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Bug 364185

Summary:

Differences of behavior when getting the first element of an empty sequence and an ordered set.

Product:

[Modeling] MMT.ATL

Reporter:

Dominique Blouin <dominique.blouin>

Component:

emfvm

Assignee:

mmt-atl.toolkit-inbox <mmt-atl.toolkit-inbox>

Status:

NEW ---

QA Contact:

Severity:

normal

Priority:

Version:

unspecified

Target Milestone:

---

Hardware:

OS:

Windows XP

Whiteboard:

Attachments:

Description	Flags
Source code of the modified class.	none

Description Dominique Blouin

2011-11-18 12:56:20 EST

Created attachment 207234 [details]
Source code of the modified class.

There is a discrepancy in the behavior of getting the first element of an empty ordered set and a sequence. When the collection is a sequence, getting the first element of the sequence returns null. When it is an ordered set, a no such element exception is thrown. On the other hand, getting the last element of an empty ordered set returns null. For the regular vm, null is returned for all these cases.

This can be fixed by modifying the ExecEnv class by changing the implementation of the registered ordered set first operation. The class is attached.