wicket-core/src/main/java/org/apache/wicket/markup/head/filter/SubresourceHeaderResponse.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 org.apache.wicket.markup.head.filter;

import org.apache.wicket.Application;
import org.apache.wicket.markup.head.HeaderItem;
import org.apache.wicket.markup.head.IHeaderResponse;
import org.apache.wicket.markup.head.ISubresourceHeaderItem;
import org.apache.wicket.markup.head.IWrappedHeaderItem;
import org.apache.wicket.markup.head.ResourceAggregator;
import org.apache.wicket.markup.html.DecoratingHeaderResponse;

/**
 * Add <em>Subresource<em> integrity and crossOrigin to all {@link ISubresourceHeaderItem}s.
 * <p>
 * The subclass implementation of {@link #configure(ISubresourceHeaderItem)} has to decide
 * on how to configure the item.
 * <p>
 * Note: please don't forget to wrap with {@link ResourceAggregator} when setting it up with
 * {@link Application#getHeaderResponseDecorators()}, otherwise dependencies will not be rendered.
 * 
 * @see ISubresourceHeaderItem
 */
public abstract class SubresourceHeaderResponse extends DecoratingHeaderResponse
{

	public SubresourceHeaderResponse(IHeaderResponse real)
	{
		super(real);
	}

	@Override
	public void render(HeaderItem item)
	{
		while (item instanceof IWrappedHeaderItem)
		{
			item = ((IWrappedHeaderItem)item).getWrapped();
		}

		if (item instanceof ISubresourceHeaderItem)
		{
			configure((ISubresourceHeaderItem)item);
		}
		
		super.render(item);
	}

	/**
	 * Configure the item <em>Subresource</em>.
	 * 
	 * @param item to configure
	 */
	protected abstract void	configure(ISubresourceHeaderItem item);
}