Bindable

Each class in Groovy has propeties, and a property is a combination of a private field and getters/setters

class Player {
  String nickname
  Integer score
}

println new Player(nickname:'josdem', score:90).properties

Output:

[nickname:josdem, class:class Player, score:90]

As you can see, properties is a map, so we can do the following:

class Player {
  String nickname
  Integer score
}

def map = new Player(nickname:'josdem', score:90).properties
println map['nickname']

Output:

josdem

@groovy.beans.Bindable is an annotation that can go either on a Groovy class property or a Groovy class itself. A bound property is a bean property for which a change to the property results in a notification being sent to some other bean.

import groovy.beans.Bindable
import groovy.transform.ToString

@ToString
class Player {
  String nickname

  @Bindable
  Integer score
}

Player player = new Player(nickname:'josdem', score:90)

player.propertyChange = {
  println "Player has new score:"
  println it.properties
}

player.score = 91

Output:

Player has new score:
[newValue:91, propertyName:score, class:class java.beans.PropertyChangeEvent, oldValue:90, propagationId:null, source:Player(josdem, 91)]

That’s it, when score changes which is a bindable field the closure propertyChange will respond with a “Player has new score:” and then print the properties from it.

Return to the main article