Criteria Many-to-Many With Custom Join Table Domain

Given the following example domains:

class UserRole implements Seriali开发者_Python百科zable {
  User user
  Role role
}

class User { 
  Set<Role> getRoles() {
    UserRole.findAllByUser(this).collect { it.role } as Set
  } 
}

class Role { 
  Set<User> getUsers() {
    UserRole.findAllByRole(this).collect { it.user } as Set
}

I can't figure out how to build the criteria to find all the users with a given role. I tried the following:

def crit = User.createCriteria()
def results = crit.list {
  roles {
    eq('authority', 'ROLE_ADMIN')
  }
}

However, it says it can't find the property 'roles' in User. The reason I need a criteria for this is because there will be additional properties in User being searched on so dynamic finders won't work for this situation.

---

If your expected result is small, it's probably easy enough to just do this:

def c = UserRole.createCriteria()
def users = c.list {
    role {
        eq('authority', 'ROLE_ADMIN')
    }
    user {
        // additional user property constraints
    }
}.collect { it.user }

If you expect a large set of results, or you need to page over them, I'm not as certain. I'll throw this out there, but I've never tried it. I don't know if you can use projections { property('association') } and have it work.

def c = UserRole.createCriteria()
def users = c.list {
    projections {
        property('user') // never tried this, but worth a shot
    }
    role {
        eq('authority', 'ROLE_ADMIN')
    }
    user {
        // additional user property constraints
    }
}

I don't think what you're trying to do in your example will work, since you don't actually have relationships defined on your User or Role classes that reference the UserRole (i.e. with a hasMany).