Persistit.Key needs a way to indicate if the current segment is null

[Jack Orenstein]

I think it's likely that the query processor's Row abstraction will need an isNull method. This can be implemented by PersistitIndexRow by calling Key.decode() and seeing if the returned object is null. But one of the points of isNull is to avoid two decodes (one to check for null, another in case the field is not null). There are easy workarounds, but if
adding something like Key.decodesToNull() is an easy enhancement to Persistit, I think it will be generally useful.

[Yuval Shavit (yshavit)]

Another use case for this is in retrieving a value that may be a primitive or a null. For instance, if we want to get a double, we can't just call key.decodeDouble() since it could be null. Instead, we have to call key.decode(), check if that's null, and then either unbox it or later call key.decodeDouble().

This is going to be somewhat important for the server, especially now that we support covering indexes.

[Nathan Williams (nwilliams)]

Added to Persistit in r198.