displayable.java

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    }

    /**
     * Get the current horizontal scroll position
     *
     * @return int The value of the current horizontal scroll position
     *             on a scale of 0-100
     */
    int getHorizontalScrollPosition() {
        return hScrollPosition;
    }

    /**
     * Get the current horizontal scroll proportion
     *
     * @return int The value of the current horizontal scroll proportion
     *             on a scale of 0-100
     */
    int getHorizontalScrollProportion() {
        return hScrollProportion;
    }

    /**
     * The vertical scroll position
     */
    private int vScrollPosition     = 0;
    /**
     * The vertical scroll proportion
     */
    private int vScrollProportion   = 100;

    /**
     * Set the vertical scroll position and proportion
     *
     * @param scrollPosition The vertical scroll position to set on a
     *                       scale of 0-100
     * @param scrollProportion The vertical scroll proportion to set on
     *                         a scale of 0-100. For example, if the viewport
     *                         is 25 pixels high and the Displayable is 100
     *                         pixels high, then the scroll proportion would
     *                         be 25, since only 25% of the Displayable can
     *                         be viewed at any one time. This proportion
     *                         value can be used by implementations which
     *                         render scrollbars to indicate scrollability
     *                         to the user.
     */
    void setVerticalScroll(int scrollPosition, int scrollProportion) {
        this.vScrollPosition = scrollPosition;
        this.vScrollProportion = scrollProportion;

        synchronized (Display.LCDUILock) {
            if ((currentDisplay != null) && currentDisplay.isShown(this)) {
                currentDisplay.setVerticalScroll(scrollPosition,
                                                 scrollProportion);
            }
        }
    }

    /**
     * Get the current vertical scroll position
     *
     * @return int The vertical scroll position on a scale of 0-100
     */
    int getVerticalScrollPosition() {
        return vScrollPosition;
    }

    /**
     * Get the current vertical scroll proportion
     *
     * @return ing The vertical scroll proportion on a scale of 0-100
     */
    int getVerticalScrollProportion() {
        return vScrollProportion;
    }

    // ************** private implementation ***********************

    /** The current Display object */
    Display currentDisplay;
    /** An array of Commands added to this Displayable */
    Command commands[];
    /** The number of Commands added to this Displayable */
    int numCommands;
    /** The CommandListener for Commands added to this Displayable */
    CommandListener listener;

    /**
     * Notify this Displayable it is being shown on the screen
     *
     * @param d The Display showing this Displayable
     */
    void showNotify(Display d) {
        synchronized (Display.LCDUILock) {
            showNotifyImpl(d);
        }

        // SYNC NOTE: Since showNotify() may result in a call into
        // application code, we first release LCDUILock and then
        // acquire calloutLock before making the call
        synchronized (Display.calloutLock) {
            // Protect from any unexpected application exceptions
            try {
                showNotify();
            } catch (Throwable thr) {
                Display.handleThrowable(thr);
            }
        }
    }

    /**
     * Notify this Displayable it is being hidden
     *
     * @param d The Display which is no longer showing this Displayable
     */
    void hideNotify(Display d) {
        synchronized (Display.LCDUILock) {
            hideNotifyImpl(d);
        }

        // SYNC NOTE: Since hideNotify() may result in a call into
        // application code, we first release LCDUILock and then
        // acquire calloutLock before making the call
        synchronized (Display.calloutLock) {
            // Protect from any unexpected application exceptions
            try {
                hideNotify();
            } catch (Throwable thr) {
                Display.handleThrowable(thr);
            }
        }
    }

    // This is the only implementation of showNotify in the LCDUI package
    /** Notify this Displayable it is being shown on the screen */
    void showNotify() { }

    // This is the only implementation of hideNotify in the LCDUI package
    /** Notify this Displayable it is being hidden */
    void hideNotify() { }

    /**
     * Notify this Displayable it is being shown on the screen
     *
     * @param d The Display showing this Displayable
     */
    void showNotifyImpl(Display d) {
        currentDisplay = d;
    }

    /**
     * Notify this Displayable it is being hidden
     *
     * @param d The Display which is no longer showing this Displayable
     */
    void hideNotifyImpl(Display d) {
        currentDisplay = null;
    }

    /**
     * Get the set of Commands that have been added to this Displayable
     *
     * @return Command[] The array of Commands added to this Displayable
     */
    Command[] getCommands() {
        return commands;
    }

    /**
     * Get the number of commands that have been added to this Displayable
     *
     * @return int The number of commands that have been added to this
     *              Displayable
     */
    int getCommandCount() {
        return numCommands;
    }

    /**
     * Get the CommandListener for this Displayable
     *
     * @return CommandListener The CommandListener listening to Commands on
     *                          this Displayable
     */
    CommandListener getCommandListener() {
        return listener;
    }

    /**
     * Add a Command to this Displayable
     *
     * @param cmd The Command to add to this Displayable
     */
    void addCommandImpl(Command cmd) {
        for (int i = 0; i < numCommands; ++i) {
            if (commands[i] == cmd) {
                return;
            }
        }

        if ((commands == null) || (numCommands == commands.length)) {
            Command[] newCommands = new Command[numCommands + 4];
            if (commands != null) {
                System.arraycopy(commands, 0, newCommands, 0, numCommands);
            }
            commands = newCommands;
        }

        commands[numCommands] = cmd;
        ++numCommands;

        if ((currentDisplay != null) && currentDisplay.isShown(this)) {
            currentDisplay.updateCommandSet();
        }
    }

    /**
     * Remove a Command from this Displayable
     *
     * @param cmd The Command to remove from this Displayable
     */
    void removeCommandImpl(Command cmd) {
        for (int i = 0; i < numCommands; ++i) {
            if (commands[i] == cmd) {
                commands[i] = commands[--numCommands];
                commands[numCommands] = null;

                if ((currentDisplay != null) &&
                        currentDisplay.isShown(this)) {
                    currentDisplay.updateCommandSet();
                }

                break;
            }
        }
    }
}