如何从Groovy中的MetaClass方法引用GroovyObject实例？

This is a contrived example of what I want to do, but minimally expresses the behavior desired. I want to reference the instance of the object on which the property access is being invoked. I tried 'this' first, but that refers to the enclosing class rather than either the MetaClass or the String instance. This is a contrived example of what I want to d