////////////////////////////////////////////////////////////////////////////////////////////////////
// Desc: Checks to see if this process is already running and if so, prevents this from running
// Args: none
// Ret : none - exits the applicaiton if an instance is already running
////////////////////////////////////////////////////////////////////////////////////////////////////
public static void checkIfAlreadyRunning()
{
    boolean running = false;
    String directoryLocation = "running_scripts/";
    String filename = directoryLocation + "my_application.txt";

    File scriptDir = new File(directoryLocation);

    // Create the directory structure if it doesn't exist.
    if (!scriptDir.exists())
    {
        scriptDir.mkdirs();
    }

    // Create the file if it doesnt exist.
    File scriptFile = new File(filename);
    if (!scriptFile.exists())
    {
        try
        {
            scriptFile.createNewFile();
        }
        catch (Exception e)
        {
            System.out.println("Error creating script file that didnt exist: " + e);
            System.exit(1);
        }

    }

    // If can get a lock on the file then this process is not already running.
    try
    {
        FileChannel channel = new RandomAccessFile(scriptFile, "rw").getChannel();
        FileLock lock = channel.tryLock();

        // Trylock returns null if overlapping lock, not an error
        if (lock == null)
        {
            String message = "You are only allowed to have one running instance of " +
                             "this app.";
            System.out.println(message);
            System.exit(0);
        }

    }
    catch (Exception p)
    {
        System.out.println("checkIfAlreadyRunning Error " + p);
        System.exit(1);
    }

}