Docs::ClassSummary

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.

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 new window).

Central structure

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 DomDoc class. An instantiation of an AppDoc based class is an XML application object. The 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.

Relationships to DomDoc children

In the diagram, the linkages which have "child" written on the DomDoc end of the don't point directly to DomDoc 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 XAO namespace).

Different frameworks

Classes listed with the framework sterotype represent end-user entry points into an application that implements the XAO as a framework. RpcController and AppDoc based classes service remote applications based clients and browser based clients respectively.

User-Defined classes
(represented using the "speculative" sterotype)

The content classes based on, and including, DomDoc (such as DbToXml) are 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 programming facilitates.