Process Management using JAVA

Question

I am developing a swing application in java that shows the memory usage of each process on my pc

The result should appear in a JTable

The JTable contains 4 columns :

• 1) Process name
• 2) PID
• 3) Session name
• 4) Memory usage

The JTable appear like

The JTable refresh itself each period using ProcessBuilder class

The problem that i felt that is method is a little bit slow and boring when the user see it

And my question:

Is there any other powerful method ? or what can i do in my code to enhance this application?

In the code :

The "processTable" field is the JTable dragged from palette (of type javax.swing.JTable)

The "status" field is the JLabel dragged also from palette (of type javax.swing.JLabel)

The method that i am used to display all the process is :

@SuppressWarnings("empty-statement")
    private void getProcessList() throws InterruptedException { 
        private DefaultTableModel table;        
        String filename = System.getProperty("java.io.tmpdir") + "\\list.txt", h;//to get %tmp%
        Scanner sc1 = null;
        int i, j, k = 0;
        table = (javax.swing.table.DefaultTableModel) processTable.getModel();
        processTable.editingStopped(null);
        table.setRowCount(0);
        try {
            ProcessBuilder builder = new ProcessBuilder("cmd.exe", "/c", "tasklist > %tmp%\\list.txt");
            builder.redirectErrorStream(true);
            Process p = builder.start();
            p.waitFor();
            try {
                sc1 = new Scanner(new File(filename));
                while (sc1.hasNext()) {
                    h = sc1.nextLine();
                    k++;
                }
                k = k - 5;
            } catch (FileNotFoundException ex) {
                System.out.println("File " + filename + " Not Found");
            };
            status.setText(" Processes: " + k);
            Object o[] = new Object[4];
            i = 0;
            try {
                j = 0;
                sc1 = new Scanner(new File(filename));
                while (sc1.hasNext()) {
                    st = new StringTokenizer(sc1.nextLine(), "\n");
                    i++;
                    if (i > 5) {
                        while (st.hasMoreTokens()) {
                            st1 = new StringTokenizer(st.nextToken(), " ");
                            if (st1.hasMoreTokens()) {
                                o[0] = st1.nextToken();
                            }
                            if (st1.hasMoreTokens()) {
                                h = st1.nextToken();
                                if (h.contains(".exe")) {
                                    o[0] = o[0] + " " + h;
                                    o[1] = st1.nextToken();
                                } else {
                                    o[1] = h;
                                }
                            }
                            if (st1.hasMoreTokens()) {
                                o[2] = st1.nextToken();
                            }
                            if (st1.hasMoreTokens()) {
                                h = st1.nextToken();
                            }
                            if (st1.hasMoreTokens()) {
                                o[3] = st1.nextToken();
                            }
                            if (st1.hasMoreTokens()) {
                                h = st1.nextToken();
                            }
                            table.addRow(o);
                            j++;
                        }
                    } else {
                        if (st.hasMoreTokens()) {
                            h = st.nextToken();
                        }
                    }
                }
            } catch (FileNotFoundException ex) {
                System.out.println("File " + filename + " Not Found");
            } catch (Exception ex) {
                System.out.println("UnknownError: " + ex.getMessage());
            } finally {
                if (sc1 != null) {
                    sc1.close();
                }
            }
        } catch (IOException ex) {
            Logger.getLogger(ProcessMan.class.getName()).log(Level.SEVERE, null, ex);
        }

    }

Upvotes: 1

Views: 1031

Answer 1

You can speed things up without too many changes by:

• Using a separate thread to poll running processes (instead of using the EDT); and writing any changes to the JTable's TableModel.
• Avoiding an intermediate file when calling tasklist, and instead reading all output to a string, which you would immediately parse.

Otherwise, you could go native: see https://stackoverflow.com/a/13478716/15472 for a example.