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.util; 018 019import org.springframework.lang.Nullable; 020 021/** 022 * Simple strategy interface for resolving a String value. 023 * Used by {@link org.springframework.beans.factory.config.ConfigurableBeanFactory}. 024 * 025 * @author Juergen Hoeller 026 * @since 2.5 027 * @see org.springframework.beans.factory.config.ConfigurableBeanFactory#resolveAliases 028 * @see org.springframework.beans.factory.config.BeanDefinitionVisitor#BeanDefinitionVisitor(StringValueResolver) 029 * @see org.springframework.beans.factory.config.PropertyPlaceholderConfigurer 030 */ 031@FunctionalInterface 032public interface StringValueResolver { 033 034 /** 035 * Resolve the given String value, for example parsing placeholders. 036 * @param strVal the original String value (never {@code null}) 037 * @return the resolved String value (may be {@code null} when resolved to a null 038 * value), possibly the original String value itself (in case of no placeholders 039 * to resolve or when ignoring unresolvable placeholders) 040 * @throws IllegalArgumentException in case of an unresolvable String value 041 */ 042 @Nullable 043 String resolveStringValue(String strVal); 044 045}