We saw earlier that Groovy supports Multimethods or multiple dispatch. Groovy will resolve the correct overloaded method to invoke based on the runtime type of the method argument. This is great to use for a clean and simple API for a class.
Suppose we have an Event
class with a list of attendees and sessions. We want to use the <<
operator to add attendees and sessions to an Event
object. The following code sample shows how we can implement this in Groovy:
class Event { List<Person> attendees = [] List<Session> sessions = [] Event leftShift(final Person person) { attendees << person this } Event leftShift(final Session session) { sessions << session this } } class Session { String title } class Person { String name } final Event gr8Conf = new Event() gr8Conf << new Person(name: 'mrhaki') << new Session(title: /Groovy's Hidden Gems/) assert gr8Conf.attendees.size() == 1 assert gr8Conf.sessions.size() == 1 assert gr8Conf.attendees[0].name == 'mrhaki' assert gr8Conf.sessions[0].title == "Groovy's Hidden Gems"