JLine 3 - Keep the prompt always at the bottom

Question

I want the prompt to display at the bottom of the page every time.

I have a GIF of that: The prompt not displaying properly

The code is that for read line:

@Override
public void run()
{
    while (((ElytraServer) ElytraAPI.getServer()).isRunning())
    {
        String cmd;
        ((ElytraServer) ElytraAPI.getServer()).getReader().getTerminal().writer().flush();
        cmd = ((ElytraServer) ElytraAPI.getServer()).getReader().readLine("> ");
        if (!cmd.isEmpty())
        {
            String[] aCMD = cmd.split(" ");
            String[] arguments = Arrays.copyOfRange(aCMD, 1, aCMD.length);
            ElytraAPI.getCommandRegistry().dispatch(ElytraAPI.getConsole(), aCMD[0], arguments);
        }
    }
}

It's in a Thread.

And there is the another Thread: With JLine 2, the code keep the prompt at the bottom (But it was buggued !)

public void run()
{
    while (((ElytraServer) ElytraAPI.getServer()).isRunning())
    {
        try
        {
            if (useJline)
            {
                /*
                JLine 2 / Old:
                reader.print(Ansi.ansi().eraseLine(Erase.ALL).toString() + '\n');
                reader.flush();
                 */
                reader.getBuffer().down();
                reader.getTerminal().flush();
                output.write("".getBytes());
                output.flush();

                /* // For JLine2
                try
                {
                    reader.drawLine();
                }
                catch (Throwable throwable)
                {
                    reader.getCursorBuffer().clear();
                }*/

                reader.getTerminal().flush();
            }
            else
            {
                output.write("".getBytes());
                output.flush();
            }
        }
        catch (IOException ioexception)
        {
            Logger.getLogger(TerminalConsoleWriterThread.class.getName()).log(Level.SEVERE, null, ioexception);
        }
    }
}

For the full source: Full source of the program

Answer 1

I posted a workaround with the current code (which works as long as the user does not use multiline input).

reader.getTerminal().puts(Capability.carriage_return);
reader.getTerminal().writer().println("World!");
reader.callWidget(LineReader.REDRAW_LINE);
reader.callWidget(LineReader.REDISPLAY);
reader.getTerminal().writer().flush();

The next jline version (3.2) will contain a better fix. See: https://github.com/jline/jline3/issues/75