/*
* 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.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.context.properties.ConfigurationPropertiesBinding;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Lazy;
import org.springframework.core.convert.converter.Converter;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.Expression;
import org.springframework.expression.ParseException;
import org.springframework.expression.spel.standard.SpelExpression;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.integration.config.IntegrationConverter;
import org.springframework.integration.context.IntegrationContextUtils;
/**
* Adds a Converter from String to SpEL Expression in the context.
*
* @author Eric Bottard
*/
@Configuration
public class SpelExpressionConverterConfiguration {
@Bean
@ConfigurationPropertiesBinding
@IntegrationConverter
public Converter<String, Expression> spelConverter() {
return new SpelConverter();
}
/**
* A simple converter from String to Expression.
*
* @author Eric Bottard
*/
public static class SpelConverter implements Converter<String, Expression> {
private SpelExpressionParser parser = new SpelExpressionParser();
@Autowired
@Qualifier(IntegrationContextUtils.INTEGRATION_EVALUATION_CONTEXT_BEAN_NAME)
@Lazy
private EvaluationContext evaluationContext;
@Override
public Expression convert(String source) {
try {
Expression expression = parser.parseExpression(source);
if (expression instanceof SpelExpression) {
((SpelExpression) expression).setEvaluationContext(evaluationContext);
}
return expression;
}
catch (ParseException e) {
throw new IllegalArgumentException(
String.format("Could not convert '%s' into a SpEL expression", source), e);
}
}
}
}