/*
* 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.ajax.markup.html;
import org.apache.wicket.Component;
import org.apache.wicket.RequestCycle;
import org.apache.wicket.ajax.AbstractDefaultAjaxBehavior;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.markup.html.IHeaderResponse;
import org.apache.wicket.markup.html.basic.Label;
import org.apache.wicket.markup.html.panel.Panel;
/**
* A panel where you can lazy load another panel. This can be used if you have a panel/component
* that is pretty heavy in creation and you first want to show the user the page and the replace the
* panel when it is ready.
*
* @author jcompagner
*
* @since 1.3
*/
public abstract class AjaxLazyLoadPanel extends Panel
{
private static final long serialVersionUID = 1L;
/**
* @param id
*/
public AjaxLazyLoadPanel(String id)
{
super(id);
setOutputMarkupId(true);
Component loadingComponent = getLoadingComponent("content");
add(loadingComponent.setRenderBodyOnly(true));
loadingComponent.add(new AbstractDefaultAjaxBehavior()
{
private static final long serialVersionUID = 1L;
protected void respond(AjaxRequestTarget target)
{
Component component = getLazyLoadComponent("content");
AjaxLazyLoadPanel.this.replace(component.setRenderBodyOnly(true));
target.addComponent(AjaxLazyLoadPanel.this);
}
public void renderHead(IHeaderResponse response)
{
super.renderHead(response);
response.renderOnDomReadyJavascript(getCallbackScript().toString());
}
});
}
/**
* @param markupId
* The components markupid.
* @return The component that must be lazy created.
*/
public abstract Component getLazyLoadComponent(String markupId);
/**
* @param markupId
* The components markupid.
* @return The component to show while the real component is being created.
*/
public Component getLoadingComponent(String markupId)
{
return new Label(markupId, "<img src=\"" +
RequestCycle.get().urlFor(AbstractDefaultAjaxBehavior.INDICATOR) + "\"/>")
.setEscapeModelStrings(false);
}
}