ActionsMenu.java

package org.sigmah.client.ui.presenter.project.logframe.menu;

/*
 * #%L
 * Sigmah
 * %%
 * Copyright (C) 2010 - 2016 URD
 * %%
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public
 * License along with this program.  If not, see
 * <http://www.gnu.org/licenses/gpl-3.0.html>.
 * #L%
 */

import java.util.ArrayList;

import org.sigmah.client.ui.presenter.project.logframe.menu.MenuAction.InactivationPolicy;
import org.sigmah.client.ui.view.project.logframe.grid.FlexTableView;

import com.extjs.gxt.ui.client.event.BaseEvent;
import com.extjs.gxt.ui.client.event.Events;
import com.extjs.gxt.ui.client.event.Listener;
import com.extjs.gxt.ui.client.widget.menu.Menu;
import com.google.gwt.user.client.ui.Widget;

/**
 * Represents an actions menu for the log frame grid.
 * 
 * @author tmi (v1.3)
 * @author Denis Colliot (dcolliot@ideia.fr) (v2.0)
 */
public abstract class ActionsMenu {

	/**
	 * The view.
	 */
	protected final FlexTableView view;

	/**
	 * The menu.
	 */
	protected final Menu menu;

	/**
	 * The inactivation policy.
	 */
	protected InactivationPolicy inactivationPolicy;

	/**
	 * All menu actions.
	 */
	protected final ArrayList<MenuAction> actions;

	public ActionsMenu(final FlexTableView view) {

		this.view = view;
		actions = new ArrayList<MenuAction>();

		// Menu.
		menu = new Menu();

		// Adds a listener to update the menu each time it is shown.
		menu.addListener(Events.BeforeShow, new Listener<BaseEvent>() {

			@Override
			public void handleEvent(BaseEvent be) {

				for (final MenuAction action : actions) {

					// Checks if this action can be performed in the current
					// state.
					final String msg = action.canBePerformed();

					// The action can be performed.
					if (msg == null || "".equals(msg.trim())) {
						action.active();
					}
					// The action cannot be performed.
					else {
						action.inactive(msg);
					}
				}
			}
		});
	}

	/**
	 * Displays this menu relative to the widget using the default alignment.
	 * 
	 * @param widget
	 *          the align widget
	 */
	public void show(Widget widget) {
		menu.show(widget);
	}

	/**
	 * Sets the inactivation policy.
	 * 
	 * @param inactivationPolicy
	 *          The new inactivation policy.
	 */
	public void setInactivationPolicy(InactivationPolicy inactivationPolicy) {

		if (inactivationPolicy == null) {
			return;
		}

		this.inactivationPolicy = inactivationPolicy;

		// Updates each item policy.
		for (final MenuAction action : actions) {
			action.setInactivationPolicy(inactivationPolicy);
		}
	}

}