/*
* Copyright 2004-2012 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.binding.expression.el;
import java.beans.FeatureDescriptor;
import java.util.Iterator;
import java.util.Map;
import javax.el.ELContext;
import javax.el.ELException;
import javax.el.ELResolver;
import javax.el.PropertyNotFoundException;
import javax.el.PropertyNotWritableException;
import org.springframework.binding.collection.MapAdaptable;
/**
* An {@link ELResolver} for properly resolving variables in an instance of {@link MapAdaptable}
* @author Jeremy Grelle
*/
public class MapAdaptableELResolver extends ELResolver {
public Class<?> getCommonPropertyType(ELContext context, Object base) {
if (base instanceof MapAdaptable) {
return Object.class;
}
return null;
}
public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext context, Object base) {
return null;
}
public Class<?> getType(ELContext context, Object base, Object property) throws NullPointerException,
PropertyNotFoundException, ELException {
if (context == null) {
throw new NullPointerException("The ELContext is null.");
}
if (base instanceof MapAdaptable) {
context.setPropertyResolved(true);
Object obj = adapt(base).get(property);
return (obj != null) ? obj.getClass() : null;
}
return null;
}
public Object getValue(ELContext context, Object base, Object property) throws NullPointerException,
PropertyNotFoundException, ELException {
if (context == null) {
throw new NullPointerException("The ELContext is null.");
}
if (base instanceof MapAdaptable) {
context.setPropertyResolved(true);
return adapt(base).get(property);
}
return null;
}
public boolean isReadOnly(ELContext context, Object base, Object property) throws NullPointerException,
PropertyNotFoundException, ELException {
if (context == null) {
throw new NullPointerException("The ELContext is null.");
}
if (base instanceof MapAdaptable) {
context.setPropertyResolved(true);
}
return false;
}
public void setValue(ELContext context, Object base, Object property, Object value) throws NullPointerException,
PropertyNotFoundException, PropertyNotWritableException, ELException {
if (context == null) {
throw new NullPointerException("The ELContext is null.");
}
if (base instanceof MapAdaptable) {
context.setPropertyResolved(true);
try {
adapt(base).put(property, value);
} catch (UnsupportedOperationException e) {
throw new PropertyNotWritableException(e);
}
}
}
@SuppressWarnings("unchecked")
private Map<Object, Object> adapt(Object base) {
MapAdaptable<Object, Object> adaptable = (MapAdaptable<Object, Object>) base;
return adaptable.asMap();
}
}