Universal Network Objects Explained

Universal Network Objects (UNO) is the component model used in the OpenOffice.org and LibreOffice computer software application suites. It is interface-based and designed to offer interoperability between different programming languages, object models and machine architectures, on a single machine, within a LAN or over the Internet.

Users can implement or access UNO components from any programming language for which a language binding exists. Complete UNO language bindings exist for C++ (compiler-dependent), Java, Object REXX, Python, and Tcl. Bindings allowing access, but not writing, to components exist for StarOffice Basic, OLE Automation and the .NET Common Language Infrastructure. In particular, this API is used by macros.

Universal Network Objects operate within the UNO Runtime Environment (URE).^[1]

The Apache OpenOffice version of UNO is released under the terms Apache License (Version 2) as free and open source software.

UNO for function-calling

Examples: an external program can export an ODT file as a PDF file, or import and convert a DOCX, calling LibreOffice by the UNO interface. Another external program can access a cell and formulas from LibreOffice Calc file.

Application examples: Docvert,^[2] JODConverter,^[3] unoConv.^[4]

UNO for Add-Ons

Programmers can write and integrate their own UNO components to OpenOffice/LibreOffice. Those components can be added to the LibreOffice menus and toolbars; they are called "Add-Ons".^[5] The Add-Ons can extend the functionality of LibreOffice.

The integration of new components is supported by some tools and services. The three main steps are as follows:^[5]

1. Register the new components within LibreOffice. This can be accomplished using the tool unopkg.
2. Integrate the new components as services. The ProtocolHandler and JobDispatch services assist you.
3. Change the user interface (menus or toolbars). This can be done almost automatically by writing an XML text file that describes the changes.

Application example: jOpenDocument.^[6]

External links

Apache OpenOffice

• UNO Development Kit project page
• Overview and technical details
• Java overview-summary
• OpenOffice.org Software Development Kit
• ODF Toolkit: Transition Steps
• Developer's Guide

LibreOffice

• see unoexe and unopkg
• Inside LibreOffice: Universal Network Objects

Language bridges (native for Java and Python)

• UNO for Object REXX
• UNO for PHP (written in C++)
• UNO for FreePascal/Delphi maybe orphaned

Notes and References

1. Web site: Universal I18n Framework for Office Applications: Technical Overview . Dieter . Loeschky . Shanmugam Senthil . 2001 . Sun Microsystems . Palo Alto . 1–26 [8] . PDF . 18 May 2010 .
2. Web site: Docvert - Office to Open Standards. holloway.co.nz. Bronwyn Holloway-Smith. 20 September 2014.
3. Web site: JODConverter. jodconverter.com. 5 September 2017.
4. Web site: DAG: unoconv: Convert between any document format supported by OpenOffice. Dag Wieërs. 20 September 2014.
5. Web site: Integrating new UNO components. 20 September 2014.
6. Web site: jOpenDocument Homepage. Open Document library. 20 September 2014.