myGrid

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: None
• Fix Version/s: 2.0 essential
• Component/s: t2 maelstrom, Taverna Core, Taverna Data, Taverna Enactor
• Labels:

  None

Some services can genuinely return "null" in various ways, for instance a SOAP service can return:

<namesp1:pollResponse xmlns:namesp1="http://www.ebi.ac.uk/WSInterProScan">
    <result xsi:nil="true" xsi:type="xsd:base64Binary" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>
</namesp1:pollResponse>

and because of xsi:nil="true" it will by Axis be translated to "null".

Note that this is not necessarily a service failure, the service might even say xsi:nilable="true" in it's schema.

We don't have a way currently of representing this value in the workflow, Taverna 1's DataThing fails purposely on attempting to register nul In many ways null can be considered the same as an empty list of depth 0, at least the behaviour of such a list is probably what most workflow designers would expect, ie. that it was just skipped by iterations, etc.

In other ways a null value can be considered an error.

See TAV-651 for an example of a service that actually returns null.

• Assignee:

  Alan Williams

  Reporter:

  Stian Soiland-Reyes

• Created:

  2007-11-21 16:26

  Updated:

  2010-04-30 11:08