/**
* Returns true if the constraint is associated with the given FromElement. Associated with means
* relating directly to a field of the QueryClass but NOT a cross-reference contraint (which
* compares two arbitrary fields of different QueryClasses.
*
* @param constraint the constraint in question
* @param fromElement the FromElement to check
* @return true if associated
*/
public static boolean isAssociatedWith(Constraint constraint, FromElement fromElement) {
Object left = getLeftArgument(constraint);
Object right = getRightArgument(constraint);
// ignore cross-references
if (left instanceof QueryEvaluable && !(isCrossReference(constraint))) {
// not a cross-reference -> at most one QueryClass. find it.
QueryClass qc = null; // TODO test for a bug here? left not assoc by right is
if (getQueryFields((QueryEvaluable) left).iterator().hasNext()) {
QueryField qf = getQueryFields((QueryEvaluable) left).iterator().next();
qc = (QueryClass) qf.getFromElement();
} else if (getQueryFields((QueryEvaluable) right).iterator().hasNext()) {
QueryField qf = getQueryFields((QueryEvaluable) right).iterator().next();
qc = (QueryClass) qf.getFromElement();
} else {
return false; // does not relate to any QueryClass
}
return (fromElement == qc);
} else if (left instanceof QueryClass && right instanceof QueryClass) {
return (fromElement == left || fromElement == right);
} else if (left instanceof QueryClass) {
return (fromElement == left);
} else if (left instanceof QueryReference) {
return (fromElement == ((QueryReference) left).getQueryClass());
} else if (right instanceof Query) {
return (fromElement == right);
}
return false;
}
/**
* Returns true if the constraint is associated with the given FromElement.
*
* @param constraint the constraint in question
* @param fromElement the FromElement to check
* @return true if associated
*/
public static boolean isRelatedTo(Constraint constraint, FromElement fromElement) {
if (isAssociatedWith(constraint, fromElement)) {
return true;
}
// also want to find out if this is referred to in a Contains or Subquery
// constraint that is associated with another fromElement.
if (constraint instanceof ContainsConstraint) {
if (fromElement == ((ContainsConstraint) constraint).getQueryClass()) {
return true;
}
} else if (constraint instanceof SubqueryConstraint) {
if (fromElement == ((SubqueryConstraint) constraint).getQuery()) {
return true;
}
} else if (constraint instanceof SimpleConstraint) {
SimpleConstraint sc = (SimpleConstraint) constraint;
Set<QueryField> qFields = getQueryFields(sc.getArg1());
qFields.addAll(getQueryFields(sc.getArg2()));
for (QueryField qf : qFields) {
if (fromElement == qf.getFromElement()) {
return true;
}
}
}
return false;
}
/**
* Returns true if the Constraint is a cross-reference between two QueryClasses. A constraint is
* deemed to be a cross-reference if it compares fields of two different QueryClasses, either
* directly or via QueryExpressions.
*
* @param constraint the contraint to test
* @return true if the contraint is a cross-reference
*/
public static boolean isCrossReference(Constraint constraint) {
if (constraint instanceof SimpleConstraint) {
// if QueryField exposed part of a subquery QueryField.getFromElement()
// returns a query, does not cause any problem.
Set<FromElement> qcs = new HashSet<FromElement>();
for (QueryField qf : getQueryFields(((SimpleConstraint) constraint).getArg1())) {
qcs.add(qf.getFromElement());
}
for (QueryField qf : getQueryFields(((SimpleConstraint) constraint).getArg2())) {
qcs.add(qf.getFromElement());
}
if (qcs.size() > 1) {
return true;
}
}
return false;
}
