I have requirement to implement like my Kafka whenever restart it should read from offset where it was stopped, i could see ConsumerSeekAware interface and AbstarctConsumerSeekAware interface, But I am exactly need to know how can I implement, what methods are require to achieve this? It would be really helpful if any realtime samples snippets are available
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Suppose I have some third party library and I want to integrate it with Spring in order to be able to use it as a part of Spring transaction. I didn't find any relevant information on the Internet and looked into the source code of integrations of RabbitMQ and MyBatis libraries. As I understood from their source code I should implement org.springframework.transaction.PlatformTransactionManager and interact with TransactionSynchronizationManager. And there are two questions:
How Spring "know" about and instanciate implementations of PlatformTransactionManager?
Suppose there are two resources been used in transaction through RabbitTemplate and
JdbcTemplate. What will be first committed - changes in database or
messages sent?
Also, I would be really appreciate if somebody point me out to some guide or book about interactions with Spring internals.
You have to instantiate them yourself, like a DataSourceTransactionManager or a HibernateTransactionManager. Spring Boot does that for you under the hood, but with plain Spring you need to do it yourself.
What you want are distributed transactions (XADataSource), which are not possible with RabbitMQ.
For RabbitMQ you should read this here first: https://www.rabbitmq.com/confirms.html . Then make sure you understand transactions on the JDBC side. Then you can reason about how they both work together.
For the Java side, you might enjoy this book entirely about transactions: https://www.marcobehler.com/books/1-java-database-connections-transactions
I'm very new to Spring Integration DSL and I need to add retrial with recovery to the existing IntegrationFlow. It takes data from Jms.messageDriverChannelAdapter and send it through different channels. I want to add RequestHandlerRetryAdvice for the whole flow.
My idea was to add it to the adapter, but it seems to support only ErrorChannel, without Advices & Retries and such. I've ended up wrapping the whole flow after Jms.messageDriverChannelAdapter in a .gateway with advice and .requireReply(false). It feels like a hack, but I couldn't find a better way to do it. Is there any better way to deal with such situation?
Unlike Spring AMQP's listener container a JMS one doesn't provide a hook to inject Advice chain into it, so, we really don't have choice and workaround it somehow. The RequestHandlerRetryAdvice and a .gateway() DSL is not so bad idea to go. The point is that a RequestHandlerRetryAdvice is applied only for the particular handleRequestMessage() method and is not propagated downstream. Having the flow wrapped into the gateway call from the mentioned handleRequestMessage() is the way to go.
I think we can come up with the solution on the JmsMessageDrivenEndpoint to wrap an internal listener with injected Advice chain, where one of them might be a RetryOperationsInterceptor.
Please, raise a GH issue and we'll think what we can do.
Does anyone know hot to use Apache AVRO RPC with Spring boot? Every single AVRO implementation I have seen is hosted on a netty server.
You might be trying to achieve the same thing I'm trying to achieve -- speeding up json serialization with spring boot and spring web. Or maybe you just want to use avro? And my comment is a little late, since it's months after you posted. I have run across this information about using an avro message converter, so thought I would share it with you to see if it helps:
https://docs.spring.io/spring-cloud-stream/docs/Brooklyn.RELEASE/reference/html/contenttypemanagement.html#_schema_based_message_converters
Or did you already find it? If so, can you share whatever solution that you came up with? Our rest json serialization takes much longer than the whole rest of the operation and I would like to speed it up as much as possible.
I have too many emails. I should write scheduler in order to send messages to them. Messages are different. I use spring framework 4.x.
I can write simple class, which connects to SMTP server. But in this case I should write my thread library too in order to send emails parallel.
Do spring have already written library which give me more flexible way to do this tasks? I do not want to use threads. It will be nice if spring already have this functionality.
Do I need Spring integration for this?
Best regards,
Yes, you definitely can do that with Spring Integration, because there is an ExecutorChannel implementation with can be supplied with an TaskExecutor from the Spring Core:
<channel id="sendEmailChannel">
<dispatcher task-executor="threadPoolTaskExecutor"/>
</channel>
<int-mail:outbound-channel-adapter channel="sendEmailChannel" mail-sender="mailSender"/>
But anyway you should keep in mind that all Spring Integration components are based on the Java and that ExecutorService is used on the background.
From other side if you need only the mail sending stuff from the Spring Integration, it would be an overhead and can simply use Core Spring Framework legacy like JavaMailSender as a bean and #Async for the sendMail method to achieve your parallel requirement.
UPDATE
could you tell me whether I need JMS for this situation?
I don't see any JMS-related stuff here. You don't have (or at least don't show) any real integration points in your solution. The same I can say even about Spring Integration just for email sending. However with the Spring Boot your SI config will be enough short. From other side if you'll study Spring Integration better eventually you'll get more gain to rely on the Integration components for your systems, as internally, as well as externally with other systems through JMS, AMQP, Kafka etc.
To be honest: a lot of years ago my first acquaintance with Spring Integration was due the requirement to get files from the FTP and have ability to pick up new files automatically. I found the solution only in the Spring Integration 1.0.0.M1. After that short XML config for the <int-ftp:inbound-channel-adapter> I loved Spring Integration and since that time it became as a part of my life. :-)
So, it's up to you to go ahead with Spring Integration in your simple app, or just follow with more formal solution with JavaMailSender direct usage.
You should use java executors framework. For example you can write something like the code below:
ExecutorService executor = Executors.newWorkStealingPool();
executor.execute(() -> mailSender.send(mail));
We have a spring boot application that is growing in complexity because of integration needs - like send an email after you do this, or broadcast a jms message after you that etc. In looking for some higher level abstractions, I came across apache camel (haven't used camel ever before). The question that I have is what do I do with the spring boot application? The application has the standard spring controllers, services and uses spring-data for connecting to databases. I didn't find much help online on how to merge camel into a spring-boot restful application. Is that even something that is doable or is camel a completely different beast that the spring boot won't fit?
I did read that Camel tightly integrates with Spring, but still I didn't know if 1) Spring Controllers are still something that can be used along with Camel 2) If I can call the other spring beans from camel routes and whether I can call invoke a camel route from a spring bean (sorry if these sound like camel newbie questions to the experts)
As an example of what we have to do:
After finishing writing anything to the database about an order, we have to send an email out to the order processing department
If someone deletes a particular user address, we have to send to a jms topic so other applications can take action.
Every http request is coming in through the Spring MVC stack today.
Is there a way to "hand-off" the processing to camel after a particular task is complete? (like writing the order to the database successfully via the Spring MVC stack and hand off to camel to send a jms message and do other things)? Or should we completely replace Spring with Camel?
Not sure what the right path is. Can someone please guide us?
This question is slightly old, but though it was worth mentioning here that Apache Camel now includes a Spring Boot component.
Details can be found here
http://camel.apache.org/spring-boot.html
and they document an example here
http://camel.apache.org/spring-boot-example.html
Follow this for the current best practice in camelising a spring boot application!
One option is to
1> define camel routes either in Spring DSL or Java DSL or other means and define it in Spring Application context.
2> And have a class that implements ApplicationContextAware and cache the Spring ApplicationContext in a Static Variable.
3> For #Controller we can get this static variable and get hold of ApplicationContext .
4> With the camel context ID we can do a getBean from ApplicationContext.
5> This is the instance of DefaultCamelContext,with this we can do a createProducer and call camel routes from #Controller.
Like some others mentioned, spring-boot-camel (but use spring-boot-camel-starter as your dependency) works very well and it is really easy to set up. When you annotate your RouteBuilder extensions and your Processor implementations with #Component, they wire up directly into the context and you are good to go. Then, you can #Autowire a CamelContext or a ProducerTemplate into your classes and use them as necessary.
You asked about how Controllers can work with Camel, and if you #Autowire any of the things you need (probably a context or a producer template), then the answer is a definite "yes" that you can use them together quite easily. And when you use spring-web, your context will start and remain running without any additional configuration, etc.
Like Matthew Wells suggested, the links will get you pointed in the right direction. If you, or others on your team, are at all familiar with Camel, then it will be very easy for you to do what you need to do. But, ah, I notice that this question is from 2014, and you're probably well past the point of your question. At least if anyone else stops by this thread, they will have plenty of information to get going. If you come by and re-visit your question, please let us know how it went for you, and what you ended up doing. Cheers!