Example
to count the procedure output node
count(bpws:getVariableData('Invoke_OrderProcessService_OrderProcessService_OutputVariable','OutputParameters','/ns8:OutputParameters/ns8:X_HEADER_TBL_VAL/ns8:X_HEADER_TBL_ITEM_VAL/ns8:ORD_LINE_TBL_VAL/ns8:ORD_LINE_TBL_ITEM_VAL[ns8:LINE_STATE
= "BOOKED"]/ns8: LINE_STATE '))