zcl_excel_writer API Reference

Complete API reference for the Excel writer classes in abap2xlsx.

Overview

The writer classes in abap2xlsx are responsible for converting the in-memory Excel object model into actual Excel files. The library provides several writer implementations for different formats and use cases src/zcl_excel_writer_2007.clas.abap:1-10.

Writer Interface

zif_excel_writer

All writer classes implement the zif_excel_writer interface src/zcl_excel_writer_2007.clas.abap:9, which provides a consistent API for file generation.

Core Method:

• write_file() - Generates Excel file content

Standard Excel Writer (XLSX)

zcl_excel_writer_2007

The primary writer class for generating Excel 2007+ (.xlsx) files src/zcl_excel_writer_2007.clas.abap:1-4.

Constructor

DATA: lo_writer TYPE REF TO zcl_excel_writer_2007.
CREATE OBJECT lo_writer.

write_file( )

Generates the complete Excel file as an xstring.

Parameters:

• io_excel - Reference to zcl_excel workbook object

Returns: xstring containing the Excel file data

Raises: zcx_excel

DATA: lo_excel TYPE REF TO zcl_excel,
      lo_writer TYPE REF TO zcl_excel_writer_2007,
      lv_file_data TYPE xstring.

CREATE OBJECT lo_writer.
lv_file_data = lo_writer->write_file( lo_excel ).

Internal Architecture

The writer follows a structured approach to Excel file generation src/zcl_excel_writer_2007.clas.abap:331-420:

1. Archive Creation: Creates ZIP container structure
2. Content Types: Defines MIME types for Excel components src/zcl_excel_writer_2007.clas.abap:597-630
3. Relationships: Establishes document relationships
4. Document Properties: Adds metadata and properties src/zcl_excel_writer_2007.clas.abap:931-990
5. Workbook Structure: Creates workbook.xml
6. Styles: Generates styles.xml with formatting definitions
7. Shared Strings: Optimizes text storage
8. Worksheets: Processes individual sheet data
9. Media Content: Handles images and charts src/zcl_excel_writer_2007.clas.abap:511-630

Key Internal Methods

create_xl_sheet( )

Creates individual worksheet XML content src/zcl_excel_writer_2007.clas.abap:125-132.

Parameters:

• io_worksheet - Worksheet object reference
• iv_active - Flag indicating if this is the active sheet

Returns: xstring containing worksheet XML

create_xl_styles( )

Generates the styles.xml file containing all formatting definitions src/zcl_excel_writer_2007.clas.abap:154-156.

Returns: xstring containing styles XML

create_xl_sharedstrings( )

Creates the shared strings XML for text optimization src/zcl_excel_writer_2007.clas.abap:122-124.

Returns: xstring containing shared strings XML

Macro-Enabled Writer (XLSM)

zcl_excel_writer_xlsm

Specialized writer for macro-enabled Excel files src/zcl_excel_writer_xlsm.clas.abap:1-4.

Inheritance Structure

CLASS zcl_excel_writer_xlsm DEFINITION
  PUBLIC
  INHERITING FROM zcl_excel_writer_2007

The XLSM writer extends the standard writer with VBA project support src/zcl_excel_writer_xlsm.clas.abap:37-45.

VBA Project Handling

The XLSM writer adds VBA project content to the Excel file:

" Add vbaProject.bin to zip
io_zip->add( name    = me->c_xl_vbaproject
             content = me->excel->zif_excel_book_vba_project~vbaproject ).

Usage Example

DATA: lo_excel TYPE REF TO zcl_excel,
      lo_writer TYPE REF TO zcl_excel_writer_xlsm.

" Create macro-enabled writer
CREATE OBJECT lo_writer.

" Generate XLSM file
DATA(lv_xlsm_data) = lo_writer->write_file( lo_excel ).

High-Performance Writer

zcl_excel_writer_huge_file

Optimized writer for processing very large datasets src/zcl_excel_writer_huge_file.clas.abap:1-6.

Key Features

• Memory Efficiency: Uses streaming approach for large files
• Simple Transformation: Leverages XSLT for XML generation src/zcl_excel_writer_huge_file.clas.abap:41-115
• Reduced Feature Set: Focuses on core functionality for performance

Cell Data Structure

TYPES:
  BEGIN OF ty_cell,
    name    TYPE c LENGTH 10, "AAA1234567"
    style   TYPE i,
    type    TYPE c LENGTH 9,
    formula TYPE string,
    value   TYPE string,
  END OF ty_cell .

Usage Pattern

DATA: lo_huge_writer TYPE REF TO zcl_excel_writer_huge_file.

CREATE OBJECT lo_huge_writer.

" Process large dataset efficiently
lo_huge_writer->get_cells( i_row = lv_row i_index = lv_index ).
DATA(lv_file) = lo_huge_writer->write_file( lo_excel ).

CSV Writer

zcl_excel_writer_csv

Simple writer for CSV format output.

Usage

DATA: lo_csv_writer TYPE REF TO zcl_excel_writer_csv.

CREATE OBJECT lo_csv_writer.
DATA(lv_csv_data) = lo_csv_writer->write_file( lo_excel ).

Writer Selection Guidelines

Choose the Right Writer

METHOD select_appropriate_writer.
  DATA: lo_writer TYPE REF TO zif_excel_writer.

  " Decision logic for writer selection
  IF iv_has_macros = abap_true.
    " Use XLSM writer for macro support
    CREATE OBJECT lo_writer TYPE zcl_excel_writer_xlsm.
    
  ELSEIF iv_row_count > 100000.
    " Use huge file writer for large datasets
    CREATE OBJECT lo_writer TYPE zcl_excel_writer_huge_file.
    
  ELSEIF iv_simple_data = abap_true.
    " Use CSV writer for simple tabular data
    CREATE OBJECT lo_writer TYPE zcl_excel_writer_csv.
    
  ELSE.
    " Use standard writer for normal cases
    CREATE OBJECT lo_writer TYPE zcl_excel_writer_2007.
  ENDIF.

  " Generate file
  DATA(lv_file_data) = lo_writer->write_file( io_excel ).
ENDMETHOD.

Advanced Writer Features

Custom Content Extension

The writer architecture supports extension through the add_further_data_to_zip() method src/zcl_excel_writer_2007.clas.abap:55-57:

" Override in child classes to add custom content
METHODS add_further_data_to_zip
  IMPORTING
    !io_zip TYPE REF TO cl_abap_zip .

XML Document Utilities

The writer provides utility methods for XML processing src/zcl_excel_writer_2007.clas.abap:224-231:

" Create XML document
METHODS create_xml_document
  RETURNING
    VALUE(ro_document) TYPE REF TO if_ixml_document.

" Render XML to xstring
METHODS render_xml_document
  IMPORTING
    io_document       TYPE REF TO if_ixml_document
  RETURNING
    VALUE(ep_content) TYPE xstring.

Error Handling

All writer methods can raise zcx_excel exceptions. Implement proper error handling:

TRY.
    DATA(lv_file) = lo_writer->write_file( lo_excel ).
    
  CATCH zcx_excel INTO DATA(lx_excel).
    MESSAGE lx_excel->get_text( ) TYPE 'E'.
ENDTRY.

Performance Considerations

Memory Management

• Standard Writer: Suitable for typical business reports (< 50,000 rows)
• Huge File Writer: Optimized for large datasets (> 100,000 rows)
• Streaming: Consider processing data in batches for very large files

File Size Optimization

• Shared Strings: Automatically optimizes repeated text values
• Style Reuse: Reuse style objects to minimize file size
• Image Compression: Optimize images before adding to workbook

Best Practices

1. Writer Selection: Choose appropriate writer based on requirements
2. Error Handling: Always wrap write operations in TRY-CATCH
3. Memory: Clear large objects after file generation
4. Testing: Test with representative data volumes
5. Format: Use XLSX for rich formatting, CSV for simple data exchange

Related Classes

• zcl_excel - Source workbook object
• zcl_excel_worksheet - Individual worksheet data
• zcl_excel_reader_2007 - Corresponding reader functionality
• cl_abap_zip - ZIP archive management for XLSX format