/*
* Copyright 2002-2008 the original author or authors.
*
* Licensed 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.springframework.beans.factory.access.el;
import java.beans.FeatureDescriptor;
import java.util.Iterator;
import javax.el.ELContext;
import javax.el.ELException;
import javax.el.ELResolver;
import javax.el.PropertyNotWritableException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.BeanFactory;
/**
* Unified EL <code>ELResolver</code> that delegates to a Spring BeanFactory,
* resolving name references to Spring-defined beans.
*
* @author Juergen Hoeller
* @since 2.5.2
* @see org.springframework.web.jsf.el.SpringBeanFacesELResolver
*/
public abstract class SpringBeanELResolver extends ELResolver {
/** Logger available to subclasses */
protected final Log logger = LogFactory.getLog(getClass());
@Override
public Object getValue(ELContext elContext, Object base, Object property) throws ELException {
if (base == null) {
String beanName = property.toString();
BeanFactory bf = getBeanFactory(elContext);
if (bf.containsBean(beanName)) {
if (logger.isTraceEnabled()) {
logger.trace("Successfully resolved variable '" + beanName + "' in Spring BeanFactory");
}
elContext.setPropertyResolved(true);
return bf.getBean(beanName);
}
}
return null;
}
@Override
public Class<?> getType(ELContext elContext, Object base, Object property) throws ELException {
if (base == null) {
String beanName = property.toString();
BeanFactory bf = getBeanFactory(elContext);
if (bf.containsBean(beanName)) {
elContext.setPropertyResolved(true);
return bf.getType(beanName);
}
}
return null;
}
@Override
public void setValue(ELContext elContext, Object base, Object property, Object value) throws ELException {
if (base == null) {
String beanName = property.toString();
BeanFactory bf = getBeanFactory(elContext);
if (bf.containsBean(beanName)) {
throw new PropertyNotWritableException(
"Variable '" + beanName + "' refers to a Spring bean which by definition is not writable");
}
}
}
@Override
public boolean isReadOnly(ELContext elContext, Object base, Object property) throws ELException {
if (base == null) {
String beanName = property.toString();
BeanFactory bf = getBeanFactory(elContext);
if (bf.containsBean(beanName)) {
return true;
}
}
return false;
}
@Override
public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext elContext, Object base) {
return null;
}
@Override
public Class<?> getCommonPropertyType(ELContext elContext, Object base) {
return Object.class;
}
/**
* Retrieve the Spring BeanFactory to delegate bean name resolution to.
* @param elContext the current ELContext
* @return the Spring BeanFactory (never <code>null</code>)
*/
protected abstract BeanFactory getBeanFactory(ELContext elContext);
}
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