RE: Need help with KeyedFile.positionCursor()

["Joe Pluta" <joepluta@xxxxxxxxxxxxxxxxx>]

RObert, you're finding out one of the key differences between record level
access and data I/O the way we think of it.  In RLA, the cursor is "on" a
record, not between them, so when you do a position and then a read next,
you actually get the NEXT record, not the one you positioned to.  This is a
little different than what we do in RPG.  I tried many combinations before I
realized that I could just trap the error and handle it.  My SETLL code
looks like this:

        try {
                keyedFile.positionCursor(keys, KeyedFile.KEY_LT);
        }
        catch (AS400Exception e) {
                String msgID = e.getAS400Message().getID();
                if (msgID.equals("CPF5006"))
                        rewind();
                else
                        error(e);
        }
        catch (Exception e) {
                error(e);
        }

And rewind looks like this:

        try {
                file.positionCursorBeforeFirst();
        }
        catch (Exception e) {
                error(e);
        }

Notice that if I get an error on the positionCursor, I simply do a
positionCursorBeforeFirst.  Now, if the file is empty, I think you might
still get an error.  I don't remember.

This code, and a whole bunch of other classes, are freely available in my
freeware classes:

http://www.zappie.net/revitalization/Alpha_2_download.htm

If you want more info, go here:

http://www.zappie.net/Java/Techniques/JDB400/com_pbd.htm


Joe Pluta
www.plutabrothers.com



> -----Original Message-----
> From: java400-l-admin@midrange.com
> [mailto:java400-l-admin@midrange.com]On Behalf Of Robert Upshall
> Sent: Thursday, December 06, 2001 9:51 PM
> To: java400-l@midrange.com
> Subject: Need help with KeyedFile.positionCursor()
>
>
> I happened to stumble accross a problem today by mistake.
>
> I have a KeyedFile object, say file.  I am trying to mimic a
> setll and reade
> in RPG terms.  The KeyedFile has 6 fields in the key but I'm only
> concerened
> with the first field.  The first key field is a 2S 0 in DSS.
> Here is a code
> snipet.
>
> KeyedFile = new KeyedFile(system,  path);
>
> file.setRecordFormat((new AS400FileRecordDescription(system,
> path)).retrieveRecordFormat()[0]);
>
> file.open(AS400File.READ_ONLY, 0, AS400File.COMMIT_LOCK_LEVEL_NONE);
>
> Object[] key = new Object[1];
> key[0] = new BigDecimal("01");
>
> file.positionCursorBefore(key);
>
> Record record = file.readNextEqual(key);
>
> The problem is, when the file only has one record it will not get a hit on
> the readNextEqual?
>
> What am I doing wrong here?
>
>
> Robert Upshall
> Professional Software of Amarillo
> (806) 358-8928
> rupshall@psasoft.com
>
>
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