Groovy extension method with traits?

Question

I'd like to know if there is any way to add methods to library classes using Groovy traits.

From what I read here @Mixin is used for this, or you can use the runtime mixin approach with metaclass. Since @Mixin is now deprecated in favor of traits, any chance to achieve the same behavior by using traits or is runtime mixin the only option?

Thank you

The Groovy documentation explains the available options very well: http://groovy-lang.org/metaprogramming.html — Emmanuel Rosa, Apr 19 '16 at 12:09

pgiecek · Accepted Answer · 2016-04-19T10:03:56.830

Groovy also supports implementing traits dynamically at runtime. It allows you to "decorate" an existing object using a trait.

You can decorate an object, however, I am afraid that it is not possible to decorate a class so that all its instances have the method available. See below a simple example that may help you or find more details here.

trait Extra {
    String extra() { "I'm an extra method" }            
}

class Something {                                       
    String doSomething() { 'Something' }                
}

def s = new Something() as Extra                        

assert s.extra() == "I'm an extra method"                                               
assert s.doSomething() == 'Something'

Groovy extension method with traits?

1 Answers1