Mark,
Sorry for the delay. I have now convinced myself this must be some sort of user error (that took a while, I was getting similar problem to what you were reporting), with this test:
Code:
@Test
public void shouldRecommendFriends() throws Exception {
User a = users.save(new User("A"));
User b = users.save(new User("B"));
User c = users.save(new User("C"));
User d = users.save(new User("D"));
User e = users.save(new User("E"));
User f = users.save(new User("F"));
User g = users.save(new User("G"));
a.add(c);
b.add(c, d);
c.add(d, e);
d.add(f);
users.save(a);
users.save(b);
users.save(c);
users.save(d);
users.save(e);
users.save(f);
users.save(g);
assertFriendSuggestions(a, b, d, e);
assertFriendSuggestions(b, a, e, f);
assertFriendSuggestions(c, f);
assertFriendSuggestions(d, a, e);
assertFriendSuggestions(e, a, b, d);
assertFriendSuggestions(f, b, c);
}
private void assertFriendSuggestions(User user, User... expectedFriendSuggestions) {
List<User> actualFriendSuggestions = users.fofs(user.id, new PageRequest(0, 20)).getContent();
assertThat(actualFriendSuggestions.size(), is(equalTo(expectedFriendSuggestions.length)));
for (int i = 0; i < expectedFriendSuggestions.length; i++) {
assertThat(actualFriendSuggestions.get(i).name, is(equalTo(expectedFriendSuggestions[i].name)));
}
}
@NodeEntity
public class User {
@GraphId
Long id;
String name;
@RelatedTo(type = "FRIEND")
private Set<User> friends = new HashSet<User>();
public User() {
}
public User(String name) {
this.name = name;
}
public void add(User... users) {
friends.addAll(asList(users));
}
}
public interface UserRepositoryExtension extends GraphRepository<User> {
@Query("start user=node({0}) match user-[:FRIEND*2..2]-friendsOfFriends, user-[r?:FRIEND]-friendsOfFriends where r IS NULL and user <> friendsOfFriends return distinct friendsOfFriends order by friendsOfFriends.name asc")
Page<User> fofs(long id, Pageable pageable);
}
So, the query is the same as you had, in essence. I've added distinct results and used multi-step relationship match. I can't tell you what the problem was, but this version works. Also, it works with both unidirectional and bidirectional relationships.
Hope this helps!
Lasse
SDN. What's wrong with my query Friends of Friends
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