/*
* 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.resolver;
import org.apache.wicket.MarkupContainer;
import org.apache.wicket.Page;
import org.apache.wicket.WicketRuntimeException;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.MarkupException;
import org.apache.wicket.markup.MarkupStream;
import org.apache.wicket.markup.WicketTag;
import org.apache.wicket.markup.html.WebMarkupContainer;
import org.apache.wicket.markup.html.WebPage;
import org.apache.wicket.markup.html.internal.HtmlHeaderContainer;
import org.apache.wicket.markup.parser.filter.HtmlHeaderSectionHandler;
import org.apache.wicket.markup.parser.filter.WicketTagIdentifier;
import org.apache.wicket.util.resource.IResourceStream;
/**
* This is a tag resolver which handles <head> and <wicket:head>tags. It must be
* registered (with the application) and assumes that a ComponentTag respectively a WicketTag has
* already been created (see HtmlheaderSectionHandler and WicketTagIdentifier).
* <p>
* Provided the current tag is a <head>, a HtmlHeaderContainer component is created, (auto)
* added to the component hierarchie and immediately rendered. Please see the javadoc for
* HtmlHeaderContainer on how it treats the tag.
* <p>
* In case of <wicket:head> a simple WebMarkupContainer handles the tag.
*
* @author Juergen Donnerstag
*/
public class HtmlHeaderResolver implements IComponentResolver
{
private static final long serialVersionUID = 1L;
static
{
// register "wicket:head"
WicketTagIdentifier.registerWellKnownTagName("head");
}
/**
* Try to resolve the tag, then create a component, add it to the container and render it.
*
* @see org.apache.wicket.markup.resolver.IComponentResolver#resolve(MarkupContainer,
* MarkupStream, ComponentTag)
*
* @param container
* The container parsing its markup
* @param markupStream
* The current markupStream
* @param tag
* The current component tag while parsing the markup
* @return true, if componentId was handle by the resolver. False, otherwise
*/
public boolean resolve(final MarkupContainer container, final MarkupStream markupStream,
final ComponentTag tag)
{
// Only <head> component tags have the id == "_header"
if (tag.getId().equals(HtmlHeaderSectionHandler.HEADER_ID))
{
// Create a special header component which will gather additional
// input the <head> from 'contributors'.
final WebMarkupContainer header = newHtmlHeaderContainer(HtmlHeaderSectionHandler.HEADER_ID +
container.getPage().getAutoIndex());
container.autoAdd(header, markupStream);
// Yes, we handled the tag
return true;
}
else if ((tag instanceof WicketTag) && ((WicketTag)tag).isHeadTag())
{
// If we found <wicket:head> without surrounding <head> on a Page,
// than we have to add wicket:head into a automatically generated
// head first.
if (container instanceof WebPage)
{
// Create a special header component which will gather
// additional input the <head> from 'contributors'.
final MarkupContainer header = newHtmlHeaderContainer(HtmlHeaderSectionHandler.HEADER_ID +
container.getPage().getAutoIndex());
// It is <wicket:head>. Because they do not provide any
// additional functionality they are merely a means of surrounding relevant
// markup. Thus we simply create a WebMarkupContainer to handle
// the tag.
final WebMarkupContainer header2 = new WebMarkupContainer(
HtmlHeaderSectionHandler.HEADER_ID)
{
private static final long serialVersionUID = 1L;
@Override
public boolean isTransparentResolver()
{
return true;
}
};
header2.setRenderBodyOnly(true);
header.add(header2);
container.autoAdd(header, markupStream);
}
else if (container instanceof HtmlHeaderContainer)
{
// It is <wicket:head>. Because they do not provide any
// additional functionality there are merely a means of surrounding
// relevant markup. Thus we simply create a WebMarkupContainer to handle
// the tag.
final WebMarkupContainer header = new WebMarkupContainer(
HtmlHeaderSectionHandler.HEADER_ID)
{
private static final long serialVersionUID = 1L;
@Override
public boolean isTransparentResolver()
{
return true;
}
};
header.setRenderBodyOnly(true);
try
{
container.autoAdd(header, markupStream);
}
catch (IllegalArgumentException ex)
{
throw new WicketRuntimeException("If the root exception says something like "
+ "\"A child with id '_header' already exists\" "
+ "then you most likely forgot to override autoAdd() "
+ "in your bordered page component.", ex);
}
}
else
{
final Page page = container.getPage();
final String pageClassName = (page != null) ? page.getClass().getName() : "unknown";
final IResourceStream stream = markupStream.getResource();
final String streamName = (stream != null) ? stream.toString() : "unknown";
throw new MarkupException(
"Mis-placed <wicket:head>. <wicket:head> must be outside of <wicket:panel>, <wicket:border>, and <wicket:extend>. Error occured while rendering page: " +
pageClassName + " using markup stream: " + streamName);
}
// Yes, we handled the tag
return true;
}
// We were not able to handle the tag
return false;
}
/**
* Return a new HtmlHeaderContainer
*
* @param id
* @return HtmlHeaderContainer
*/
protected HtmlHeaderContainer newHtmlHeaderContainer(String id)
{
return new HtmlHeaderContainer(id);
}
}
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