/*
* 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.
*/
/*
* $Id: CreateValueChangeListenerCommand.java 471910 2006-11-06 22:44:56Z gvanmatre $
*/
package org.apache.shale.clay.component.chain;
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 org.apache.commons.chain.Context;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.shale.clay.config.beans.AttributeBean;
import org.apache.shale.clay.config.beans.ComponentBean;
/**
* <p>
* Creates a {@link ValueChangeListener} and assign it to the
* <code>parent</code> property in the {@link ClayContext}.
*/
public class CreateValueChangeListenerCommand extends AbstractCommand {
/**
* <p>
* Common Logging utility.
* </p>
*/
private static Log log;
static {
log = LogFactory.getLog(CreateValueChangeListenerCommand.class);
}
/**
* <p>
* Creates a <code>ValueChangeListener</code> and assigns it to the
* <code>parent</code> attribute.
* </p>
*
* @param context common chains
* @return <code>true</code> if the chain is complete
* @exception Exception propagated up to the top of the chain
*/
public boolean execute(Context context) throws Exception {
boolean isFinal = false;
ClayContext clayContext = (ClayContext) context;
if (clayContext == null) {
throw new NullPointerException(getMessages()
.getMessage("clay.null.clayContext"));
}
UIComponent child = (UIComponent) clayContext.getChild();
if (child == null) {
throw new NullPointerException(getMessages()
.getMessage("clay.null.childComponent"));
}
ComponentBean displayElement = clayContext.getDisplayElement();
if (displayElement == null) {
throw new NullPointerException(getMessages()
.getMessage("clay.null.componentBean"));
}
EditableValueHolder parent = (EditableValueHolder) clayContext
.getParent();
if (parent == null) {
throw new NullPointerException(getMessages()
.getMessage("clay.null.parentComponent"));
}
FacesContext facesContext = clayContext.getFacesContext();
if (facesContext == null) {
throw new NullPointerException(getMessages()
.getMessage("clay.null.facesContext"));
}
ValueChangeListener listener = null;
try {
AttributeBean attr = displayElement.getAttribute("binding");
if (attr != null && isValueReference(attr.getValue())) {
clayContext.setAttribute(attr);
String expr = replaceMnemonic(clayContext);
ValueBinding vb = facesContext.getApplication().createValueBinding(expr);
listener = (ValueChangeListener) vb.getValue(facesContext);
} else {
ClassLoader loader = Thread.currentThread().getContextClassLoader();
if (loader == null) {
loader = getClass().getClassLoader();
}
listener = (ValueChangeListener) loader.loadClass(
displayElement.getComponentType()).newInstance();
loader = null;
}
} catch (Exception e) {
log.error(getMessages().getMessage("create.valueChangeListener"), e);
throw e;
}
parent.addValueChangeListener(listener);
// reassign the child to the valueChangeListener for the
// AssignPropertiesCommand
clayContext.setChild(listener);
return isFinal;
}
}