SAP CPI UDF Execution type All values of Queue

Hi, I have requirement where custom udf ( groovy -> function) has to execute all the values of queue. When I try to execute it's by default it is executing as "All values of Context". I have gone through SAP CPI Java Docs where in the Output interface documentation clearly mentioned about execution type "All values of Queue". Can anybody help me on this?

<<public interface Output

This class is used in advanced user-defined functions (execution type "All values of Context" or "All values of a Queue") to return the result of a function>>

Thank you,

Rao Malisetti