ajaxcallthrottlingdecorator.java

Wicket一个开发Java Web应用程序框架。它使得开发web应用程序变得容易而轻松。 Wicket利用一个POJO data beans组件使得它可以与任何持久层技术相结合。

/*
 * 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 org.apache.wicket.ajax.calldecorator;

import org.apache.wicket.ajax.AbstractDefaultAjaxBehavior;
import org.apache.wicket.ajax.IAjaxCallDecorator;
import org.apache.wicket.util.string.Strings;
import org.apache.wicket.util.time.Duration;

/**
 * Adds throttling to the ajax call. Throttled behaviors only execute once within the given delay
 * even though they can be triggered multiple times.
 * <p>
 * For example, this is useful when attaching an event behavior to the onkeypress event. It is not
 * desirable to have an ajax call made every time the user types so we can throttle that call to a
 * desirable delay, such as once per second. This gives us a near real time ability to provide
 * feedback without overloading the server.
 * 
 * @since 1.2
 * 
 * @author Igor Vaynberg (ivaynberg)
 * 
 */
public final class AjaxCallThrottlingDecorator extends AjaxPostprocessingCallDecorator
{
	private static final long serialVersionUID = 1L;

	private final Duration duration;
	private final String id;

	/**
	 * Construct.
	 * 
	 * @param id
	 *            throttle id
	 * @param delay
	 *            throttle delay
	 */
	public AjaxCallThrottlingDecorator(String id, Duration delay)
	{
		this(null, id, delay);
	}

	/**
	 * Construct.
	 * 
	 * @param decorator
	 *            wrapped decorator
	 * @param id
	 *            throttle id
	 * @param delay
	 *            throttle delay
	 */
	public AjaxCallThrottlingDecorator(IAjaxCallDecorator decorator, String id, Duration delay)
	{
		super(decorator);
		if (Strings.isEmpty(id))
		{
			throw new IllegalArgumentException("id cannot be an empty string");
		}
		this.id = id;
		this.duration = delay;
	}


	/**
	 * @see org.apache.wicket.ajax.calldecorator.AjaxPostprocessingCallDecorator#postDecorateScript(CharSequence)
	 */
	public final CharSequence postDecorateScript(CharSequence script)
	{
		return AbstractDefaultAjaxBehavior.throttleScript(script, id, duration);
	}

}