public List<VariableAssignment> traceAtomEvent(Atom atom) {
Collection<Atom> atoms = dependence.get(atom.getPredicate());
List<VariableAssignment> vars = new ArrayList<VariableAssignment>(atoms.size());
for (Atom entry : atoms) {
// Check whether arguments match
VariableAssignment var = new VariableAssignment();
Term[] argsGround = atom.getArguments();
Term[] argsTemplate = entry.getArguments();
assert argsGround.length == argsTemplate.length;
for (int i = 0; i < argsGround.length; i++) {
if (argsTemplate[i] instanceof Variable) {
// Add mapping
assert argsGround[i] instanceof GroundTerm;
var.assign((Variable) argsTemplate[i], (GroundTerm) argsGround[i]);
} else {
// They must be the same
if (!argsTemplate[i].equals(argsGround[i])) {
var = null;
break;
}
}
}
if (var != null) vars.add(var);
}
return vars;
}
public DNFClause(List<Atom> posLiterals, List<Atom> negLiterals) {
this.posLiterals = new ArrayList<Atom>(posLiterals);
this.negLiterals = new ArrayList<Atom>(negLiterals);
dependence = ArrayListMultimap.create();
Set<Variable> allowedVariables = new HashSet<Variable>();
Set<Variable> variablesToCheck = new HashSet<Variable>();
boolean tempAllVariablesBound = true;
/*
* Checks if all Variables in the clause appear in a positive literal
* with a StandardPredicate.
*/
Set<Variable> setToAdd;
for (Atom atom : posLiterals) {
if (atom.getPredicate() instanceof StandardPredicate) setToAdd = allowedVariables;
else setToAdd = variablesToCheck;
for (Term t : atom.getArguments()) {
if (t instanceof Variable) setToAdd.add((Variable) t);
}
}
for (Atom atom : negLiterals)
for (Term t : atom.getArguments())
if (t instanceof Variable) variablesToCheck.add((Variable) t);
isGround = (allowedVariables.size() + variablesToCheck.size() == 0) ? true : false;
for (Variable v : variablesToCheck)
if (!allowedVariables.contains(v)) tempAllVariablesBound = false;
allVariablesBound = tempAllVariablesBound;
/*
* Processes the positive literals with StandardPredicates further
*/
for (int i = 0; i < posLiterals.size(); i++)
if (posLiterals.get(i).getPredicate() instanceof StandardPredicate)
dependence.put(posLiterals.get(i).getPredicate(), posLiterals.get(i));
if (posLiterals.size() == 0) query = null;
else if (posLiterals.size() == 1) query = (allVariablesBound) ? posLiterals.get(0) : null;
else
query =
(allVariablesBound)
? new Conjunction(posLiterals.toArray(new Formula[posLiterals.size()]))
: null;
}