Once, you have created a KnowledgeBase instance (for example, by Loading a knowledge base), you can run a problem-solving session. During a problem-solving session you enter Question-Value pairs (Fact) and the system will derive appropriate solutions for the entered facts.
Sessions are represented by instances of Session. Use the SessionFactory to quickly create a new Session instance for the KnowledgeBase instance:
Session session = SessionFactory.createSession(knowledgeBase);
The Interview, which can be accessed from the session by using the interview problem solver (PSMethod), determines the next question to be presented to the user. More precisely, a FormStrategy computes the next From that is presented in the dialog. A Form consists of a title and a list of active questions:
Interview interview = session.getSessionObject(session.getPSMethodInstance(PSMethodInterview.class)); Form form = interview.nextForm(); List<Question> activeQuestions = form.getActiveQuestions();
To retrieve a single question contained in the Form you may use the NextUnansweredQuestionFormStrategy. This can be explicitly set by
interview.setFormStrategy(new NextUnansweredQuestionFormStrategy());
Next, we subsequently add facts to the session. When already having the appropriate instances of Question and Value, respectively, we are able to simply set the value by
Question question = kb.getManager().searchQuestion("QuestionName"); ChoiceValue value = new ChoiceValue("ChoiceName"); Fact fact = FactFactory.createFact(session, question, value, PSMethodUserSelected.getInstance(), PSMethodUserSelected.getInstance()); session.getBlackboard().addValueFact(fact);
Please note, that we create a new Fact having the question and value. Additionally, the source of the fact is the User (PSMethodUserSelected) and the corresponding problem-solver is also the user. In different scenarios, the source may be the instance of a Rule used in the context of a particular PSMethod instance.
We retrieve the list of derived solutions together with their state by iterating over all solutions in the knowledge base and by asking for a diagnosis Rating that is different from UNCLEAR. This way, we return solution instances with states ESTABLISHED, SUGGESTED, and EXCLUDED.
for (Solution solution : knowledgeBase.getManager().getSolutions()) { Rating state = session.getBlackboard().getRating(solution); if (!state.hasState(Rating.State.UNCLEAR)) out.println(" " + solution + " (" + state + ")"); }
Sometimes it is easier (and a bit faster) to just get all solutions in a particular state, e.g. all established solutions:
out.println("All established solutions:"); for (Solution solution : session.getBlackboard().getSolutions(Rating.State.ESTABLISHED)) { out.println(solution); }
You can simply retrieve all entered facts by the following code block:
for (ProtocolEntry entry : session.getProtocol().getProtocolHistory()) { out.println(entry); }
Please note, that the session manages a Protocol, where entered findings (question/value tuples) are stored in a chronological order.
Note: The current version of the full example should be found in d3web-GlobalTests as the class de.d3web.demos.RunningACase.
public void runDemoCase() throws IOException { KnowledgeBase knowledgeBase = buildKnowledgeBase(); PrintStream out = System.out; // Create a case (problem-solving session and set // all specified question/answers out.println("+++ Setting values +++"); Session session = SessionFactory.createSession(knowledgeBase); // set: pregnant = yes Fact fact1 = FactFactory.createUserEnteredFact( pregnant, yes); session.getBlackboard().addValueFact(fact1); out.println(fact1); // set: weight = 80 Fact fact2 = FactFactory.createUserEnteredFact( weight, new NumValue(80)); session.getBlackboard().addValueFact(fact2); out.println(fact2); // Print all solutions with a state != UNCLEAR out.println("+++ Solutions +++"); for (Solution solution : knowledgeBase.getManager().getSolutions()) { Rating state = session.getBlackboard().getRating(solution); if (!state.hasState(Rating.State.UNCLEAR)) { out.println(" " + solution + " (" + state + ")"); } } // Show all entered findings out.println("+++ Entered Questions +++"); for (ProtocolEntry entry : session.getProtocol().getProtocolHistory()) { out.println(" " + entry); } } private KnowledgeBase buildKnowledgeBase() throws IOException { // root {container} // - demoQuestion {containers} // -- pregnant [oc] // -- weight [num] // Solution: dangerousMood InitPluginManager.init(); KnowledgeBase kb = KnowledgeBaseUtils.createKnowledgeBase(); QASet root = kb.getRootQASet(); demoQuestions = new QContainer(root, "demoQuestions"); pregnant = new QuestionOC(demoQuestions, "pregnant", "yes", "no"); yes = new ChoiceValue(KnowledgeBaseUtils.findChoice(pregnant, "yes")); weight = new QuestionNum(demoQuestions, "weight"); dangerousMood = new Solution(kb.getRootSolution(), "dangerousMood"); // Define the init questionnaire kb.setInitQuestions(Arrays.asList(demoQuestions)); // Define the magic rule: preganant=yes AND weight > 70 => dangerousMood // (P7) List<Condition> terms = new ArrayList<Condition>(); terms.add(new CondEqual(pregnant, yes)); terms.add(new CondNumGreater(weight, (double) 70)); RuleFactory.createHeuristicPSRule(dangerousMood, Score.P7, new CondAnd(terms)); return kb; }