A custom result processor must implement the GemFire XD
ProcedureResultProcessor interface. GemFire XD calls the processor implementation
after a client invokes a procedure using the WITH RESULT PROCESSOR clause and
begins retrieving results.
The basic result processor API operates in the following manner:
- GemFire XD calls the init()
method of the implementation to provide the
object. The ProcedureProcessorContext provides important details about the
procedure implementation and the procedure call that is returning results to
describes the methods that you can use to obtain context information and obtain
nested JDBC connections.
- Your implementation uses
object to obtain the OUT parameters and result sets that the procedure is
returning to the client, so that it can process the results as necessary. OUT
parameters and result sets are obtained using the getIncomingOutParameters()
and getIncomingResultSets() methods, respectively. Both of these methods
which you can use to obtain metadata about the result set itself and inspect
individual rows of the result set.
- GemFire XD calls the
getNextResultRow() and getOutParameters() methods in your implementation to
provide modified results to the client. The getNextResultRow() method of your
implementation is called each time the next row of a particular result set must
be returned to the client. The getOutParameters() should return all of the
procedure's OUT parameters to the client.
- GemFire XD calls your
implementation's close() method when the associated statement is closed and the
output processor is no longer required. Free resources and perform any final
cleanup in this method.
Procedure Result Processor Interfaces
provides a complete reference to the methods defined in
ProcedureResultProcessor, ProcedureProcessorContext, and IncomingResultSet.