abstractheadercontributor.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.behavior;

import org.apache.wicket.markup.html.IHeaderContributor;
import org.apache.wicket.markup.html.IHeaderResponse;

/**
 * Behavior that delegates header contribution to a number of other contributors. It checks the
 * contributions that were made in the same request to avoid double contributions.
 * 
 * @author Eelco Hillenius
 */
public abstract class AbstractHeaderContributor extends AbstractBehavior
		implements
			IHeaderContributor
{
	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	/**
	 * Construct.
	 */
	public AbstractHeaderContributor()
	{
	}

	/**
	 * Gets the header contributors for this behavior.
	 * 
	 * @return the header contributors; may return null if there are none
	 */
	public abstract IHeaderContributor[] getHeaderContributors();

	/**
	 * @see org.apache.wicket.markup.html.IHeaderContributor#renderHead(org.apache.wicket.markup.html.IHeaderResponse)
	 */
	public final void renderHead(final IHeaderResponse response)
	{
		IHeaderContributor[] contributors = getHeaderContributors();
		// do nothing if we don't need to
		if (contributors == null)
		{
			return;
		}

		for (int i = 0; i < contributors.length; i++)
		{
			if (response.wasRendered(contributors[i]) == false)
			{
				contributors[i].renderHead(response);
				response.markRendered(contributors[i]);
			}
		}
	}

}