Loading a Knowledge Base#

The central class of the knowledge base persistence is the PersistenceManager that organizes the reading and writing of a knowledge base by a collection of plugins (KnowledgeReader, KnowledgeWriter, FragmentHandler). A d3web knowledge base is a jar file consisting of several files (mostly XML), and different plugins handle the different files contained in the jar. We refer to How-To Knowledge Persistence for a detailed description of how to implement your own PersistenceHandler plugin.

Of course the plugin manager has to be initialized. To run a small demo, you can use same initialization as in JUnit tests How-To Initialize Plugin Manager for JUnit Tests. After initialization, you are able to load the knowledge base into a KnowledgeBase instance by the following call

KnowledgeBase knowledgeBase = persistenceManager.load(new File(knowledgeFilename));

where knowledgeFilename is a simple file path, such as "/temp/carDiagnosis.jar".

Play a little bit around#

You are able to return the list of all solutions (Solution Javadoc) by

List<Solution> solutions = knowledgeBase.getManager().getSolutions();

Analogously, you retrieve a flat list of all questions of the knowledge base by

List<Question> questions = knowledgeBase.getManager().getQuestions();

The Complete Code Example#

// Initializing the plugins for the persistence 
InitPluginManager.init();
PersistenceManager persistenceManager = PersistenceManager.getInstance();
// Load knowledge base
KnowledgeBase knowledgeBase = persistenceManager.load(new File(knowledgeFilename));

List<Solution> solutions = knowledgeBase.getManager().getSolutions();
System.out.println(solutions);

List<Question> questions = knowledgeBase.getManager().getQuestions();
System.out.println(questions);