/*
* 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.myfaces.taglib.core;
import org.apache.myfaces.shared_impl.util.ClassUtils;
import javax.faces.component.EditableValueHolder;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.el.ValueBinding;
import javax.faces.event.ValueChangeListener;
import javax.faces.webapp.UIComponentTag;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.Tag;
import javax.servlet.jsp.tagext.TagSupport;
/**
* Adds the specified ValueChangeListener to the nearest parent
* UIComponent (which is expected to be a UIInput component).
* Whenever the form containing the parent UIComponent is submitted,
* an instance of the specified type is created. If the submitted
* value from the component is different from the component's current
* value then a ValueChangeEvent is queued. When the ValueChangeEvent
* is processed (at end of the validate phase for non-immediate components,
* or at end of the apply-request-values phase for immediate components)
* the object's processValueChange method is invoked.
* <p>
* Unless otherwise specified, all attributes accept static values
* or EL expressions.
*
* @JSFJspTag
* name="f:valueChangeListener"
* bodyContent="empty"
*
* @author Manfred Geiler (latest modification by $Author: skitching $)
* @version $Revision: 670058 $ $Date: 2008-06-20 15:54:48 -0500 (Fri, 20 Jun 2008) $
*/
public class ValueChangeListenerTag
extends TagSupport
{
//private static final Log log = LogFactory.getLog(ValueChangeListenerTag.class);
private static final long serialVersionUID = 2155190261951046892L;
private String _type = null;
public ValueChangeListenerTag()
{
}
/**
* The name of a Java class that implements ValueChangeListener.
*
* @JSFJspAttribute required="true"
*/
public void setType(String type)
{
_type = type;
}
public int doStartTag() throws JspException
{
if (_type == null)
{
throw new JspException("type attribute not set");
}
//Find parent UIComponentTag
UIComponentTag componentTag = UIComponentTag.getParentUIComponentTag(pageContext);
if (componentTag == null)
{
throw new JspException("ValueChangeListenerTag has no UIComponentTag ancestor");
}
if (componentTag.getCreated())
{
//Component was just created, so we add the Listener
UIComponent component = componentTag.getComponentInstance();
if (component instanceof EditableValueHolder)
{
String className;
if (UIComponentTag.isValueReference(_type))
{
FacesContext facesContext = FacesContext.getCurrentInstance();
ValueBinding vb = facesContext.getApplication().createValueBinding(_type);
className = (String)vb.getValue(facesContext);
}
else
{
className = _type;
}
ValueChangeListener vcl = (ValueChangeListener)ClassUtils.newInstance(className);
((EditableValueHolder)component).addValueChangeListener(vcl);
}
else
{
throw new JspException("Component " + component.getId() + " is no EditableValueHolder");
}
}
return Tag.SKIP_BODY;
}
}