org.primefaces.el.ValueExpressionAnalyzer Maven / Gradle / Ivy
/*
* Copyright 2009-2014 PrimeTek.
*
* 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.primefaces.el;
import javax.el.ELContext;
import javax.el.ValueExpression;
import javax.el.ValueReference;
import javax.faces.el.CompositeComponentExpressionHolder;
public class ValueExpressionAnalyzer {
public static ValueReference getReference(ELContext elContext, ValueExpression expression) {
ValueReference reference = toValueReference(expression, elContext);
// check for a CC expression
if (reference != null && isCompositeComponentReference(reference)) {
ValueExpression unwrapped = unwrapCompositeComponentReference(reference);
// check for nested CC expressions
if (unwrapped != null && isCompositeComponentReference(toValueReference(unwrapped, elContext))) {
reference = getReference(elContext, unwrapped);
}
}
return reference;
}
public static ValueExpression getExpression(ELContext elContext, ValueExpression expression) {
ValueReference reference = toValueReference(expression, elContext);
// check for a CC expression
if (reference != null && isCompositeComponentReference(reference)) {
ValueExpression unwrapped = unwrapCompositeComponentReference(reference);
if (unwrapped != null) {
// check for nested CC expressions
if (isCompositeComponentReference(toValueReference(unwrapped, elContext))) {
return getExpression(elContext, unwrapped);
}
else {
return unwrapped;
}
}
}
return expression;
}
public static boolean isCompositeComponentReference(ValueReference vr) {
return vr != null && vr.getBase() != null && vr.getBase() instanceof CompositeComponentExpressionHolder;
}
public static ValueExpression unwrapCompositeComponentReference(ValueReference vr) {
return ((CompositeComponentExpressionHolder) vr.getBase()).getExpression((String) vr.getProperty());
}
public static ValueReference intercept(ELContext elContext, ValueExpression expression) {
if (expression == null) {
return null;
}
InterceptingResolver resolver = new InterceptingResolver(elContext.getELResolver());
ELContext interceptingContext = new InterceptingContext(elContext, resolver);
// #getType throws a PropertyNotFoundException when a sub-expression is null
expression.getType(interceptingContext);
// intercept EL calls
expression.getValue(interceptingContext);
return resolver.getValueReference();
}
public static ValueReference toValueReference(ValueExpression ve, ELContext elContext) {
ValueReference reference = ve.getValueReference(elContext);
// e.g. TagValueExpression returns null
if (reference == null) {
reference = intercept(elContext, ve);
}
return reference;
}
}