RFC Lookup is simple UDF that can be used to execute RFC from UDF and fetch the output. This UDF uses RFC channel to make the calls to the SAP system.

getRFCLookupUDF.java

public String getRFCLookupUDF(Container container) throws StreamTransformationException{
	GlobalContainer globalContainer;
	MappingTrace trace;
	java.util.Map map;
	
	trace = container.getTrace();
	globalContainer = container.getGlobalContainer();
	map = globalContainer.getTransformationParameters();
  
	SystemAccessor rfcAccessor = null;
	InputStream inputStream;
	InputStream responseStream;
	ByteArrayOutputStream out = null;
	String rfcXMLMessage = new String();
	String rfcContent = "";

	try
	{
		//Lookup for the channel
		Channel rfcChannel = LookupService.getChannel("BS_SAP_ECC_SYSTEM","CC_SAP_ECC_Lookup_RFC_Receiver");
		rfcAccessor = LookupService.getSystemAccessor(rfcChannel);
		rfcAccessor.setOperationName("Z_PDM_RFC_MATNR_EXISTCHECK"); //This is the Custom RFC Name
		rfcAccessor.setOperationName("urn:sap-com:document:sap:rfc:functions"); //Namespace

		//Prepare the RFC XML Message
		rfcXMLMessage = "<?xml version=\"1.0\" encoding=\"UTF-8\"?><ns0:Z_PDM_RFC_MATNR_EXISTCHECK xmlns:ns0=\"urn:sap-com:document:sap:rfc:functions\"><MATNR_EXISTCHECK>";
		rfcXMLMessage = rfcXMLMessage + "<item><MATNR>" + MaterialNo + "</MATNR><WERKS>" + PlantCode + "</WERKS> <MATNR_EXIST/> <DEL_FLAG/></item>";
		rfcXMLMessage = rfcXMLMessage + "</MATNR_EXISTCHECK></ns0:Z_PDM_RFC_MATNR_EXISTCHECK>";

		//Execute the RFC
		trace.addInfo("rfcXMLMessage: " + rfcXMLMessage);
		inputStream = new ByteArrayInputStream(rfcXMLMessage.getBytes());
		XmlPayload inPayload = LookupService.getXmlPayload(inputStream);
		Payload outPayload = rfcAccessor.call(inPayload);
		
		//Get the Output from the Lookup
		trace.addInfo("Output from the RFC: " + outPayload.toString());
		responseStream = outPayload.getContent();
		trace.addInfo("responseStream: " + responseStream.toString());
		out = new ByteArrayOutputStream(1024);
		byte[] buffer = new byte[1024];
		for (int read =responseStream.read(buffer);read>0;read=responseStream.read(buffer))
		{
			out.write(buffer,0,read);
		}
		
		//Write the Output
		rfcContent = out.toString();
		trace.addInfo(rfcContent);
			
	}catch(Exception e) 
	{
		throw new Exception("Error in the RFCLookup." + e.getMessage());
	} 
	finally 
	{					
		if (out!=null) 
		{
			try 
			{
				out.close();
			} 
			catch (Exception e) 
			{
				throw new RuntimeException("Unable to Close the instance of ByteArrayOutputStream." + e.getMessage());
			}
		}
		
		if (rfcAccessor !=null) 
		{
			try 
			{
				rfcAccessor.close();
			} 
			catch (Exception e) 
			{
				throw new RuntimeException("Unable to close the rfcAccessor" + e.getMessage());
			}
		}
	}//end of finally
	return rfcContent;
}