public CellReference(String cellRef) 
{
                                   
        String[] parts = separateRefParts(cellRef);
        _sheetName = parts[0];
        String colRef = parts[1]; 
        if (colRef.length() <  1) {
            throw new IllegalArgumentException("Invalid Formula cell reference: '"+cellRef+"'");
        }
        _isColAbs = colRef.charAt(0) == '$";
        if (_isColAbs) {
            colRef=colRef.substring(1);
        }
        _colIndex = convertColStringToNum(colRef);
        String rowRef=parts[2];
        if (rowRef.length() <  1) {
            throw new IllegalArgumentException("Invalid Formula cell reference: '"+cellRef+"'");
        }
        _isRowAbs = rowRef.charAt(0) == '$";
        if (_isRowAbs) {
            rowRef=rowRef.substring(1);
        }
        _rowIndex = Integer.parseInt(rowRef)-1; // -1 to convert 1-based to zero-based
}

Create an cell ref from a string representation. Sheet names containing special characters should be delimited and escaped as per normal syntax rules for formulas.

 public CellReference(int pRow,
    int pCol,
    boolean pAbsRow,
    boolean pAbsCol) 
{
        this(null, pRow, pCol, pAbsRow, pAbsCol);
}

 public CellReference(String pSheetName,
    int pRow,
    int pCol,
    boolean pAbsRow,
    boolean pAbsCol) 
{
        // TODO - "-1" is a special value being temporarily used for whole row and whole column area references.
        // so these checks are currently N.Q.R.
        if(pRow <  -1) {
            throw new IllegalArgumentException("row index may not be negative");
        }
        if(pCol <  -1) {
            throw new IllegalArgumentException("column index may not be negative");
        }
        _sheetName = pSheetName;
        _rowIndex=pRow;
        _colIndex=pCol;
        _isRowAbs = pAbsRow;
        _isColAbs=pAbsCol;
}

  void appendCellReference(StringBuffer sb) 
{
        if(_isColAbs) {
            sb.append(ABSOLUTE_REFERENCE_MARKER);
        }
        sb.append( convertNumToColString(_colIndex));
        if(_isRowAbs) {
            sb.append(ABSOLUTE_REFERENCE_MARKER);
        }
        sb.append(_rowIndex+1);
}

Appends cell reference with '$' markers for absolute values as required. Sheet name is not included.

 protected static String convertNumToColString(int col) 
{
        String retval = null;
        int mod = col % 26;
        int div = col / 26;
        char small=(char)(mod + 65);
        char big = (char)(div + 64);
        if (div == 0) {
            retval = ""+small;
        } else {
            retval = ""+big+""+small;
        }
        return retval;
}

Takes in a 0-based base-10 column and returns a ALPHA-26 representation. eg column #3 -> D

 public String formatAsString() 
{
        StringBuffer sb = new StringBuffer(32);
        if(_sheetName != null) {
            SheetNameFormatter.appendFormat(sb, _sheetName);
            sb.append(SHEET_NAME_DELIMITER);
        }
        appendCellReference(sb);
        return sb.toString();
}

Example return values:

Result	Comment
A1	Cell reference without sheet
Sheet1!A1	Standard sheet name
'O''Brien''s Sales'!A1'	Sheet name with special characters

 public short getCol() 
{
return (short) _colIndex;
}

 public int getRow() 
{
return _rowIndex;
}

 public String getSheetName() 
{
        return _sheetName;
}

 public boolean isColAbsolute() 
{
return _isColAbs;
}

 public boolean isRowAbsolute() 
{
return _isRowAbs;
}

 public String toString() 
{
        StringBuffer sb = new StringBuffer(64);
        sb.append(getClass().getName()).append(" [");
        sb.append(formatAsString());
        sb.append("]");
        return sb.toString();
}