JRecord - Formatting file transferred from Mainframe

Question

I am trying to display a mainframe file in a eclipse RCP application using JRecord library.I already have the COBOL copybook as a text file. to accomplish that,

1. I am transferring the file from mainframe to my desktop through apache commons net FTPClient API
2. Now I have a text file
3. I am removing the newline and carriage return characters
4. then I read it via ., a CobolIoProvider and convert it into a ArrayList of type AbstractLine

But I have offset issues because of some special charcters . here are the issues

1. when I dont perform step #3 , there are offset issues right from record 1. hence I included step #3
2. even when I perform step #3 , the first few thounsands of records seem to be formatted(or read ) by the AbstractLineReader correctly unless it encounters a special character (not sure but thats my assumption).

Code snippet:

ArrayList<AbstractLine> lines = new ArrayList<AbstractLine>();
        InputStream copyStream;
        InputStream fis;
        try {
            copyStream = new FileInputStream(new File(copybookfile));

            String filec = FileUtils.readFileToString(new File(datafile));
            System.out.println("initial len: "+filec.length());
            filec=filec.replaceAll("\r", "");
            filec=filec.replaceAll("\n", "");
            System.out.println("initial len: "+filec.length());

            fis= new ByteArrayInputStream(filec.getBytes());

            CobolIoProvider ioProvider = CobolIoProvider.getInstance();
            AbstractLineReader reader = ioProvider.newIOBuilder(copyStream, "REQUEST",
                    Convert.FMT_MAINFRAME).newReader(fis);
            AbstractLine line;
            while ((line = reader.read()) != null) {
                lines.add(line);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

What am I missing here ? is there an additional preprocessing that I need to do for the file transferred from mainframe ?

Answer 1

If it is a Text File (no binary data) with \r\n line delimiters try:

    ArrayList<AbstractLine> lines = new ArrayList<AbstractLine>();
    InputStream copyStream;
    InputStream fis;
    try {
        copyStream = new FileInputStream(new File(copybookfile));

        AbstractLineReader reader = CobolIoProvider.getInstance() 
            .newIOBuilder(copyStream, "REQUEST", ICopybookDialects.FMT_MAINFRAME)
                .setFileOrganization(Constants.IO_STANDARD_TEXT_FILE)
            .newReader(datafile);
        AbstractLine line;
        while ((line = reader.read()) != null) {
            lines.add(line);
        }
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

Note: The setFileOrganization tells JRecord what type of file it is. So .setFileOrganization(Constants.IO_STANDARD_TEXT_FILE) tells JRecord it is a Text file with \n or \r\n end-of-line markers. Here is a Description of FileOrganisation in JRecord.

The special charcters worry me though, if there is a \n in the 'Data' it will be treated as an end-of-line. You may need to do binary transfer and keep the RDW (Record-Descriptor-Word) if it is a VB file.

If The file contains Binary data, you will need:

• do a binary transfer (with RDW if it is a VB file)
• use the appropriate File-Organisation
• Specify Ebcdic (.setFont("cp037") tells JRecord is US-Ebcdic)

---

I will add a second answer for Generating Code using the RecordEditor

---

If you are absolutely sure all the records are the same length you can use the low-level routines to do the reading see the ReadAqtrans.java program in https://sourceforge.net/p/jrecord/discussion/678634/thread/4b00fed4/

basically you would do:

    ICobolIOBuilder iobuilder = CobolIoProvider.getInstance()
            .newIOBuilder("copybookFileName", ICopybookDialects.FMT_MAINFRAME)
                    .setFont("CP037")
                    .setFileOrganization(Constants.IO_FIXED_LENGTH);
    LayoutDetail layout = iobuilder.getLayout();
    FixedLengthByteReader br 
         = new FixedLengthByteReader(layout.getMaximumRecordLength() + 2);
    br.open("...");

    byte[] bytes;
    while ((bytes = br.read()) != null) {           
        lines.add(iobuilder.newLine(bytes));
    }

Answer 2

Future Reference / Binary File

If the file does contain Binary Data, you really need to do a binary transfer. You may find the RecordEditor useful.

The RecordEditor 0.98 has a JRecord code Generation function. The advantages of using the RecordEditor Generate function are

• The Recordeditor will try and work out the appropriate File attributes by looking at the File
• You can try out various attributes (left hand pane) and see what the file looks like with those attributes (right hand side).

• When happy, hit the Generate button and the RecordEditor will generate JRecord code. There are several Code Templates available:

  • Standard - will generate basic JRecord code (with a field name class
  • lineWrapper - will generate a "wrapper" class with the Cobol fields represented as get/set methods

RecordEditor Generate

In the RecordEditor select Generate >>> Java~JRecord code for Cobol

Generate Screen

Enter the Cobol CopyBook / Sample file and adjust the attributes as needed

Code Template

Next you can select the Code Template

Generated Code

Finally the RecordEditor will generate JRecord code based on the Attributes entered.