private Path<?> findPathOnParent(
Path<?> parent, Class<?> targetType, JoinDescription joinDescription) {
while (!targetType.equals(Object.class)) {
// TODO more efficient cache key
String cacheKey =
parent.getClass().getName()
+ parent.toString()
+ targetType.getSimpleName()
+ joinDescription.getOriginalAlias().toString();
Path cached = aliasCache.get(cacheKey);
if (cached != null && !cached.equals(nullPath)) {
// TODO test
// TODO optimize inheritance cases
return cached;
}
List<Path<?>> candidatePaths = new ArrayList<>();
for (Field field : parent.getClass().getFields()) {
Object candidate = getField(field, parent);
testAliasCandidate(targetType, candidatePaths, candidate);
}
if (candidatePaths.isEmpty()) {
for (Class child : ReflectionUtils.getSubclasses(parent.getType(), entityManager)) {
Class<?> real;
Constructor<?> constructor;
try {
real =
Class.forName(
parent.getClass().getPackage().getName() + ".Q" + child.getSimpleName());
constructor = real.getConstructor(String.class);
} catch (Exception e) {
throw new RuntimeException();
}
Object childInstance;
try {
childInstance = constructor.newInstance(parent.getMetadata().getElement());
} catch (Exception e) {
throw new RuntimeException();
}
for (Field field : real.getFields()) {
Object candidate = getField(field, childInstance);
testAliasCandidate(targetType, candidatePaths, candidate);
}
}
}
if (candidatePaths.isEmpty()) {
// TODO may be exception?
J.unrollChildrenJoins(Collections.singletonList(joinDescription))
.forEach(j -> j.fetch(false));
aliasCache.put(cacheKey, nullPath);
targetType = targetType.getSuperclass();
} else if (candidatePaths.size() == 1) {
aliasCache.put(cacheKey, candidatePaths.get(0));
return candidatePaths.get(0);
} else {
// Multiple associations on parent, try find by specified alias
String targetFieldName = joinDescription.getOriginalAlias().toString();
for (Path<?> candidatePath : candidatePaths) {
if (targetFieldName.equals(candidatePath.getMetadata().getElement())) {
aliasCache.put(cacheKey, candidatePath);
return candidatePath;
}
}
// TODO add candidates to exception
throw new JoinerException(
"Join with ambiguous alias : "
+ joinDescription
+ ". Multiple mappings found: "
+ candidatePaths);
}
}
return null;
}
protected StartExpression.StartNodesLookup lookup(
Path<?> entity, String indexName, Expression.Identifier key, Expression.Value value) {
return StartExpression.lookup(entity.toString(), indexName, key, value);
}
protected StartExpression.StartNodesQuery query(
Path<?> entity, String indexName, Predicate query) {
return query(entity.toString(), indexName, query);
}
protected StartExpression.StartNodesLookup lookup(
Path<?> entity, String indexName, Path<?> key, String value) {
return StartExpression.lookup(
entity.toString(), indexName, key.getMetadata().getExpression().toString(), value);
}
protected StartExpression.StartNodes node(Path<?> entity, String parameter) {
return StartExpression.node(entity.toString(), parameter);
}
// Additional QueryDSL methods
protected StartExpression.StartNodes node(Path<?> entity, long... id) {
return StartExpression.node(entity.toString(), id);
}
protected OrderByExpression property(Path<?> path, OrderByExpression.Order order) {
return OrderByExpression.property(path.toString(), order);
}
protected OrderByExpression property(Path<?> path) {
return OrderByExpression.property(path.toString());
}