If you wish your application to use an Application Ontology object configured from the application's configuration file, you can make use of the application section handler that is part of the TMCore library. To do this you will need to add the following line into the configSections part of the application configuration file:

<section name="ontology" type="NetworkedPlanet.TMCore.Utils.OntologySectionHandler, tmcore"/>

From within your code, you can then use this section handler to retrieve an instance of the NetworkedPlanet.TMCore.Utils.ApplicationOntology class that represents the configured Application Ontology. e.g.

ApplicationOntology ontology = 
  System.Configuration.ConfigurationSettings.GetConfig(
    "ontology") as ApplicationOntology;

If you wish to use the XML configuration from some configuration file other than the application configuration file, you must instead pass the XmlElement object that represents the ontology element to the constructor of the ApplicationOntology class. e.g.

ApplicationOntology applicationOntology;
XmlDocument configDoc = new XmlDocument();
configDoc.Load("myconfig.xml")
XmlElement ontologyElement = configDoc.SelectSingleNode("/config/ontology");
if (ontologyElement != null) {
  applicationOntology = new ApplicationOntology(ontologyElement);
} else {
  applicationOntology = new ApplicationOntology();
}

Finally, it is also possible to set up all of the mappings for the Application Ontology directly from code. The methods for doing this are ApplicationOntology.AddPrefix(string shortIdPrefix, string subjectIdentifierPrefix) and ApplicationOntology.AddIdentifier(string shortId, string subjectIdentifier). e.g.

ApplicationOntology ontology = new ApplicationOntology();
ontology.AddPrefix("org", "http://www.networkedplanet.com/2005/01/organisation/");
ontology.AddIdentifier("title", "http://purl.org/dc/1.1/title");

The second step in configuring an ApplicationOntology instance for use is to specify the topic map or topic maps on which it operates. These topic maps are the ones in which the Application Ontology object will search for topics by their full subject identifier. The Application Ontology object will search the topic maps it is connected to in strict order, returning the first topic that matches. A topic map can be added to the end of the search list using the method ApplicationOntology.AddTopicMap(ITopicMap tm) and can be removed using the method ApplicationOntology.RemoveTopicMap(ITopicMap tm). e.g.

ITopicMap coreMap = m_topicMapSystem.GetTopicMap("core.xtm");
ontology.AddTopicMap(coreMap)

In some cases you may want to combine a predefined set of mappings that are set up programatically with a user-defined set of mappings which could be specified in an app.config or other XML configuration file. To support this you may nest one ApplicationOntology instance within another. Every ApplicationOntology instance supports just one nested instance. When an ApplicationOntology is asked to map a short identifier, it will first attempt to perform the mapping to a full subject identifier and then to a topic using its own configured mappings and topic maps, if that fails to find a match the short identifier will then be passed to the nested ApplicationOntology instance for it to resolve (and if that instance cannot resolve the short identifier, it will in turn pass the identifier on to its nested instance - if any - and so on).

The nested ontology can only be specified through the use of the appropriate constructor for the ApplicationOntology object. e.g.

// Get the inner ontology from the application configuration file
ApplicationOntology innerOntology = 
  System.Configuration.ConfigurationSettings.GetConfig(
    "ontology") as ApplicationOntology;

// Create an outer ontology programatically:
ApplicationOntology outerOntology = new ApplicationOntology(innerOntology);
outerOntology.AddPrefix("org", "http://www.networkedplanet.com/2005/01/organisation/");