public SelectionBuilder reset(){
  tableName=null;
  projectionMap.clear();
  selection.setLength(0);
  selectionArgs.clear();
  groupBy.clear();
  return this;
}

public SelectionBuilder reset ( ) { tableName = null ; projectionMap . clear ( ) ; selection . setLength ( 0 ) ; selectionArgs . clear ( ) ; groupBy . clear ( ) ; return this ; }
reset any internal state , allowing this builder to be recycled .
