001/*
002 * Copyright 2002-2012 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.context.expression;
018
019import org.springframework.beans.factory.config.BeanExpressionContext;
020import org.springframework.expression.AccessException;
021import org.springframework.expression.EvaluationContext;
022import org.springframework.expression.PropertyAccessor;
023import org.springframework.expression.TypedValue;
024
025/**
026 * EL property accessor that knows how to traverse the beans and contextual objects
027 * of a Spring {@link org.springframework.beans.factory.config.BeanExpressionContext}.
028 *
029 * @author Juergen Hoeller
030 * @author Andy Clement
031 * @since 3.0
032 */
033public class BeanExpressionContextAccessor implements PropertyAccessor {
034
035        @Override
036        public boolean canRead(EvaluationContext context, Object target, String name) throws AccessException {
037                return ((BeanExpressionContext) target).containsObject(name);
038        }
039
040        @Override
041        public TypedValue read(EvaluationContext context, Object target, String name) throws AccessException {
042                return new TypedValue(((BeanExpressionContext) target).getObject(name));
043        }
044
045        @Override
046        public boolean canWrite(EvaluationContext context, Object target, String name) throws AccessException {
047                return false;
048        }
049
050        @Override
051        public void write(EvaluationContext context, Object target, String name, Object newValue) throws AccessException {
052                throw new AccessException("Beans in a BeanFactory are read-only");
053        }
054
055        @Override
056        public Class<?>[] getSpecificTargetClasses() {
057                return new Class<?>[] {BeanExpressionContext.class};
058        }
059
060}