headerfooter.java

一个非常有用的操作MCRSOFT EXCEL文件的工具。可以用JAVA方便的新建

     * determine if fontName is a valid font.
     * 
     * @param fontName name of the font to use
     */
    protected void setFontName(String fontName)
    {
      // Font name must be in quotations
      appendInternal("&\"");
      appendInternal(fontName);
      appendInternal('\"');
    }

    /**
     * Sets the font size of text subsequently appended to this
     * object. Previously appended text is not affected.
     * <p/>
     * Valid point sizes are between 1 and 99 (inclusive). If
     * size is outside this range, this method returns false
     * and does not change font size. If size is within this
     * range, the font size is changed and true is returned. 
     * 
     * @param size The size in points. Valid point sizes are
     * between 1 and 99 (inclusive).
     * @return true if the font size was changed, false if font
     * size was not changed because 1 > size > 99. 
     */
    protected boolean setFontSize(int size)
    {
      if (size < 1 || size > 99)
      {
        return false;
      }
  	
      // A two digit number should be used -- even if the
      // leading number is just a zero.
      String fontSize;
      if (size < 10) 
      {
  	  // single-digit -- make two digit
        fontSize = "0" + size; 
      }
      else
      {
        fontSize = Integer.toString(size);
      }
  	
      appendInternal('&');
      appendInternal(fontSize);
      return true;
    }
  
    /**
     * Appends the page number
     */
    protected void appendPageNumber()
    {
      appendInternal(PAGENUM);
    }
  
    /**
     * Appends the total number of pages
     */
    protected void appendTotalPages()
    {
      appendInternal(TOTAL_PAGENUM);
    }
  
    /**
     * Appends the current date
     */
    protected void appendDate()
    {
      appendInternal(DATE); 
    }
  
    /**
     * Appends the current time
     */
    protected void appendTime()
    {
      appendInternal(TIME);
    }
  
    /**
     * Appends the workbook name
     */
    protected void appendWorkbookName()
    {
      appendInternal(WORKBOOK_NAME);
    }
    
    /**
     * Appends the worksheet name
     */
    protected void appendWorkSheetName()
    {
      appendInternal(WORKSHEET_NAME);
    }

    /**
     * Clears the contents of this portion
     */
    protected void clear()
    {
      contents = null;
    }

    /**
     * Queries if the contents are empty
     *
     * @return TRUE if the contents are empty, FALSE otherwise
     */
    protected boolean empty()
    {
      if (contents == null || contents.length() == 0)
      {
        return true;
      }
      else
      {
        return false;
      }
    }
  }

  /**
   * The left aligned header/footer contents
   */
  private Contents left;

  /**
   * The right aligned header/footer contents
   */
  private Contents right;

  /**
   * The centrally aligned header/footer contents
   */
  private Contents centre;

  /**
   * Default constructor.
   */
  protected HeaderFooter()
  {
    left = createContents();
    right = createContents();
    centre = createContents();
  }

  /**
   * Copy constructor
   *
   * @param c the item to copy
   */
  protected HeaderFooter(HeaderFooter hf)
  {
    left = createContents(hf.left);
    right = createContents(hf.right);
    centre = createContents(hf.centre);
  }

  /**
   * Constructor used when reading workbooks to separate the left, right
   * a central part of the strings into their constituent parts
   */
  protected HeaderFooter(String s)
  {
    if (s == null || s.length() == 0)
    {
      left = createContents();
      right = createContents();
      centre = createContents();
      return;
    }

    int pos = 0;
    int leftPos = s.indexOf(LEFT_ALIGN);
    int rightPos = s.indexOf(RIGHT_ALIGN);
    int centrePos = s.indexOf(CENTRE);

    // Do the left position string
    if (pos == leftPos)
    {
      if (centrePos != -1)
      {
        left = createContents(s.substring(pos + 2, centrePos));
        pos = centrePos;
      }
      else if (rightPos != -1 )
      {
        left = createContents(s.substring(pos + 2, rightPos));
        pos = rightPos;
      }
      else
      {
        left = createContents(s.substring(pos + 2));
        pos = s.length();
      }
    }

    // Do the centrally positioned part of the string.  This is the default
    // if no alignment string is specified
    if (pos == centrePos ||
        (leftPos == -1 && rightPos == -1 && centrePos == -1))
    {
      if (rightPos != -1)
      {
        centre = createContents(s.substring(pos + 2, rightPos));
        pos = rightPos;
      }
      else
      {
        centre = createContents(s.substring(pos + 2));
        pos = s.length();
      }
    }

    // Do the right positioned part of the string
    if (pos == rightPos)
    {
      right = createContents(s.substring(pos + 2));
      pos = s.length();
    }

    if (left == null)
    {
      left = createContents();
    }

    if (centre == null)
    {
      centre = createContents();
    }

    if (right == null)
    {
      right = createContents();
    }
  }

  /**
   * Retrieves a <code>String</code>ified
   * version of this object
   *
   * @return the header string
   */
  public String toString()
  {
    StringBuffer hf = new StringBuffer();
    if (!left.empty())
    {
      hf.append(LEFT_ALIGN);
      hf.append(left.getContents());
    }

    if (!centre.empty())
    {
      hf.append(CENTRE);
      hf.append(centre.getContents());
    }

    if (!right.empty())
    {
      hf.append(RIGHT_ALIGN);
      hf.append(right.getContents());
    }

    return hf.toString();
  }

  /**
   * Accessor for the contents which appear on the right hand side of the page
   *
   * @return the right aligned contents
   */
  protected Contents getRightText()
  {
    return right;
  }

  /**
   * Accessor for the contents which in the centre of the page
   *
   * @return the centrally  aligned contents
   */
  protected Contents getCentreText()
  {
    return centre;
  }

  /**
   * Accessor for the contents which appear on the left hand side of the page
   *
   * @return the left aligned contents
   */
  protected Contents getLeftText()
  {
    return left;
  }

  /**
   * Clears the contents of the header/footer
   */
  protected void clear()
  {
    left.clear();
    right.clear();
    centre.clear();
  }

  /**
   * Creates internal class of the appropriate type
   */
  protected abstract Contents createContents();

  /**
   * Creates internal class of the appropriate type
   */
  protected abstract Contents createContents(String s);

  /**
   * Creates internal class of the appropriate type
   */
  protected abstract Contents createContents(Contents c);
}