KeyParserGroupBy()
Abstract class that extends the KeyParser interface.
The KeyParserGroupBy is an auxiliary abstract class that adds more information about the key that are needed to perform the groupBy operation.
All keys used in a groupBy query can be summarize as a pair (x,y) where x is the most significant part and identify a group and y is the least significant part that identify the range. The KeyParserGroupBy helps the Connector to identify the x and y part of a key.