NewSetOrderedImplementation.groovy

//Original: http://mrhaki.blogspot.com.br/search/label/Groovy%3AGoodness
//Português: http://santograils.org/2015/06/12/descubra-os-novos-metodos-do-groovy-para-ordenacao-e-remocao-de-duplicacoes/

@groovy.transform.Sortable
@groovy.transform.ToString
class User {
    String username, email
}

def mrhaki1 = new User(username: 'mrhaki', email: 'mrhaki@localhost')
def mrhaki2 = new User(username: 'mrhaki', email: 'user@localhost')
def hubert1 = new User(username: 'hubert', email: 'user@localhost')
def hubert2 = new User(username: 'hubert', email: 'hubert@localhost')


// We make the list immutable,
// so we check the toSorted and toUnique methods
// do not alter it.
def users = [mrhaki1, mrhaki2, hubert1, hubert2].asImmutable()


// toSorted 
def sortedUsers = users.toSorted()

// @Sortable adds a compareTo method 
// to User class to sort first by username
// and then email.
assert sortedUsers == [hubert2, hubert1, mrhaki1, mrhaki2]

// Original list is unchanged.
assert users == [mrhaki1, mrhaki2, hubert1, hubert2]

// Use toSorted with closure.
def sortedByEmail = users.toSorted { a, b -> a.email <=> b.email }
assert sortedByEmail == [hubert2, mrhaki1, mrhaki2, hubert1]

// Or use toSorted with Comparator.
// @Sortable added static comparatorByProperty
// methods.
def sortedByEmailComparator = users.toSorted(User.comparatorByEmail())
assert sortedByEmailComparator == [hubert2, mrhaki1, mrhaki2, hubert1]


// toUnique with Comparator.
def uniqueUsers = users.toUnique(User.comparatorByUsername())
assert uniqueUsers == [mrhaki1, hubert1]
assert users == [mrhaki1, mrhaki2, hubert1, hubert2]

// toUnique with Closure.
def uniqueByEmail = users.toUnique { a, b -> a.email <=> b.email }
assert uniqueByEmail == [mrhaki1, mrhaki2, hubert2]