codepanel.java

this is decision tree ID3 algorithm, this algorithm is one of decision tree algorithm like cart, cha

    }
  }

  /**
   * Displays the function at the specified index
   * in the code window.  The index corresponds to the
   * position of the function in the original code file,
   * with the first function at index position 1.  This
   * method is thread-safe.
   *
   * @param index The index position of the function
   *        to display.  If the index is out of
   *        range, the display remains unchanged.
   */
  public void displayFunction( final int index )
  {
    if( index < 1 || index > m_functions.size() ) return;

    Runnable displayFunction =
      new Runnable() {
        public void run() {
          Vector listData =
            (Vector)m_functions.elementAt( index - 1 );
          m_list.setListData( listData );
          m_functionName =
            new String( (String)m_functionNames.elementAt( index - 1) );
        }
      };

    try {
      if( SwingUtilities.isEventDispatchThread() )
        displayFunction.run();
      else
        SwingUtilities.invokeLater( displayFunction );
    }
    catch( Exception e ) {
      e.printStackTrace();
    }
  }

  /**
   * Highlights the specified line of code in the
   * code window.  This method is thread-safe.
   *
   * @param lineNum The line number to highlight.
   *        The first line in the window is line 1.
   *        If the line number is out of range, the
   *        display remains unchanged.
   */
  public void notifyHighlight( final int lineNum )
  {
    if( lineNum < 1 || lineNum > m_list.getModel().getSize() ) return;

    Runnable highlight =
      new Runnable() {
        public void run() {
          m_list.ensureIndexIsVisible( lineNum - 1 );
          m_list.setSelectedIndex( lineNum - 1 );
        }
      };

    try {
      if( SwingUtilities.isEventDispatchThread() )
        highlight.run();
      else
        SwingUtilities.invokeLater( highlight );
    }
    catch( Exception e ) {
      e.printStackTrace();
    }
  }

  /**
   * Clears the highlighted line in the code window.
   * This method is thread-safe.
   */
  public void notifyClearHighlight()
  {
    Runnable clearHighlight =
      new Runnable() {
        public void run() {
          m_list.getSelectionModel().clearSelection();
        }
      };

    try {
      if( SwingUtilities.isEventDispatchThread() )
        clearHighlight.run();
      else
        SwingUtilities.invokeLater( clearHighlight );
    }
    catch( Exception e ) {
      e.printStackTrace();
    }
  }

  // Private methods

  /**
   * Builds and arranges the various GUI components
   * for this panel.
   */
  private void buildPanel()
  {
    GridBagLayout layout = new GridBagLayout();
    setLayout( layout );
    GridBagConstraints c = new GridBagConstraints();

    // Currently, there is only a single cell inside
    // the panel, which holds the scrollable list.
    c.gridx = 0;
    c.gridy = 0;
    c.gridwidth  = 1;
    c.gridheight = 1;
    c.weightx = 1.0;
    c.weighty = 1.0;
    c.fill = GridBagConstraints.BOTH;

    m_list = new JList();

    // The list is disabled, so the user can't manually
    // highlight lines of code.
    m_list.setEnabled( false );

    // Fix the cell height, so that lines of
    // pseudocode are spaced as closely as possible.
    m_list.setFixedCellHeight( ROW_HEIGHT );

    JScrollPane scrollPane = new JScrollPane( m_list );
    scrollPane.setHorizontalScrollBarPolicy(
      JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED );
    scrollPane.setVerticalScrollBarPolicy(
      JScrollPane.VERTICAL_SCROLLBAR_ALWAYS );

    layout.setConstraints( scrollPane, c );
    add( scrollPane );
  }

  /**
   * Parses the lines contained in the 'lines' Vector,
   * extracting and assembling the various functions.
   *
   * @throws InvalidCodeFileException If the code file
   *         contains a syntax error.
   */
  private void parseLines( Vector lines )
    throws InvalidCodeFileException
  {
    m_functions     = new Vector();
    m_functionNames = new Vector();

    while( true ) {
      // Find the start of a function.
      String text = null;

      if( lines.size() == 0 ) return;

      while( lines.size() != 0 ) {
        text = (String)lines.remove( 0 );

        if( text.indexOf( FUNCTION_START ) != -1 ) break;

        if( lines.size() == 0 ) return;
      }

      // Extract the name of the function and
      // store it.
      text = extractFunctionName( text );

      // Extract the lines of this function.
      extractFunctionLines( text, lines );
    }
  }

  /**
   * Extract the name of a function from a 'function'
   * tag contained in the supplied line of text.
   *
   * @return The remainder of the line, after the
   *         'function' tag has been removed, or null
   *         if the line is empty after the tag.
   *
   * @throws InvalidCodeFileException If a function
   *         name cannot be extracted.
   */
  private String extractFunctionName( String line )
    throws InvalidCodeFileException
  {
    // Ignore the start of the line.
    String parsedLine;

    int functionStart =
      line.indexOf( FUNCTION_START ) + FUNCTION_START.length();

    try {
      parsedLine = line.substring( functionStart );
    }
    catch( IndexOutOfBoundsException e ) {
      throw new
        InvalidCodeFileException( "Missing 'name' " +
        "parameter after function tag start." );
    }

    int nameStart;

    // Grab the function name.
    if( (nameStart = parsedLine.indexOf( NAME_START ) ) != -1 ) {
      nameStart += NAME_START.length();
      int nameEnd = parsedLine.indexOf( NAME_END );

      if( nameEnd > nameStart ) {
        // Extract name.
        m_functionNames.add( parsedLine.substring( nameStart, nameEnd ) );

        if( parsedLine.length() > (nameEnd + NAME_END.length()) )
          return parsedLine.substring( nameEnd + NAME_END.length() );
        else
          return null;
      }
      else {
        throw new
          InvalidCodeFileException( "Function name " +
            "missing or tag malformed." );
      }
    }
    else {
      throw new
        InvalidCodeFileException( "Function name " +
          "missing or tag malformed." );
    }
  }

  /**
   * Extract the lines of text that form the function
   * body.
   *
   * @param text A String containing any text remaining
   *        from previous parsing.
   *
   * @param lines Remaining lines of code text.
   *
   * @throws InvalidCodeFileException If the pseudo-code
   *         file contains a syntax error.
   *
   */
  private void extractFunctionLines( String text, Vector lines )
    throws InvalidCodeFileException
  {
    StringBuffer codeLine = new StringBuffer( HTML_LINE_HEADER );
    String       currLine = null;
    Vector       function = new Vector();

    if( text != null )
      currLine = new String( text );
    else
      currLine = new String();

    while( true ) {
      while( !currLine.endsWith( "." ) ) {
        if( currLine.length() > 0 )
          codeLine.append( currLine );

        if( lines.size() == 0 )
          throw new
            InvalidCodeFileException( "Missing " +
              "line terminator and closing function tag." );

        currLine = ((String)lines.remove( 0 )).trim();
      }

      // Strip the period off the end of the line.
      codeLine.append( currLine.substring( 0, currLine.length() - 1 ) );

      // Grabbed one complete line.
      String newLine = modifyTabs( codeLine ) + HTML_LINE_TERMINATOR;

      function.add( newLine );
      codeLine = new StringBuffer( HTML_LINE_HEADER );

      if( lines.size() == 0 )
        throw new
          InvalidCodeFileException( "Missing closing function tag." );

      currLine = (String)lines.remove( 0 );

      if( currLine.trim().endsWith( FUNCTION_END ) ) {
        m_functions.add( function );
        return;
      }
    }
  }

  /**
   * Performs a search and replace, removing all the tab
   * markers on a line and replacing them with their
   * HTML equivalent.
   *
   * @return A String with all tab markers converted
   *         to HTML 'non-breaking' spaces.
   */
  private String modifyTabs( StringBuffer text )
  {
    while( true ) {
      String line = text.toString();

      int pos;

      if( (pos = line.indexOf( TAB_MARKER )) == - 1 ) return text.toString();
        text.replace( pos, pos + TAB_MARKER.length(), TAB );
    }
  }
}