/*
 * Copyright 2002-2018 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.
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package org.springframework.context.event;

import java.lang.reflect.Method;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.expression.AnnotatedElementKey;
import org.springframework.context.expression.BeanFactoryResolver;
import org.springframework.context.expression.CachedExpressionEvaluator;
import org.springframework.context.expression.MethodBasedEvaluationContext;
import org.springframework.expression.Expression;
import org.springframework.lang.Nullable;

Utility class handling the SpEL expression parsing. Meant to be used as a reusable, thread-safe component.
Author:Stephane Nicoll
See Also:
Since:4.2
/** * 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 { private final Map<ExpressionKey, Expression> conditionCache = new ConcurrentHashMap<>(64);
Specify if the condition defined by the specified expression matches.
/** * Specify if the condition defined by the specified expression matches. */
public boolean condition(String conditionExpression, ApplicationEvent event, Method targetMethod, AnnotatedElementKey methodKey, Object[] args, @Nullable BeanFactory beanFactory) { EventExpressionRootObject root = new EventExpressionRootObject(event, args); MethodBasedEvaluationContext evaluationContext = new MethodBasedEvaluationContext( root, targetMethod, args, getParameterNameDiscoverer()); if (beanFactory != null) { evaluationContext.setBeanResolver(new BeanFactoryResolver(beanFactory)); } return (Boolean.TRUE.equals(getExpression(this.conditionCache, methodKey, conditionExpression).getValue( evaluationContext, Boolean.class))); } }