JPOS NACChannel Unable to Parse Incoming Message with Header

Question

I am using NACChannel of JPOS v2.1.0. I am using GenericPackager for packing my message. I am able to successfully send message to my ISO application. But while receiving incoming message my NACChannel.receive() throws parsing error.

My incoming message has a custom Header. I suspect this is causing the parsing error. So my questions are:

1. How can I handle this ISOMsg header in my incoming response?
2. Is there any way I can disable the Parsing Step and Receive the byte[] response from the channel?

My JPOS client code I am using:

public class BuildISOMessage {

public static void main(String[] args) throws IOException, ISOException {
    createISOMessage();

}

public static byte[] createISOMessage() throws ISOException {
    String HOST = "localhost";
    int PORT = 40021;

    // Create Packager based on XML that contain DE type
    ISOBasePackager packager = new GenericPackager("800_fields.xml");

    NACChannel testchannel = new NACChannel();

    testchannel.setHost(HOST, PORT);

    ISOMsg isoMsg = build200ISOMessage(packager);

    // print the DE list
    logISOMsg(isoMsg);

    // Get and print the output result
    byte[] data = isoMsg.pack();

    try {           
        testchannel.setPackager(isoMsg.getPackager());
        testchannel.setHeader(("ISO01" + String.format("%04d", data.length)).getBytes());

        testchannel.connect();          
        testchannel.send(isoMsg);

        if (testchannel.isConnected()) {
            ISOMsg response = testchannel.receive();
        }
        testchannel.disconnect();

    } catch (Exception e) {
        e.printStackTrace();
    }
    return data;
}

private static ISOMsg build200ISOMessage(ISOBasePackager packager)
        throws ISOException {
    // Create ISO Message
    ISOMsg isoMsg = new ISOMsg();
    isoMsg.setPackager(packager);
    isoMsg.setMTI("200");       
    isoMsg.set(2, "4622871000060891");
    isoMsg.set(3, "300000");
    isoMsg.set(4, "100");       
    isoMsg.set(7, "1026043633");
    isoMsg.set(11, "999901");       
    isoMsg.set(12, "113633");
    isoMsg.set(13, "1026");
    isoMsg.set(15, "1116");
    isoMsg.set(16, "1116");     
    isoMsg.set(18, "6011");
    isoMsg.set(22, "21");       
    isoMsg.set(32, "0000004");
    isoMsg.set(33, "0000004");
    isoMsg.set(35, "4622871000060891=22082211963393100000");
    isoMsg.set(37, "829911364035");
    isoMsg.set(43, "TBNKTAS2B065B999P999300501000050      TH");
    isoMsg.set(48, "00000000040000000002000000013000000000005000000000007000TYRIONLANNISER ARYA STARK000000003334000000000202        00000000000000000000");
    isoMsg.set(49, "764");      
    isoMsg.set(52, "FFFFFFFFFFFFFFFF");
    isoMsg.set(62, "221000000000");

    return isoMsg;
}

private static void logISOMsg(ISOMsg msg) {
    System.out.println("----ISO MESSAGE-----");
    try {
        System.out.println("  MTI : " + msg.getMTI());
        for (int i = 1; i <= msg.getMaxField(); i++) {
            if (msg.hasField(i)) {
                System.out.println("    Field-" + i + " : "
                        + msg.getString(i));
            }
        }
    } catch (ISOException e) {
        e.printStackTrace();
    } finally {
        System.out.println("--------------------");
    }
}
}

Answer 1

Thanks all for your help. While looking for an answer for debug purpose, I created a subclass of NACChannel and put some debug statements. By doing that I realized the issue was with my field definition and nothing to do with JPOS framework.

I was setting a header(e.g. ISO010200 where message length is 200) of length '9' by the below code.

testchannel.setHeader(("ISO01" + String.format("%04d", data.length)).getBytes());

My response also had a similar header of length '9'. So the NACChanel receive() method was able to extract the 9 digit Header correctly. But failed to parse the response message, my field definition was not correct.

Once that was fixed, JPOS was able to parse the response message coorectly.