Apache POI

Apache POI, a project run by the Apache Software Foundation, and previously a sub-project of the Jakarta Project, provides pure Java libraries for reading and writing files in Microsoft Office formats, such as Word, PowerPoint and Excel.

Apache POI
Developer(s)Apache Software Foundation
Stable release
4.1.2 / February 14, 2020 (2020-02-14)[1]
RepositoryPOI Repository
Written inJava
Operating systemCross-platform
TypeAPI to access Microsoft Office formats
LicenseApache License 2.0
Websitepoi.apache.org

History and roadmap

The name was originally an acronym for "Poor Obfuscation Implementation",[2] referring humorously to the fact that the file formats seemed to be deliberately obfuscated, but poorly, since they were successfully reverse-engineered. This explanation – and those of the similar names for the various sub-projects – were removed from the official web pages in order to better market the tools to businesses who would not consider such humor appropriate. The original authors (Andrew C. Oliver and Marc Johnson) also noted the existence of the Hawaiian poi dish, made of mashed taro root, which had similarly derogatory connotations.[3]

Office Open XML support

POI supports the ISO/IEC 29500:2008 Office Open XML file formats since version 3.5. A significant contribution for OOXML support came from Sourcesense,[4] an open source company which was commissioned by Microsoft to develop this contribution.[5] This link spurred controversy, some POI contributors questioning POI OOXML patent protection regarding Microsoft's Open Specification Promise patent license.[6]

Architecture

The Apache POI project contains the following subcomponents (meaning of acronyms is taken from old documentation):

  • POIFS (Poor Obfuscation Implementation File System[2]) – This component reads and writes Microsoft's OLE 2 Compound document format. Since all Microsoft Office files are OLE 2 files, this component is the basic building block of all the other POI elements. POIFS can therefore be used to read a wider variety of files, beyond those whose explicit decoders are already written in POI.
  • HSSF (Horrible SpreadSheet Format[2]) – reads and writes Microsoft Excel (XLS) format files. It can read files written by Excel 97 onwards; this file format is known as the BIFF 8 format. As the Excel file format is complex and contains a number of tricky characteristics, some of the more advanced features cannot be read.
  • XSSF (XML SpreadSheet Format) – reads and writes Office Open XML (XLSX) format files. Similar feature set to HSSF, but for Office Open XML files.
  • HPSF (Horrible Property Set Format[2]) – reads "Document Summary" information from Microsoft Office files. This is essentially the information that one can see by using the File|Properties menu item within an Office application.
  • HWPF (Horrible Word Processor Format[7]) – aims to read and write Microsoft Word 97 (DOC) format files. This component is in initial stages of development.
  • XWPF (XML Word Processor Format[7]) – similar feature set to HWPF, but for Office Open XML files.
  • HSLF (Horrible Slide Layout Format[7]) – a pure Java implementation for Microsoft PowerPoint files. This provides the ability to read, create and edit presentations (though some things are easier to do than others)
  • HDGF (Horrible DiaGram Format[7]) – an initial pure Java implementation for Microsoft Visio binary files. It provides an ability to read the low level contents of the files.
  • HPBF (Horrible PuBlisher Format) – a pure Java implementation for Microsoft Publisher files.[8]
  • HSMF (Horrible Stupid Mail Format[9]) – a pure Java implementation for Microsoft Outlook MSG files.[10]
  • DDF (Dreadful Drawing Format[7]) – a package for decoding the Microsoft Office Drawing format.

The HSSF component is the most advanced feature of the library.[11] Other components (HPSF, HWPF, and HSLF) are usable, but less full-featured.[12][13]

The POI library is also provided as a Ruby[14] or ColdFusion extension.

There are modules for Big Data platforms (e.g. Apache Hive/Apache Flink/Apache Spark), which provide certain functionality of Apache POI, such as the processing of Excel files.[15][16]

Version history
Legend: Old version, not maintained Older version, still maintained Current stable version Latest preview version Future release

Version number

 Date of release
Current stable version: 4.1.2 14. February 2020
Old version, no longer maintained: 4.1.1 20. October 2019
Old version, no longer maintained: 4.1.0 09. April 2019
Old version, no longer maintained: 4.0.0 07. September 2018
Old version, no longer maintained: 3.17 15. September 2017
Old version, no longer maintained: 3.16 19. April 2017
Old version, no longer maintained: 3.15 21. September 2016
Old version, no longer maintained: 3.14 2. March 2016
Old version, no longer maintained: 3.13 29. September 2015
Old version, no longer maintained: 3.12 11. May 2015
Old version, no longer maintained: 3.11 21. December 2014
Old version, no longer maintained: 3.10.1 18. August 2014
Old version, no longer maintained: 3.10 8. February 2014
Old version, no longer maintained: 3.9 3. December 2012
Old version, no longer maintained: 3.8 26. March 2012
Old version, no longer maintained: 3.7 29. October 2010
Old version, no longer maintained: 3.6 14. December 2009
Old version, no longer maintained: 3.5 28. September 2009
Old version, no longer maintained: 3.2 19. October 2008
Old version, no longer maintained: 3.1 29. June 2008
Old version, no longer maintained: 3.0.2 4. February 2008
Old version, no longer maintained: 3.0.1 5. July 2007
Old version, no longer maintained: 3.0 18. May 2007
Old version, no longer maintained: 2.5.1 29. February 2004
Old version, no longer maintained: 2.5 29. February 2004
Old version, no longer maintained: 2.0 26. January 2004
Old version, no longer maintained: 1.5.1 16. June 2002
Old version, no longer maintained: 1.5 6. May 2002
Old version, no longer maintained: 1.2.0 19. January 2002
Old version, no longer maintained: 1.1.0 4. January 2002
Old version, no longer maintained: 1.0.2 11. January 2002
Old version, no longer maintained: 1.0.1 4. January 2002
Old version, no longer maintained: 1.0.0 30. December 2001
gollark: In practice it doesn't apply to very big things.
gollark: Ah yes.
gollark: Which bit are you complaining about specifically?
gollark: It seems like he thought he found it, but it doesn't actually *work*.
gollark: That's not really true though.

See also

References
  1. "History of Changes". 2020-02-14. Retrieved 2020-02-15.
  2. Sundaram, Elango (22 March 2004), "Excelling in Excel with Java", JavaWorld, retrieved 2020-07-21
  3. POI homepage from October 2004, Coyote Song, archived from the original on 2004-10-15, showing original explanations for naming.
  4. SourceSense
  5. McDougall, Paul (26 March 2008). "Microsoft Eyes Open Source Components for Office 2007". InformationWeek. Retrieved 2020-07-21.
  6. Oliver, Andrew C. (27 March 2008), "Rejection of any ENCUMBERED Microsoft Donation to POI", POI development mailing list archives, retrieved 2020-07-21
  7. "POI API Documentation". Poi.apache.org. Retrieved 2019-03-07.
  8. "POI-HPBF - Java API To Access Microsoft Publisher Format Files". Poi.apache.org. Retrieved 2019-03-07.
  9. Codeplex NPOI, Microsoft, archived from the original on 2012-03-28
  10. POI-HSMF, Apache, archived from the original on 2011-08-07, retrieved 2011-07-31
  11. POI-HSSF, Apache
  12. POI-HWPF, Apache
  13. POI-HSLF, Apache
  14. POI-Ruby, Apache
  15. "HadoopOffice for Hive/Flink/Spark". Github.com. 2018-07-19. Retrieved 2019-03-07.
  16. "Spark Excel". Github.com. Retrieved 2019-03-07.
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