Problem implementing declarative transactions

Question

I want to implement transaction control at the function level. What i want is something like this.

class MyService{

static transactional = false

@Transactional(readOnly = false, propagation = Propagation.REQUIRES_NEW)

public def saveCountry(){ Country co = new Country(name:'mycountry') co.save() createState()

}

@Transactional(readOnly = false, propagation = Propagation.REQUIRES_NEW)

public def createState(){ State state = new State(name:'state') state.save() throw new RuntimeException() } }

What i want is that createState() creates a new transaction independent of the saveCountry(),such that if createState() fails,

the country object already saved is not revoked. Though I ve given the annotations but they dont produce the desired effect. A single transaction is created here, and it is revoked when the exception is thrown.None of the object is saved.

Can anybody help

Answer 1

I would not recommend taking this approach. When you reach the createState() method, grails will attempt to use any open transactions before creating a new one if none are available.

Instead I would just use small transaction blocks that surround only the necessary grails code instead of trying to declare the methods transactional

http://www.grails.org/doc/1.3.x/ref/Domain%20Classes/withTransaction.html

for example I can have a block anywhere such as

State.withTransaction { status -> 
   //all the code in here has an explicit transaction   
}

This transaction either flushes or rolls back at the end of the block and the transaction has a reference to a spring object TransactionStatus. This gives you fine grain control on error handling. This will allow you to have large transactional blocks but still decide when and where transactions end.

I would change the code to

public def saveCountry() {
    Country.withTransaction { status ->
        Country co = new Country(name:'mycountry')
        co.save()
    }
    createState()
}

public def createState(){
    State.withTransaction { status ->
        State state = new State(name:'state')
        state.save()
        throw new Exception
    }  
}

In this case the country will be saved but the state's transaction will be rolled back