/*
* 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.basic;
import org.apache.wicket.Component;
import org.apache.wicket.markup.html.WebMarkupContainer;
import org.apache.wicket.util.lang.Args;
/**
* <code><wicket:enclosure></code> is nice and prevents that users have to add boilerplate to
* their application. But it is not without problems. The child components are children in the
* markup, but the auto-component generated for the enclosure tag will not magically re-parent the
* child components. Thus the markup hierarchy and the component hierarchy will be out of sync. The
* automatically created enclosure container will be created along side its "children" with both
* attached to the very same parent container. That leads to a tricky situation since e.g.
* <code>onBeforeRender()</code> will be called for enclosure children even if the enclosure is made
* invisible by it controlling child.
* <p>
* On top auto-components cannot keep any state. A new instance is created during each render
* process and automatically deleted at the end. That implies that we cannot prevent
* <code>validation()</code> from being called, since validation() is called before the actual
* render process has started.
* </p>
* <p>
* Where any of these problems apply, you may replace the tag and manually add this simple container
* which basically does the same. But instead of adding the children to the Page, Panel whatever,
* you must add the children to this container in order to keep the component hierarchy in sync.
* </p>
*
* @author Juergen Donnerstag
* @since 1.5
*/
public class EnclosureContainer extends WebMarkupContainer
{
private static final long serialVersionUID = 1L;
/** The child component to delegate the isVisible() call to */
private final Component child;
/**
* Construct.
*
* @param id
* @param child
* child component that will control the visibility of the enclosure
*/
public EnclosureContainer(final String id, final Component child)
{
super(id);
Args.notNull(child, "child");
this.child = child;
// Usually we don't want this extra tag
setRenderBodyOnly(true);
}
/**
* Overriden to set the visibility depending on childs {@link #determineVisibility()}.
*/
@Override
protected void onConfigure()
{
child.configure();
setVisible(child.determineVisibility());
}
}