/*
* 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.webflow.expression.el;
import java.beans.FeatureDescriptor;
import java.util.Iterator;
import javax.el.ELContext;
import javax.el.ELResolver;
import javax.el.PropertyNotWritableException;
import org.springframework.webflow.execution.RequestContext;
import org.springframework.webflow.execution.RequestContextHolder;
/**
* Custom EL resolver that resolves the current RequestContext under the variable {@link #REQUEST_CONTEXT_VARIABLE_NAME}
* . Allows for accessing any property of the RequestContext instance. For example:
* "#{flowRequestContext.conversationScope.myProperty}".
*
* @author Jeremy Grelle
*/
public class RequestContextELResolver extends ELResolver {
/**
* Name of the request context variable.
*/
public static final String REQUEST_CONTEXT_VARIABLE_NAME = "flowRequestContext";
private RequestContext context;
public RequestContextELResolver() {
}
public RequestContextELResolver(RequestContext context) {
this.context = context;
}
public Class<?> getCommonPropertyType(ELContext elContext, Object base) {
if (base == null) {
return RequestContext.class;
}
return null;
}
public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext elContext, Object base) {
return null;
}
public Class<?> getType(ELContext elContext, Object base, Object property) {
if (base == null && REQUEST_CONTEXT_VARIABLE_NAME.equals(property)) {
elContext.setPropertyResolved(true);
return RequestContext.class;
} else {
return null;
}
}
public Object getValue(ELContext elContext, Object base, Object property) {
if (base == null && REQUEST_CONTEXT_VARIABLE_NAME.equals(property)) {
elContext.setPropertyResolved(true);
return getRequestContext();
} else {
return null;
}
}
public boolean isReadOnly(ELContext elContext, Object base, Object property) {
if (base == null && REQUEST_CONTEXT_VARIABLE_NAME.equals(property)) {
elContext.setPropertyResolved(true);
return true;
} else {
return false;
}
}
public void setValue(ELContext elContext, Object base, Object property, Object value) {
if (base == null && REQUEST_CONTEXT_VARIABLE_NAME.equals(property)) {
elContext.setPropertyResolved(true);
throw new PropertyNotWritableException("The RequestContext cannot be set with an expression.");
}
}
protected RequestContext getRequestContext() {
return context != null ? context : RequestContextHolder.getRequestContext();
}
}