EventPublisher.java

/*
 * 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 2
 * 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

package net.rrm.ehour.ui.common.event;

import org.apache.wicket.Component;
import org.apache.wicket.MarkupContainer;
import org.apache.wicket.Page;
import org.apache.wicket.util.visit.IVisit;
import org.apache.wicket.util.visit.IVisitor;

public class EventPublisher {
    private EventPublisher() {
    }

    // purely for junit testing
    public static AjaxEventListener listenerHook;

    /**
     * Publish ajax event to container and upwards upto and including the page
     */
    public static void publishAjaxEvent(Component container, AjaxEvent event) {
        notifyHook(event);

        recursivePublishAjaxEvent(container, event);
    }

    private static void recursivePublishAjaxEvent(Component container, AjaxEvent event) {
        boolean proceed = true;

        if (container instanceof AjaxEventListener) {
            proceed = ((AjaxEventListener) container).ajaxEventReceived(event);
        }

        if (proceed && !(container instanceof Page)) {
            MarkupContainer parent = container.getParent();

            if (parent == null) {
                parent = container.getPage();
            }

            recursivePublishAjaxEvent(parent, event);
        }
    }

    /**
     * Publish ajax event to children of parent container
     *
     * @param parent
     * @param event
     */
    public static void publishAjaxEventToParentChildren(MarkupContainer parent, AjaxEvent event) {
        notifyHook(event);

        parent.visitChildren(AjaxEventListener.class, new AjaxEventVisitor(event));
    }

    private static void notifyHook(AjaxEvent event) {
        if (listenerHook != null) {
            listenerHook.ajaxEventReceived(event);
        }
    }

    private static class AjaxEventVisitor implements IVisitor<Component, Void> {
        private AjaxEvent event;

        private AjaxEventVisitor(AjaxEvent ajaxEvent) {
            this.event = ajaxEvent;
        }

        public void component(Component component, IVisit iVisit) {
            boolean proceed = true;

            if (component instanceof AjaxEventListener) {
                proceed = ((AjaxEventListener) component).ajaxEventReceived(event);
            }

            if (!proceed) {
                iVisit.stop();
            }
        }
    }
}