Example usage for org.apache.commons.rdf.api Graph remove

Introduction

In this page you can find the example usage for org.apache.commons.rdf.api Graph remove.

Prototype

void remove(BlankNodeOrIRI subject, IRI predicate, RDFTerm object);

Source Link

Document

Remove a concrete pattern of triples from the graph.

Usage

From source file:example.IntroToRDF.java

public static void main(String[] args) {
    RDF rdf = new SimpleRDF();

    IRI alice = rdf.createIRI("Alice");
    System.out.println(alice.ntriplesString());

    IRI knows = rdf.createIRI("knows");
    IRI bob = rdf.createIRI("Bob");

    Triple aliceKnowsBob = rdf.createTriple(alice, knows, bob);
    System.out.println(aliceKnowsBob.getSubject().ntriplesString());

    System.out.println(aliceKnowsBob);

    Graph graph = rdf.createGraph();
    graph.add(aliceKnowsBob);//from   w ww .  ja  v a  2  s  . c  om

    IRI charlie = rdf.createIRI("Charlie");

    IRI plays = rdf.createIRI("plays");

    IRI football = rdf.createIRI("Football");
    IRI tennis = rdf.createIRI("Tennis");

    graph.add(alice, knows, charlie);
    graph.add(alice, plays, tennis);
    graph.add(bob, knows, charlie);
    graph.add(bob, plays, football);
    graph.add(charlie, plays, tennis);

    System.out.println("Who plays Tennis?");
    for (Triple triple : graph.iterate(null, plays, tennis)) {
        System.out.println(triple.getSubject());
        System.out.println(plays.equals(triple.getPredicate()));
        System.out.println(tennis.equals(triple.getObject()));
    }

    System.out.println("Who does Alice know?");
    for (Triple triple : graph.iterate(alice, knows, null)) {
        System.out.println(triple.getObject());
    }

    System.out.println("Does Alice anyone that plays Football?");
    for (Triple triple : graph.iterate(alice, knows, null)) {
        RDFTerm aliceFriend = triple.getObject();
        if (!(aliceFriend instanceof BlankNodeOrIRI)) {
            continue;
        }
        if (graph.contains((BlankNodeOrIRI) aliceFriend, plays, football)) {
            System.out.println("Yes, it is " + aliceFriend);
        }
    }

    Literal aliceName = rdf.createLiteral("Alice W. Land");
    IRI name = rdf.createIRI("name");
    graph.add(alice, name, aliceName);

    Optional<? extends Triple> nameTriple = graph.stream(alice, name, null).findAny();
    if (nameTriple.isPresent()) {
        System.out.println(nameTriple.get());
    }

    graph.stream(alice, name, null).findAny().map(Triple::getObject).filter(obj -> obj instanceof Literal)
            .map(literalName -> ((Literal) literalName).getLexicalForm()).ifPresent(System.out::println);

    IRI playerRating = rdf.createIRI("playerRating");
    Literal aliceRating = rdf.createLiteral("13.37", Types.XSD_FLOAT);
    graph.add(alice, playerRating, aliceRating);

    Literal footballInEnglish = rdf.createLiteral("football", "en");
    Literal footballInNorwegian = rdf.createLiteral("fotball", "no");
    graph.add(football, name, footballInEnglish);
    graph.add(football, name, footballInNorwegian);

    Literal footballInAmericanEnglish = rdf.createLiteral("soccer", "en-US");
    graph.add(football, name, footballInAmericanEnglish);

    BlankNode someone = rdf.createBlankNode();
    graph.add(charlie, knows, someone);
    graph.add(someone, plays, football);

    BlankNode someoneElse = rdf.createBlankNode();
    graph.add(charlie, knows, someoneElse);

    for (Triple heKnows : graph.iterate(charlie, knows, null)) {
        if (!(heKnows.getObject() instanceof BlankNodeOrIRI)) {
            continue;
        }
        BlankNodeOrIRI who = (BlankNodeOrIRI) heKnows.getObject();
        System.out.println("Charlie knows " + who);
        for (Triple whoPlays : graph.iterate(who, plays, null)) {
            System.out.println("  who plays " + whoPlays.getObject());
        }
    }

    // Delete previous BlankNode statements
    graph.remove(null, null, someone);
    graph.remove(someone, null, null);

    // no Java variable for the new BlankNode instance
    graph.add(charlie, knows, rdf.createBlankNode("someone"));
    // at any point later (with the same RDF instance)
    graph.add(rdf.createBlankNode("someone"), plays, football);

    for (Triple heKnows : graph.iterate(charlie, knows, null)) {
        if (!(heKnows.getObject() instanceof BlankNodeOrIRI)) {
            continue;
        }
        BlankNodeOrIRI who = (BlankNodeOrIRI) heKnows.getObject();
        System.out.println("Charlie knows " + who);
        for (Triple whoPlays : graph.iterate(who, plays, null)) {
            System.out.println("  who plays " + whoPlays.getObject());
        }
    }

}

---