/**
* Returns true if it was cleaned, or false if the clause was unsatisfiable
*
* @param sample
* @return
*/
public static ValueSet<NodeValue> toValueSet(Sample<NodeValue> sample) {
if (sample.getPositives().size() > 1
|| (!sample.getPositives().isEmpty()
&& sample.getNegatives().containsAll(sample.getPositives()))) {
/**
* If there are .) multiple positive constants in a clause, such as in [?x = a, ?x = b] .) or
* the negatives contain the positive, such as in [?x = a, !(?x = a)] then the clause is
* unsatisfiable and no value contraint can be derived
*/
return ValueSet.create();
}
if (!sample.getPositives().isEmpty()) {
/**
* Just in case deal with the case [?x = a, !(?x = b)] ---> [?x = a]
*
* <p>So positive takes precedence over negative
*/
sample.getNegatives().clear();
}
return sample.getPositives().isEmpty()
? ValueSet.create(sample.getNegatives(), false)
: ValueSet.create(sample.getPositives(), true);
}
public static Map<Var, ValueSet<NodeValue>> extractValueConstraintsDnfClause(
Set<Expr> dnfClause) {
Map<Var, Sample<NodeValue>> tmp = new HashMap<Var, Sample<NodeValue>>();
for (Expr expr : dnfClause) {
boolean isNegative = (expr instanceof E_LogicalNot);
if (isNegative) {
expr = ((E_LogicalNot) expr).getArg();
}
if (!(expr instanceof E_Equals)) {
continue;
}
Pair<Var, NodeValue> constraint = extractValueConstraint(expr);
if (constraint == null) {
continue;
}
Sample<NodeValue> sample = tmp.get(constraint.getKey());
if (sample == null) {
sample = Sample.create();
tmp.put(constraint.getKey(), sample);
}
if (isNegative) {
sample.getNegatives().add(constraint.getValue());
} else {
sample.getPositives().add(constraint.getValue());
}
}
Map<Var, ValueSet<NodeValue>> result = new HashMap<Var, ValueSet<NodeValue>>();
// Phase 2: Create the value sets
for (Map.Entry<Var, Sample<NodeValue>> entry : tmp.entrySet()) {
ValueSet<NodeValue> valueSet = toValueSet(entry.getValue());
if (valueSet.isUnknown()) {
continue;
}
result.put(entry.getKey(), valueSet);
}
return result;
}