CODEWITHSUNDEEP
javatransactions
Byju Veedu
Byju Veedu

Reputation: 1986

How to do distributed transaction in java involving jdbc,jms and webservices

I was asked the following question in an interview and couldn't answer that.

How do you include a jdbc operation,a web service call and a JMS operation into one single transaction. That means if one of them fails all has to be roll backed.

I have heard about two-phase commit protocol and oracl XA in case of database transactions involving multiple databases. But not sure whether the same can be used here.

Upvotes: 5

Views: 1615

Answers (5)

Siva Tumma
Siva Tumma

Reputation: 1701

To my mind, it looks like interviewer liked to understand your ability to think in terms of enterprise wide distribution. Few points:

  1. JDBC is used for Database connectivity
  2. WebService is probably a mechanism to send control command to a server from any client.
  3. JMS is mainly used for alerts of what is being happened in the system.

My guess is your interviewer might be having a typical scenario with him that they wish to suffice the following situation:

Data is on one tier ( cluster, or machine ) Clients may be any kind, mobile, app, ios, objective c, browser pay, etc. JMS is configured to listen to topics. Or is that he wishes he could do that.

Now probably the best approach is to write a JMS Subscriber which decides what to do in the onMessage() method. As an example, suppose a web service is initiated a payment request from client. This will initiate a JMS publisher to tell a DAO do the necessary internal connection to database and when transaction is in middle and when it finishes, one message will be published to subscriber. You will have full grain control of every step as that would be configured to be published through JMS. Though this is difficult to achieve, this could be your interviewer's expected approach from you. (This is Only my guess, and please note.)

Upvotes: 0

Uttesh Kumar
Uttesh Kumar

Reputation: 290

We had same situation like web service will push the data, we have to read the xml stream and persist to db(oracle). implementation we followed is.

  1. Web service send soap message and that will contain xml stream data.

  2. all request soap messages pushed to jms.

  3. respective listner will read the stream and persist the data into 'Temporary tables'.

  4. if request processed successfully then move data from temp table to actual table.

  5. if any error roll back.

    hope above points may help.

Upvotes: 0

Tim B
Tim B

Reputation: 41168

You are never going to be able to do this in a completely bomb-proof way as the systems are separate. A failure in one stage of the system (for example between the SQL commit and the JMS commit the power on your server gets turned off) will leave the SQL commit in place.

The only way to resolve that would be to keep some record of partial commits somewhere and scan that on startup to fix any resulting problems but now what happens if you have a failure processing or keeping that list.

Essentially the solution is to do your own implementation of the multiple-stage-commit and rollback process wrapping the three operations you need to make. If any of the operations fails then you need to reverse (preferably using an internal transaction mechanism, if not then by issuing reversing commands) any that have been done so far.

There are a lot of corner cases and potential ways for a system like this to fail though, so really the first approach should be to consider whether you can redesign the system so you don't need to do this at all!

Upvotes: 1

boucekv
boucekv

Reputation: 1230

It may be trick question and the right answer is "it can not be done".

But I would try to pseodo-code something like this:

try{
jdbc.startTransaction();
Savepoint saveJdbc = jdbc.setSavepoint();
JMS.startTransaction();
Savepoint saveJMS = JMS.setSavepoint();
jdbs.doSomeStuff();
JMS.doSomeStuff();
jdbc.commit();
JMS.commit(); 
if(webServise.doSomeStuff() == fail){throw new Exception();} 
}
catch(Eception e){
jdbc.rollback(saveJdbc);
JMS.rollback(saveJMS);
}

You prepare one servise that has roll back. You prepare second servise that has roll back. You will try web servise and if web servise fail you will roll back those two which have rollback.

May be it is a way to implement rollback to your web servise.

Upvotes: 0

stevedbrown
stevedbrown

Reputation: 8934

The critical factor is that the web services you connect to have been built using a web services framework that supports transactions. JBoss Narayana is one such web services framework. Once the web services endpoint you are connecting to is on such a framework, it's just a matter of configuring spring to use the appropriate client.

In the case of Narayana, the spring config (from http://bgshinhung.blogspot.ca/2012/10/integrating-spring-framework-jetty-and.html) for transactions with web services:

Upvotes: 5

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