A value of null should be allowed to make the APIs more flexible and forgiving. null will have the same meaning as Double.NaN: "no data available"
Done - r1322.
this was fixed for 1.1.2 but just never resolved.
Closing with no testing, since this wasn't put in our queue during the release in which it was fixed.
This bug was previously known as http://jira.rhq-project.org/browse/RHQ-769