#296 convenience methods for PropertyType.NumericalFingerprint

[dim8]

We should implement convenience methods to set and get integer arrays or ArrayLists for the PopertyType NumericalFingerprint in StringProperty (such a for BinFingerprint). Furthermore, we should implement a lenght method.

Old Request

The type allows to be processed only as String, although in the description is said to be of the form int, int, .... While this may be only in terms of values' meaning, extending it to actual ints would be of use. Because by being parsed as String, any such value cannot really be used in a meaningful way, e.g. to cluster or plot it. Proof in action: Try to plot the EStateNumericalFingerprint descriptor's value.

[Till Schäfer]

The reason we do not store a actually a vector of integers is, that we need to store that data in a database column. Many databases do not even have such a type and you would need to map the vector to multiple rows, which makes such types a bit complex to handle properly. Furthermore, as long it is not absolutily necessary, we do not want to change the database layout in order to keep the database backward compatible.

However, I would appreaciate a conveinience methods in the class StringProperty, such as we have done for the BitFingerprint type. Thus, we can create the methods getNumericalFingerprint, setNumericalFingerprint and getNumericalFingerprintLength.

If you are actually working on a plugin or some other feature that uses the NumericalFingerprint type, please create such conveinice methods and create a seperate merge request. I will also keep the bug open for ourself. We could port the EStateNumericalFingerprinter to that methods.