Spring Integration Email Redelivery on Exception - email

Question

I have a web service that via a GET Http method, the user requests for a person object. This person is sent to a JMS Queue and then with the help of Spring Integration, I send it to a fake email address (https://papercut.codeplex.com/). I have written the code with Spring Integration Java DSL. I would like to ask:
Is there a more flexible way to send the email message?
If an exception is thrown, how can the mail be redelivered with the help of Spring Integration? (e.g. for 5 times and if it is not sent then the exception gets handled and the program stops)
Here is my code:
Web Service
public Person findById(Integer id) {
Person person = jpaPersonRepository.findOne(id);
jmsTemplate.convertAndSend("testQueue", person);
return jpaPersonRepository.findOne(id);
}
Java Confiuration
#Configuration
#EnableIntegration
#ComponentScan
public class JavaConfig {
private static final String DEFAULT_BROKER_URL = "tcp://localhost:61616";
private static final String DEFAULT_QUEUE = "testQueue";
#Bean
public ActiveMQConnectionFactory connectionFactory() {
ActiveMQConnectionFactory connectionFactory = new ActiveMQConnectionFactory();
connectionFactory.setBrokerURL(DEFAULT_BROKER_URL);
return connectionFactory;
}
#Bean
public JmsTemplate jmsTemplate() {
JmsTemplate template = new JmsTemplate();
template.setConnectionFactory(this.connectionFactory());
template.setDefaultDestinationName(DEFAULT_QUEUE);
return template;
}
#Bean
public DefaultMessageListenerContainer defaultMessageListenerContainer() {
DefaultMessageListenerContainer defaultMessageListenerContainer = new DefaultMessageListenerContainer();
defaultMessageListenerContainer.setDestinationName(DEFAULT_QUEUE);
defaultMessageListenerContainer.setConnectionFactory(this.connectionFactory());
return defaultMessageListenerContainer;
}
#Bean(name="inputChannel")
public DirectChannel directChannel() {
return new DirectChannel();
}
#Bean
public IntegrationFlow orders() {
return IntegrationFlows
.from(Jms.messageDrivenChannelAdapter(defaultMessageListenerContainer()))
.transform(new ObjectToStringTransformer())
.enrichHeaders(p -> p.header(MailHeaders.TO, "Papercut0#test.com"))
.handle(Mail.outboundAdapter("127.0.0.1")
.credentials("test","test").port(25)
.javaMailProperties(p -> p.put("mail.debug", "true")),
e -> e.id("sendMailEndpoint"))
.get();
}
}

Answer 1

Is there a more flexible way to send the email message?
Sorry, the question isn't clear. You have enough short code to do that. Mail.outboundAdapter() and all its fluent API. What should be more flexible?
If an exception is thrown, how can the mail be redelivered with the help of Spring Integration?
For this purpose Spring Integration suggests RequestHandlerRetryAdvice. And Mail.outboundAdapter() can be configured with that as:
#Bean
public Advice retryAdvice() {
RequestHandlerRetryAdvice advice = new RequestHandlerRetryAdvice();
RetryTemplate retryTemplate = new RetryTemplate();
SimpleRetryPolicy retryPolicy = new SimpleRetryPolicy();
retryPolicy.setMaxAttempts(5);
retryTemplate.setRetryPolicy(retryPolicy);
advice.setRetryTemplate(retryTemplate);
advice.setRecoveryCallback(new ErrorMessageSendingRecoverer(emailErrorChannel()));
return advice;
}
...
.handle(Mail.outboundAdapter("127.0.0.1")
.credentials("test","test").port(25)
.javaMailProperties(p -> p.put("mail.debug", "true")),
e -> e.id("sendMailEndpoint")
.advice(retryAdvice())) // HERE IS THE TRICK!
See its JavaDocs and Reference Manual on the matter.