Pattern 35 (Pre-Do)
The ability for a resource to execute a work item ahead of the time that it has been offered or allocated to resources working on a given case. Only work items that do not depend on data elements from preceding work items can be "pre-done".
The Inspector has completed the Charge Suspect work item even though the preceding Interview Witness work items have not yet been completed.
The Pre-Do pattern provides resources with the ability to complete work items in a case ahead of the time that they are required to be executed i.e. prior to them being offered or allocated to resources working on the case. The motivation for this being that overall throughput of the case may be expedited by completing work items as soon as possible regardless of the order in which they appear in the actual process specification.
The Pre-Do pattern effectively provides a means of completing the work items in a case in a user-selected sequence. There are difficulties associated with doing this where later work items rely on data elements from earlier work items hence the pattern is not a common PAIS feature, however for situations where all of the work items in a case are allocated to the same user and there is less data coupling or the implications of shared data can be managed by resources (e.g. in a case handling system), the problem is more tractable. This pattern is not illustrated in Figure 6.
There is one context condition associated with this pattern: any shared data elements (i.e. block, scope, case data etc.) must be created at the beginning of the case.
Of the offerings examined, only FLOWer provides the ability to pre-do a work item.
One consideration associated with pre-doing work items is the fact that outcomes of preceding work items that are executed after the time at which the "pre-done" work item is completed may result in the "pre-done" work item being repeatedly re-executed.
There is no immediate solution to this problem other than careful selection of work items that are to be done in advance. As a general rule, work items that are to be "pre-done" should not be dependent on data elements that are shared with preceding work items or the outcome of these work items.
Full support for this pattern is demonstrated by any offering which provides a construct which satisfies the description when used in a context satisfying the context assumption.
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|
|FLOWer||3.0||+||Users can undertaken a work item ahead of the wavefront|
|Oracle BPEL||10.1.2||-||Oracle BPEL PM offers no support for this pattern|
|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