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This page was last updated
Thursday 25 September 2003
This UML class diagram provides a birds-eye view of how the XAO library
is modelled. Member attributes and methods are not shown (maintained) in
the diagram. We suggest using this diagram in concert with the
where member attributes and methods
are fully detailed.
Introducing the XAO classes
If you haven;t alread read the nutshell concept summary
on the front page, then please do so now.
Which classes you need to know about
The good news is that you really only need to know about the 2 classes
listed in bold type. Most of the other classes are simply there to support
these. Most of the classes under construction are for advanced applications
with special needs.
|implemented and ready for use
All the core classes to the XAO framework are here. They are
enough for most applications.
These should come online fairly quickly since all the
groundwork is done (XaoRoot, DomDoc, Exceptions).
UML class diagram (names only)
Move your mouse pointer over a class to see a brief description tool-tip
(IE only). Click on it to see the methods/attributes documentation (opens in
XaoRoot forms the basis of all
classes in the XAO library and is pretty thin. The class that gives
XAO it's real personality is
DomDoc, because it is the base content
class that represents an XML packet. The
AppDoc class which
represents the entire content document for any given script is a
class. An instantiation of an
AppDoc based class
is an XML
DbToXML class is a
DomDoc class because
it contains business payload data. DbToXml is really just a utlity class
and sites along side other user-defined classes which represent business
data (destined to be aggregated). Any user-defined
class that represents content should inherit
DomDoc or at
least have it somewhere in it's ancestory. Any class that
does NOT inherit from the
DomDoc class in XAO is
not considdered to be a content-related class. Content means
business payload, not system data.
In the diagram, the linkages which have "child" written on the
DomDoc end of the don't point directly to
as suggested in the diagram. "child" means that it is pointing
to a derivative (child) of the class. So, for instance, DbToXml qualifies
in this relationsip but it is not shown on the diagram.
Exceptional condition messaging
Notice that the
Exceptions class is only bound to
DomDoc, meaning that
only classes inheriting from
DomDoc can use them. This is because the
messaging that the
Exceptions class is concerned with is neccesarily
embedded in the content payload encapsulated as XML (in the separate
Classes listed with the framework sterotype represent end-user entry
points into an application that implements the XAO as a framework.
AppDoc based classes
service remote applications based clients and browser
based clients respectively.
(represented using the "speculative" sterotype)
The content classes based on, and including,
designed to be inherited by the end-user. In any medium to large-scale
application, the developer is not expected to instatiate these classes
directly. Doing so would reduce the scalability and flexibility that OO