001/* 002 * Copyright 2002-2016 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.util.StringValueResolver; 020 021/** 022 * {@link StringValueResolver} adapter for resolving placeholders and 023 * expressions against a {@link ConfigurableBeanFactory}. 024 * 025 * <p>Note that this adapter resolves expressions as well, in contrast 026 * to the {@link ConfigurableBeanFactory#resolveEmbeddedValue} method. 027 * The {@link BeanExpressionContext} used is for the plain bean factory, 028 * with no scope specified for any contextual objects to access. 029 * 030 * @author Juergen Hoeller 031 * @since 4.3 032 * @see ConfigurableBeanFactory#resolveEmbeddedValue(String) 033 * @see ConfigurableBeanFactory#getBeanExpressionResolver() 034 * @see BeanExpressionContext 035 */ 036public class EmbeddedValueResolver implements StringValueResolver { 037 038 private final BeanExpressionContext exprContext; 039 040 private final BeanExpressionResolver exprResolver; 041 042 043 public EmbeddedValueResolver(ConfigurableBeanFactory beanFactory) { 044 this.exprContext = new BeanExpressionContext(beanFactory, null); 045 this.exprResolver = beanFactory.getBeanExpressionResolver(); 046 } 047 048 049 @Override 050 public String resolveStringValue(String strVal) { 051 String value = this.exprContext.getBeanFactory().resolveEmbeddedValue(strVal); 052 if (this.exprResolver != null && value != null) { 053 Object evaluated = this.exprResolver.evaluate(value, this.exprContext); 054 value = (evaluated != null ? evaluated.toString() : null); 055 } 056 return value; 057 } 058 059}