org.eclipse.osbp.vaadin.addons.designer.overlay/src/org/eclipse/osbp/vaadin/addons/designer/overlay/client/widgets/OOverlayController.java

/**
 *                                                                            
 * Copyright (c) 2011, 2016 - Loetz GmbH&Co.KG (69115 Heidelberg, Germany)
 *                                                                            
 * 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:   
 * Florian Pirchner <florian.pirchner@gmail.com> - Initial implementation
 */
package org.eclipse.osbp.vaadin.addons.designer.overlay.client.widgets;

import java.util.HashMap;
import java.util.Map;
import java.util.Stack;

import org.eclipse.osbp.vaadin.addons.designer.overlay.client.OAbstractOverlay;

import com.google.gwt.dom.client.Element;
import com.google.gwt.user.client.ui.Widget;

/**
 * Controls, that only one overlay is opened at a time. The delay for closing
 * the overlay is too long to avoid multiple overlays.
 */
public class OOverlayController {

	/** The Constant instance. */
	private static final OOverlayController instance = new OOverlayController();

	/**
	 * Gets the single instance of OOverlayController.
	 *
	 * @return single instance of OOverlayController
	 */
	public static OOverlayController getInstance() {
		return instance;
	}

	/** The show timer. */
	// private Timer showTimer;

	/** The current opened. */
	private OAbstractOverlay currentOpened;

	private Map<Element, OAbstractOverlay> map = new HashMap<>();
	private Stack<Element> navigationStack = new Stack<>();

	/**
	 * Instantiates a new o overlay controller.
	 */
	private OOverlayController() {

	}

	/**
	 * Registers the element with the overlay. This is required to use arrow UP
	 * to navigate to the next higher overlay in the element hierarchy.
	 * 
	 * @param element
	 * @param overlay
	 */
	public void register(Element element, OAbstractOverlay overlay) {
		map.put(element, overlay);
	}

	/**
	 * Unregisters the element with its overlay.
	 * 
	 * @param element
	 */
	public void unregister(Element element) {
		map.remove(element);
	}

	/**
	 * Uses the current opened overlay and navigates up the element hierarchy
	 * until an element associated with an overlay could be found. This overlay
	 * will be shown.
	 */
	public void navigateUp() {
		if (currentOpened == null) {
			navigationStack.clear();
			return;
		}

		Element element = currentOpened.getOwner().getElement();
		OAbstractOverlay nextHigher = findOverlayInParent(element);
		if (nextHigher != null) {
			navigationStack.push(element);
			Widget widget = nextHigher.getOwner();
			show(nextHigher, widget.getElement().getAbsoluteLeft(), widget.getElement().getAbsoluteTop(), false);
		}
	}

	/**
	 * Uses the current opened overlay and navigates down the last opened
	 * overlays.
	 */
	public void navigateDown() {
		if (currentOpened == null || navigationStack.isEmpty()) {
			navigationStack.clear();
			return;
		}

		Element lastElement = navigationStack.pop();
		if (lastElement != null) {
			show(map.get(lastElement), lastElement.getAbsoluteLeft(), lastElement.getAbsoluteTop(), false);
		}
	}

	private OAbstractOverlay findOverlayInParent(Element element) {
		Element parent = element.getParentElement();
		if (parent == null) {
			return null;
		}
		if (map.containsKey(parent)) {
			return map.get(parent);
		}

		return findOverlayInParent(parent);
	}

	/**
	 * Notifies the controller, that a new overlay is about to show. The
	 * controller will ensure, that a currently opened overlay will be closed
	 * Immediately.
	 *
	 * @param overlay
	 *            the overlay
	 * @param left
	 *            the left
	 * @param top
	 *            the top
	 */
	public void show(OAbstractOverlay overlay, int left, int top) {
		show(overlay, left, top, true);
	}

	private void show(OAbstractOverlay overlay, int left, int top, boolean clearStack) {
		if (clearStack) {
			navigationStack.clear();
		}

		if (currentOpened == overlay && currentOpened.isShowing()) {
			return;
		}

		if (currentOpened != null) {
			currentOpened.hide();
		}

		overlay.setPopupPosition(left, top);
		currentOpened = overlay;

		if (currentOpened != null) {
			currentOpened.show();
		}
	}

	/**
	 * Closes the currently opened overlay.
	 */
	public void close() {
		navigationStack.clear();
		if (currentOpened != null) {
			currentOpened.hide();
			currentOpened = null;
		}
	}

}