/*
* 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.ajax.markup.html;
import java.util.Optional;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.markup.html.WebPage;
import org.apache.wicket.markup.html.basic.Label;
import org.apache.wicket.markup.html.link.Link;
import org.apache.wicket.model.AbstractReadOnlyModel;
import org.apache.wicket.request.mapper.parameter.PageParameters;
import org.apache.wicket.util.string.StringValue;
public class StatelessAjaxFallbackLinkDoNotRecreatePage extends WebPage
{
private static final long serialVersionUID = 1L;
private static final String COUNTER_PARAM = "counter";
/**
* Constructor that is invoked when page is invoked without a session.
*
* @param parameters
* Page parameters
*/
public StatelessAjaxFallbackLinkDoNotRecreatePage(final PageParameters parameters)
{
super(parameters);
setStatelessHint(true);
final Label incrementLabel = new Label("incrementLabel", new AbstractReadOnlyModel<Integer>()
{
private static final long serialVersionUID = 1L;
@Override
public Integer getObject()
{
final String counter = getParameter(parameters, COUNTER_PARAM);
return counter != null ? Integer.parseInt(counter) : 0;
}
});
final Link<?> incrementLink = new AjaxFallbackLink<Void>("incrementLink")
{
private static final long serialVersionUID = 1L;
@Override
public void onClick(final Optional<AjaxRequestTarget> targetOptional)
{
Integer counter = (Integer) incrementLabel.getDefaultModelObject();
updateParams(getPageParameters(), counter);
targetOptional.ifPresent(target -> target.add(incrementLabel, this));
}
@Override
protected boolean getStatelessHint()
{
return true;
}
};
add(incrementLink);
add(incrementLabel.setOutputMarkupId(true));
}
private String getParameter(final PageParameters parameters, final String key)
{
final StringValue value = parameters.get(key);
if (value.isNull() || value.isEmpty())
{
return null;
}
return value.toString();
}
protected final void updateParams(final PageParameters pageParameters, final int counter)
{
pageParameters.set(COUNTER_PARAM, Integer.toString(counter + 1));
}
}