Groovy - sorting my object list using two criterias

Question

Following this class:

class Report
{
  String firstName
  String lastName
}

I need to sort my Person list first by the last name and then by the first name.

I tried to make it using this code:

persons.sort{[it.lastName, it.firstName]}

But it didn't managed to do so.
Are there any other suggestions to have sorting by two criterias?

Answer 1

With latest version of groovy You can achieve this with @Sortable annotation.

Second option is to implement Comparable and use spaceship (<=>) operator.

And here's sample just with sort method:

import groovy.transform.ToString

@ToString
class R {
  def f
  def l
}

def list = [new R(f: 'A', l: 'B'),new R(f: 'A', l: 'A'),new R(f: 'A', l: 'C'),new R(f: 'B', l: 'C')]

list.sort {left, right -> left.l <=> right.l ?: left.f <=> right.f}