Delete Flag Empty -does this imply record valid?

[James Clinton]

Background: At the moment I am implementing the 'find(cret)' method to build a list of records which match some criteria. This function invokes 'read(recNo)' to grab a record for some processing and catches any RecordNotFoundException's etc etc.

My Assignment:In my assignment '1' indicates deleted, '0' indicates valid record.

Question:When I read in the 'delete byte' the value is empty. Can I safely assume 'empty' implies record is valid, or do I have a bug to sort out? (I was expecting '0').

byte[] flagBuf = new byte[1];
file.read(flagBuf);
String deleteFlag = new String(flagBuf,"US-ASCII");
System.out.println("Delete flag: " + deleteFlag);

Thanks.

[James Clinton]

corrupt?

I'm not so sure because all the other details are read OK, theres a total of approx 29/30 records.

Anton, did you have the same assignment as mine?

URLyBird
Data file Format
The format of data in the database file is as follows:

Start of file
4 byte numeric, magic cookie value. Identifies this as a data file
4 byte numeric, total overall length in bytes of each record
2 byte numeric, number of fields in each record

Schema description section.
Repeated for each field in a record:
2 byte numeric, length in bytes of field name
n bytes (defined by previous entry), field name
2 byte numeric, field length in bytes
end of repeating block

Data section.
Repeat to end of file:
1 byte "deleted" flag. 0 implies valid record, 1 implies deleted record
Record containing fields in order specified in schema section, no separators between fields, each field fixed length at maximum specified in schema information

End of file

James
[ November 26, 2004: Message edited by: James Clinton ]

[Anton Golovin]

Hi, James! Thanks for posting the code. This makes things easier. When a byte has the value -1, the String constructor does not know how to convert it. There is no error. Try the following:

byte flag = file.readByte();
System.out.println(flag);

If it is -1 or 0, it is ok.
[ November 26, 2004: Message edited by: Anton Golovin ]