Template Inheritance

[BevanWeiss]

I think the current Template system could do with a minor enhancement.

The way that templates currently work is that unless one Template is nested within another Template (as a Template Instance) there is no way for two Templates to 'share' information (objects etc).

I think that it would be incredibly useful if it was possible to have a Template 'Inherit' from another Template.

This would add a new InheritTemplateId property to each Template, which would default to being NULL (matching the current behaviour).

The way that this would work is, the InheritTemplateId property can be set to reference an existing Template.  When this is done, the new Template (with the InheritTemplateId set) will have ALL of the objects from the referenced Template (just as though the Template was itself a Template Instance of the inherited Template).  However, it would also be possible to add new items to the new Template (to extend the original Inherited Template).

The use case for this feature is:

We currently end up creating numerous templates for very similar devices.  That is, for 'pumps' we will often have half a dozen different variants on a pump template, with large amounts of the points and graphics identical between the different variants (i.e. they will almost always all have a 'Running Feedback' and a 'Fault' indication, and a common symbol). But some pumps have seal monitoring (in which case they will have a seal failure alarm), some pumps have VSDs (in which case they will have speed feedback), some pumps will have current monitoring (in which case they will have current feedback), some will have local control (in which case they get Hand-Off-Auto type of feedback), some will have SCADA Manual control (in which case they get SCADA Auto, SCADA Manual, SCADA Manual Start, SCADA Manual Stop etc).  We currently have to duplicate huge amounts of objects between these templates, and manually keep them 'in synch'.

The Template Inheritance concept would reduce this manual effort, and allow for greater consistency within the systems.

[sbeadle]

Thank you.