Source Classes

See User-Defined Source for general information about implementing the UDSource and SourceFactory classes. This section describes information that is specific to the C++ API.

In addition to the examples in this section, see C++ Example: Cancelable UDSource.

UDSource API

The API provides the following methods for extension by subclasses:

virtual void setup(ServerInterface &srvInterface);

virtual bool useSideChannel();

virtual StreamState process(ServerInterface &srvInterface, DataBuffer &output)=0;

virtual StreamState processWithMetadata(ServerInterface &srvInterface, DataBuffer &output, LengthBuffer &output_lengths)=0;
				
virtual void cancel(ServerInterface &srvInterface);
				
virtual void destroy(ServerInterface &srvInterface);
				
virtual vint getSize();
				
virtual std::string getUri();

ContinuousUDSource API

The ContinuousUDSource class extends UDSource and adds the following methods for extension by subclasses:

virtual void initialize(ServerInterface &srvInterface);
 
virtual void run();
 
virtual void deinitialize(ServerInterface &srvInterface);

SourceFactory API

The API provides the following methods for extension by subclasses:

virtual void plan(ServerInterface &srvInterface, NodeSpecifyingPlanContext &planCtxt);

// must implement exactly one of prepareUDSources() or prepareUDSourcesExecutor()
virtual std::vector< UDSource * > prepareUDSources(ServerInterface &srvInterface, 
			NodeSpecifyingPlanContext &planCtxt);
				
virtual std::vector< UDSource * > prepareUDSourcesExecutor(ServerInterface &srvInterface, 
			ExecutorPlanContext &planCtxt);
				
virtual void getParameterType(ServerInterface &srvInterface, 
			SizedColumnTypes &parameterTypes);
				
virtual bool isSourceApportionable();
				
ssize_t getDesiredThreads(ServerInterface &srvInterface, 
			ExecutorPlanContext &planContext);

After creating your SourceFactory, you must register it with the RegisterFactory macro.