Runtime.exec() in a seperate thread, and multithreading in general

Question

Hey guys -
I've scoured the web trying to learn how to make separate threads in Java, but to no avail. My situation is that I am using mplayer in Linux with my application, but the JFrame that I am using freezes after selecting the file and mplayer successfully being launched in the background and playing. The JFrame has a textbox that is trying to get the output of the command from the console using a simple BufferedReader.
private void jButton1MouseClicked(java.awt.event.MouseEvent evt) {                                     
           int status = musicfile_dialog.showOpenDialog(null);
           if (status == musicfile_dialog.APPROVE_OPTION)
                 File selectedFile = musicfile_dialog.getSelectedFile();
                 String[] cmd = {"mplayer", selectedFile.toString()};
                 try                        
                     int index = 0;
                     double current = 0.0;
                     double end = 0.0;
                     char[] split_up;
                     boolean output_percent = true;
                     String line;
                     Process p = Runtime.getRuntime().exec(cmd);
                     catch (InterruptedException interrupt)
                     BufferedReader input = new BufferedReader(new InputStreamReader(p.getInputStream()));
                     while ((line = input.readLine()) != null)
                         split_up = line.toCharArray();
                         for(int x=0;x<line.length();x++)
                             try{current = Double.parseDouble(String.valueOf(split_up[3]) + String.valueOf(split_up[4]) + String.valueOf(split_up[5]) + String.valueOf(split_up[6]) + String.valueOf(split_up[8])); output_percent = true;}
                             catch (NumberFormatException numf) // happens becuase mplayer outputs some junk at very beginning of output
                                 output_percent = false;
                             if(split_up[x]=='f')
                                 try{end = Double.parseDouble(String.valueOf(split_up[x+2]) + String.valueOf(split_up[x+3]) + String.valueOf(split_up[+4]) + String.valueOf(split_up[x+5])); output_percent = true;}
                                 catch (NumberFormatException numf2) // happens becuase mplayer outputs some junk at very beginning of output
                                     output_percent = false;
                             if(output_percent)
                                 double percent = (current/end)*100;
                                 String display_percent = Double.toString(percent);
                                 jTextField1.setText(jTextField1.getText() + "\n" + display_percent);
                                 System.out.println(display_percent);
                     input.close();
                catch (IOException e) { e.printStackTrace();}           
    } So essentially, I'm trying to make it so that the JFrame doesn't freeze up when given the command
jTextField1.setText(jTextField1.getText() + "\n" + display_percent);and also so that mplayer's console output is still available to the JFrame for processing.
Any ideas?
Thank you so much,
Andrew
Edited by: AndrewTheArt on Nov 4, 2007 6:29 AM

Answer 1

I've scoured the web trying to learn how to make separate threads in Java, but to no avail. Err.. the first Google hit - http://java.sun.com/docs/books/tutorial/essential/concurrency/ . Also there is a section of Threading within Swing in the Swing tutorial.