T R A N S A C T I O N S  

   { 

As you see on the top to define the default transaction attribute is as simple as adding the 

XDoclet tag  ejb:transaction . Below you see how you can specify a transaction attribute for 

a specific method (which does not exists like this in the real example). 

Now to the more interesting part: the client. In this example there is only a remote Java 

client, which only differs from the web client in the way that the remote client needs a user 

transaction for remote clients. The code looks like this: 

InitialContext lContext = new InitialContext(); 

Object lObject = lContext.lookup( "ejb/bank/BankSession" ); 

BankSessionHome lBankHome = (BankSessionHome) 

   PortableRemoteObject.narrow( lObject, BankSessionHome.class ); 

BankSession lBankSession = lBankHome.create(); 

BankData lBank = lBankSession.createBank( "Test", "1234 Test Avenue, Test City" ); 

lObject = lContext.lookup( "ejb/bank/TellerSession" ); 

TellerSessionHome lTellerHome = (TellerSessionHome) 

   PortableRemoteObject.narrow( lObject, TellerSessionHome.class ); 

TellerSession lTeller = lTellerHome.create(); 

CustomerData lCustomerA = lTeller.createCustomer( lBank.getId(), "Andreas Schaefer", 100 ); 

AccountData lCheckingAccountA = lTeller.getAccount( lCustomerA.getId(), Constants.CHECKING 

); 

AccountData lSavingsAccountA = lTeller.createAccount( lCustomerA.getId(), Constants.SAVING, 

250 ); 

lTeller.transfer( lSavingsAccountA.getId(), lCheckingAccountA.getId(), 125 ); 

CustomerData lCustomerB =  lTeller.createCustomer( lBank.getId(), "Marc Fleury", 500 ); 

AccountData lCheckingAccountB =  lTeller.getAccount( lCustomerA.getId(), Constants.CHECKING 

); 

UserTransaction lTransaction = (UserTransaction) lContext.lookup( "UserTransaction" ); 

lTransaction.begin(); 

try { 

   lTeller.withdraw( lCheckingAccountA.getId(), 165 ); 

   lTeller.deposit( lCheckingAccountB.getId(), 165 ); 

   lTransaction.commit(); 

} 

catch( Exception e ) { 

   lTransaction.rollback(); 

} 

The client first creates a bank and look up for a Teller Session Bean. Then trough the teller 

it creates a customer and a second account, transfers money from one account to another. 

For this transfer there is no user transaction necessary because the transfer method creates 

it own transaction (attribute is set to  Required ). Now the Teller creates another customer 

and retrieves a user transaction because the withdrawal on one's customer's account and the 

deposit on the other's customer's account is not part of a transaction. But here the client 

wants to have the withdrawal and deposit either done completely or not done at all. 

Therefore the client starts the user transaction (lTransaction.begin()), makes the withdrawal 

and deposit and commits the transfer afterwards (lTransaction.commit()) if no exception is 

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