def transferFunds() {
Account.withTransaction { status ->
def source = Account.get(params.from)
def dest = Account.get(params.to)
def amount = params.amount.toInteger()
if (source.active) {
if (dest.active) {
source.balance -= amount
dest.amount += amount
}
else {
status.setRollbackOnly()
}
}
}
}9 Programmatic Transactions
Version: 2023.3.0-SNAPSHOT
9 Programmatic Transactions
GORM’s transaction management is built on Spring and uses Spring’s Transaction abstraction for dealing with programmatic transactions.
However, GORM classes have been enhanced to make this simpler with the withTransaction(Closure) method. This method has a single parameter, a Closure, which has a single parameter which is a Spring TransactionStatus instance.
9.1 Using the withTransaction Method
Here’s an example of using withTransaction in a controller methods:
In this example we rollback the transaction if the destination account is not active.
Also, if an Exception (both checked or runtime exception) or Error is thrown during the process the transaction will automatically be rolled back..
GORM versions prior to 6.0.0 did not roll back transactions for a checked Exception.
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You can also use "save points" to rollback a transaction to a particular point in time if you don’t want to rollback the entire transaction. This can be achieved through the use of Spring’s SavePointManager interface.
The withTransaction method deals with the begin/commit/rollback logic for you within the scope of the block.
9.2 Using TransactionService
Since GORM 6.1, if you need more flexibility then instead you can instead take advantage of the TransactionService, which can be obtained by looking it up from from the HibernateDatastore:
import grails.gorm.transactions.*
TransactionService transactionService = datastore.getService(TransactionService)Or via dependency injection:
import grails.gorm.transactions.*
@Autowired TransactionService transactionServiceOnce you have an instance then there are various including withTransaction, withRollback, withNewTransaction etc. which helps with the construction of programmatic transactions.