A class annotation used to make a class Comparable by multiple Comparators. As an example, given this class:
@Sortable
class Person {
String first
String last
Integer born
}
The generated Groovy class will:
Comparable
interfacecompareTo
method based on the first
,
last
and born
properties (priority ordering will be according
to the ordering of property definition, highest first, unless 'includes' is used; in which case,
priority will be according to the order given in the includes list)Comparator
methods named comparatorByFirst
,
comparatorByLast
and comparatorByBorn
Comparable
or @Sortable
.
More examples:
//-------------------------------------------------------------------------- import groovy.transform.Sortable import groovy.transform.ToString @Sortable @ToString class Course { // Order of properties determines priority when sorting String title Date beginDate Integer maxAttendees // int doesn't implement Comparable, so use Integer } final Course groovy = new Course( title: 'Groovy', beginDate: new Date() + 7, maxAttendees: 40) final Course groovy2 = new Course( title: 'Groovy', beginDate: new Date() + 2, maxAttendees: 50) final Course grails = new Course( title: 'Grails', beginDate: new Date() + 1, maxAttendees: 20) final List<Course> courses = [groovy, groovy2, grails] assert courses.last().title == 'Grails' // Use toSorted() method to sort final List<Course> sorted = courses.toSorted() assert sorted.first().title == 'Grails' assert sorted.last().title == 'Groovy' assert sorted.maxAttendees == [20, 50, 40]
//-------------------------------------------------------------------------- // Order of fields for includes determines priority when sorting import groovy.transform.Sortable import groovy.transform.ToString @Sortable(includes = ['title', 'maxAttendees']) // Or @Sortable(excludes = ['beginDate']) @ToString class Course { String title Date beginDate Integer maxAttendees } final Course groovy = new Course( title: 'Groovy', beginDate: new Date() + 7, maxAttendees: 40) final Course groovy2 = new Course( title: 'Groovy', beginDate: new Date() + 2, maxAttendees: 50) final Course grails = new Course( title: 'Grails', beginDate: new Date() + 1, maxAttendees: 20) final List<Course> courses = [groovy, groovy2, grails] // Use toSorted() method to sort final List<Course> sorted = courses.toSorted() assert sorted.first().title == 'Grails' assert sorted.last().title == 'Groovy' assert sorted.maxAttendees == [20, 40, 50] //-------------------------------------------------------------------------- // Static methods to create comparators. final Comparator byMaxAttendees = Course.comparatorByMaxAttendees() final List<Course> sortedByMaxAttendees = courses.sort(false, byMaxAttendees) assert sortedByMaxAttendees.maxAttendees == [20, 40, 50] // beginDate is not used for sorting assert sortedByMaxAttendees[2].beginDate < sortedByMaxAttendees[1].beginDate assert Course.declaredMethods.name.findAll { it.startsWith('comparatorBy') }.toSorted() == ['comparatorByMaxAttendees', 'comparatorByTitle']