ARROW-1361: [Java] Adding methods to get type param values in NullableValueVector

[BryanCutler]

Adding type param getters to NullableValueVectors as a convenience over getting the Field and casting the type to get the param values. These getters just call the inner vector FixedValueVectors which also contains these param values. Since NullableValueVectors does not use the param variables except during initialization they are removed here.

[BryanCutler]

cc @julienledem @siddharthteotia @icexelloss

[icexelloss]

This looks fine to me. We should probably add this too all vector templates:

• VariableLengthVectors.java
• FixedValueVectors.java
• NullableValueVetors.java

[wesm]

@icexelloss there has been some discussion about this in the JIRA: https://issues.apache.org/jira/browse/ARROW-1361

[siddharthteotia]

LGTM. However, we may want to revisit this once we start working on https://issues.apache.org/jira/browse/ARROW-1463

[BryanCutler]

Thanks @icexelloss and @siddharthteotia . Yes, I'll hold off on this for now.

[icexelloss]

Hey @BryanCutler seems like the changes here can be made on the new vectors now. Do you still want to add the methods?

[BryanCutler]

Yeah I've been meaning to look into this. It seems like not so much a requirement for me any more but I can still do it if you think it's a useful addition?

…

On Feb 2, 2018 9:21 AM, "Li Jin" ***@***.***> wrote: Hey @BryanCutler <https://github.com/bryancutler> seems like the changes here can be made on the new vectors now. Do you still want to add the methods? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#972 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AEUwdb_4mfHRweCO0XnZI-saa2qTO5nxks5tQzjAgaJpZM4O5W_r> .

[icexelloss]

Yeah I think DecimalVector should have getPrecision() and getScale() methods. Unfortunately(?) now we need to do this on a vector by vector basis. FixedSizeListVector already has getListSize(). I checked other vectors seems to be fine.

[BryanCutler]

Closing this, now it will have to be done on the individual vector classes.