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package tools.refinery.store.query.equality;
import tools.refinery.store.query.dnf.Dnf;
import tools.refinery.store.query.term.Variable;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class LiteralEqualityHelper {
private final DnfEqualityChecker dnfEqualityChecker;
private final Map<Variable, Variable> leftToRight;
private final Map<Variable, Variable> rightToLeft;
public LiteralEqualityHelper(DnfEqualityChecker dnfEqualityChecker, List<Variable> leftParameters,
List<Variable> rightParameters) {
this.dnfEqualityChecker = dnfEqualityChecker;
var arity = leftParameters.size();
if (arity != rightParameters.size()) {
throw new IllegalArgumentException("Parameter lists have unequal length");
}
leftToRight = new HashMap<>(arity);
rightToLeft = new HashMap<>(arity);
for (int i = 0; i < arity; i++) {
if (!variableEqual(leftParameters.get(i), rightParameters.get(i))) {
throw new IllegalArgumentException("Parameter lists cannot be unified: duplicate parameter " + i);
}
}
}
public boolean dnfEqual(Dnf left, Dnf right) {
return dnfEqualityChecker.dnfEqual(left, right);
}
public boolean variableEqual(Variable left, Variable right) {
if (checkMapping(leftToRight, left, right) && checkMapping(rightToLeft, right, left)) {
leftToRight.put(left, right);
rightToLeft.put(right, left);
return true;
}
return false;
}
private static boolean checkMapping(Map<Variable, Variable> map, Variable key, Variable expectedValue) {
var currentValue = map.get(key);
return currentValue == null || currentValue.equals(expectedValue);
}
}
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