Examples of com.hp.hpl.jena.reasoner.transitiveReasoner.TransitiveGraphCache

Package com.hp.hpl.jena.reasoner.transitiveReasoner

Examples of com.hp.hpl.jena.reasoner.transitiveReasoner.TransitiveGraphCache

com.hp.hpl.jena.reasoner.transitiveReasoner.TransitiveGraphCache
Datastructure used to represent a closed transitive reflexive relation. It (mostly) incrementally maintains a transitive reduction and transitive closure of the relationship and so queries should be faster than dynamically computing the closed or reduced relations.
The implementation stores the reduced and closed relations as real graph (objects linked together by pointers). For each graph node we store its direct predecessors and successors and its closed successors. A cost penalty is the storage turnover involved in turning the graph representation back into triples to answer queries. We could avoid this by optionally also storing the manifested triples for the links.
Cycles are currently handled by collapsing strongly connected components. Incremental deletes would be possible but at the price of substanially more storage and code complexity. We compromise by doing the easy cases incrementally but some deletes (those that break strongly connected components) will trigger a fresh rebuild.
TODO Combine this with interval indexes (Agrawal, Borigda and Jagadish 1989) for storing the closure of the predecessor relationship. Typical graphs will be nearly tree shaped so the successor closure is modest (L^2 where L is the depth of the tree branch) but the predecessor closure would be expensive. The interval index would handle predecessor closure nicely.

    private void resetTGCCache() {
        if (schemaGraph != null) {
            transitiveEngine = new TransitiveEngine(((FBRuleInfGraph)schemaGraph).transitiveEngine);
        } else {
            transitiveEngine = new TransitiveEngine(
                new TransitiveGraphCache(ReasonerVocabulary.directSubClassOf.asNode(), RDFS.subClassOf.asNode()),
                new TransitiveGraphCache(ReasonerVocabulary.directSubPropertyOf.asNode(), RDFS.subPropertyOf.asNode()));
        }
    }

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    private void resetTGCCache() {
        if (schemaGraph != null) {
            transitiveEngine = new TransitiveEngine(((FBRuleInfGraph)schemaGraph).transitiveEngine);
        } else {
            transitiveEngine = new TransitiveEngine(
                new TransitiveGraphCache(ReasonerVocabulary.directSubClassOf.asNode(), RDFS.subClassOf.asNode()),
                new TransitiveGraphCache(ReasonerVocabulary.directSubPropertyOf.asNode(), RDFS.subPropertyOf.asNode()));
        }
    }

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    /**
     * Test the clone operation
     */
    public void testCloning() {
        initCache();
        TransitiveGraphCache clone = cache.deepCopy();
        // Mess with the original to check cloning
        cache.addRelation(new Triple(a, closedP, d));
        cache.addRelation(new Triple(g, closedP, a));
        doBasicTest(clone);
    }

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    /**
     * Initialize the cache with some test data
     */
    private void initCache() {
        // Create a graph with reflexive references, cycles, redundant links
        cache = new TransitiveGraphCache(directP, closedP);        
        cache.addRelation(new Triple(a, closedP, b));
        cache.addRelation(new Triple(b, closedP, e));
        cache.addRelation(new Triple(b, closedP, c));
        cache.addRelation(new Triple(e, closedP, f));
        cache.addRelation(new Triple(c, closedP, f));

View Full Code Here

    /**
     * Test a a case where an earlier version had a bug due to removing
     * a link which was required rather than redundant.
     */
    public void testBug1() {
        TransitiveGraphCache cache = new TransitiveGraphCache(directP, closedP);
        cache.addRelation(new Triple(a, closedP, b));  
        cache.addRelation(new Triple(c, closedP, a));        
        cache.addRelation(new Triple(c, closedP, b));
        cache.addRelation(new Triple(a, closedP, c));     
        TestUtil.assertIteratorValues(this, 
            cache.find(new TriplePattern(a, directP, null)),
            new Object[] {
                new Triple(a, closedP, a),
                new Triple(a, closedP, b),
                new Triple(a, closedP, c),
            });

View Full Code Here

     * be incomplete. The links just
     * form a linear chain, with all closed links provided. But inserted
     * in a particular order.
     */
    public void testBug2() {
        TransitiveGraphCache cache = new TransitiveGraphCache(directP, closedP);
        cache.addRelation(new Triple(a, closedP, b));
        cache.addRelation(new Triple(a, closedP, c));
        cache.addRelation(new Triple(b, closedP, c));        
        TestUtil.assertIteratorValues(this, 
            cache.find(new TriplePattern(a, directP, null)),
            new Object[] {
                new Triple(a, closedP, a),
                new Triple(a, closedP, b)
            });

View Full Code Here

        
    /**
     * Test the removeRelation functionality.
     */
    public void testRemove() {
        TransitiveGraphCache cache = new TransitiveGraphCache(directP, closedP);
        cache.addRelation(new Triple(a, closedP, b));
        cache.addRelation(new Triple(a, closedP, c));
        cache.addRelation(new Triple(b, closedP, d));
        cache.addRelation(new Triple(c, closedP, d));
        cache.addRelation(new Triple(d, closedP, e));
        TestUtil.assertIteratorValues(this, 
            cache.find(new TriplePattern(a, closedP, null)),
            new Object[] {
                new Triple(a, closedP, a),
                new Triple(a, closedP, b),
                new Triple(a, closedP, b),
                new Triple(a, closedP, c),
                new Triple(a, closedP, d),
                new Triple(a, closedP, e)
            });
        TestUtil.assertIteratorValues(this, 
            cache.find(new TriplePattern(b, closedP, null)),
            new Object[] {
                new Triple(b, closedP, b),
                new Triple(b, closedP, d),
                new Triple(b, closedP, e)
            });
        cache.removeRelation(new Triple(b, closedP, d));
        TestUtil.assertIteratorValues(this, 
            cache.find(new TriplePattern(a, closedP, null)),
            new Object[] {
                new Triple(a, closedP, a),
                new Triple(a, closedP, b),
                new Triple(a, closedP, b),
                new Triple(a, closedP, c),
                new Triple(a, closedP, d),
                new Triple(a, closedP, e)
            });
        TestUtil.assertIteratorValues(this, 
            cache.find(new TriplePattern(b, closedP, null)),
            new Object[] {
                new Triple(b, closedP, b),
            });
        cache.removeRelation(new Triple(a, closedP, c));
        TestUtil.assertIteratorValues(this, 
            cache.find(new TriplePattern(a, closedP, null)),
            new Object[] {
                new Triple(a, closedP, a),
                new Triple(a, closedP, b)
            });
        TestUtil.assertIteratorValues(this, 
            cache.find(new TriplePattern(b, closedP, null)),
            new Object[] {
                new Triple(b, closedP, b),
            });
    }

View Full Code Here

    
    /**
     * Test direct link case with adverse ordering.
     */
    public void testDirect() {
        TransitiveGraphCache cache = new TransitiveGraphCache(directP, closedP);
        cache.addRelation(new Triple(a, closedP, b));
        cache.addRelation(new Triple(c, closedP, d));
        cache.addRelation(new Triple(a, closedP, d));
        cache.addRelation(new Triple(b, closedP, c));
        TestUtil.assertIteratorValues(this, 
            cache.find(new TriplePattern(a, directP, null)),
            new Object[] {
                new Triple(a, closedP, a),
                new Triple(a, closedP, b),
            });
    }

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    /**
     * Test cycle detection.
     */
    public void testCycle() {
        TransitiveGraphCache cache = new TransitiveGraphCache(directP, closedP);
        cache.addRelation(new Triple(a, closedP, b));
        cache.addRelation(new Triple(b, closedP, c));
        cache.addRelation(new Triple(a, closedP, c));
        cache.addRelation(new Triple(c, closedP, b));
        TestUtil.assertIteratorValues(this, 
            cache.find(new TriplePattern(a, directP, null)),
            new Object[] {
                new Triple(a, closedP, a),
                new Triple(a, closedP, b),
                new Triple(a, closedP, c),
            });

View Full Code Here

    
    /**
     * A ring of three cycle
     */
    public void testCycle2() {
        TransitiveGraphCache cache = new TransitiveGraphCache(directP, closedP);
        cache.addRelation(new Triple(a, closedP, b));
        cache.addRelation(new Triple(a, closedP, c));
        cache.addRelation(new Triple(f, closedP, b));
        cache.addRelation(new Triple(b, closedP, g));
        cache.addRelation(new Triple(b, closedP, d));
        cache.addRelation(new Triple(d, closedP, c));
        cache.addRelation(new Triple(d, closedP, e));
        cache.addRelation(new Triple(c, closedP, e));
        cache.addRelation(new Triple(c, closedP, b));
        TestUtil.assertIteratorValues(this, 
                cache.find(new TriplePattern(c, directP, null)),
                new Object[] {
                    new Triple(c, closedP, e),
                    new Triple(c, closedP, g),
                    new Triple(c, closedP, b),
                    new Triple(c, closedP, d),
                    new Triple(c, closedP, c),
                });
        TestUtil.assertIteratorValues(this, 
                cache.find(new TriplePattern(null, directP, c)),
                new Object[] {
                    new Triple(a, closedP, c),
                    new Triple(b, closedP, c),
                    new Triple(d, closedP, c),
                    new Triple(f, closedP, c),
                    new Triple(c, closedP, c),
                });
        TestUtil.assertIteratorValues(this, 
                cache.find(new TriplePattern(f, closedP, null)),
                new Object[] {
                    new Triple(f, closedP, f),
                    new Triple(f, closedP, b),
                    new Triple(f, closedP, c),
                    new Triple(f, closedP, d),

View Full Code Here

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Related Classes of com.hp.hpl.jena.reasoner.transitiveReasoner.TransitiveGraphCache

com.hp.hpl.jena.reasoner.rulesys.FBRuleInfGraph

com.hp.hpl.jena.reasoner.test.TestTransitiveGraphCache

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