Pattern 22 (Resource-Initiated Execution - Allocated Work Item)
The ability for a resource to commence work on a work item that is allocated to it.
The Courier Driver selects the next Delivery work item which is allocated to it and commences work on it.
Where a resource has work items that it has committed to execute, but has not yet commenced, a means of signalling their commencement is required. This pattern fulfils that requirement.
This pattern corresponds to the R:start transition illustrated in Figure 5. It results in the status of the selected work item being changed from allocated to started. It remains in the same work list.
There are no specific context conditions associated with this pattern.
The general means of handling that a work item has been allocated to a resource is to place it on a resource-specific work queue. This ensures that the work item is not undertaken by another resource and that the commitment made by the resource to which it is allocated is maintained. Staffware, WebSphere MQ, FLOWer, COSA and Oracle BPEL all support the concept of resource-specific work queues and provide mechanisms in the work list handlers for resources to indicate that an allocated work item has been commenced.
An offering achieves full support if it satisfies the description for 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.
|Staffware||9||+||Directly supported as a standard consequence of starting an item on a work queue|
|Websphere MQ Workflow||3.4||+||Standard means for a resource to initiate a work item is to select one from those allocated to it|
|COSA||4||+||Resources ca initiate allocated work items from their work queues|
|Oracle BPEL||10.1.2||+||In Oracle BPEL PM resources are able to commence the execution of a work item available at their own worklists at a time of their own choosing, but before the task has expired. Therefore this pattern is supported directly.|
|jBPM||3.1.4||+||In jBPM, a work item that is allocated to a resource can be started by the resource selecting the work item from their work list.|
|OpenWFE||1.7.3||-||OpenWFE does not support this pattern.|
|Enhydra Shark||2||-||Enhydra Shark does not support this pattern. In order to be initiated a work item first needs to be allocated, a state which does not exist in Enhydra Shark.|
Summary of Evaluation