/*
* 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.DequeueContext;
import org.apache.wicket.IQueueRegion;
import org.apache.wicket.MarkupContainer;
import org.apache.wicket.markup.IMarkupFragment;
import org.apache.wicket.markup.html.WebMarkupContainer;
import org.apache.wicket.model.IModel;
import org.apache.wicket.util.lang.Args;
/**
* Usually you either have a markup file or a xml tag with wicket:id="myComponent" to associate
* markup with a component. However in some use cases, especially when working with small panels it
* is a bit awkward to maintain tiny pieces of markup in plenty of panel markup files. Use cases are
* for example list views where list items are different depending on a state.
* <p>
* Fragments provide a means to maintain the panels tiny piece of markup. Since it can be anywhere,
* the component whose markup contains the fragment's markup must be provided (markup provider).
* <p>
*
* <pre>
* <span wicket:id="myPanel">Example input (will be removed)</span>
*
* <wicket:fragment wicket:id="frag1">panel 1</wicket:fragment>
* <wicket:fragment wicket:id="frag2">panel 2</wicket:fragment>
* </pre>
*
* <pre>
* add(new Fragment("myPanel1", "frag1", myPage);
* </pre>
*
* @author Juergen Donnerstag
*/
public class Fragment extends WebMarkupContainer implements IQueueRegion
{
private static final long serialVersionUID = 1L;
/** The wicket:id of the associated markup fragment */
private final String associatedMarkupId;
private final MarkupContainer markupProvider;
/**
* Constructor.
*
* @see org.apache.wicket.Component#Component(String)
*
* @param id
* The component id
* @param markupId
* The associated id of the associated markup fragment
* @param markupProvider
* The component whose markup contains the fragment's markup
*/
public Fragment(final String id, final String markupId, final MarkupContainer markupProvider)
{
this(id, markupId, markupProvider, null);
}
/**
* Constructor.
*
* @see org.apache.wicket.Component#Component(String)
*
* @param id
* The component id
* @param markupId
* The associated id of the associated markup fragment
* @param markupProvider
* The component whose markup contains the fragment's markup
* @param model
* The model for this fragment
*/
public Fragment(final String id, final String markupId, final MarkupContainer markupProvider,
final IModel<?> model)
{
super(id, model);
associatedMarkupId = Args.notNull(markupId, "markupId");
this.markupProvider = markupProvider;
}
/**
* {@inheritDoc}
*/
@Override
protected IMarkupSourcingStrategy newMarkupSourcingStrategy()
{
return new FragmentMarkupSourcingStrategy(associatedMarkupId, markupProvider)
{
@Override
public IMarkupFragment chooseMarkup(Component component)
{
return Fragment.this.chooseMarkup(getMarkupProvider(component));
}
};
}
/**
* Get the markup stream which shall be used to search for the fragment
*
* @param provider
* @return The markup stream to be used to find the fragment markup
*/
protected IMarkupFragment chooseMarkup(final MarkupContainer provider)
{
return provider.getMarkup(null);
}
/**
* @return the markup id associated to this Fragment
*/
public final String getAssociatedMarkupId()
{
return associatedMarkupId;
}
@Override
public DequeueContext newDequeueContext()
{
IMarkupFragment markup = getMarkupSourcingStrategy().getMarkup(this, null);
if (markup == null)
{
return null;
}
return new DequeueContext(markup, this, true);
}
}