Groovy Higher order functions

Groovy-Higher-order-functions.groovy

class Person {
    String name
    int age
    Gender gender
    enum Gender {
        MALE, FEMALE, UNKNOWN
    }
}

def persons = [new Person(name: 'Bob',   age: 25, gender: Person.Gender.MALE), 
               new Person(name: 'Alice', age: 42, gender: Person.Gender.FEMALE)]

persons.findAll { 
    Person v -> 
        (v.age < 27 && 
         v.age > 24 && 
        (v.gender == Person.Gender.MALE || v.gender ==Person.Gender.UNKNOWN)) 
}.collect{ "${it.name}, ${it.age}, ${it.gender}" }

Output:
[Bob, 25, MALE]