/*
* 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.form;
import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.ajax.IAjaxCallDecorator;
import org.apache.wicket.ajax.form.AjaxFormSubmitBehavior;
import org.apache.wicket.markup.ComponentTag;
import org.apache.wicket.markup.html.form.AbstractSubmitLink;
import org.apache.wicket.markup.html.form.Form;
import org.apache.wicket.util.string.AppendingStringBuffer;
/**
* A link that submits a form via ajax. Since this link takes the form as a constructor argument it
* does not need to be inside form's component hierarchy.
*
* <p/> It works by splitting the javascript/Ajax calls from the normal non-ajax requests by
* generating:
*
* <pre>
* <a href="normal action url" onclick="ajax javascript script; return
* false;">link</a>
* </pre>
*
* If/when javascript is turned off in the browser, or it doesn't support javascript, then the
* browser will not respond to the onclick event, using the href directly. Wicket will then use a
* normal request target, and call the serverside onClick with a null {@link AjaxRequestTarget}.
*
* If javascript is enabled, Wicket will send an ajax request, and process it serverside with an
* {@link AjaxRequestTarget} that is supplied to the server-side onClick method. The "return false"
* in the <a href> onclick handler ensures the browser doesn't perform the normal request too.
*
* The latter is nicely illustrated with this:
*
* <pre>
* <a href="javascript:alert('href event handler');"
* onclick="alert('onclick event handler');">clicking me gives two
* alerts</a>
*
* <a href="javascript:alert('href event handler');"
* onclick="alert('onclick event handler');return false;">clicking me
* gives only one alert</a>
* </pre>
*
* @since 1.2
*
* @author Igor Vaynberg (ivaynberg)
*/
public abstract class AjaxSubmitLink extends AbstractSubmitLink
{
private static final long serialVersionUID = 1L;
/**
* Construct.
*
* @param id
*/
public AjaxSubmitLink(String id)
{
this(id, null);
}
/**
* Construct.
*
* @param id
* @param form
*/
public AjaxSubmitLink(String id, final Form form)
{
super(id);
add(new AjaxFormSubmitBehavior(form, "onclick")
{
private static final long serialVersionUID = 1L;
protected void onSubmit(AjaxRequestTarget target)
{
AjaxSubmitLink.this.onSubmit(target, form);
}
protected void onError(AjaxRequestTarget target)
{
AjaxSubmitLink.this.onError(target, form);
}
protected CharSequence getEventHandler()
{
return new AppendingStringBuffer(super.getEventHandler()).append("; return false;");
}
protected IAjaxCallDecorator getAjaxCallDecorator()
{
return AjaxSubmitLink.this.getAjaxCallDecorator();
}
protected void onComponentTag(ComponentTag tag)
{
// write the onclick handler only if link is enabled
if (isLinkEnabled())
{
super.onComponentTag(tag);
}
}
});
}
/**
* Returns the {@link IAjaxCallDecorator} that will be used to modify the generated javascript.
* This is the preferred way of changing the javascript in the onclick handler
*
* @return call decorator used to modify the generated javascript or null for none
*/
protected IAjaxCallDecorator getAjaxCallDecorator()
{
return null;
}
protected void onComponentTag(ComponentTag tag)
{
super.onComponentTag(tag);
if (isLinkEnabled())
{
if (tag.getName().toLowerCase().equals("a"))
{
tag.put("href", "#");
}
}
else
{
disableLink(tag);
}
}
/**
* Final implementation of the Button's onSubmit. AjaxSubmitLinks have there own onSubmit which
* is called.
*
* @see org.apache.wicket.markup.html.form.Button#onSubmit()
*/
public final void onSubmit()
{
}
/**
* Listener method invoked on form submit
*
* @param target
* @param form
*/
protected abstract void onSubmit(AjaxRequestTarget target, Form form);
/**
* Listener method invoked on form submit with errors
*
* @param target
* @param form
*
* TODO 1.3: Make abstract to be consistent with onsubmit()
*/
protected void onError(AjaxRequestTarget target, Form form)
{
}
}