/*
* 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.extensions.breadcrumb;
import org.apache.wicket.extensions.breadcrumb.panel.BreadCrumbPanel;
import org.apache.wicket.markup.html.link.Link;
import org.apache.wicket.version.undo.Change;
/**
* A link that when clicked will set the the active
* {@link IBreadCrumbParticipant bread crumb participant} to the one that is returned by
* {@link #getParticipant(String)}. It is used internally by
* {@link BreadCrumbBar the the bread crumb bar component}, and you can use it for rendering links
* e.g. with {@link BreadCrumbPanel bread crumb panel components}.
*
* <p>
* When clicked, it registers a change for backbutton support.
* </p>
*
* @author Eelco Hillenius
*/
public abstract class BreadCrumbLink extends Link<Void>
{
private static final long serialVersionUID = 1L;
/** The bread crumb model. */
private final IBreadCrumbModel breadCrumbModel;
/**
* Construct.
*
* @param id
* The link id
* @param breadCrumbModel
* The bread crumb model
*/
public BreadCrumbLink(String id, IBreadCrumbModel breadCrumbModel)
{
super(id);
this.breadCrumbModel = breadCrumbModel;
}
/**
* @see org.apache.wicket.markup.html.link.Link#onClick()
*/
@Override
public void onClick()
{
// get the currently active particpant
final IBreadCrumbParticipant active = breadCrumbModel.getActive();
if (active == null)
{
throw new IllegalStateException("The model has no active bread crumb. Before using " +
this + ", you have to have at least one bread crumb in the model");
}
// get the participant to set as active
final IBreadCrumbParticipant participant = getParticipant(active.getComponent().getId());
// add back button support
addStateChange(new Change()
{
private static final long serialVersionUID = 1L;
@Override
public void undo()
{
breadCrumbModel.setActive(active);
}
});
// set the next participant as the active one
breadCrumbModel.setActive(participant);
}
/**
* Gets the {@link IBreadCrumbParticipant bread crumb participant} to be set active when the
* link is clicked.
*
* @param componentId
* When the participant creates it's own view, it typically should use this component
* id for the component that is returned by
* {@link IBreadCrumbParticipant#getComponent()}.
* @return The bread crumb participant
*/
protected abstract IBreadCrumbParticipant getParticipant(String componentId);
}