Groovy++ Mixin and Category

@Typed
package categoriestest

@Category(List)
@Typed
class Shuffler {
    def shuffleit() {
        def result = new ArrayList(this)
        Collections.shuffle(result)
        result
    }
}

// @Mixin(Shuffler)
@Typed
class Sentence extends ArrayList {
    Sentence(Collection initial) { super(initial) }
}

@Typed
class Main {
    static main(args) {
        def words = ["The", "quick", "brown", "fox"]
        
        Sentence.mixin Shuffler.class

        def sentence = new Sentence(words)
        println sentence.shuffleit()
    }
}

Main.main(null)

http://gppconsole.appspot.com/script/20001

see http://code.google.com/p/groovypptest/downloads/list