static int convertCellType(int val) 
{
        switch (val) {
            case CELL_TYPE_INTEGER :
            case CELL_TYPE_FLOAT :
                return HSSFCell.CELL_TYPE_NUMERIC;
            case CELL_TYPE_STRING :
                return HSSFCell.CELL_TYPE_STRING;
            case CELL_TYPE_FORMULA :
                return HSSFCell.CELL_TYPE_FORMULA;
            default :
                return HSSFCell.CELL_TYPE_BLANK;
        }
}

Convert a CellType enum into an HSSFCell enum

 public static boolean isValid(int val) 
{
        switch (val) {
            case CELL_TYPE_EMPTY :
            case CELL_TYPE_BOOLEAN :
            case CELL_TYPE_INTEGER :
            case CELL_TYPE_FLOAT :
            case CELL_TYPE_ERROR :
            case CELL_TYPE_STRING :
            case CELL_TYPE_FORMULA :
            case CELL_TYPE_CELLRANGE :
            case CELL_TYPE_ARRAY :
                return true;
            default :
                return false;
        }
}

Is this a valid cell type?