IFS file copy using JT400 in code

Question

I have this piece of code that would copy files from IFS to a local drive. And I would like to ask some suggestions on how to make it better.

public void CopyFile(AS400 system, String source, String destination){
    File destFile = new File(destination);
    IFSFile sourceFile = new IFSFile(system, source);
    if (!destFile.exists()){
        try {
            destFile.createNewFile();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
            IFSFileInputStream in = null;
    OutputStream out = null;
    try {
         in = new IFSFileInputStream(sourceFile);
         out = new FileOutputStream(destFile);

            // Transfer bytes from in to out
            byte[] buf = new byte[1024];
            int len;
            while ((len = in.read(buf)) > 0) {
                out.write(buf, 0, len);
            }
        } catch (AS400SecurityException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if(in != null) {
                    in.close();
                }
                if(out != null) {
                    out.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        } // end try catch finally

} // end method

Where

• source = full IFS path + filename and
• destination = full local path + filename

I would like to ask some things regarding the following:

• a. Performance considerations

  1. would this have a big impact in terms for CPU usage for the host AS400 system?
  2. would this have a big impact on the JVM to be used (in terms of memory usage)
  3. would including this to a web app affect app server performance (would it be a heavy task or not)?
  4. would using this to copy multiple files (running it redundantly) be a big burden to all resources involved?

• b. Code Quality

  1. Did my implementation of IFSFileInputStream suffice, or would a simple FileInputStream object do the job nicely?

AFAIK, I just needed the AS400 object to make sure the source file referenced is a file from IFS.

I am a noob at AS400 and IFS an would like to ask an honest opinion from experienced ones.

Answer 1

All in all it looks fine (without trying). It should not have a noticeable impact.

• in.read() may return 0. Test for -1 instead.
• Instead of manually buffering, just wrap in and out with their respective BufferedInputStream/BufferedOutputstream and read one character at a time and test it for -1.
• try-catch is hard to get pretty. This will do, but you will later get more experience and learn how to do it somewhat better.
• Do NOT swallow exceptions and print them. The code calling you will have no idea whether it went well or not.
• When done with an AS400 object, use as400.disconnectAllServices().

Answer 2

See IBM Help example code:

http://publib.boulder.ibm.com/infocenter/iadthelp/v7r1/index.jsp?topic=/com.ibm.etools.iseries.toolbox.doc/ifscopyfileexample.htm

Regards