OpenOffice.org BASIC Guide - OpenOffice.org wiki

Modules, Services and Interfaces
Modules, Services and Interfaces
OpenOffice.org provides hundreds of services. To provide an overview of these services, they have been
combined into modules. The modules are of no other functional importance for OpenOffice.org Basic
programmers. When specifying a service name, it is only the module name which is of any importance because
this must be also listed in the name. The complete name of a service consists of the com.sun.star expression,
which specifies that it is a OpenOffice.org service, followed by the module name, such as frame, and finally the
actual service name, such as Desktop. The complete name in the named example would be:
com.sun.star.frame.Desktop
In addition to the module and service terms, UNO introduces the term 'interface'. While this term may be
familiar to Java programmers, it is not used in Basic.
An interface combines several methods. In the strictest sense of the word, a service in UNO does not support
methods, but rather interfaces, which in turn provide different methods. In other words, the methods are assigned
(as combinations) to the service in interfaces. This detail may be of interest in particular to Java- or C++
programmers, since in these languages, the interface is needed to request a method. In OpenOffice.org Basic, this
is irrelevant. Here, the methods are called directly by means of the relevant object.
For an understanding of the API, it is, however, useful to have the assignment of methods to various interfaces
handy, since many interfaces are used in the different services. If you are familiar with an interface, then you can
transfer your knowledge from one service to another.
Some central interfaces are used so frequently, triggered by different services, that they are shown again at the end
of this chapter.
Tools for Working with UNO
The question remains as to which objects — or services if we are going to remain with UNO terminology —
support which properties, methods and interfaces and how these can be determined. In addition to this guide, you
can get more information about objects from the following sources: the supportsService method, the debug
methods as well as the Developer's Guide, and the API reference.
The supportsService Method
A number of UNO objects support the supportsService method, with which you can establish whether an
object supports a particular service. The following call, for example, determines whether the TextElement object
supports the com.sun.star.text.Paragraph service.
Ok = TextElement.supportsService("com.sun.star.text.Paragraph")
Debug Properties
Every UNO object knows what properties, methods and interfaces it already contains. OpenOffice.org Basic
provides properties that return these in the form of a string containing a list. The corresponding properties are:
DBG_properties
returns a string containing all properties of an object
DBG_methods
returns a string containing all methods of an object
DBG_supportedInterfaces
returns a string containing all interfaces which support an object.
Chapter 4 · Introduction to the API 53