HasNavBarListenersPanel.java

/*******************************************************************************
 * 
 * Copyright 2011-2014 Spiffy UI Team   
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 ******************************************************************************/
package org.spiffyui.client.nav;

import java.util.ArrayList;
import java.util.List;

import com.google.gwt.user.client.ui.FlowPanel;

/**
 * This is a FlowPanel that calls events by listeners listening for changes in navigation
 * such as MainNavBar or logout on MainHeader.
 */
public class HasNavBarListenersPanel extends FlowPanel
{

    private List<NavBarListener> m_listeners = new ArrayList<NavBarListener>();   
    private boolean m_enabled = true;
    /**
     * @return Returns the enabled.
     */
    public boolean isEnabled()
    {
        return m_enabled;
    }

    /**
     * @param enabled The enabled to set.
     */
    public void setEnabled(boolean enabled)
    {
        m_enabled = enabled;
    }

    /**
     * Notifies listeners of a request to select an
     * item, giving listeners a change to cancel the event
     * 
     * @param item   the nav item that was clicked
     * @return boolean true to continue, false to cancel
     */
    public boolean firePreEvent(NavItem item)
    {
        boolean go = true;
        if (m_enabled) {
            for (NavBarListener listener : m_listeners) {
                if (!listener.preItemSelected(item)) {
                    go = false;
                }
            }
        }
        return go;
    }

    /**
     * Fires the click event on the specified nav item
     * 
     * @param item   the nav item that was clicked
     */
    public void fireEvent(NavItem item)
    {
        fireEvent(item, true);
    }
    
    /**
     * Fires the click event on the specified nav item
     * 
     * @param item   the nav item that was clicked
     * @param addToHistory
     *               true if this item should be added to the browser history and false otherwise
     */
    protected void fireEvent(NavItem item, boolean addToHistory)
    {
        if (m_enabled) {
            for (NavBarListener listener : m_listeners) {
                listener.itemSelected(item);
            }
        }
    }
    
    /**
     * Adds a NavBarListener to this navigation bar
     * 
     * @param listener the listener to add
     */
    public void addListener(NavBarListener listener)
    {
        m_listeners.add(listener); 
    }
    
    /**
     * Removes a NavBarListener from this navigation bar.
     * 
     * @param listener the listener to remove
     */
    public void removeListener(NavBarListener listener)
    {
        m_listeners.remove(listener);
    }
    

}