org.springframework.kafka.config.MethodKafkaListenerEndpoint Maven / Gradle / Ivy
/*
* Copyright 2016-2017 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.kafka.config;
import java.lang.reflect.Method;
import java.util.Arrays;
import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.kafka.listener.KafkaListenerErrorHandler;
import org.springframework.kafka.listener.MessageListenerContainer;
import org.springframework.kafka.listener.adapter.BatchMessagingMessageListenerAdapter;
import org.springframework.kafka.listener.adapter.HandlerAdapter;
import org.springframework.kafka.listener.adapter.MessagingMessageListenerAdapter;
import org.springframework.kafka.listener.adapter.RecordMessagingMessageListenerAdapter;
import org.springframework.kafka.support.converter.BatchMessageConverter;
import org.springframework.kafka.support.converter.MessageConverter;
import org.springframework.kafka.support.converter.RecordMessageConverter;
import org.springframework.messaging.handler.annotation.SendTo;
import org.springframework.messaging.handler.annotation.support.MessageHandlerMethodFactory;
import org.springframework.messaging.handler.invocation.InvocableHandlerMethod;
import org.springframework.util.Assert;
/**
* A {@link KafkaListenerEndpoint} providing the method to invoke to process
* an incoming message for this endpoint.
*
* @param the key type.
* @param the value type.
*
* @author Stephane Nicoll
* @author Artem Bilan
* @author Gary Russell
* @author Venil Noronha
*/
public class MethodKafkaListenerEndpoint extends AbstractKafkaListenerEndpoint {
private Object bean;
private Method method;
private MessageHandlerMethodFactory messageHandlerMethodFactory;
private KafkaListenerErrorHandler errorHandler;
/**
* Set the object instance that should manage this endpoint.
* @param bean the target bean instance.
*/
public void setBean(Object bean) {
this.bean = bean;
}
public Object getBean() {
return this.bean;
}
/**
* Set the method to invoke to process a message managed by this endpoint.
* @param method the target method for the {@link #bean}.
*/
public void setMethod(Method method) {
this.method = method;
}
public Method getMethod() {
return this.method;
}
/**
* Set the {@link MessageHandlerMethodFactory} to use to build the
* {@link InvocableHandlerMethod} responsible to manage the invocation
* of this endpoint.
* @param messageHandlerMethodFactory the {@link MessageHandlerMethodFactory} instance.
*/
public void setMessageHandlerMethodFactory(MessageHandlerMethodFactory messageHandlerMethodFactory) {
this.messageHandlerMethodFactory = messageHandlerMethodFactory;
}
/**
* Set the {@link KafkaListenerErrorHandler} to invoke if the listener method
* throws an exception.
* @param errorHandler the error handler.
* @since 1.3
*/
public void setErrorHandler(KafkaListenerErrorHandler errorHandler) {
this.errorHandler = errorHandler;
}
private String getReplyTopic() {
Method method = getMethod();
if (method != null) {
SendTo ann = AnnotationUtils.getAnnotation(method, SendTo.class);
if (ann != null) {
String[] destinations = ann.value();
if (destinations.length > 1) {
throw new IllegalStateException("Invalid @" + SendTo.class.getSimpleName() + " annotation on '"
+ method + "' one destination must be set (got " + Arrays.toString(destinations) + ")");
}
return destinations.length == 1 ? resolve(destinations[0]) : "";
}
}
return null;
}
/**
* Return the {@link MessageHandlerMethodFactory}.
* @return the messageHandlerMethodFactory
*/
protected MessageHandlerMethodFactory getMessageHandlerMethodFactory() {
return this.messageHandlerMethodFactory;
}
@Override
protected MessagingMessageListenerAdapter createMessageListener(MessageListenerContainer container,
MessageConverter messageConverter) {
Assert.state(this.messageHandlerMethodFactory != null,
"Could not create message listener - MessageHandlerMethodFactory not set");
MessagingMessageListenerAdapter messageListener = createMessageListenerInstance(messageConverter);
messageListener.setHandlerMethod(configureListenerAdapter(messageListener));
String replyTopic = getReplyTopic();
if (replyTopic != null) {
Assert.state(getReplyTemplate() != null, "a KafkaTemplate is required to support replies");
messageListener.setReplyTopic(replyTopic);
}
if (getReplyTemplate() != null) {
messageListener.setReplyTemplate(getReplyTemplate());
}
return messageListener;
}
/**
* Create a {@link HandlerAdapter} for this listener adapter.
* @param messageListener the listener adapter.
* @return the handler adapter.
*/
protected HandlerAdapter configureListenerAdapter(MessagingMessageListenerAdapter messageListener) {
InvocableHandlerMethod invocableHandlerMethod =
this.messageHandlerMethodFactory.createInvocableHandlerMethod(getBean(), getMethod());
return new HandlerAdapter(invocableHandlerMethod);
}
/**
* Create an empty {@link MessagingMessageListenerAdapter} instance.
* @param messageConverter the converter (may be null).
* @return the {@link MessagingMessageListenerAdapter} instance.
*/
protected MessagingMessageListenerAdapter createMessageListenerInstance(MessageConverter messageConverter) {
MessagingMessageListenerAdapter listener;
if (isBatchListener()) {
BatchMessagingMessageListenerAdapter messageListener = new BatchMessagingMessageListenerAdapter(
this.bean, this.method, this.errorHandler);
if (messageConverter instanceof BatchMessageConverter) {
messageListener.setBatchMessageConverter((BatchMessageConverter) messageConverter);
}
listener = messageListener;
}
else {
RecordMessagingMessageListenerAdapter messageListener = new RecordMessagingMessageListenerAdapter(
this.bean, this.method, this.errorHandler);
if (messageConverter instanceof RecordMessageConverter) {
messageListener.setMessageConverter((RecordMessageConverter) messageConverter);
}
listener = messageListener;
}
if (getBeanResolver() != null) {
listener.setBeanResolver(getBeanResolver());
}
return listener;
}
private String resolve(String value) {
if (getResolver() != null) {
Object newValue = getResolver().evaluate(value, getBeanExpressionContext());
Assert.isInstanceOf(String.class, newValue, "Invalid @SendTo expression");
return (String) newValue;
}
else {
return value;
}
}
@Override
protected StringBuilder getEndpointDescription() {
return super.getEndpointDescription()
.append(" | bean='").append(this.bean).append("'")
.append(" | method='").append(this.method).append("'");
}
}