org.springframework.integration.util.AbstractExpressionEvaluator Maven / Gradle / Ivy
/*
* Copyright 2002-2019 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
*
* https://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.integration.util;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.expression.BeanFactoryResolver;
import org.springframework.core.convert.ConversionService;
import org.springframework.expression.EvaluationException;
import org.springframework.expression.Expression;
import org.springframework.expression.ExpressionParser;
import org.springframework.expression.spel.standard.SpelExpressionParser;
import org.springframework.expression.spel.support.StandardEvaluationContext;
import org.springframework.integration.expression.ExpressionUtils;
import org.springframework.integration.support.DefaultMessageBuilderFactory;
import org.springframework.integration.support.MessageBuilderFactory;
import org.springframework.integration.support.utils.IntegrationUtils;
import org.springframework.lang.Nullable;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHandlingException;
/**
* @author Mark Fisher
* @author Dave Syer
* @author Oleg Zhurakousky
* @author Artem Bilan
* @author Gary Russell
*
* @since 2.0
*/
public abstract class AbstractExpressionEvaluator implements BeanFactoryAware, InitializingBean {
protected final Log logger = LogFactory.getLog(this.getClass());
protected static final ExpressionParser EXPRESSION_PARSER = new SpelExpressionParser();
private final BeanFactoryTypeConverter typeConverter = new BeanFactoryTypeConverter();
private volatile StandardEvaluationContext evaluationContext;
private volatile BeanFactory beanFactory;
private volatile MessageBuilderFactory messageBuilderFactory = new DefaultMessageBuilderFactory();
/**
* Specify a BeanFactory in order to enable resolution via @beanName in the expression.
*/
@Override
public void setBeanFactory(final @Nullable BeanFactory beanFactory) {
if (beanFactory != null) {
this.beanFactory = beanFactory;
this.typeConverter.setBeanFactory(beanFactory);
if (this.evaluationContext != null && this.evaluationContext.getBeanResolver() == null) {
this.evaluationContext.setBeanResolver(new BeanFactoryResolver(beanFactory));
}
}
}
protected BeanFactory getBeanFactory() {
return this.beanFactory;
}
public void setConversionService(ConversionService conversionService) {
if (conversionService != null) {
this.typeConverter.setConversionService(conversionService);
}
}
protected MessageBuilderFactory getMessageBuilderFactory() {
return this.messageBuilderFactory;
}
@Override
public final void afterPropertiesSet() throws Exception {
getEvaluationContext();
if (this.beanFactory != null) {
this.messageBuilderFactory = IntegrationUtils.getMessageBuilderFactory(this.beanFactory);
}
onInit();
}
protected StandardEvaluationContext getEvaluationContext() {
return this.getEvaluationContext(true);
}
/**
* Emits a WARN log if the beanFactory field is null, unless the argument is false.
* @param beanFactoryRequired set to false to suppress the warning.
* @return The evaluation context.
*/
protected final StandardEvaluationContext getEvaluationContext(boolean beanFactoryRequired) {
if (this.evaluationContext == null) {
if (this.beanFactory == null && !beanFactoryRequired) {
this.evaluationContext = ExpressionUtils.createStandardEvaluationContext();
}
else {
this.evaluationContext = ExpressionUtils.createStandardEvaluationContext(this.beanFactory);
}
this.evaluationContext.setTypeConverter(this.typeConverter);
if (this.beanFactory != null) {
ConversionService conversionService = IntegrationUtils.getConversionService(this.beanFactory);
if (conversionService != null) {
this.typeConverter.setConversionService(conversionService);
}
}
}
return this.evaluationContext;
}
protected T evaluateExpression(Expression expression, Message message, Class expectedType) {
try {
return evaluateExpression(expression, (Object) message, expectedType);
}
catch (EvaluationException e) {
Throwable cause = e.getCause();
if (this.logger.isDebugEnabled()) {
this.logger.debug("SpEL Expression evaluation failed with EvaluationException.", e);
}
throw new MessageHandlingException(message, "Expression evaluation failed: "
+ expression.getExpressionString(), cause == null ? e : cause);
}
catch (Exception e) {
if (this.logger.isDebugEnabled()) {
this.logger.debug("SpEL Expression evaluation failed with Exception." + e);
}
throw new MessageHandlingException(message, "Expression evaluation failed: "
+ expression.getExpressionString(), e);
}
}
protected Object evaluateExpression(String expression, Object input) {
return this.evaluateExpression(expression, input, null);
}
protected T evaluateExpression(String expression, Object input, Class expectedType) {
return EXPRESSION_PARSER.parseExpression(expression)
.getValue(this.getEvaluationContext(), input, expectedType);
}
protected Object evaluateExpression(Expression expression, Object input) {
return this.evaluateExpression(expression, input, null);
}
protected T evaluateExpression(Expression expression, Class expectedType) {
return expression.getValue(this.getEvaluationContext(), expectedType);
}
protected Object evaluateExpression(Expression expression) {
return expression.getValue(this.getEvaluationContext());
}
protected T evaluateExpression(Expression expression, Object input, Class expectedType) {
return expression.getValue(this.getEvaluationContext(), input, expectedType);
}
protected void onInit() {
}
}