The topic map programming model embodies two major pieces of work - the development of a topic map data model; and the development of an object-oriented API for mainstream object-oriented languages such as Java, C++ and Python. In our opinion, it is the latter which is the important end-product of this process and it is that which we focus on in this paper. Our justification for focusing on the API is that it should be possible for any data model which supports a complete implementation of the topic map concepts to be mapped to a standard API which provides access to topic map constructs.
Standard APIs are in general a Good Thing. The benefits of a standard API are reduced developer learning curve, application portability and the enabling of widespread library development.
By introducing a standard API for topic maps, a developer can take her knowledge from one implementation of a topic map system to another without having to spend significant amounts of time learning a new API. Additionally, by standardising on a single API, training material and developer support communities need not be restricted to the vendors - this would make it possible for a much larger body of training material to be made available to the topic map "newbie". An extant example of this is the number of DOM API training courses which are available (A quick Google search lists 6,260 hits for the search string "DOM API Training")
For organisations making investment in developing topic map applications, the existence of a standard API provides a degree of protection for that investment. The current situation for topic map application developers is that moving between systems would require a complete rewrite of the customised code, so despite having invested in a portable format for information organisation and exchange, customers are still locked-in to a particular vendor's implementation by the APIs used to develop their bespoke applications or application extensions.
A standard API for topic map access and manipulation would also allow developers to create higher-level application development libraries and tools which are portable across all systems implementing that API. This could enable the development of high-level toolkits such as standard indexing and querying APIs, toolkits for topic map generation from meta data sources and topic map visualisation and navigation applications. Again, XML's SAX and DOM show the way, with applications ranging from transformation (XSLT) to content management applications (e.g. Cocoon) all being created on top of these standard access and manipulation APIs.
Standard APIs also enable easier integration of the technology within the wide-spread wide-spread consumer applications such as web browsers and operating systems.
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