Dear all,
this discussion thread is intended to finalize the job sub-state
discussion from the last phone conference.
Quoting from the DRMAA2 Draft2:
"The jobStatus() method SHALL return the job status, together with an
implementation specific sub state. This is intended to be a more
detailed description of the current DRMAA job state, for example the
specific kind of HOLD state (user-triggered, system-triggered). It
MUST be allowed by the language binding to not retrieve this
information (e.g. by passing a NULL value). Applications SHOULD NOT
expect this information to be available in all cases."
Daniel T. did a great job in summarizing the current discussion
status, which is about the data type for this sub-state information.
We have three alternatives: integer, string, or untyped struct /
object pointer. All three constructs are expressible in IDL.
Strings require string comparison, which is only natural in scripting
languages.
Integers might look inappropriate if the language supports native
enumerations.
In all three cases, the returned information must be interpreted
according to DRM-specific information (header file / type definition).
This normally leads to a build dependency, e.g. in the form of DRM-
specific string constants, numerical constants, or type definitions.
In all three cases, moving a binary DRMAA application with sub-state
usage to another DRM brings up a problem. With pointers, the
application is likely to crash (ClassCastException, SEGFAULT). With
integers, the application will perform wrong, since a wrong numerical
match occurs. With a string, no match will occur in most cases, so the
application will at least behave differently.
Last remark: For implementation-specific JT attributes, we have a
lengthly discussion in the document of how to deal with DRM-specific
data types (introspection, late binding). This can be counted as
consistency argument for the object pointer approach.
/Peter.
