AjaxUpdateEvent.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 ro.nextreports.server.web.common.event;

import org.apache.wicket.Component;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.util.visit.IVisit;
import org.apache.wicket.util.visit.IVisitor;

/**
 * Very simple event mechanism for loose coupling of wicket components for ajax updates.
 * 
 * @author Decebal Suiu
 */
public class AjaxUpdateEvent {

	private final Component source;
	private final AjaxRequestTarget target;

	public AjaxUpdateEvent(final Component source, final AjaxRequestTarget target) {
		this.source = source;
		this.target = target;
	}

	public Component getSource() {
		return source;
	}

	public AjaxRequestTarget getTarget() {
		return target;
	}
	
	public void addToTarget(Component component) {
		target.add(component);
	}

	/**
	 * Fire this event, i.e. notify listeners. This is done by visiting all children of the 
	 * source component's page.
	 */
	public final void fire() {
		getSource().getPage().visitChildren(new NotifyVisitor(this));
	}

	/**
	 * Visitor to notify all children of a page.
	 */
	private static final class NotifyVisitor implements IVisitor<Component, Void> {
		
		private final AjaxUpdateEvent event;

		public NotifyVisitor(final AjaxUpdateEvent event) {
			this.event = event;
		}

		public void component(Component object, IVisit<Void> visit) {
			if (object instanceof AjaxUpdateListener) {
				((AjaxUpdateListener) object).onAjaxUpdate(event);
			}
		}
		
	}
	
}