org.eclipse.osbp.runtime.web.vaadin.common/src/org/eclipse/osbp/runtime/web/vaadin/common/shortcuts/ShortcutHandler.java

/**
 * Copyright (c) 2011, 2015 - Lunifera GmbH (Gross Enzersdorf, Austria), 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 - Initial implementation
 */
package org.eclipse.osbp.runtime.web.vaadin.common.shortcuts;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import org.eclipse.osbp.runtime.common.keystroke.KeyStrokeCallback;
import org.eclipse.osbp.runtime.common.keystroke.KeyStrokeDefinition;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.vaadin.event.ActionManager;
import com.vaadin.event.ShortcutListener;
import com.vaadin.ui.AbstractComponent;
import com.vaadin.ui.Component;
import com.vaadin.ui.Panel;

// TODO: Auto-generated Javadoc
/**
 * Is responsible to add shortcut listeners to the root panel. And to remove
 * them too.
 * <p>
 * Attention: There must be a panel in the parent hierarchy of the component be
 * available. Otherwise an Exception is thrown during activate.
 */
public class ShortcutHandler {

	/** The Constant LOGGER. */
	private static final Logger LOGGER = LoggerFactory
			.getLogger(ShortcutHandler.class);

	/** The def. */
	private KeyStrokeDefinition def;
	
	/** The callback. */
	private KeyStrokeCallback callback;
	
	/** The component. */
	private Component component;

	/** The root panel. */
	private Panel rootPanel;
	
	/** The listener. */
	private ShortcutListener listener;

	/**
	 * Instantiates a new shortcut handler.
	 *
	 * @param def
	 *            the def
	 * @param callback
	 *            the callback
	 * @param component
	 *            the component
	 */
	public ShortcutHandler(KeyStrokeDefinition def, KeyStrokeCallback callback,
			Component component) {
		super();
		this.def = def;
		this.callback = callback;
		this.component = component;
	}

	/**
	 * Tries to find a panel in the parent hierarchy.
	 *
	 * @param component
	 *            the component
	 * @return the panel
	 */
	protected Panel findPanel(Component component) {

		if (component == null) {
			return null;
		}

		if (component instanceof Panel) {
			return (Panel) component;
		}

		return findPanel(component.getParent());
	}

	/**
	 * Activate.
	 */
	@SuppressWarnings("serial")
	public void activate() {

		if (rootPanel == null) {
			this.rootPanel = findPanel(component);

			if (rootPanel == null) {
				throw new IllegalStateException(
						"No root panel found. Can not attach shortcutListener to component.");
			}
		}

		if (listener == null) {
			this.listener = new ShortcutListener(def.getCaption(),
					def.getKeyCode(), def.getModifierKeys()) {
				@Override
				public void handleAction(Object sender, Object target) {
					callback.callback(sender, target);
				}
			};
		}

		ActionManager manager = getActionManager();
		manager.addAction(listener);
	}

	/**
	 * Deactivate.
	 */
	public void deactivate() {
		ActionManager manager = getActionManager();
		manager.removeAction(listener);
	}

	/**
	 * Gets the action manager.
	 *
	 * @return the action manager
	 */
	protected ActionManager getActionManager() {
		ActionManager actionManager = null;
		try {
			Method m = AbstractComponent.class.getDeclaredMethod(
					"getActionManager", new Class[0]);
			if (!m.isAccessible()) {
				m.setAccessible(true);
			}
			actionManager = (ActionManager) m.invoke(rootPanel, new Object[0]);
		} catch (NoSuchMethodException | IllegalAccessException
				| InvocationTargetException e) {
			LOGGER.error("{}", e);
		}
		return actionManager;
	}

}