why does VariableFieldPackager not get value form Map like FixedFieldPackager do in the pack method?

[Zhangkc]

VariableFieldPackager returns delimiter if value is null.
FixedFieldPackager would get value from map if value is null.

public byte[] pack(Map<String, String> fields) throws ISOException {
		if (value == null || value.equals("")) {
			return new byte[] { delimiter.byteValue() };
		}



public byte[] pack(Map<String, String> fields) throws ISOException {
		if (value== null) {
			value = fields.get(getName());
		}
		else {
			fields.put(getName(), value);
		}

this causes packing empty value when VariableFieldPackager in a nested FSDMsgX.

[mchhil-incomm]

Could you provide a simple reproducer code ?
Its been ages since I looked at this module.

[mchhil-incomm]

I don't know if this related to your issue or not but I it was missing a setValue("") which cause the hexdump method to err out with a null pointer exception.

The idea is that when it eventually gets to a VariableFieldPackager the field can be set with string or null. If its an empty string or null the delimiter must be added to indicate the field is present with no data.

VariableFieldPackager ad the setValue

	public byte[] pack(Map<String, String> fields) throws ISOException {

		if (value == null || value.equals("")) {
			// if field is not set, make sure to send the delimiter to indicate
			// its presence.
                         setValue(""); // set this as the hexdump method chokes because field is not set
			return new byte[] { delimiter.byteValue() };
		}
		if (value.length() <= maxSize) {
			byte[] b = new byte[interpreter.getPackedLength(value.length() + 1)];
			interpreter.interpret(value, b, 0);
			b[b.length - 1] = delimiter.byteValue();

			return b;
		}
		throw new ISOException(String.format("Size [%d] is greater than maxSize[%d] ", value.length(), maxSize));
	}

Test

    public static void main(String[] args) throws ISOException {
        VariableFieldPackager f1  = new VariableFieldPackager("F1", 20, Byte.valueOf((byte) 0x1c),
                                                              AsciiInterpreter.INSTANCE);

        FSDMsgX               msg = new FSDMsgX("Test1");
        msg.add("F1", f1);

        byte[] arr = msg.pack();

        System.out.println(msg.getParserTree(""));
        System.out.println(msg.hexDump(""));

    }

Output

[Test1]
Field [F1] : VAR[0..20] delimiter[0x1C] or EOM  : 

0000  1C                                                .

---

If this is not your issue please provide a reproducer and I will try an look into it.

[Zhangkc]

thanks for reply, here is reproducer demo.

            FSDMsgX demo = new FSDMsgX("demo");
            AFSDFieldPackager f1 = new FixedFieldPackager(
                    "F1", 1, AsciiInterpreter.INSTANCE);

            //branch
            FSDMsgX container = new FSDMsgX("n1");
            AFSDFieldPackager var = new VariableFieldPackager("var", 9, new Byte((byte) 0x1c),
                    AsciiInterpreter.INSTANCE);
            AFSDFieldPackager nf1 = new FixedFieldPackager(
                    "NF1", 1, AsciiInterpreter.INSTANCE);
            container.add(var);
            container.add(nf1);

            Map<String, AFSDFieldPackager> cases = new HashMap<String, AFSDFieldPackager>();
            cases.put("1", container);

            BranchFieldPackager branch1 = new BranchFieldPackager(
                    "branch", "F1", cases, null);

            demo.add(f1);
            demo.add(branch1);

            demo.set("F1", "1");
            demo.set("var", "111222333");
            demo.set("NF1", "N");

            byte[] os = demo.pack();
            System.out.println(demo.dump("dump"));
            System.out.println(demo.getParserTree("tree>"));
            System.out.println(ISOUtil.hexdump(os));

output

0000 31 1C 4E 1.N

field var packed empty value

[Zhangkc]

I know I can set field value in branch FSDMsgX, but when nest more than 1 branch, it's hard to set value in branch FSDMsgX

[mchhil-incomm]

Thank you for the reproducer.

Can you test it with this pack method

    @Override
    public byte[] pack(Map<String, String> fields) throws ISOException {

        if (value == null || value.equals("")) {
            // if field is not set, make sure to send the delimiter to indicate
            // its presence.
            value = fields.get(getName());
            if (value == null || value.equals("")) {
                setValue(""); // set this as the hexdump method throws NPE
                return new byte[] { delimiter.byteValue() };
            }



        }

        if (value.length() <= maxSize) {
            byte[] b = new byte[interpreter.getPackedLength(value.length() + 1)];
            interpreter.interpret(value, b, 0);
            b[b.length - 1] = delimiter.byteValue();

            return b;
        }
        throw new ISOException(String.format("Size [%d] is greater than maxSize[%d] ", value.length(), maxSize));
    }

Test code

    public static void test2() throws ISOException {
        FSDMsgX demo = getMessage();
        demo.set("F1", "1");
        demo.set("var", "111222333");
        demo.set("NF1", "N");
        byte[] os = demo.pack();

        System.out.println(demo.dump("dump-pack"));
        System.out.println(demo.getParserTree("tree>"));
        System.out.println(ISOUtil.hexdump(os));

        demo = getMessage();
        demo.unpack(os);
        System.out.println(demo.dump("dump-unpack"));
        System.out.println(demo.getParserTree("tree>"));
        System.out.println(ISOUtil.hexdump(os));


    }

    protected static FSDMsgX getMessage() {
        FSDMsgX           demo = new FSDMsgX("demo");
        AFSDFieldPackager f1   = new FixedFieldPackager("F1", 1, AsciiInterpreter.INSTANCE);

        // branch
        FSDMsgX           container = new FSDMsgX("n1");
        AFSDFieldPackager var1      = new VariableFieldPackager("var", 9, Byte.valueOf((byte) 0x1c),
                                                                AsciiInterpreter.INSTANCE);
        AFSDFieldPackager nf1       = new FixedFieldPackager("NF1", 1, AsciiInterpreter.INSTANCE);
        container.add(var1);
        container.add(nf1);

        Map<String, AFSDFieldPackager> cases = new HashMap<>();
        cases.put("1", container);

        BranchFieldPackager branch1 = new BranchFieldPackager("branch", "F1", cases, null);

        demo.add(f1);
        demo.add(branch1);


        return demo;
    }

Output

dump-pack<fsdmsgX name="demo">
dump-pack	<field id="F1" value="1"/>
dump-pack	<fsdmsgX name="n1">
dump-pack		<field id="var" value="111222333"/>
dump-pack		<field id="NF1" value="N"/>
dump-pack	</fsdmsgX>
dump-pack</fsdmsgX>

tree>[demo]
tree>Field [F1] : Fixed [1] : 1
tree>Field [branch] : [Branch]
	switch (F1)
		1:
			[n1]
			Field [var] : VAR[0..9] delimiter[0x1C] or EOM  : 111222333
			Field [NF1] : Fixed [1] : N
		default:
			[Not Set]
0000  31 31 31 31 32 32 32 33  33 33 1C 4E              1111222333.N

dump-unpack<fsdmsgX name="demo">
dump-unpack	<field id="F1" value="1"/>
dump-unpack	<fsdmsgX name="n1">
dump-unpack		<field id="var" value="111222333"/>
dump-unpack		<field id="NF1" value="N"/>
dump-unpack	</fsdmsgX>
dump-unpack</fsdmsgX>

tree>[demo]
tree>Field [F1] : Fixed [1] : 1
tree>Field [branch] : [Branch]
	switch (F1)
		1:
			[n1]
			Field [var] : VAR[0..9] delimiter[0x1C] or EOM  : 111222333
			Field [NF1] : Fixed [1] : N
		default:
			[Not Set]
0000  31 31 31 31 32 32 32 33  33 33 1C 4E              1111222333.N

---

Currently the fsdmsgx.hexdump does not work, it needs to be fixed, but its usage is for debugging , I will try and get to it later. ISOUtil.hexdump works fine and can be used.

[Zhangkc]

thanks a lot! I have tested and it seems ok!