Over a million developers have joined DZone.
{{announcement.body}}
{{announcement.title}}

Groovy Goodness: Apply Mixin to Object Instances

DZone's Guide to

Groovy Goodness: Apply Mixin to Object Instances

· Java Zone
Free Resource

Learn how to troubleshoot and diagnose some of the most common performance issues in Java today. Brought to you in partnership with AppDynamics.

In Groovy we can add extra functionality to a class with so-called mixins. In the previous blog post we added extra functionality to a class, but we can also apply run-time mixins to an object instance. The syntax is slightly different, because we must use the mixin() method on the metaClass property of the object.

class Parrot {
    static String speak(Message text) {
        /"$text" Polly wants a cracker!/
    }
}

// Runtime mixin on String object instead of class. 
String s = 'Groovy is Gr8'
s.metaClass.mixin Parrot

assert s.speak() == '"Groovy is Gr8" Polly wants a cracker!'


String other = 'Groovy and Grails'
try {
    other.speak()
} catch (MissingMethodException e) {
    assert e.message.startsWith('No signature of method: java.lang.String.speak() is applicable for argument types: () values: []')
}

 

Understand the needs and benefits around implementing the right monitoring solution for a growing containerized market. Brought to you in partnership with AppDynamics.

Topics:

Published at DZone with permission of Hubert Klein Ikkink, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

THE DZONE NEWSLETTER

Dev Resources & Solutions Straight to Your Inbox

Thanks for subscribing!

Awesome! Check your inbox to verify your email so you can start receiving the latest in tech news and resources.

X

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}