ManagedPropertyProducer.java

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 1997-2016 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
 *
 * Contributor(s):
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */
package com.sun.faces.cdi;

import static com.sun.faces.cdi.CdiUtils.getBeanReference;
import static com.sun.faces.cdi.CdiUtils.getCurrentInjectionPoint;

import java.lang.reflect.Type;

import javax.enterprise.inject.spi.BeanManager;
import javax.faces.annotation.ManagedProperty;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;

/**
 * <p class="changed_added_2_3">
 * The ManagedPropertyProducer is the CDI producer that allows evaluation 
 * of arbitrary EL expressions.
 * </p>
 *
 * @since 2.3
 * @see ExternalContext
 */
public class ManagedPropertyProducer extends CdiProducer<Object> {
    
    /**
     * Serialization version
     */
    private static final long serialVersionUID = 1L;
    
    private Class<?> expectedClass;
    
    public ManagedPropertyProducer(Type type, BeanManager beanManager) {
        super.beanClass(ManagedPropertyProducer.class)
             .types(type)
             .qualifiers(new ManagedPropertyLiteral())
             .addToId(type)
             .create(creationalContext -> {
                 
                 // TODO: handle no InjectionPoint available
                 String expression = getCurrentInjectionPoint(beanManager, creationalContext)
                                         .getAnnotated()
                                         .getAnnotation(ManagedProperty.class)
                                         .value();
                 
                 return evaluateExpressionGet(beanManager, expression, expectedClass);}
             
             );
        
        expectedClass = getExpectedClass(type);
        
    }
    
    private static Class<?> getExpectedClass(Type type) {
        if (type instanceof Class) {
            return (Class<?>) type;
        }
        
        if (type instanceof ParameterizedTypeImpl) {
            return getExpectedClass( ((ParameterizedTypeImpl) type).getRawType());
        }
        
        return Object.class;
    }
    
    public static <T> T evaluateExpressionGet(BeanManager beanManager, String expression, Class<T> expectedClass) {
        if (expression == null) {
            return null;
        }
        
        FacesContext context = getBeanReference(beanManager, FacesContext.class);

        return (T) context.getApplication()
                          .evaluateExpressionGet(context, expression, expectedClass);
    }

}