logcanvas.java

MoMELog是J2ME的日志框架。它是非常简单的

   * Sets given line at specified position.
   * 
   * @param i
   *          position of line to set.
   * @param line
   *          line to set.
   */
  private void setLine(int i, char[] line)
  {
    this.page[getLinePos(i)] = line;
  }

  /**
   * Returns position of EOL of line at specified position.
   * 
   * @param i
   *          position of line, EOL offset of which to return.
   * @return position of EOL of line.
   */
  private int getEOL(int i)
  {
    return this.eols[getLinePos(i)];
  }

  /**
   * Sets position of EOL of line at specified position.
   * 
   * @param i
   *          position of line, EOL offset of which to set.
   * @param eol
   *          EOL offset to set.
   */
  private void setEOL(int i, int eol)
  {
    this.eols[getLinePos(i)] = eol;
  }

  /**
   * Retruns line's offset in array
   * 
   * @param pos
   *          position of line.
   * @return line's offset in array
   */
  private int getLinePos(int pos)
  {
    pos += this.shift;
    if (pos > this.lpp)
      pos -= this.lpp + 1;
    if (pos < 0)
      pos += this.lpp + 1;
    return pos;
  }

  /**
   * Scrolls screen one line down.
   */
  protected void nextLine()
  {
    if (this.needScrollBar && getEOL(this.lpp - 1) < this.text.length())
    {
      this.vStart = getEOL(0);
      this.shift++;
      if (this.shift > this.lpp)
        this.shift = 0;
      this.lines--;
      grabNextLines();
      show();
      if (this.needScrollBar)
        showScrollBar();
      flushGraphics();
      repaint();
    }
  }

  /**
   * Scrolls screen one page (all fully visible on page lines except two) down.
   */
  protected void nextPage()
  {
    if (this.needScrollBar && getEOL(this.lpp - 1) < this.text.length())
    {
      this.vStart = getEOL(this.lpp - 3);
      this.shift += this.lpp - 2;
      if (this.shift > this.lpp)
        this.shift -= this.lpp + 1;
      this.lines = 3;
      grabNextLines();
      show();
      if (this.needScrollBar)
        showScrollBar();
      flushGraphics();
      repaint();
    }
  }

  /**
   * Scrolls logging screen one line up.
   */
  protected void prevLine()
  {
    if (this.needScrollBar && this.vStart > 0)
    {
      if (this.lines > this.lpp)
        this.lines--;
      grabPrevLines();
      show();
      if (this.needScrollBar)
        showScrollBar();
      flushGraphics();
      repaint();
    }
  }

  /**
   * Scrolls logging screen to top.
   */
  protected void topLine()
  {
    if (this.needScrollBar && this.vStart > 0)
    {
      this.vStart = this.lines = this.shift = 0;
      grabNextLines();
      show();
      if (this.needScrollBar)
        showScrollBar();
      flushGraphics();
      repaint();
    }
  }

  /**
   * Scrolls logging screen to bottom.
   */
  protected void bottomLine()
  {
    int textLength = this.text.length();
    if (this.needScrollBar && getEOL(this.lpp - 1) < textLength)
    {
      this.lines = this.shift = 0;
      this.vStart = textLength;
      grabNextLines();
      show();
      if (this.needScrollBar)
        showScrollBar();
      flushGraphics();
      repaint();
    }
  }

  /**
   * Scrolls one page (all visible on page lines except two) up.
   */
  protected void prevPage()
  {
    if (this.vStart > 0)
    {
      this.lines = 3;
      grabPrevLines();
      show();
      if (this.needScrollBar)
        showScrollBar();
      flushGraphics();
      repaint();
    }
  }

  /**
   * Renders scrollbar on buffer.
   */
  protected void showScrollBar()
  {
    Graphics g = graphics();
    g.setColor(this.scrollBarColor);
    g.fillRect(this.textWidthView, 0, 3, this.height);
    int end = getEOL(this.lpp - 1);
    int sStart = this.height * this.vStart / this.text.length();
    int sLength = this.height * (end - this.vStart) / this.text.length() + 1;
    if (sLength < 5)
    {
      sLength = 5;
      int d = sStart + sLength - this.height;
      if (d > 0)
        sStart -= d;
    }
    if (this.vStart == 0 || end == this.text.length())
      g.setColor(this.scrollBarCursorEdgeColor);
    else g.setColor(this.scrollBarCursorColor);
    g.fillRect(this.textWidthView, sStart, 3, sLength);
  }

  /**
   * Renders view on buffer.
   */
  void show()
  {
    Graphics g = graphics();
    g.setColor(this.bgColor);
    g.fillRect(0, 0, this.textWidthView, this.height);
    g.setColor(this.fgColor);
    g.setFont(this.font);
    int curY = 0;
    for (int i = 0; i < this.lines; curY += this.fontHeight, i++)
    {
      char[] line = getLine(i);
      g.drawChars(line, 2, line[1], 0, curY, TOP_LEFT);
    }
  }

  /**
   * Initializes logging screen.
   */
  private void initTextView()
  {
    this.textWidthView = this.width;
    this.lines = this.shift = 0;
    grabNextLines();
    this.needScrollBar = this.lines > this.lpp || this.vStart > 0;
    if (this.needScrollBar)
    {
      this.textWidthView -= 3;
      this.lines = this.shift = 0;
      grabNextLines();
    }
    show();
    if (this.needScrollBar)
      showScrollBar();
    flushGraphics();
    repaint();
  }

  /**
   * Caches next possible not accessed lines.
   * 
   * @return {@code true} if some lines were cached, {@code false} otherwise.
   */
  private boolean grabNextLines()
  {
    boolean res = false;
    int textLength = this.text.length();
    for (int end = this.lines > 0 ? getEOL(this.lines - 1) : this.vStart; end < textLength
        && this.lines <= this.lpp; this.lines++)
    {
      res = true;
      end = grabNextLine(end, this.lines);
    }

    for (; this.vStart > 0 && this.lines < this.lpp; this.lines++)
    {
      this.shift--;
      if (this.shift < 0)
        this.shift = this.lpp;
      res = true;
      this.vStart = grabPrevLine(this.vStart, 0);
    }
    return res;
  }

  /**
   * Caches previous possible not accessed lines.
   * 
   * @return {@code true} if some lines were cached, {@code false} otherwise.
   */
  private boolean grabPrevLines()
  {
    boolean res = false;

    for (; this.vStart > 0 && this.lines <= this.lpp; this.lines++)
    {
      this.shift--;
      if (this.shift < 0)
        this.shift = this.lpp;
      res = true;
      this.vStart = grabPrevLine(this.vStart, 0);
    }

    for (int end = getEOL(this.lines - 1); end < this.text.length()
        && this.lines <= this.lpp; this.lines++)
    {
      res = true;
      end = grabNextLine(end, this.lines);
    }
    return res;
  }

  /**
   * Caches next line at specified position starting from specified offset.
   * 
   * @param start
   *          offset to start grabbing from.
   * @param linePos
   *          position of line to cache to.
   * @return offset of next line.
   */
  private int grabNextLine(int start, int linePos)
  {
    char c = 0;
    int l = 2;
    char[] line = getLine(linePos);
    int lineSize = line[0] + 2;
    for (int w = 0; start < this.text.length()
        && (c = this.text.charAt(start)) != '\n'
        && (w += this.font.charWidth(c)) <= this.textWidthView; start++)
    {
      if (l == lineSize)
      {
        int newSize = lineSize * 2;
        char[] newLine = new char[newSize];
        System.arraycopy(line, 1, newLine, 1, lineSize - 1);
        setLine(linePos, line = newLine);
        line[0] = (char) ((lineSize = newSize) - 2);
      }
      line[l++] = c;
    }
    line[1] = (char) (l - 2);

    if (c == '\n')
      start++;
    setEOL(linePos, start);
    return start;
  }

  /**
   * Caches previous line at specified position starting from specified offset.
   * 
   * @param start
   *          offset to start grabbing from.
   * @param linePos
   *          position of line to cache to.
   * @return offset of previous line.
   */
  private int grabPrevLine(int start, int linePos)
  {
    if (start > 0)
    {
      char[] line = getLine(linePos);
      setEOL(linePos, start);
      int lineSize = line[0];
      int l = lineSize + 1;
      char c = this.text.charAt(--start);
      if (c == '\n')
        start--;
      for (int w = 0; start >= 0 && (c = this.text.charAt(start)) != '\n'
          && (w += this.font.charWidth(c)) <= this.textWidthView; start--)
      {
        if (l == 1)
        {
          int newSize = (lineSize + 2) * 2;
          char[] newLine = new char[newSize];
          l = newSize - lineSize - 1;
          System.arraycopy(line, 2, newLine, l + 1, lineSize);
          setLine(linePos, line = newLine);
          line[0] = (char) (lineSize = newSize - 2);
        }
        line[l--] = c;
      }
      int ll = lineSize - (++l) + 2;
      System.arraycopy(line, l, line, 2, ll);
      line[1] = (char) ll;
      start++;
    }
    return start;
  }

  /**
   * Formats given logging event by configured {@link Formatter} and appends it
   * to the buffer. Sends command to refresh it's view.
   * 
   * @see momelog.LogListener#onLog(momelog.LogEvent)
   */
  public void onLog(LogEvent event)
  {
    Formatter formatter = Logger.getFormatter();
    formatter.format(event, this.text);
    this.text.append('\n');
    pushCommand(APPEND_LOG);

  }

  /*
   * (non-Javadoc)
   * 
   * @see javax.microedition.lcdui.Canvas#keyPressed(int)
   */
  protected void keyPressed(int keyCode)
  {
    switch (keyCode)
    {
    case RESET_KEY:
      pushCommand(RESET);
      break;

    case TOGGLE_FULLSCREEN_KEY:
      pushCommand(TOGGLE_FULLSCREEN);
      break;

    case TOP_LINE_KEY:
      pushCommand(TOP_LINE);
      break;

    case BOTTOM_LINE_KEY:
      pushCommand(BOTTOM_LINE);
      break;

    default:
      keyRepeated(keyCode);
    }
  }

  /*
   * (non-Javadoc)
   * 
   * @see javax.microedition.lcdui.Canvas#keyRepeated(int)
   */
  protected void keyRepeated(int keyCode)
  {
    switch (getGameAction(keyCode))
    {
    case NEXT_LINE_KEY:
      pushCommand(NEXT_LINE);
      break;

    case PREV_LINE_KEY:
      pushCommand(PREV_LINE);
      break;

    case NEXT_PAGE_KEY:
      pushCommand(NEXT_PAGE);
      break;

    case PREV_PAGE_KEY:
      pushCommand(PREV_PAGE);
      break;

    }
  }

  /**
   * Pushes command to the commands execution thread.
   * 
   * @param cmd
   *          An object identifying the command.
   * @since 1.0
   */
  void pushCommand(Object cmd)
  {
    synchronized (this.executorLock)
    {
      this.cmds.addElement(cmd);
      this.executorLock.notifyAll();
    }
  }

  /**
   * Pops command from queue.
   * 
   * @return - The first Command in the execution queue if there is one,
   *         {@code null} otherwise.
   * @since 1.0
   */
  private Object popCommand()
  {
    Object res = null;
    synchronized (this.executorLock)
    {
      while (this.runner != null && res == null)
      {
        if (this.cmds.size() > 0)
        {
          res = this.cmds.firstElement();
          this.cmds.removeElementAt(0);
        } else
        {