HoverModel.java

/*******************************************************************************
 * Copyright (c) 2014, 2017 itemis AG 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:
 *     Matthias Wienand (itemis AG) - initial API and implementation
 *
 *******************************************************************************/
package org.eclipse.gef.mvc.fx.models;

import org.eclipse.gef.common.dispose.IDisposable;
import org.eclipse.gef.mvc.fx.parts.IContentPart;
import org.eclipse.gef.mvc.fx.parts.IVisualPart;
import org.eclipse.gef.mvc.fx.viewer.IViewer;

import javafx.beans.property.ObjectProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.collections.MapChangeListener;
import javafx.scene.Node;

/**
 * The {@link HoverModel} is used to store the current viewer's mouse hover
 * target, i.e. the {@link IVisualPart} that is currently under the mouse
 * cursor.
 *
 * @author mwienand
 *
 */
public class HoverModel
		extends org.eclipse.gef.common.adapt.IAdaptable.Bound.Impl<IViewer>
		implements IDisposable {

	/**
	 * This is the name of the property that stores the currently hovered
	 * {@link IVisualPart}.
	 */
	final public static String HOVER_PROPERTY = "hover";

	/**
	 * This property stores the intended hovered
	 */
	final public static String HOVER_INTENT_PROPERTY = "hoverIntent";

	private ObjectProperty<IVisualPart<? extends Node>> hoverProperty = new SimpleObjectProperty<>(
			this, HOVER_PROPERTY);
	private ObjectProperty<IContentPart<? extends Node>> hoverIntentProperty = new SimpleObjectProperty<>(
			this, HOVER_INTENT_PROPERTY);

	private MapChangeListener<Node, IVisualPart<? extends Node>> visualPartMapListener = new MapChangeListener<Node, IVisualPart<? extends Node>>() {
		@Override
		public void onChanged(
				javafx.collections.MapChangeListener.Change<? extends Node, ? extends IVisualPart<? extends Node>> change) {
			// keep model in sync with part hierarchy
			if (change.wasRemoved()) {
				IVisualPart<? extends Node> valueRemoved = change
						.getValueRemoved();
				if (hoverProperty.get() == valueRemoved) {
					clearHover();
				}
				if (hoverIntentProperty.get() == valueRemoved) {
					clearHoverIntent();
				}
			}
		}
	};

	/**
	 * Sets the hovered part to <code>null</code>.
	 */
	public void clearHover() {
		setHover(null);
	}

	/**
	 * Sets the intentionally hovered part to <code>null</code>.
	 */
	public void clearHoverIntent() {
		setHoverIntent(null);
	}

	/**
	 * @since 1.1
	 */
	@Override
	public void dispose() {
		// setAdaptable() already clears hover and hoverIntent
	}

	/**
	 * Returns the currently hovered {@link IVisualPart} or <code>null</code> if
	 * no visual part is hovered.
	 *
	 * @return the currently hovered {@link IVisualPart} or <code>null</code>
	 */
	public IVisualPart<? extends Node> getHover() {
		return hoverProperty.get();
	}

	/**
	 * Returns the current hover intent {@link IContentPart} or
	 * <code>null</code> if no content part is intentionally hovered.
	 *
	 * @return The current hover intent {@link IContentPart} or
	 *         <code>null</code>
	 */
	public IContentPart<? extends Node> getHoverIntent() {
		return hoverIntentProperty.get();
	}

	/**
	 * Returns an object property representing the hover intent part.
	 *
	 * @return A property named {@link #HOVER_INTENT_PROPERTY}.
	 */
	public ObjectProperty<IContentPart<? extends Node>> hoverIntentProperty() {
		return hoverIntentProperty;
	}

	/**
	 * Returns an object property representing the current hover part.
	 *
	 * @return A property named {@link #HOVER_PROPERTY}.
	 */
	public ObjectProperty<IVisualPart<? extends Node>> hoverProperty() {
		return hoverProperty;
	}

	@Override
	public void setAdaptable(IViewer adaptable) {
		if (getAdaptable() != null) {
			// unregister visual-part-map listener
			getAdaptable().visualPartMapProperty()
					.removeListener(visualPartMapListener);
		}
		super.setAdaptable(adaptable);
		if (adaptable != null) {
			// register for visual-part-map changes
			adaptable.visualPartMapProperty()
					.addListener(visualPartMapListener);
		}
		// start with a clean HoverModel
		clearHover();
		clearHoverIntent();
	}

	/**
	 * Sets the hovered {@link IVisualPart} to the given value. The given part
	 * may be <code>null</code> in order to unhover.
	 *
	 * @param cp
	 *            hovered {@link IVisualPart} or <code>null</code>
	 */
	public void setHover(IVisualPart<? extends Node> cp) {
		if (cp != hoverProperty.get()) {
			hoverProperty.set(cp);
		}
	}

	/**
	 * Sets the hover intent {@link IContentPart} to the given value. The given
	 * part may be <code>null</code> to indicate unhovering.
	 *
	 * @param cp
	 *            The hover intent {@link IContentPart} or <code>null</code>.
	 */
	public void setHoverIntent(IContentPart<? extends Node> cp) {
		if (cp != hoverIntentProperty.get()) {
			hoverIntentProperty.set(cp);
		}
	}
}