tagtypehandler.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.markup.parser.filter;

import java.text.ParseException;
import java.util.HashMap;
import java.util.Map;

import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.MarkupElement;
import org.apache.wicket.markup.parser.AbstractMarkupFilter;
import org.apache.wicket.markup.parser.XmlTag;
import org.apache.wicket.util.collections.ArrayListStack;


/**
 * This is a markup inline filter. It identifies tags which are allowed open-close in the markup,
 * but which for Wicket to be processed correctly must be open-body-close.
 * 
 * @author Juergen Donnerstag
 */
public final class TagTypeHandler extends AbstractMarkupFilter
{
	/** Tag stack to find balancing tags */
	final private ArrayListStack stack = new ArrayListStack();

	/** Map of simple tags. */
	private static final Map requireOpenBodyCloseTag = new HashMap();

	static
	{
		// Tags which require open-body-close
		requireOpenBodyCloseTag.put("select", Boolean.TRUE);
	}

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

	/**
	 * Get the next MarkupElement from the parent MarkupFilter and handle it if the specific filter
	 * criteria are met. Depending on the filter, it may return the MarkupElement unchanged,
	 * modified or it remove by asking the parent handler for the next tag.
	 * 
	 * @see org.apache.wicket.markup.parser.IMarkupFilter#nextTag()
	 * @return Return the next eligible MarkupElement
	 */
	public MarkupElement nextTag() throws ParseException
	{
		// If there is something in the stack, ...
		while (stack.size() > 0)
		{
			final ComponentTag top = (ComponentTag)stack.pop();
			return top;
		}

		// Get the next tag. If null, no more tags are available
		// in the markup
		final ComponentTag tag = (ComponentTag)getParent().nextTag();
		if (tag == null)
		{
			return tag;
		}

		if (tag.isOpenClose())
		{
			String name = tag.getName();
			if (tag.getNamespace() != null)
			{
				name = tag.getNamespace() + ":" + tag.getName();
			}

			// Pop any simple tags off the top of the stack
			if (requiresOpenBodyCloseTag(name))
			{
				tag.setType(XmlTag.OPEN);
				XmlTag closeTag = new XmlTag();
				closeTag.setType(XmlTag.CLOSE);
				closeTag.setName(tag.getName());
				closeTag.setNamespace(tag.getNamespace());
				closeTag.closes(tag);

				stack.push(new ComponentTag(closeTag));
			}
		}

		return tag;
	}

	/**
	 * Gets whether this tag does not require open-body-close tags.
	 * 
	 * @param name
	 *            The tag's name, e.g. a, br, div, etc.
	 * @return True if this tag must be converted into open-body-close if openClose
	 */
	public static boolean requiresOpenBodyCloseTag(final String name)
	{
		return requireOpenBodyCloseTag.get(name) != null;
	}
}