public final IBindingSet newBindingSet(final IRule rule) {
final IBindingSet constants = rule.getConstants();
final int nconstants = constants.size();
final IBindingSet bindingSet = new ListBindingSet()
// new ArrayBindingSet(rule.getVariableCount()+ nconstants)
;
if (nconstants > 0) {
/*
* Bind constants declared by the rule before returning the binding
* set to the caller.
*/
final Iterator<Map.Entry<IVariable, IConstant>> itr = constants.iterator();
while (itr.hasNext()) {
final Map.Entry<IVariable, IConstant> entry = itr.next();
bindingSet.set(entry.getKey(), entry.getValue());
}
}
return bindingSet;
}
/**
* Constructs the element iff requested, saves the rule reference iff requested, and clones and
* saves the bindingSet iff requested. The requested behavior depends on {@link
* IJoinNexus#solutionFlags()}. When requested, the element is created using {@link
* IRelation#newElement(IPredicate, IBindingSet)} for the {@link IRelation} that is named by the
* head of the rule.
*
* @param e The element.
* @param rule The rule.
* @param bindingSet The binding set for this solution. If {@link IJoinNexus#BINDINGS} was
* specified, then the binding set will be <em>cloned</em> by this ctor.
* @throws IllegalArgumentException if any parameter is <code>null</code>.
*/
@SuppressWarnings("unchecked")
public Solution(final IJoinNexus joinNexus, final IRule<E> rule, final IBindingSet bindingSet) {
if (joinNexus == null) throw new IllegalArgumentException();
if (rule == null) throw new IllegalArgumentException();
if (bindingSet == null) throw new IllegalArgumentException();
final int flags = joinNexus.solutionFlags();
if ((flags & IJoinNexus.ELEMENT) != 0) {
/*
* The relation is responsible for how the elements are materialized
* from the bindings.
*
* Note: Caching for this relation is very important!
*/
// the head of the rule.
final IPredicate head = rule.getHead();
// the relation for the head of the rule.
final IRelation relation = joinNexus.getHeadRelationView(head);
// use the relation's element factory.
this.e =
(E) relation.newElement(head.args(), bindingSet); // TODO BOp.args() is not efficient!
// // use the relation's element factory.
// this.e = (E) relation.newElement(head, bindingSet);
} else {
this.e = null;
}
if ((flags & IJoinNexus.BINDINGS) != 0) {
this.bindingSet = bindingSet.clone();
} else {
this.bindingSet = null;
}
if ((flags & IJoinNexus.RULE) != 0) {
this.rule = rule;
} else {
this.rule = null;
}
}
/**
* Return the bound value for the variable.
*
* @param v The variable.
* @param bset The source solution.
* @param required <code>true</code> iff the variable must be bound.
* @return The bound value and <code>null</code> if the variable is not bound.
*/
@SuppressWarnings("rawtypes")
protected static IV getIV(
final IVariable<?> var, final IBindingSet bset, final boolean required) {
@SuppressWarnings("unchecked")
final IConstant<IV> constant = bset.get(var);
if (constant == null) {
if (required) throw new RuntimeException("Variable is not bound: " + var);
return null;
}
final IV _s = (IV) constant.get();
return _s;
}
@SuppressWarnings("unchecked")
private final void copyValues(
final IElement e, final IPredicate<?> pred, final IBindingSet bindingSet) {
for (int i = 0; i < pred.arity(); i++) {
final IVariableOrConstant<?> t = pred.get(i);
if (t.isVar()) {
final IVariable<?> var = (IVariable<?>) t;
final Constant<?> newval = new Constant(e.get(i));
bindingSet.set(var, newval);
}
}
}
/**
* Creates a {@link Justification}, writes it on the store using {@link
* RDFJoinNexus#newInsertBuffer(IMutableRelation)}, verifies that we can read it back from the
* store, and then retracts the justified statement and verifies that the justification was also
* retracted.
*/
public void test_writeReadRetract() {
final Properties properties = super.getProperties();
// override the default axiom model.
properties.setProperty(
com.bigdata.rdf.store.AbstractTripleStore.Options.AXIOMS_CLASS, NoAxioms.class.getName());
final AbstractTripleStore store = getStore(properties);
try {
if (!store.isJustify()) {
log.warn("Test skipped - justifications not enabled");
}
/*
* the explicit statement that is the support for the rule.
*/
final IV U = store.addTerm(new URIImpl("http://www.bigdata.com/U"));
final IV A = store.addTerm(new URIImpl("http://www.bigdata.com/A"));
final IV Y = store.addTerm(new URIImpl("http://www.bigdata.com/Y"));
store.addStatements(
new SPO[] { //
new SPO(U, A, Y, StatementEnum.Explicit) //
}, //
1);
assertTrue(store.hasStatement(U, A, Y));
assertEquals(1, store.getStatementCount());
final InferenceEngine inf = store.getInferenceEngine();
final Vocabulary vocab = store.getVocabulary();
// the rule.
final Rule rule = new RuleRdf01(store.getSPORelation().getNamespace(), vocab);
final IJoinNexus joinNexus =
store
.newJoinNexusFactory(
RuleContextEnum.DatabaseAtOnceClosure,
ActionEnum.Insert,
IJoinNexus.ALL,
null /* filter */)
.newInstance(store.getIndexManager());
/*
* The buffer that accepts solutions and causes them to be written
* onto the statement indices and the justifications index.
*/
final IBuffer<ISolution[]> insertBuffer = joinNexus.newInsertBuffer(store.getSPORelation());
// the expected justification (setup and verified below).
final Justification jst;
// the expected entailment.
final SPO expectedEntailment =
new SPO( //
A, vocab.get(RDF.TYPE), vocab.get(RDF.PROPERTY), StatementEnum.Inferred);
{
final IBindingSet bindingSet = joinNexus.newBindingSet(rule);
/*
* Note: rdfs1 is implemented using a distinct term scan. This
* has the effect of leaving the variables that do not appear in
* the head of the rule unbound. Therefore we DO NOT bind those
* variables here in the test case and they will be represented
* as ZERO (0L) in the justifications index and interpreted as
* wildcards.
*/
// bindingSet.set(Var.var("u"), new Constant<IV>(U));
bindingSet.set(Var.var("a"), new Constant<IV>(A));
// bindingSet.set(Var.var("y"), new Constant<IV>(Y));
final ISolution solution = new Solution(joinNexus, rule, bindingSet);
/*
* Verify the justification that will be built from that
* solution.
*/
{
jst = new Justification(solution);
/*
* Verify the bindings on the head of the rule as
* represented by the justification.
*/
assertEquals(expectedEntailment, jst.getHead());
/*
* Verify the bindings on the tail of the rule as
* represented by the justification. Again, note that the
* variables that do not appear in the head of the rule are
* left unbound for rdfs1 as a side-effect of evaluation
* using a distinct term scan.
*/
final SPO[] expectedTail =
new SPO[] { //
new SPO(NULL, A, NULL, StatementEnum.Inferred) //
};
if (!Arrays.equals(expectedTail, jst.getTail())) {
fail("Expected: " + Arrays.toString(expectedTail) + ", but actual: " + jst);
}
}
// insert solution into the buffer.
insertBuffer.add(new ISolution[] {solution});
}
// SPOAssertionBuffer buf = new SPOAssertionBuffer(store, store,
// null/* filter */, 100/* capacity */, true/* justified */);
//
// assertTrue(buf.add(head, jst));
// no justifications before hand.
assertEquals(0L, store.getSPORelation().getJustificationIndex().rangeCount());
// flush the buffer.
assertEquals(1L, insertBuffer.flush());
// one justification afterwards.
assertEquals(1L, store.getSPORelation().getJustificationIndex().rangeCount());
/*
* verify read back from the index.
*/
{
final ITupleIterator<Justification> itr =
store.getSPORelation().getJustificationIndex().rangeIterator();
while (itr.hasNext()) {
final ITuple<Justification> tuple = itr.next();
// de-serialize the justification from the key.
final Justification tmp = tuple.getObject();
// verify the same.
assertEquals(jst, tmp);
// no more justifications in the index.
assertFalse(itr.hasNext());
}
}
/*
* test iterator with a single justification.
*/
{
final FullyBufferedJustificationIterator itr =
new FullyBufferedJustificationIterator(store, expectedEntailment);
assertTrue(itr.hasNext());
final Justification tmp = itr.next();
assertEquals(jst, tmp);
}
// an empty focusStore.
final TempTripleStore focusStore =
new TempTripleStore(store.getIndexManager().getTempStore(), store.getProperties(), store);
try {
/*
* The inference (A rdf:type rdf:property) is grounded by the
* explicit statement (U A Y).
*/
assertTrue(
Justification.isGrounded(
inf,
focusStore,
store,
expectedEntailment,
false /* testHead */,
true /* testFocusStore */,
new VisitedSPOSet(focusStore.getIndexManager())));
// add the statement (U A Y) to the focusStore.
focusStore.addStatements(
new SPO[] { //
new SPO(U, A, Y, StatementEnum.Explicit) //
}, //
1);
/*
* The inference is no longer grounded since we have declared
* that we are also retracting its grounds.
*/
assertFalse(
Justification.isGrounded(
inf,
focusStore,
store,
expectedEntailment,
false /* testHead */,
true /* testFocusStore */,
new VisitedSPOSet(focusStore.getIndexManager())));
} finally {
/*
* Destroy the temp kb, but not the backing TemporaryStore. That
* will be destroyed when we destroy the IndexManager associated
* with the main store (below).
*/
focusStore.destroy();
}
/*
* remove the justified statements.
*/
assertEquals(
1L,
store
.getAccessPath(expectedEntailment.s, expectedEntailment.p, expectedEntailment.o)
.removeAll());
/*
* verify that the justification for that statement is gone.
*/
{
final ITupleIterator<?> itr =
store.getSPORelation().getJustificationIndex().rangeIterator();
assertFalse(itr.hasNext());
}
} finally {
store.__tearDownUnitTest();
}
}