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Wim · Posted: Fri Mar 21, 2008 3:27 am Post subject:

Hi,

The message I'm trying to model in toolkit V6.0.2 is physically one long string of characters (no delimiters or separators) and it is structured as follows:

Field1 is 5 characters long and acts as a length code for Field2
Field2 is "a record".

These 2 fields are repeated until the end of the stream.

The 'record'-part is identified by the first 2 characters of the record (i.e. record-type).
I can have 16 different types of record; they are described in a COBOL copybook. All but one are optional and they can repeat.
One record has a structure "OCCURS 0 TO 30 DEPENDING ON (previously-defined-field)" in it. This structure appears at the end of the record, but the record appears somewhere in the middle of the stream.

I modeled the message in TDS as a sequence of 2 elements:
- A local element (length field)
- A complex type (choice)
The complex type of composition "choice" has TDS DES="Tagged Fixed Length". The choice is resolved by the 2 character record-type as a tag.
This works fine until I encounter the record with the repeating structure in it.
The parser insists on creating 30 structures even if the previously-defined-field has a value of say "02". The result is that the remaining records are "eaten up" and eventually I get a parser exception.

I hoped that somehow the length field would restrict the number of characters that are passed to the choice, and therefor stop creating structures when it runs out of "record", but this does not seem to be the case

So, is there a way to indicate the number of repeats for this structure? In TDS I only see "Repeating Element Delimiter" ... but the message doesn't have delimiters. All the other stuff is about "length".

In the CWF properties I found Repeat References so I figured that maybe a CWF model could parse the message.
After a lot of reading in the docs and in the forums, it became clear that a choice in CWF was not possible because the records I have are not the same length. So I decided to convert everything to a multipart message in CWF. I treated every record as a separate message, with the value of the record-type interpreted as MessageIdentity in combination with the Message Alias for the selection (instead of choice). But now I'm stuck with the length field in front of each record. I cannot seem to indicate that the parser should interpret this field as being the length of the record that follows...

If all the above is correct, I have 4 options to model my message:
1. CWF with choice
2. CWF with multipart message
3. TDS with choice
4. TDS with multipart message

1: doesn't work because the record lengths are different
2: doesn't work because I cannot interpret the length field
3: doesn't work because of the structure that repeats n times based on a previous field
4: haven't tried yet but I guess it wouldn't work for the same reason as 3.

Any ideas to get me out of this mess

would be greatly appreciated.
-=Wim=-