How do I check in openhab 2 whether a item is not defined and assign a value

Setup, Configuration and Use Beginners
1

how do I check in openhab 2 whether a item is not defined and assign a value.

A check working in openhab 1 see below does not seem to work anymore
Example:
if ((BedShut.state == Undefined) || (BedShut.state == Uninitialized)) sendCommand(BedShut,100)