/*
* 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.view.facelets.tag.jsf.core;
import java.io.IOException;
import java.io.Serializable;
import javax.el.ELException;
import javax.el.ValueExpression;
import javax.faces.FacesException;
import javax.faces.component.EditableValueHolder;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.event.AbortProcessingException;
import javax.faces.event.ValueChangeEvent;
import javax.faces.event.ValueChangeListener;
import javax.faces.view.EditableValueHolderAttachedObjectHandler;
import javax.faces.view.facelets.ComponentHandler;
import javax.faces.view.facelets.FaceletContext;
import javax.faces.view.facelets.FaceletException;
import javax.faces.view.facelets.TagAttribute;
import javax.faces.view.facelets.TagAttributeException;
import javax.faces.view.facelets.TagConfig;
import javax.faces.view.facelets.TagException;
import javax.faces.view.facelets.TagHandler;
import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFFaceletAttribute;
import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFFaceletTag;
import org.apache.myfaces.view.facelets.FaceletCompositionContext;
import org.apache.myfaces.view.facelets.util.ReflectionUtil;
/**
* Register an ValueChangeListener instance on the UIComponent associated with the closest parent UIComponent custom
* action.<p/> See <a target="_new"
* href="http://java.sun.com/j2ee/javaserverfaces/1.1_01/docs/tlddocs/f/valueChangeListener.html">tag documentation</a>.
*
* @author Jacob Hookom
* @version $Id: ValueChangeListenerHandler.java 1194861 2011-10-29 10:02:34Z struberg $
*/
@JSFFaceletTag(
name = "f:valueChangeListener",
bodyContent = "empty",
tagClass="org.apache.myfaces.taglib.core.ValueChangeListenerTag")
public final class ValueChangeListenerHandler extends TagHandler
implements EditableValueHolderAttachedObjectHandler
{
private static class LazyValueChangeListener implements ValueChangeListener, Serializable
{
private static final long serialVersionUID = 7613811124326963180L;
private final String type;
private final ValueExpression binding;
public LazyValueChangeListener(String type, ValueExpression binding)
{
this.type = type;
this.binding = binding;
}
public void processValueChange(ValueChangeEvent event) throws AbortProcessingException
{
ValueChangeListener instance = null;
FacesContext faces = FacesContext.getCurrentInstance();
if (faces == null)
{
return;
}
if (this.binding != null)
{
instance = (ValueChangeListener) binding.getValue(faces.getELContext());
}
if (instance == null && this.type != null)
{
try
{
instance = (ValueChangeListener) ReflectionUtil.forName(this.type).newInstance();
}
catch (Exception e)
{
throw new AbortProcessingException("Couldn't Lazily instantiate ValueChangeListener", e);
}
if (this.binding != null)
{
binding.setValue(faces.getELContext(), instance);
}
}
if (instance != null)
{
instance.processValueChange(event);
}
}
}
private final TagAttribute binding;
private final String listenerType;
public ValueChangeListenerHandler(TagConfig config)
{
super(config);
this.binding = this.getAttribute("binding");
TagAttribute type = this.getAttribute("type");
if (type != null)
{
if (!type.isLiteral())
{
throw new TagAttributeException(type, "Must be a literal class name of type ValueChangeListener");
}
else
{
// test it out
try
{
ReflectionUtil.forName(type.getValue());
}
catch (ClassNotFoundException e)
{
throw new TagAttributeException(type, "Couldn't qualify ValueChangeListener", e);
}
}
this.listenerType = type.getValue();
}
else
{
this.listenerType = null;
}
}
/**
* See taglib documentation.
*
* @see javax.faces.view.facelets.FaceletHandler#apply(javax.faces.view.facelets.FaceletContext, javax.faces.component.UIComponent)
*/
public void apply(FaceletContext ctx, UIComponent parent) throws IOException, FacesException, FaceletException,
ELException
{
if (!ComponentHandler.isNew(parent))
{
return;
}
if (parent instanceof EditableValueHolder)
{
applyAttachedObject(ctx.getFacesContext(), parent);
}
else if (UIComponent.isCompositeComponent(parent))
{
FaceletCompositionContext mctx = FaceletCompositionContext.getCurrentInstance(ctx);
mctx.addAttachedObjectHandler(parent, this);
}
else
{
throw new TagException(this.tag,
"Parent not composite component or an instance of EditableValueHolder: " + parent);
}
}
public void applyAttachedObject(FacesContext context, UIComponent parent)
{
// Retrieve the current FaceletContext from FacesContext object
FaceletContext faceletContext = (FaceletContext) context.getAttributes().get(
FaceletContext.FACELET_CONTEXT_KEY);
EditableValueHolder evh = (EditableValueHolder) parent;
ValueExpression b = null;
if (this.binding != null)
{
b = this.binding.getValueExpression(faceletContext, ValueChangeListener.class);
}
ValueChangeListener listener = new LazyValueChangeListener(this.listenerType, b);
evh.addValueChangeListener(listener);
}
/**
* TODO: Document me!
*/
@JSFFaceletAttribute
public String getFor()
{
TagAttribute forAttribute = getAttribute("for");
if (forAttribute == null)
{
return null;
}
else
{
return forAttribute.getValue();
}
}
}