/*
* 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.el.ELException;
import javax.el.ValueExpression;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.event.ActionListener;
import javax.faces.webapp.UIComponentClassicTagBase;
import javax.faces.webapp.UIComponentELTag;
import javax.servlet.jsp.JspException;
import javax.servlet.jsp.tagext.Tag;
import javax.servlet.jsp.tagext.TagSupport;
/**
* @author Andreas Berger (latest modification by $Author: lu4242 $)
* @version $Revision: 695050 $ $Date: 2008-09-13 18:38:43 -0400 (Sat, 13 Sep 2008) $
* @since 1.2
*/
public abstract class GenericListenerTag<_Holder, _Listener>
extends TagSupport
{
private ValueExpression _type = null;
private ValueExpression _binding = null;
private Class<_Holder> _holderClazz;
protected GenericListenerTag(Class<_Holder> holderClazz)
{
super();
_holderClazz = holderClazz;
}
public void setType(ValueExpression type)
{
_type = type;
}
public void setBinding(ValueExpression binding)
{
_binding = binding;
}
public void release()
{
super.release();
_type = null;
_binding = null;
}
protected abstract void addListener(_Holder holder, _Listener listener);
protected abstract _Listener createDelegateListener(ValueExpression type, ValueExpression binding);
public int doStartTag() throws JspException
{
UIComponentClassicTagBase componentTag = UIComponentELTag.getParentUIComponentClassicTagBase(pageContext);
if (componentTag == null)
{
throw new JspException("no parent UIComponentTag found");
}
if (_type == null && _binding == null)
{
throw new JspException("\"actionListener\" must have binding and/or type attribute.");
}
if (!componentTag.getCreated())
{
return Tag.SKIP_BODY;
}
_Holder holder = null;
UIComponent component = componentTag.getComponentInstance();
try
{
holder = (_Holder) component;
} catch (ClassCastException e)
{
throw new JspException(
"Component " + ((UIComponent) holder).getId() + " is not instance of " + _holderClazz.getName());
}
if (_type != null && _type.isLiteralText())
{
createListener(holder,component);
}else{
addListener(holder, createDelegateListener(_type,_binding));
}
return Tag.SKIP_BODY;
}
protected void createListener(_Holder holder, UIComponent component)
throws JspException
{
FacesContext facesContext = FacesContext.getCurrentInstance();
_Listener listener;
// type and/or binding must be specified
try
{
if (null != _binding)
{
try
{
listener = (_Listener) _binding.getValue(facesContext.getELContext());
if (null != listener)
{
addListener(holder, listener);
// no need for further processing
return;
}
}
catch (ELException e)
{
throw new JspException("Exception while evaluating the binding attribute of Component "
+ component.getId(), e);
}
}
if (null != _type)
{
String className;
if (_type.isLiteralText())
{
className = _type.getExpressionString();
//If type is literal text we should create
//a new instance
listener = (_Listener) ClassUtils.newInstance(className);
} else
{
className = (String) _type.getValue(facesContext.getELContext());
listener = null;
}
if (null != _binding)
{
try
{
_binding.setValue(facesContext.getELContext(), listener);
} catch (ELException e)
{
throw new JspException("Exception while evaluating the binding attribute of Component "
+ component.getId(), e);
}
}else{
//Type is a EL expression, and there is
//no binding property so we should create
//a new instance
listener = (_Listener) ClassUtils.newInstance(className);
}
addListener(holder, listener);
}
} catch (ClassCastException e)
{
throw new JspException(e);
}
}
}