Bug 494946

Summary:	ChangeAttributeOperation does not differentiate between attribute with null value and not contained attribute.
Product:	[Tools] GEF	Reporter:	Alexander Nyßen <nyssen>
Component:	GEF Zest	Assignee:	gef-inbox <gef-inbox>
Status:	NEW ---	QA Contact:
Severity:	normal
Priority:	P3	CC:	matthias.wienand
Version:	0.2.0
Target Milestone:	---
Hardware:	All
OS:	All
Whiteboard:	low-hanging fruit

Description Alexander Nyßen

2016-05-30 13:46:58 EDT

When retrieving the old value of an attribute, ChangeAttributeOperation does not differentiate between an attribute that is not contained in the IAttributeStore (containsKey() == false) and one whose value is mapped to null. Therefore, it does not properly restore the initial situation upon undo. 

Further, ChangeAttributeValue always sets a property with null value, in case the given new value is null. Either we need a separate operation for the case that an attribute is to be removed, or this should be specifiable.

Comment 1 Alexander Nyßen

2016-05-31 02:46:09 EDT

We should rename ChangeAttributeOperation into SetAttributeOperation and augment it with an UnsetAttributeOperation.