org.springframework.integration.aggregator.DelegatingMessageGroupProcessor Maven / Gradle / Ivy
/*
* Copyright 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.aggregator;
import java.util.Map;
import java.util.function.Function;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.context.Lifecycle;
import org.springframework.integration.store.MessageGroup;
import org.springframework.integration.support.AbstractIntegrationMessageBuilder;
import org.springframework.integration.support.DefaultMessageBuilderFactory;
import org.springframework.integration.support.MessageBuilderFactory;
import org.springframework.integration.support.utils.IntegrationUtils;
import org.springframework.messaging.Message;
import org.springframework.util.Assert;
/**
* The {@link MessageGroupProcessor} implementation with delegation to the provided {@code delegate}
* and optional aggregation for headers.
*
* Unlike {@link AbstractAggregatingMessageGroupProcessor} this processor checks a result
* of the {@code delegate} call and aggregates headers into the output only
* if the result is not a {@link Message} or {@link AbstractIntegrationMessageBuilder}.
*
* This processor is used internally for wrapping provided non-standard {@link MessageGroupProcessor}
* when a aggregate headers {@link Function} is provided.
* For POJO method invoking or SpEL expression evaluation it is recommended to use an
* {@link AbstractAggregatingMessageGroupProcessor} implementations.
*
*
* @author Artem Bilan
*
* @since 5.2
*/
public class DelegatingMessageGroupProcessor implements MessageGroupProcessor, BeanFactoryAware, Lifecycle {
private final MessageGroupProcessor delegate;
private final Function> headersFunction;
private MessageBuilderFactory messageBuilderFactory = new DefaultMessageBuilderFactory();
private volatile boolean messageBuilderFactorySet;
private BeanFactory beanFactory;
public DelegatingMessageGroupProcessor(MessageGroupProcessor delegate,
Function> headersFunction) {
Assert.notNull(delegate, "'delegate' must not be null");
Assert.notNull(headersFunction, "'headersFunction' must not be null");
this.delegate = delegate;
this.headersFunction = headersFunction;
}
@Override
public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
this.beanFactory = beanFactory;
if (this.delegate instanceof BeanFactoryAware) {
((BeanFactoryAware) this.delegate).setBeanFactory(beanFactory);
}
}
@Override
public Object processMessageGroup(MessageGroup group) {
Object result = this.delegate.processMessageGroup(group);
if (!(result instanceof Message) && !(result instanceof AbstractIntegrationMessageBuilder)) {
result = getMessageBuilderFactory()
.withPayload(result)
.copyHeadersIfAbsent(this.headersFunction.apply(group));
}
return result;
}
private MessageBuilderFactory getMessageBuilderFactory() {
if (!this.messageBuilderFactorySet) {
if (this.beanFactory != null) {
this.messageBuilderFactory = IntegrationUtils.getMessageBuilderFactory(this.beanFactory);
}
this.messageBuilderFactorySet = true;
}
return this.messageBuilderFactory;
}
@Override
public void start() {
if (this.delegate instanceof Lifecycle) {
((Lifecycle) this.delegate).start();
}
}
@Override
public void stop() {
if (this.delegate instanceof Lifecycle) {
((Lifecycle) this.delegate).stop();
}
}
@Override
public boolean isRunning() {
return this.delegate instanceof Lifecycle && ((Lifecycle) this.delegate).isRunning();
}
}