Implementing Retry feature in SFTP

[Charanjith A C]

Hello guys,

Need:

The SFTP stack does not have an option to set timeout for a command.

Changes that I made:

1) In SftpMessageStore, setResponseTimeout() has been added to set the timeout passed by user.
2) In SftpMessageStore, I have modified the getMessage() method to use this timeout value, instead of waiting indefinitely. The current stack in wob just sleeps every 5 seconds and expects someone to help out.
3) Even after sufficient wait time if I am not getting any response from the server I am throwing an exception, which will be caught by the actual client to retry the last command again.

For implementing this I included a responseTimeout variable in SftpMessageStore and the method 'getMessage' is changed as follows :-

    public synchronized SubsystemMessage getMessage(UnsignedInteger32 requestId)
        throws InterruptedException, IOException {
        Iterator it;
        SubsystemMessage msg;
       
        //Getting the expiration time. (current time + response timeout)
        Date expiration = responseTimeout == 0
        ? null : new Date(new Date().getTime() + (responseTimeout
                                                  ));
       
        // If there ae no messages available then wait untill there are.
        while (getState().getValue() == OpenClosedState.OPEN) {
            if (messages.size() > 0) {
                it = messages.iterator();

                while (it.hasNext()) {
                    msg = (SubsystemMessage) it.next();

                    if (msg instanceof MessageRequestId) {
                        if (((MessageRequestId) msg).getId().equals(requestId)) {
                            messages.remove(msg);

                            return msg;
                        }
                    }
                }
            }
           
            log.debug("Waiting for new messages");
            wait(5000);
            //If expiration has happened throw Response Timeout
            if (expiration != null && expiration.before(new Date())){
                throw new IOException("Response Timeout occured");
            }
        }

        return null;
    }

Is there any anticipated or known issues here?