org.apache.wicket.markup.html.panel.AbstractMarkupSourcingStrategy Maven / Gradle / Ivy

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Wicket is a Java web application framework that takes simplicity, separation of concerns and ease of development to a whole new level. Wicket pages can be mocked up, previewed and later revised using standard WYSIWYG HTML design tools. Dynamic content processing and form handling is all handled in Java code using a first-class component model backed by POJO data beans that can easily be persisted using your favorite technology.

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/*
 * 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.html.panel;

import org.apache.wicket.Component;
import org.apache.wicket.MarkupContainer;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.IMarkupFragment;
import org.apache.wicket.markup.MarkupException;
import org.apache.wicket.markup.MarkupStream;
import org.apache.wicket.markup.html.internal.HtmlHeaderContainer;
import org.apache.wicket.markup.parser.XmlTag.TagType;
import org.apache.wicket.markup.resolver.IComponentResolver;
import org.apache.wicket.util.lang.Classes;
import org.apache.wicket.util.visit.IVisit;
import org.apache.wicket.util.visit.IVisitor;

/**
 * Implements boilerplate as needed by many markup sourcing strategies.
 * 
 * @author Juergen Donnerstag
 */
public abstract class AbstractMarkupSourcingStrategy implements IMarkupSourcingStrategy
{
	/**
	 * Construct.
	 */
	public AbstractMarkupSourcingStrategy()
	{
	}

	@Override
	public abstract IMarkupFragment getMarkup(final MarkupContainer container, final Component child);

	/**
	 * If the child has not been directly added to the container, but via a
	 * TransparentWebMarkupContainer, then we are in trouble. In general Wicket iterates over the
	 * markup elements and searches for associated components, not the other way around. Because of
	 * TransparentWebMarkupContainer (or more generally resolvers), there is no "synchronous" search
	 * possible.
	 * 
	 * @param container
	 *            the parent container.
	 * @param child
	 *            The component to find the markup for.
	 * @return the markup fragment for the child, or {@code null}.
	 */
	protected IMarkupFragment searchMarkupInTransparentResolvers(final MarkupContainer container,
		final Component child)
	{
		return container.visitChildren(MarkupContainer.class, new IVisitor()
		{
			@Override
			public void component(MarkupContainer resolvingContainer, IVisit visit)
			{
				//prevents possible searching loops
				if (child == resolvingContainer) 
				{
					visit.dontGoDeeper();
					return;
				}
				
				if (resolvingContainer instanceof IComponentResolver)
				{
					visit.dontGoDeeper();

					IMarkupFragment childMarkup = resolvingContainer.getMarkup(child);

					if (childMarkup != null && childMarkup.size() > 0)
					{
						IComponentResolver componentResolver = (IComponentResolver)resolvingContainer;

						MarkupStream stream = new MarkupStream(childMarkup);

						ComponentTag tag = stream.getTag();

						Component resolvedComponent = resolvingContainer.get(tag.getId());
						if (resolvedComponent == null)
						{
							resolvedComponent = componentResolver.resolve(resolvingContainer, stream, tag);
						}

						if (child == resolvedComponent)
						{
							visit.stop(childMarkup);
						}
					}
				}				
			}
		});
	}

	/**
	 * Make sure we open up open-close tags to open-body-close
	 */
	@Override
	public void onComponentTag(final Component component, final ComponentTag tag)
	{
		if (tag.isOpenClose())
		{
			tag.setType(TagType.OPEN);
		}
	}

	/**
	 * Skip the components body which is expected to be raw markup only (no wicket components). It
	 * will be replaced by the associated markup.
	 */
	@Override
	public void onComponentTagBody(final Component component, final MarkupStream markupStream,
		final ComponentTag openTag)
	{
		// Skip the components body. It will be replaced by the associated markup or fragment
		if (markupStream.getPreviousTag().isOpen())
		{
			markupStream.skipRawMarkup();
			if (markupStream.get().closes(openTag) == false)
			{
				throw new MarkupException(
					markupStream,
					"Close tag not found for tag: " +
						openTag.toString() +
						". For " +
							Classes.simpleName(component.getClass()) +
								" Components only raw markup is allow in between the tags but not other Wicket Component." +
								". Component: " + component.toString());
			}
		}
	}

	/**
	 * Empty. Nothing to be added to the response by default.
	 */
	@Override
	public void renderHead(final Component component, HtmlHeaderContainer container)
	{
	}
}