diff --git a/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/config/SpelExpressionConverterConfiguration.java b/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/config/SpelExpressionConverterConfiguration.java new file mode 100644 index 000000000..f4de29191 --- /dev/null +++ b/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/config/SpelExpressionConverterConfiguration.java @@ -0,0 +1,61 @@ +/* + * Copyright 2015 the original author or authors. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.springframework.cloud.stream.config; + +import org.springframework.context.annotation.Bean; +import org.springframework.context.annotation.Configuration; +import org.springframework.core.convert.converter.Converter; +import org.springframework.expression.Expression; +import org.springframework.expression.ParseException; +import org.springframework.expression.spel.standard.SpelExpressionParser; + +/** + * Adds a Converter from String to SpEL Expression in the context. + * By default, ConfigurationPropertiesBindingPostProcessor adds all converters it finds + * in the context to its own conversionService, so this is useful for binding properties + * of type Expression in {@literal @}ConfigurationProperties annotated classes. + * + * @author Eric Bottard + */ +@Configuration +public class SpelExpressionConverterConfiguration { + + @Bean + public Converter spelConverter() { + return new SpelConverter(); + } + + /** + * A simple converter from String to Expression. + * + * @author Eric Bottard + */ + public static class SpelConverter implements Converter { + + private SpelExpressionParser parser = new SpelExpressionParser(); + + @Override + public Expression convert(String source) { + try { + return parser.parseExpression(source); + } + catch (ParseException e) { + throw new IllegalArgumentException(String.format("Could not convert '%s' into a SpEL expression", source), e); + } + } + } +}