/*
* 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.renderStrategy;
import org.apache.wicket.Component;
import org.apache.wicket.MarkupContainer;
import org.apache.wicket.markup.html.internal.HtmlHeaderContainer;
import org.apache.wicket.util.lang.Args;
import org.apache.wicket.util.visit.IVisit;
import org.apache.wicket.util.visit.IVisitor;
/**
* This has been Wicket's default header render strategy before WICKET 1.5 which uses
* {@link MarkupContainer#visitChildren(org.apache.wicket.util.visit.IVisitor)} to traverse the hierarchy to
* render the children headers.
*
* Since child contributions are added to the markup after the parent contributions, children may
* replace / modify existing settings. Which is not good. Instead the parent (container) should be
* in control (see <a href="https://issues.apache.org/jira/browse/WICKET-2693">WICKET-2693</a>).
*
* @author Juergen Donnerstag
*/
public class ParentFirstHeaderRenderStrategy extends AbstractHeaderRenderStrategy
{
/**
* Construct.
*/
public ParentFirstHeaderRenderStrategy()
{
}
@Override
protected void renderChildHeaders(final HtmlHeaderContainer headerContainer,
final Component rootComponent)
{
Args.notNull(headerContainer, "headerContainer");
Args.notNull(rootComponent, "rootComponent");
// Only MarkupContainer can have children. Component's don't
if (rootComponent instanceof MarkupContainer)
{
// Visit the children with parent first, than children
((MarkupContainer)rootComponent).visitChildren(new IVisitor<Component, Void>()
{
@Override
public void component(final Component component, final IVisit<Void> visit)
{
if (component.isVisibleInHierarchy())
{
component.internalRenderHead(headerContainer);
}
else
{
visit.dontGoDeeper();
}
}
});
}
}
}