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PrimeFaces is one of the most popular UI libraries in Java EE Ecosystem and widely used by software companies, world renowned brands, banks, financial institutions, insurance companies, universities and more.
/**
* The MIT License
*
* Copyright (c) 2009-2019 PrimeTek
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package org.primefaces.el;
import javax.el.ELContext;
import javax.el.ValueExpression;
import javax.el.ValueReference;
import javax.faces.context.FacesContext;
import javax.faces.el.CompositeComponentExpressionHolder;
import org.primefaces.context.PrimeApplicationContext;
public class ValueExpressionAnalyzer {
private ValueExpressionAnalyzer() {
}
public static ValueReference getReference(ELContext elContext, ValueExpression expression) {
if (expression == null) {
return null;
}
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) {
ValueReference unwrappedRef = toValueReference(unwrapped, elContext);
if (isCompositeComponentReference(unwrappedRef)) {
return getReference(elContext, unwrapped);
}
else {
return unwrappedRef;
}
}
}
return reference;
}
public static ValueExpression getExpression(ELContext elContext, ValueExpression expression) {
if (expression == null) {
return null;
}
// Unwrapping is required e.g. for p:graphicImage to support nested expressions in composites
// The unwrapping requires EL 2.2
if (PrimeApplicationContext.getCurrentInstance(FacesContext.getCurrentInstance()).getEnvironment().isAtLeastEl22()) {
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;
}
}