stockmidlet.java

j2me Demos for example

     * <p>This class is the Listener for ALL of the events that
     * take place during
     * life span of the <code>MIDlet</code>.  It handles <code>Command</code>
     * events and list selections which are the only events that this
     * <code>MIDlet</code> will generate.  In order to determine what to do,
     * the Listener checks the name of the command and the currently displayed
     * menu/list and matches them up to execute the appropriate action.</p>
     * <BR>
     * NOTE: The parseCommandString(String) is only there because the getXXX
     *       methods are missing from the Command class.  When they are added,
     *       this method can be removed and the Command.getLabel() can be used
     */
    private class StockCommandListener implements CommandListener, Runnable {
        /** Current command to process. */
        private Command currentCommand;

        /** Displayable of the current command to process. */
        private Displayable currentDisplayable;

        /** The current command processing thread. */
        private Thread commandThread;

        /**
         * <p>The method to determine what action to take</p>
         *
         * @param c The <code>Command</code> object that has been activated
         * @param d The <code>Displayable</code> object that the command was
         *          associated with
         */
        public void commandAction(Command c, Displayable d) {
            synchronized (this) {
                if (commandThread != null) {
                    // process only one command at a time
                    return;
                }

                currentCommand = c;
                currentDisplayable = d;
                commandThread = new Thread(this);
                commandThread.start();
            }
        }

        /**
         * Perform the current command set by the method commandAction.
         */
        public void run() {
            String type = currentCommand.getLabel();

            // Main command executed, always show Main Menu regardless of
            // which screen is showing
            if (type.equals("Main")) {
                mainMenu();

                // Back command executed, check which screen is and move to
                // the previous one
            } else if (type.equals("Back")) {
                // Screens off the Main Menu
                if (currentMenu.equals("View") || currentMenu.equals("WhatChoose") ||
                        currentMenu.equals("AlertMenu") || currentMenu.equals("Settings")) {
                    mainMenu();

                    // Screens off the Settings menu
                } else if (currentMenu.equals("Add") || currentMenu.equals("Updates") ||
                        currentMenu.equals("RemoveStock")) {
                    settings(false);
                } else if (currentMenu.equals("stockInfo")) {
                    chooseStock(false, "View", Choice.IMPLICIT, true);
                } else if (currentMenu.equals("WhatIfForm")) {
                    chooseStock(false, "WhatChoose", Choice.IMPLICIT, false);
                } else if (currentMenu.equals("AlertForm")) {
                    chooseStock(false, "AddAlert", Choice.IMPLICIT, false);
                } else if (currentMenu.equals("AnswerForm")) {
                    whatIfForm(stockSymbol);

                    // Screens off the Alerts menu
                } else if (currentMenu.equals("RemoveAlert") || currentMenu.equals("AddAlert")) {
                    alertMenu(false);
                } else if (currentMenu.equals("AddStock")) {
                    settings(false);
                }

                /*
                 * OK command executed, perform different actions
                 * depending on which screen is showing
                 */
            } else if (type.equals("Done")) {
                if (currentMenu.equals("AddStock")) {
                    if ((!stockSymbolBox.getString().trim().equals("")) &&
                            (addNewStock(stockSymbolBox.getString().trim()))) {
                        settings(true);
                    }
                } else if (currentMenu.equals("AlertForm")) {
                    setAlert(((TextBox)currentDisplayable).getString());
                    alertMenu(true);

                    // Remove an alert
                } else if (currentMenu.equals("RemoveAlert")) {
                    boolean[] chosen = new boolean[choose.size()];
                    choose.getSelectedFlags(chosen);

                    for (int i = 0; i < chosen.length; i++) {
                        if (chosen[i]) {
                            removeAlert(choose.getString(i));
                        }
                    }

                    alertMenu(true);

                    // Remove a Stock
                } else if (currentMenu.equals("RemoveStock")) {
                    boolean[] chosen = new boolean[choose.size()];
                    choose.getSelectedFlags(chosen);

                    for (int i = 0; i < chosen.length; i++) {
                        if (chosen[i]) {
                            deleteStock(choose.getString(i));
                        }
                    }

                    chosen = null;
                    settings(true);

                    // Set the quote update interval
                } else if (currentMenu.equals("Updates")) {
                    switch (updatesChoices.getSelectedIndex()) {
                    case 0:
                        refresh_interval = 30000;

                        break;

                    case 1:
                        refresh_interval = 900000;

                        break;

                    case 2:
                        refresh_interval = 1800000;

                        break;

                    case 3:
                        refresh_interval = 3600000;

                        break;

                    case 4:
                        refresh_interval = 10800000;

                        break;

                    default:
                        break;
                    }

                    stockRefreshTask.cancel();
                    stockRefreshTask = new StockRefreshTask();
                    stockRefresh.schedule(stockRefreshTask, 0, refresh_interval);
                    settings(true);
                }

                // Exit command executed
            } else if (type.equals("Exit")) {
                try {
                    destroyApp(true);
                } catch (MIDletStateChangeException msce) {
                    mainMenu();
                }

                // Calc command executed
            } else if (type.equals("Calc")) {
                if (origPurchPriceField.size() == 0) {
                    error("You must enter the price you originally " + "purchased the stock at.",
                        2000);
                } else {
                    if (numSharesField.size() == 0) {
                        error("You must specify the number of shares" + " to calculate with.", 2000);
                    } else {
                        calc();
                    }
                }

                /*
                 * No command button was pressed but a list selection
                 * was made
                 */
            } else {
                List shown = (List)display.getCurrent();

                /*
                 * if it's a menu not a list of stocks then we'll
                 * use a switch to select which action to perform
                 */
                if (currentMenu.equals("Main") || currentMenu.equals("Settings") ||
                        currentMenu.equals("AlertMenu")) {
                    switch (shown.getSelectedIndex()) {
                    case 0:

                        // View Stocks
                        if (currentMenu.equals("Main")) {
                            chooseStock(true, "View", Choice.IMPLICIT, true);

                            // Updates
                        } else if (currentMenu.equals("Settings")) {
                            updates();

                            // Add Alert
                        } else {
                            chooseStock(true, "AddAlert", Choice.IMPLICIT, false);
                        }

                        break;

                    case 1:

                        // What If?
                        if (currentMenu.equals("Main")) {
                            chooseStock(true, "WhatChoose", Choice.IMPLICIT, false);

                            // Add Stock
                        } else if (currentMenu.equals("Settings")) {
                            addStock();

                            // Remove Alert
                        } else {
                            viewAlerts();
                        }

                        break;

                    case 2:

                        // Alerts
                        if (currentMenu.equals("Main")) {
                            alertMenu(false);

                            // Remove Stock
                        } else if (currentMenu.equals("Settings")) {
                            chooseStock(true, "RemoveStock", Choice.MULTIPLE, false);
                        }

                        break;

                    case 3:

                        // Settings
                        if (currentMenu.equals("Main")) {
                            settings(false);
                        }

                        break;

                    default:
                        break;
                    }

                    /*
                     * we've now determined that it is a menu of stocks
                     * so we have to either show the stock info (from the
                     * View menu), add an alert (if Alert Choose screen is
                     * showing) or perform a What If? (if the What If?
                     * Choose screen is showing)
                     */
                } else {
                    if (currentMenu.equals("View")) {
                        displayStock(choose.getString(choose.getSelectedIndex())
                                           .substring(0,
                                choose.getString(choose.getSelectedIndex()).indexOf('@') - 1));
                    } else if (currentMenu.equals("WhatChoose")) {
                        if (choose.getSelectedIndex() >= 0) {
                            whatIfForm(choose.getString(choose.getSelectedIndex()));
                        }
                    } else if (currentMenu.equals("AddAlert")) {
                        if (choose.getSelectedIndex() >= 0) {
                            alertForm(choose.getString(choose.getSelectedIndex()));
                        }
                    }
                }
            }

            synchronized (this) {
                // signal that another command can be processed
                commandThread = null;
            }
        }
    }

    /**
     * <p>This is an extension of the <code>TimerTask</code> class which runs
     * when called by <code>Timer</code>.  It refreshes the stock info for
     * each stock from the quote server and checks to see if any of the alerts
     * should be fired.</p>
     *
     * @see java.util.TimerTask
     */
    private class StockRefreshTask extends TimerTask {
        /**
         * <p>Execute the Timer's Task</p>
         */
        public void run() {
            try {
                // Just return if the database is empty
                if (stocks.getNumRecords() == 0) {
                    return;
                }

                // Get all the records
                RecordEnumeration re = stocks.enumerateRecords();

                while (re.hasNextElement()) {
                    String tkrSymbol = Stock.getName(new String(re.nextRecord()));

                    try {
                        byte[] rec = getStockQuote(tkrSymbol).getBytes();

                        // Update the record and check for any alerts that
                        // may need to be executed
                        stocks.update(tkrSymbol, rec);
                        checkAlerts(tkrSymbol);
                    } catch (NumberFormatException nfe) {
                        error("\"" + tkrSymbol + "\" not found on server, or invalid data " +
                            "received from server", 2000);
                    }
                }
            } catch (Exception e) {
                error("Update Failed\n\nStocks were not updated", 2000);
            }
        }
    }
}