Using user-defined vertex ids

How to use a user-defined vertex id in queries.

Vertices can be filtered using a hasId() traversal step and providing a particular user-defined vertex id:
g.V().hasId(['~label':'fridgeSensor', 'stateId':31, 'cityId':100, 'sensorId':1]).valueMap()
A vertex can be queried directly using a user-defined vertex id:
g.V(['~label':'fridgeSensor', 'stateId':31, 'cityId':100, 'sensorId':1]).valueMap()