Using Groovy Closures To Simplify Working With Alfresco Transactions

If you are familiar with Alfresco transactions than you will be familiar with the following:
  
Boolean result = transactionService.getRetryingTransactionHelper().doInTransaction(new RetryingTransactionHelper.RetryingTransactionCallback<Boolean>() {
            public Boolean execute() throws Throwable {
                //Your code
                return true;
            }
}, false, true);
This is quite a bit of code and gets ugly if you start embedding a bunch of code inside this block. It is also not very testable with out some crazy mocking.


Groovy Closures to the rescue. http://groovy.codehaus.org/Closures
I created a simple TransactionHelper Groovy class with a method that takes a closure and wraps the closure inside of the above code required for a transaction and wired it as a Spring Bean.

import org.alfresco.repo.transaction.RetryingTransactionHelper
import org.alfresco.service.transaction.TransactionService
class TransactionHelper {
    private TransactionService transactionService
    def executeInSperarateTransaction(closure) {
        Boolean result = transactionService.getRetryingTransactionHelper().doInTransaction(new RetryingTransactionHelper.RetryingTransactionCallback<Boolean>() {
            public Boolean execute() throws Throwable {
                closure()
                return true
            }
        }, false, true)
    }
    void setTransactionService(TransactionService transactionService) {
        this.transactionService = transactionService
    }
}

Now if I need to execute a transaction I can simply do the following.
transactionHelper.executeInSperarateTransaction({ nodeService.addAspect(nodeRef, MyModel.THUMBNAIL_ASPECT, new HashMap<QName, Serializable>())})

You can simply pass a closure statement like above or pass in a closure like the following.

def closure() {
  def localVariable = new java.util.Date()
  return { println localVariable }
}
transactionHelper.executeInSeperateTransaction(closure)
 

For more information on Groovy and Closures see http://groovy.codehaus.org/Closures