org.springframework.boot.autoconfigure.condition.OnExpressionCondition Maven / Gradle / Ivy
/*
* Copyright 2012-2013 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.boot.autoconfigure.condition;
import org.springframework.beans.factory.config.BeanExpressionContext;
import org.springframework.beans.factory.config.BeanExpressionResolver;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.context.annotation.ConditionContext;
import org.springframework.context.expression.StandardBeanExpressionResolver;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.core.type.AnnotatedTypeMetadata;
import org.springframework.core.type.ClassMetadata;
/**
* A Condition that evaluates a SpEL expression.
*
* @author Dave Syer
* @see ConditionalOnExpression
*/
@Order(Ordered.LOWEST_PRECEDENCE - 20)
class OnExpressionCondition extends SpringBootCondition {
@Override
public ConditionOutcome getMatchOutcome(ConditionContext context,
AnnotatedTypeMetadata metadata) {
String expression = (String) metadata
.getAnnotationAttributes(ConditionalOnExpression.class.getName())
.get("value");
String rawExpression = expression;
if (!expression.startsWith("#{")) {
// For convenience allow user to provide bare expression with no #{} wrapper
expression = "#{" + expression + "}";
}
// Explicitly allow environment placeholders inside the expression
expression = context.getEnvironment().resolvePlaceholders(expression);
ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
BeanExpressionResolver resolver = (beanFactory != null)
? beanFactory.getBeanExpressionResolver() : null;
BeanExpressionContext expressionContext = (beanFactory != null)
? new BeanExpressionContext(beanFactory, null) : null;
if (resolver == null) {
resolver = new StandardBeanExpressionResolver();
}
boolean result = (Boolean) resolver.evaluate(expression, expressionContext);
StringBuilder message = new StringBuilder("SpEL expression");
if (metadata instanceof ClassMetadata) {
message.append(" on " + ((ClassMetadata) metadata).getClassName());
}
message.append(": " + rawExpression);
return new ConditionOutcome(result, message.toString());
}
}