Adding attachment from PI level

Question

Hi all,
   I am trying to add some attachment to payload using JAVA Mapping.
public void transform(TransformationInput arg0, TransformationOutput arg1)     throws StreamTransformationException
          try{
                    System.out.println("JAVA Mapping  is Initiated");
                    //getTrace().addInfo("JAVA Mapping HMAC is Initiated");
                    InputStream stream1 = arg0.getInputPayload().getInputStream();
                    String inputPayload = convertInputStreamToString(stream1);
                    System.out.println("input file "+inputPayload);
                    String outputPayload = "";
                    outputPayload = inputPayload;
                    byte[] b = inputPayload.getBytes();
                    System.out.println("JAVA Mapping  "+b.length);
                    try{
                    *OutputAttachments outputAttachments = arg1.getOutputAttachments();     
                    Attachment attachments = outputAttachments.create("sd", b); *
                    outputAttachments.setAttachment(attachments);
                    } catch (Exception e)
                    {//getTrace().addInfo("JAVA Mapping Trace "+e);
                         System.out.println("test "+e);}
               arg1.getOutputPayload().getOutputStream().write(outputPayload.getBytes("UTF-8"));
               } catch (Exception e)
               {System.out.println(e.getStackTrace());}
I am getting null pointer exception from below line
*Attachment attachments = outputAttachments.create("sd", b); *
feels like
outputAttachments = arg1.getOutputAttachments();     is returning null.
Please help me in solving same
Regards
Pradeep

Answer 1

Have you tried working with the addAttachment() method of the Message interface (http://help.sap.com/javadocs/pi/SP3/xpi/com/sap/engine/interfaces/messaging/api/Message.html#addAttachment%28com.sap.engine.interfaces.messaging.api.Payload%29) ... It may require some (major) redesign of your JAVA mapping (I'm still on XI, so I can't validate this assumption)
Chris