org.springframework.cache.interceptor.ExpressionEvaluator 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.cache.interceptor;
import java.lang.reflect.Method;
import java.util.Collection;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.springframework.aop.support.AopUtils;
import org.springframework.cache.Cache;
import org.springframework.context.expression.AnnotatedElementKey;
import org.springframework.context.expression.CachedExpressionEvaluator;
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.
*
* Performs internal caching for performance reasons
* using {@link AnnotatedElementKey}.
*
* @author Costin Leau
* @author Phillip Webb
* @author Sam Brannen
* @author Stephane Nicoll
* @since 3.1
*/
class ExpressionEvaluator extends CachedExpressionEvaluator {
/**
* Indicate that there is no result variable.
*/
public static final Object NO_RESULT = new Object();
/**
* Indicate that the result variable cannot be used at all.
*/
public static final Object RESULT_UNAVAILABLE = new Object();
/**
* The name of the variable holding the result object.
*/
public static final String RESULT_VARIABLE = "result";
// shared param discoverer since it caches data internally
private final ParameterNameDiscoverer paramNameDiscoverer = new DefaultParameterNameDiscoverer();
private final Map keyCache = new ConcurrentHashMap(64);
private final Map conditionCache = new ConcurrentHashMap(64);
private final Map unlessCache = new ConcurrentHashMap(64);
private final Map targetMethodCache =
new ConcurrentHashMap(64);
/**
* Create an {@link EvaluationContext} without a return value.
* @see #createEvaluationContext(Collection, Method, Object[], Object, Class, Object)
*/
public EvaluationContext createEvaluationContext(Collection caches,
Method method, Object[] args, Object target, Class targetClass) {
return createEvaluationContext(caches, method, args, target, targetClass, NO_RESULT);
}
/**
* Create an {@link EvaluationContext}.
* @param caches the current caches
* @param method the method
* @param args the method arguments
* @param target the target object
* @param targetClass the target class
* @param result the return value (can be {@code null}) or
* {@link #NO_RESULT} if there is no return at this time
* @return the evaluation context
*/
public EvaluationContext createEvaluationContext(Collection caches,
Method method, Object[] args, Object target, Class targetClass, Object result) {
CacheExpressionRootObject rootObject = new CacheExpressionRootObject(caches,
method, args, target, targetClass);
Method targetMethod = getTargetMethod(targetClass, method);
CacheEvaluationContext evaluationContext = new CacheEvaluationContext(rootObject,
targetMethod, args, this.paramNameDiscoverer);
if (result == RESULT_UNAVAILABLE) {
evaluationContext.addUnavailableVariable(RESULT_VARIABLE);
}
else if (result != NO_RESULT) {
evaluationContext.setVariable(RESULT_VARIABLE, result);
}
return evaluationContext;
}
public Object key(String keyExpression, AnnotatedElementKey methodKey, EvaluationContext evalContext) {
return getExpression(this.keyCache, methodKey, keyExpression).getValue(evalContext);
}
public boolean condition(String conditionExpression, AnnotatedElementKey methodKey, EvaluationContext evalContext) {
return getExpression(this.conditionCache, methodKey, conditionExpression).getValue(evalContext, boolean.class);
}
public boolean unless(String unlessExpression, AnnotatedElementKey methodKey, EvaluationContext evalContext) {
return getExpression(this.unlessCache, methodKey, unlessExpression).getValue(evalContext, boolean.class);
}
/**
* Clear all caches.
*/
void clear() {
this.keyCache.clear();
this.conditionCache.clear();
this.unlessCache.clear();
this.targetMethodCache.clear();
}
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;
}
}