Branch locking of job tickets to control concurrency

To control concurrent access problems, the job ticket service may employ branch locking features, that is, the capability to lock a job ticket at the branch level. The branch locking may be accomplished by one of several methods. The work flow controller may assign one or more specific processors to perform the tasks identified with the branch to be locked. Where more than one processor is authorized access to the same branch, the job ticket service may lock the branch when one of the authorized processors actually acquire the branch. The job ticket service may lock the branches by setting a lock/unlock flag for each branch. Processors accessing the job ticket may then review the lock/unlock flag status to determine if the branch may be accessed. In some circumstances, the job ticket service may allow access only to those branches that are unlocked. A processor that has completed a task defined by the branch may need to have the branch unlocked in order to modify the branch.