Question

Suppose that I have an application using ibatis 2 and spring 1. I have an external class that calls the dao method. What will happen if the following code is run:

// external class

public void doSomething() {
    try {
        daoLayer.startTransaction();
        daoLayer.firstOperation();
        daoLayer.secondOperation();
    } finally {
        daoLayer.endTransaction();
    }
}

// dao layer which extends from org.springframework.orm.ibatis.support.SqlMapClientDaoSupport.SqlMapClientDaoSupport

public void startTransaction() { sqlMap.startTransaction(); }
public void firstOperation() { sqlMap.update("someQuery"); }
public void secondOperation() { sqlMap.update("someOtherQuery"); }
public void endTransaction() { sqlMap.endTransaction(); }

1. Will this code cause database connections to be leaked?
2. Will end transaction be run on the same transaction/db connection which executed the startTransaction, firstOperation, and secondOperation methods? Or might dbcp/ibatis pick a different connection out of the pool?
3. What could I do to test and make sure that the same connection is used for all the operations and that the transaction is working correctly?
4. (Added via Edit) – Would anything change if I moved all my logic into a single method in the dao? Would that be more transaction safe?

Answer 1

Will this code cause database connections to be leaked?

No. but to commit data, you need to include sqlMap.commitTransaction() after daoLayer.secondOperation().

Will end transaction be run on the same transaction/db connection which executed the startTransaction, firstOperation, and secondOperation methods? Or might dbcp/ibatis pick a different connection out of the pool?

Yes .. if are opening a transaction you need to close it otherwise database server doesn’t close the transaction and it will be expired as per server settings.

What could I do to test and make sure that the same connection is used for all the operations and that the transaction is working correctly?

In java: check logs for connection id. You can also check database server for assigned connection id.

Would anything change if I moved all my logic into a single method in the dao? Would that be more transaction safe?

No matter, if you have a single or multiple DAO operations in a single transaction.