/*
* 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.Component;
import org.apache.wicket.MarkupContainer;
import org.apache.wicket.Page;
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.TransparentWebMarkupContainer;
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.html.internal.HtmlHeaderItemsContainer;
import org.apache.wicket.markup.parser.filter.HtmlHeaderSectionHandler;
import org.apache.wicket.markup.parser.filter.WicketTagIdentifier;
import org.apache.wicket.util.resource.IResourceStream;
import org.apache.wicket.util.visit.IVisit;
import org.apache.wicket.util.visit.IVisitor;
/**
* 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 {@link HtmlHeaderSectionHandler} and {@link WicketTagIdentifier}).
* <p>
* Provided the current tag is a <head>, a {@link HtmlHeaderContainer} component is created,
* (auto) added to the component hierarchy and immediately rendered. Please see the javadoc for
* {@link HtmlHeaderContainer} on how it treats the tag.
* <p>
* In case of <wicket:head> a simple {@link TransparentWebMarkupContainer} handles the tag.
*
* @author Juergen Donnerstag
*/
public class HtmlHeaderResolver implements IComponentResolver
{
private static final long serialVersionUID = 1L;
/** */
public static final String HEAD = "head";
public static final String HEADER_ITEMS = "header-items";
@Override
public Component resolve(final MarkupContainer container, final MarkupStream markupStream,
final ComponentTag tag)
{
final Page page = container.getPage();
// <head> or <wicket:header-items/> 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'.
return newHtmlHeaderContainer(tag.getId(), tag);
}
else if ((tag instanceof WicketTag) && ((WicketTag)tag).isHeadTag())
{
// If we found <wicket:head> without surrounding <head> on a Page,
// then we have to add wicket:head into a automatically generated
// head first.
if (container instanceof WebPage)
{
HtmlHeaderContainer header = container.visitChildren(new IVisitor<Component, HtmlHeaderContainer>()
{
@Override
public void component(final Component component, final IVisit<HtmlHeaderContainer> visit)
{
if (component instanceof HtmlHeaderContainer)
{
visit.stop((HtmlHeaderContainer) component);
} else if (component instanceof TransparentWebMarkupContainer == false)
{
visit.dontGoDeeper();
}
}
});
// 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 (class WicketHeadContainer).
if (header == null)
{
// Create a special header component which will gather
// additional input the <head> from 'contributors'.
header = newHtmlHeaderContainer(tag.getId(), tag);
header.add(new WicketHeadContainer());
return header;
}
WicketHeadContainer wicketHeadContainer =
header.visitChildren(new FindWicketHeadContainer());
//We just need one WicketHeadContainer, no matter how
//many <wicket:head> we have.
if (wicketHeadContainer == null)
{
wicketHeadContainer = new WicketHeadContainer();
header.add(wicketHeadContainer);
}
return wicketHeadContainer;
}
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.
WebMarkupContainer header = new WicketHeadContainer();
return header;
}
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 occurred while rendering page: " +
pageClassName + " using markup stream: " + streamName);
}
// We were not able to handle the tag
return null;
}
/**
* Return a new HtmlHeaderContainer
*
* @param id
* @return HtmlHeaderContainer
* @deprecated Use #newHtmlHeaderContainer(String, ComponentTag) instead
*/
@Deprecated
protected HtmlHeaderContainer newHtmlHeaderContainer(String id)
{
return new HtmlHeaderContainer(id);
}
/**
* Return a new HtmlHeaderContainer
*
* @param id
* @return HtmlHeaderContainer
*/
protected HtmlHeaderContainer newHtmlHeaderContainer(String id, ComponentTag tag)
{
HtmlHeaderContainer htmlHeaderContainer;
if (HtmlHeaderResolver.HEADER_ITEMS.equalsIgnoreCase(tag.getName()))
{
htmlHeaderContainer = new HtmlHeaderItemsContainer(id);
}
else
{
htmlHeaderContainer = newHtmlHeaderContainer(id);
}
return htmlHeaderContainer;
}
/**
* A component for <wicket:head> elements
*/
private static class WicketHeadContainer extends WebMarkupContainer
{
/**
* Constructor.
*/
public WicketHeadContainer()
{
super(HtmlHeaderSectionHandler.HEADER_ID);
setRenderBodyOnly(true);
}
}
/**
* Visitor to find children of type {@link WicketHeadContainer}}
*/
private static class FindWicketHeadContainer implements
IVisitor<Component, WicketHeadContainer>
{
@Override
public void component(Component component, IVisit<WicketHeadContainer> visit)
{
if (component instanceof WicketHeadContainer)
{
WicketHeadContainer result = (WicketHeadContainer) component;
visit.stop(result);
}
}
}
}