/*
 * 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.transformer;

import org.apache.wicket.Component;
import org.apache.wicket.Page;
import org.apache.wicket.WicketRuntimeException;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.MarkupResourceStream;

/**
 * An IBehavior which can be added to any component except ListView. It allows to post-process
 * (XSLT) the markup generated by the component. The *.xsl resource must be located in the same path
 * as the nearest parent with an associated markup and must have a filename equal to the component's
 * id.
 * <p>
 * The containers tag will be the root element of the xml data applied for transformation to ensure
 * the xml data are well formed (single root element). In addition the attribute
 * <code>xmlns:wicket="http://wicket.apache.org/dtds.data/wicket-xhtml1.3-strict.dtd</code> is added
 * to the root element to allow the XSL processor to handle the wicket namespace.
 * <p>
 * The reason why the transformer can not be used to XSLT the ListViews output is because of the
 * ListViews markup being reused for each ListItem. Please use a XsltOutputTransformerContainer
 * instead. Note: if the ListView is used to print a list of <tr> tags, than the transformer
 * container must enclose the <table> tag as well to be HTML compliant.
 * 
 * @see org.apache.wicket.markup.transformer.AbstractOutputTransformerContainer
 * @see org.apache.wicket.markup.transformer.XsltOutputTransformerContainer
 * 
 * @author Juergen Donnerstag
 */
public class XsltTransformerBehavior extends AbstractTransformerBehavior
{
	private static final long serialVersionUID = 1L;

	/** An optional xsl file path */
	private final String xslFile;

	/**
	 * Construct.
	 */
	public XsltTransformerBehavior()
	{
		xslFile = null;
	}

	/**
	 * @param xslFilePath
	 * @see XsltTransformer#XsltTransformer(String)
	 */
	public XsltTransformerBehavior(final String xslFilePath)
	{
		xslFile = xslFilePath;
	}

	@Override
	public void onComponentTag(final Component component, final ComponentTag tag)
	{
		// Make the XSLT processor happy and allow it to handle the wicket tags
		// and attributes that are in the wicket namespace
		tag.put("xmlns:wicket", MarkupResourceStream.WICKET_XHTML_DTD);

		super.onComponentTag(component, tag);
	}

	@Override
	public CharSequence transform(final Component component, final CharSequence output)
		throws Exception
	{
		return new XsltTransformer(xslFile).transform(component, output);
	}

	@Override
	public void bind(final Component component)
	{
		if (component instanceof Page)
		{
			throw new WicketRuntimeException(
				"You can not attach a XstlTransformerBehavior to a Page. It can be attached to any other component.");
		}
		super.bind(component);
	}
}