In business processes, it may be required to send multiple tasks to different human agents at the same time to expedite the progress of the overall process. When the number of parallel paths are known at development time this can easily be achieve using a split. However in some cases the number of paths will not be know until runtime. Such situations can be modeled using parallel activities.
A parallel activity acts as a wrapper around existing activities. The effect of using one of these new activities at runtime is that multiple instances of the wrapped activity are executed in parallel. To date, the only supported types of wrapped activity are Manual (Manual) and Decision (Decision) activities. Therefore, executing a parallel activity currently equates to the creation and allocation of multiple tasks in parallel.