org.springframework.context.event.EventExpressionEvaluator Maven / Gradle / Ivy
/*
* Copyright 2002-2015 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.context.event;
import java.lang.reflect.Method;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.springframework.aop.support.AopUtils;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.expression.AnnotatedElementKey;
import org.springframework.context.expression.CachedExpressionEvaluator;
import org.springframework.context.expression.MethodBasedEvaluationContext;
import org.springframework.core.DefaultParameterNameDiscoverer;
import org.springframework.core.ParameterNameDiscoverer;
import org.springframework.expression.EvaluationContext;
import org.springframework.expression.Expression;
/**
* Utility class handling the SpEL expression parsing. Meant to be used
* as a reusable, thread-safe component.
*
* @author Stephane Nicoll
* @since 4.2
* @see CachedExpressionEvaluator
*/
class EventExpressionEvaluator extends CachedExpressionEvaluator {
// shared param discoverer since it caches data internally
private final ParameterNameDiscoverer paramNameDiscoverer = new DefaultParameterNameDiscoverer();
private final Map conditionCache = new ConcurrentHashMap(64);
private final Map targetMethodCache = new ConcurrentHashMap(64);
/**
* Create the suitable {@link EvaluationContext} for the specified event handling
* on the specified method.
*/
public EvaluationContext createEvaluationContext(ApplicationEvent event, Class targetClass,
Method method, Object[] args) {
Method targetMethod = getTargetMethod(targetClass, method);
EventExpressionRootObject root = new EventExpressionRootObject(event, args);
return new MethodBasedEvaluationContext(root, targetMethod, args, this.paramNameDiscoverer);
}
/**
* Specify if the condition defined by the specified expression matches.
*/
public boolean condition(String conditionExpression,
AnnotatedElementKey elementKey, EvaluationContext evalContext) {
return getExpression(this.conditionCache, elementKey, conditionExpression)
.getValue(evalContext, boolean.class);
}
private Method getTargetMethod(Class targetClass, Method method) {
AnnotatedElementKey methodKey = new AnnotatedElementKey(method, targetClass);
Method targetMethod = this.targetMethodCache.get(methodKey);
if (targetMethod == null) {
targetMethod = AopUtils.getMostSpecificMethod(method, targetClass);
if (targetMethod == null) {
targetMethod = method;
}
this.targetMethodCache.put(methodKey, targetMethod);
}
return targetMethod;
}
}