strength;
+
+	private Point location;
+
+	/**
+	 * Initializes me with my {@code strength}.
+	 * 
+	 * @param strength
+	 *            my strength
+	 */
+	public DefaultMagnet(int strength) {
+		super();
+
+		this.strength = strength;
+	}
+
+	@Override
+	public final int getStrength() {
+		return strength;
+	}
+
+	@Override
+	public void setLocation(Point location) {
+		this.location = location;
+	}
+
+	@Override
+	public Point getLocation() {
+		return location;
+	}
+
+	@Override
+	public boolean influences(@SuppressWarnings("hiding") Point location) {
+		return (this.location != null) && (this.location.getDistance(location) <= 1.5 * strength);
+	}
+
+	@SuppressWarnings("boxing")
+	@Override
+	public String toString() {
+		return String.format("DefaultMagnet at (%s, %s), strength %s", //$NON-NLS-1$
+				location.preciseX(), location.preciseY(), strength);
+	}
+}

plugins/org.eclipse.papyrus.uml.diagram.sequence.figure/src/org/eclipse/papyrus/uml/diagram/sequence/figure/magnets/IMagnet.java

@@ -0,0 +1,77 @@
+/*****************************************************************************
+ * Copyright (c) 2018 Christian W. Damus 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:
+ *   Christian W. Damus - Initial API and implementation
+ *****************************************************************************/
+
+package org.eclipse.papyrus.uml.diagram.sequence.figure.magnets;
+
+import org.eclipse.draw2d.geometry.Point;
+import org.eclipse.draw2d.geometry.Rectangle;
+
+/**
+ * Protocol of a <em>magnet</em> that draws objects towards it (connection bendpoints and endpoints, shapes)
+ * that are being dragged about by the mouse pointer.
+ */
+public interface IMagnet {
+	/**
+	 * Obtain the magnet's strength, which is the square radius within which it captures the mouse pointer.
+	 * 
+	 * @return a positive strength, in pixels
+	 */
+	int getStrength();
+
+	/**
+	 * Queries whether a {@code location} is within my {@linkplain #getStrength() square radius}.
+	 * 
+	 * @param location
+	 *            a location in absolute coördinates
+	 * @return whether I capture the {@code location}
+	 */
+	default boolean captures(Point location) {
+		Point self = getLocation();
+		int strength = getStrength();
+		int x = self.x - strength;
+		int y = self.y - strength;
+		int size = strength << 1;
+
+		Rectangle.SINGLETON.setBounds(x, y, size, size);
+
+		return Rectangle.SINGLETON.contains(location);
+	}
+
+	/**
+	 * Query the location of the magnet, in absolute coördinates.
+	 * 
+	 * @return the location
+	 */
+	Point getLocation();
+
+	/**
+	 * Update (move) the location of the magnet.
+	 * 
+	 * @param location
+	 *            the new location of the magnet
+	 */
+	void setLocation(Point location);
+
+	/**
+	 * Determine whether a {@code location} feels my magnetic influence. This does not necessarily mean that I
+	 * {@link #captures(Point) capture} the mouse pointer from that {@code location}. My influence could
+	 * extend beyond my {@link #getStrength() strength}.
+	 * 
+	 * @param location
+	 *            a location
+	 * @return whether the {@code location} feels my influence
+	 * @see #getStrength()
+	 */
+	boolean influences(Point location);
+
+	// TODO: API for showing and hiding feedback (with a secondary radius within which it is activated?)
+}

plugins/org.eclipse.papyrus.uml.diagram.sequence.figure/src/org/eclipse/papyrus/uml/diagram/sequence/figure/magnets/IMagnetManager.java

@@ -0,0 +1,101 @@
+/*****************************************************************************
+ * Copyright (c) 2018 Christian W. Damus 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:
+ *   Christian W. Damus - Initial API and implementation
+ *****************************************************************************/
+
+package org.eclipse.papyrus.uml.diagram.sequence.figure.magnets;
+
+import java.util.Optional;
+import java.util.stream.Stream;
+
+import org.eclipse.core.runtime.Adapters;
+import org.eclipse.core.runtime.Platform;
+import org.eclipse.draw2d.geometry.Point;
+import org.eclipse.gef.SnapToHelper;
+import org.eclipse.gef.tools.AbstractTool;
+import org.eclipse.swt.SWT;
+
+/**
+ * Protocol for management of {@link IMagnet}s on a shape in the diagram editor to which connection ends snap.
+ * Note that we do not use this for snapping of shapes, as GEF already provides support for that via the
+ * {@link SnapToHelper} API which does not deal with connections but only shapes.
+ */
+public interface IMagnetManager {
+
+	/**
+	 * Key modifier for ignoring snap while dragging. It's <tt>CTRL</tt> on Mac and <tt>ALT</tt> on all other
+	 * platforms, as defined in the GEF {@link AbstractTool} class.
+	 */
+	int MODIFIER_NO_SNAPPING = Platform.OS_MACOSX.equals(Platform.getOS()) ? SWT.CTRL : SWT.ALT;
+
+	/**
+	 * Add a {@code magnet} to the diagram editor.
+	 * 
+	 * @param magnet
+	 *            the magnet to add
+	 */
+	void addMagnet(IMagnet magnet);
+
+	/**
+	 * Remove a {@code magnet} from the diagram editor.
+	 * 
+	 * @param magnet
+	 *            the magnet to remove
+	 */
+	void removeMagnet(IMagnet magnet);
+
+	/**
+	 * Find the magnets within whose influence the given {@code location} lies, in increasing order of
+	 * distance from that location (and so decreasing order of influence).
+	 * 
+	 * @param location
+	 *            a location in the diagram, in absolute coördinates
+	 * @return the magnets whose influence is felt at that {@code location}
+	 */
+	Stream<IMagnet> getMagnets(Point location);
+
+	/**
+	 * Find the magnet that captures a {@code location}.
+	 * 
+	 * @param location
+	 *            a location, in absolute coördinates
+	 * @return the magnet that captures the {@code location}
+	 */
+	Optional<IMagnet> getCapturingMagnet(Point location);
+
+	/**
+	 * Queries whether the magnet manager is currently enabled. When it is not enabled, then snapping
+	 * connections to magnets does not happen.
+	 * 
+	 * @return whether the magnet manager is enabled
+	 */
+	boolean isEnabled();
+
+	/**
+	 * Get the magnet manager for an {@code object}, usually an edit-part or figure. There should be exactly
+	 * one magnet manager for the diagram, maintained by a root-ish edit-part or figure, which always exists.
+	 * 
+	 * @param object
+	 *            an object in the diagram
+	 * @return its magnet manager. Never {@code null}
+	 * @throws IllegalStateException
+	 *             if the {@code object} does not trace to some magnet manager
+	 */
+	static IMagnetManager get(Object object) {
+		IMagnetManager result = Adapters.adapt(object, IMagnetManager.class);
+
+		if (result == null) {
+			throw new IllegalStateException("object has no magnet manager: " + object); //$NON-NLS-1$
+		}
+
+		return result;
+	}
+
+}

plugins/org.eclipse.papyrus.uml.diagram.sequence.figure/src/org/eclipse/papyrus/uml/diagram/sequence/figure/magnets/MagnetManager.java

@@ -0,0 +1,121 @@
+/*****************************************************************************
+ * Copyright (c) 2018 Christian W. Damus 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:
+ *   Christian W. Damus - Initial API and implementation
+ *****************************************************************************/
+
+package org.eclipse.papyrus.uml.diagram.sequence.figure.magnets;
+
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+import java.util.Optional;
+import java.util.function.Predicate;
+import java.util.function.ToDoubleFunction;
+import java.util.stream.Stream;
+
+import org.eclipse.draw2d.geometry.Point;
+import org.eclipse.gef.tools.AbstractTool.Input;
+
+/**
+ * A manager of {@link IMagnet}s.
+ */
+public class MagnetManager implements IMagnetManager {
+
+	// If scale becomes a problem, we may need a quad-tree or some such
+	private final List<IMagnet> magnets = new ArrayList<>();
+
+	private Input currentInput;
+
+	/**
+	 * Initializes me.
+	 */
+	public MagnetManager() {
+		super();
+	}
+
+	@Override
+	public void addMagnet(IMagnet magnet) {
+		magnets.add(magnet);
+	}
+
+	@Override
+	public void removeMagnet(IMagnet magnet) {
+		magnets.remove(magnet);
+	}
+
+	/**
+	 * Find the magnets within whose influence the given {@code location} lies, in increasing order of
+	 * distance from that location (and so decreasing order of influence).
+	 * 
+	 * @param location
+	 *            a location in the diagram, in absolute coördinates
+	 * @return the magnets whose influence is felt at that {@code location}
+	 */
+	@Override
+	public Stream<IMagnet> getMagnets(Point location) {
+		if (!isEnabled()) {
+			return Stream.empty();
+		}
+
+		return magnets.stream().filter(influences(location))
+				.sorted(Comparator.comparingDouble(distance(location)));
+	}
+
+	/**
+	 * Find the magnet that captures a {@code location}.
+	 * 
+	 * @param location
+	 *            a location, in absolute coördinates
+	 * @return the magnet that captures the {@code location}
+	 */
+	@Override
+	public Optional<IMagnet> getCapturingMagnet(Point location) {
+		// The first magnet is the nearest, and if it isn't capturing, then none is
+		return getMagnets(location).findFirst().filter(captures(location));
+	}
+
+	@Override
+	public boolean isEnabled() {
+		Input input = getCurrentInput();
+		return input == null || !input.isModKeyDown(MODIFIER_NO_SNAPPING);
+	}
+
+	/**
+	 * @return the currentInput
+	 */
+	public Input getCurrentInput() {
+		return currentInput;
+	}
+
+	/**
+	 * @param currentInput
+	 *            the currentInput to set
+	 */
+	public void setCurrentInput(Input currentInput) {
+		this.currentInput = currentInput;
+	}
+
+	private Predicate<IMagnet> influences(Point location) {
+		return magnet -> magnet.influences(location);
+	}
+
+	private Predicate<IMagnet> captures(Point location) {
+		return magnet -> magnet.captures(location);
+	}
+
+	private ToDoubleFunction<IMagnet> distance(Point location) {
+		return magnet -> magnet.getLocation().getDistance(location);
+	}
+
+	public static Optional<MagnetManager> get(Object object) {
+		return Optional.ofNullable(IMagnetManager.get(object)).filter(MagnetManager.class::isInstance)
+				.map(MagnetManager.class::cast);
+	}
+}