JRecord

JRecord

This project provides code to

1. Read and write files of length based records (both fixed length records and Length field based records).
2. Read and write CSV files.
3. Read and Write Flat Fixed width files (Text and Binary) via either a Xml-Record-Layout or a Cobol Copybook..
4. Read and write XML files (via StAX parser).
5. Common IO routines across all File Types (XML, CSV, Fixed field Width).
6. Support for various Flat file formats (Fixed, Delimited, Length based Files (i.e. Mainframe VB).

Guiding Principles

1. Method of reading / writing files should be the same no matter what the file format is.
2. Programmer should be shielded from the files format.
3. You should be able to edit files using the files description (Cobol Copybook, Xml or what ever).
4. Package should be flexible - easy to add new file formats or Record-Layout formats.

Package Structure

The JRecord package consists of

• Low level line IO routines (ByteReader / ByteWriter). These classes read a line from a file as an array of Bytes (Formats supported include Fixed Length and various Length based file formats). These could be of interest to any one reading / writing Legacy Files.
• Classes to read / write File-Descriptions to/from external files
• High level IO Routines Supporting field level access.

Issues

1. Code was written as part of the RecordEditor not as a Java library, This has both advantages and disadvantages:
   • The RecordEditor has had 20,000 downloads over several years. Many parts of the package have been well tested
   • Some code is there for the RecordEditor making the JRecord package larger that it would be otherwise be.
   • Classes minimizing space at the expense of speed. This makes sense in a Editor but not for reading / writing in Java..
   • Package is still being adapted for use as a Java package, More work is needed.
2. A way of tailoring the conversion of Cobol Copybooks is needed.
3. Currently the System has 2 ways of representing a Record-Layout

   LayoutDetail	The original format it holds only the bare minimum needed by the package
   ExternalRecord	A general purpose interchange format. This was introduced latter on to support conversion between file formats / Database (RecordEditor).

   Having two classes representing the same thing is not ideal. I may provide greater support for ExternalRecord's through out the package. There is a class ToLayoutDetail that can convert one to the other

To Do

1. Support for more files Structures
2. Support for Shorter Type-Names.
3. Greater Flexibility in importing Cobol Copybooks
4. Support for more Cobol dialects.
5. More work on the Documentation.
6. More options for parsing XML files (would be useful to convert child elements to fields).
7. One possible change is to have the Open methods return the object. This would allow

           AbstractLineReader reader = new XmlLineReader(true).open(filename);
       or
           AbstractLineReader reader = LineIOProvider.getInstance()
   				.getLineReader(Constants.IO_FIXED_LENGTH).open(filename);                                                  
   

   any thoughts anybody.
8. Bettetr class naming standards.

JRecord at SourceForge

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