BPEL provides two other loops: while and repeatUntil.
The while activity defines a loop that iterates while a Boolean expression at the top of the loop evaluates to true. If the expression initially evaluates to false, the loop does not run.
<while> <condition>$numberOfDrivers < 5</condition> <sequence> . . </sequence> </while>
The repeatUntil activity defines a loop that always runs at least once. The loop iterates until the Boolean expression at the bottom of the loop evaluates to true.
<repeatUntil> <sequence> . . </sequence> <condition>$numberOfDrivers = 5</condition> </repeatUntil>