Pattern 20 (Late Distribution)
The ability to advertise and distribute work items to resources after the task to which the work item corresponds has been enabled for execution.
The Service Car work item is allocated to a Mechanic after the car has been delivered for repair and the mechanic has less than 5 items in their worklist.
Late Distribution of work items effectively provides a means of "demand driving" a process by only advertising or allocating work items to resources after the tasks to which they correspond have already been enabled for execution. This could potentially be much later than the time the tasks were enabled. By adopting this approach, it is possible to reduce the current volume of work in progress within a process instance. Often this strategy is undertaken with the aim of preventing resources from becoming overwhelmed by the apparent workload even though they may not be required to undertake all of it themselves.
Where a task is identified as being subject to Late Distribution, the enablement of the task does not necessarily result in the associated work items being distributed to resources for execution. Generally other factors are taken into consideration (e.g. number of active work items, available resources etc.) before the decision is made to advise resources of its existence. This approach to work distribution provides the system with flexibility in determining when work items are made available for execution and offers the potential to reduce context switching when resources have multiple work items that they are attempting to deal with. This approach to work distribution is often used in conjunction with "heads down" processing where the focus is on maximising work throughput and the distribution of work is largely under the auspices of the system. At the other end of the spectrum to this approach is Case Handling where the distribution and management of work is largely at the discretion of individual resources.
There are no specific context conditions associated with this pattern.
None of the offerings examined support the notion of Late Distribution for newly created work items. However, a similar notion is used by some PAIS for redeploying work items that have been allocated to resources or possibly have even commenced execution. COSA supports manual rerouting of work items by workflow users. WebSphere MQ provides an API for rerouting of work items. By doing this, the resources to which they are ultimately allocated are unaware of their existence until they are placed in their worklist.
An offering achieves full support if it satisfies the description of the pattern.
To achieve a + rating (direct support) or a +/- rating (partial support) the product should satisfy the corresponding evaluation criterion of the pattern. Otherwise a - rating (no support) is assigned.
|Websphere MQ Workflow||3.4||-||Not supported|
|Oracle BPEL||10.1.2||-||Oracle BPEL PM does not support this pattern since by any work item requires to have an assignee. Since the work item has to be allocated or offered to a user/role from the moment of creation, the late distribution is not possible|
|jBPM||3.1.4||-||jBPM does not support this pattern.|
|OpenWFE||1.7.3||-||OpenWFE does not support this pattern.|
|Enhydra Shark||2||-||Enhydra Shark does not support this pattern.|
Summary of Evaluation