Getting Started

Requirements

This example requires Java (JDK) 7 or newer.
Download the following package graal-getting-started-with-kb-example.zip and extract it where you want.

Build

Open a terminal and go into the extracted folder. Then, execute the following command:

javac -cp getting-started-with-kb-example-1.3.1.jar fr/lirmm/graphik/graal/examples/getting_started/GettingStarted.java

Run the example

Execute the following command:

java -cp getting-started-with-kb-example-1.3.1.jar fr/lirmm/graphik/graal/examples/getting_started/GettingStarted ./data/

What does this example do?

Create a KBBuilder:


    KBBuilder kbb = new KBBuilder();

Load an ontology and facts from a DLGP file:


    kbb.addAll(new DlgpParser(new File(rootDir, "animals.dlp")));

Generate the KnowledgeBase, by default facts are stored in main memory:
```
    KnowledgeBase kb = kbb.build();
    
```
Create a DLGP writer:
```
    writer = new DlgpWriter();
    
```

Print the ontology in DLGP format:


    writer.write("\n= Ontology =\n");
    writer.write(kb.getOntology());

Print the facts in DLGP format:


    writer.write("\n= Facts =\n");
    writer.write(kb.getFacts());

Parse a query from a Java String and print it:


    ConjunctiveQuery query = DlgpParser.parseQuery("?(X) :- mammal(X).");
    writer.write("\n= Query =\n");
    writer.write(query);

Query the KB, here the KB will use the RulesSetAnalyser module to analyze the rule base and select a query answering technique (ie saturation, rewriting or a combination of both) :
CloseableIterator resultIterator = kb.query(query);

Iterate and print the answers:
if (resultIterator.hasNext()) { do { writer.write(resultIterator.next().toString()); writer.write("\n"); } while (resultIterator.hasNext()); } else { writer.write("No answers.\n"); }

Close resources:
kb.close(); writer.close();