001/*
002 * Copyright 2002-2017 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.beans.factory.config;
018
019import org.springframework.beans.BeansException;
020import org.springframework.lang.Nullable;
021
022/**
023 * Strategy interface for resolving a value through evaluating it
024 * as an expression, if applicable.
025 *
026 * <p>A raw {@link org.springframework.beans.factory.BeanFactory} does not
027 * contain a default implementation of this strategy. However,
028 * {@link org.springframework.context.ApplicationContext} implementations
029 * will provide expression support out of the box.
030 *
031 * @author Juergen Hoeller
032 * @since 3.0
033 */
034public interface BeanExpressionResolver {
035
036        /**
037         * Evaluate the given value as an expression, if applicable;
038         * return the value as-is otherwise.
039         * @param value the value to check
040         * @param evalContext the evaluation context
041         * @return the resolved value (potentially the given value as-is)
042         * @throws BeansException if evaluation failed
043         */
044        @Nullable
045        Object evaluate(@Nullable String value, BeanExpressionContext evalContext) throws BeansException;
046
047}