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

/*********************************************************************
 *
 *      Copyright (C) 2004 Andrew Khan, Eric Jung
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 ***************************************************************************/

package jxl.biff;

import common.Assert;
import common.Logger;

/**
 * Class which represents an Excel header or footer. Information for this
 * class came from Microsoft Knowledge Base Article 142136 
 * (previously Q142136).
 *
 * This class encapsulates three internal structures representing the header
 * or footer contents which appear on the left, right or central part of the 
 * page
 */
public abstract class HeaderFooter
{
  /**
   * The logger
   */
  private static Logger logger = Logger.getLogger(HeaderFooter.class);

  // Codes to format text

  /**
   * Turns bold printing on or off
   */
  private static final String BOLD_TOGGLE = "&B";

  /**
   * Turns underline printing on or off
   */
  private static final String UNDERLINE_TOGGLE = "&U";

  /**
   * Turns italic printing on or off
   */
  private static final String ITALICS_TOGGLE = "&I";

  /**
   * Turns strikethrough printing on or off
   */
  private static final String STRIKETHROUGH_TOGGLE = "&S";

  /**
   * Turns double-underline printing on or off
   */
  private static final String DOUBLE_UNDERLINE_TOGGLE = "&E";

  /**
   * Turns superscript printing on or off
   */
  private static final String SUPERSCRIPT_TOGGLE = "&X";

  /**
   * Turns subscript printing on or off
   */
  private static final String SUBSCRIPT_TOGGLE = "&Y";

  /**
   * Turns outline printing on or off (Macintosh only)
   */
  private static final String OUTLINE_TOGGLE = "&O";

  /**
   * Turns shadow printing on or off (Macintosh only)
   */
  private static final String SHADOW_TOGGLE = "&H";

  /**
   * Left-aligns the characters that follow
   */
  private static final String LEFT_ALIGN = "&L";

  /**
   * Centres the characters that follow
   */
  private static final String CENTRE = "&C";

  /**
   * Right-aligns the characters that follow
   */
  private static final String RIGHT_ALIGN = "&R";
  
  // Codes to insert specific data

  /**
   * Prints the page number
   */
  private static final String PAGENUM = "&P";

  /**
   * Prints the total number of pages in the document
   */
  private static final String TOTAL_PAGENUM = "&N";

  /**
   * Prints the current date
   */
  private static final String DATE = "&D";

  /**
   * Prints the current time
   */
  private static final String TIME = "&T";

  /**
   * Prints the name of the workbook
   */
  private static final String WORKBOOK_NAME = "&F";

  /**
   * Prints the name of the worksheet
   */
  private static final String WORKSHEET_NAME = "&A";

  /**
   * The contents - a simple wrapper around a string buffer
   */
  protected static class Contents
  {
    /**
     * The buffer containing the header/footer string
     */
    private StringBuffer contents;

    /**
     * The constructor
     */
    protected Contents()
    {
      contents = new StringBuffer();
    }

    /**
     * Constructor used when reading worksheets.  The string contains all
     * the formatting (but not alignment characters
     *
     * @param s the format string
     */
    protected Contents(String s)
    {
      contents = new StringBuffer(s);
    }

    /**
     * Copy constructor
     *
     * @param copy the contents to copy
     */
    protected Contents(Contents copy)
    {
      contents = new StringBuffer(copy.getContents());
    }

    /**
     * Retrieves a <code>String</code>ified
     * version of this object
     *
     * @return the header string
     */
    protected String getContents()
    {
      return contents != null ? contents.toString() : "";
    }

    /**
     * Internal method which appends the text to the string buffer
     *
     * @param txt
     */
    private void appendInternal(String txt)
    {
      if (contents == null)
      {
        contents = new StringBuffer();
      }

      contents.append(txt);
    }

    /**
     * Internal method which appends the text to the string buffer
     *
     * @param ch
     */
    private void appendInternal(char ch)
    {
      if (contents == null)
      {
        contents = new StringBuffer();
      }

      contents.append(ch);
    }

    /**
     * Appends the text to the string buffer
     *
     * @param txt
     */
    protected void append(String txt)
    {
      appendInternal(txt);
    }
  
    /**
     * Turns bold printing on or off. Bold printing
     * is initially off. Text subsequently appended to
     * this object will be bolded until this method is
     * called again.
     */
    protected void toggleBold()
    {
     appendInternal(BOLD_TOGGLE);
    }

    /**
     * Turns underline printing on or off. Underline printing
     * is initially off. Text subsequently appended to
     * this object will be underlined until this method is
     * called again.
     */
    protected void toggleUnderline()
    {
      appendInternal(UNDERLINE_TOGGLE);
    }

    /**
     * Turns italics printing on or off. Italics printing
     * is initially off. Text subsequently appended to
     * this object will be italicized until this method is
     * called again.
     */
    protected void toggleItalics()
    {
      appendInternal(ITALICS_TOGGLE);
    }

    /**
     * Turns strikethrough printing on or off. Strikethrough printing
     * is initially off. Text subsequently appended to
     * this object will be striked out until this method is
     * called again.
     */
    protected void toggleStrikethrough()
    {
      appendInternal(STRIKETHROUGH_TOGGLE);
    }  

    /**
     * Turns double-underline printing on or off. Double-underline printing
     * is initially off. Text subsequently appended to
     * this object will be double-underlined until this method is
     * called again.
     */
    protected void toggleDoubleUnderline()
    {
      appendInternal(DOUBLE_UNDERLINE_TOGGLE);
    }      

    /**
     * Turns superscript printing on or off. Superscript printing
     * is initially off. Text subsequently appended to
     * this object will be superscripted until this method is
     * called again.
     */
    protected void toggleSuperScript()
    {
      appendInternal(SUPERSCRIPT_TOGGLE);
    } 	

    /**
     * Turns subscript printing on or off. Subscript printing
     * is initially off. Text subsequently appended to
     * this object will be subscripted until this method is
     * called again.
     */
    protected void toggleSubScript()
    {
      appendInternal(SUBSCRIPT_TOGGLE);
    }   
    
    /**
     * Turns outline printing on or off (Macintosh only).
     * Outline printing is initially off. Text subsequently appended
     * to this object will be outlined until this method is
     * called again.
     */
    protected void toggleOutline()
    {
     appendInternal(OUTLINE_TOGGLE);
    }
    
    /**
     * Turns shadow printing on or off (Macintosh only).
     * Shadow printing is initially off. Text subsequently appended
     * to this object will be shadowed until this method is
     * called again.
     */
    protected void toggleShadow()
    {
      appendInternal(SHADOW_TOGGLE);
    }
    
    /**
     * Sets the font of text subsequently appended to this
     * object.. Previously appended text is not affected.
     * <p/>
     * <strong>Note:</strong> no checking is performed to