Is it possible to point to anonymous class by .THIS keyword?

Question

SSCCE:

public class Test {
    public Test() {
        new Anonymous1() {
            void validate() {
                new Anonymous2() {
                    int calculate() {
                        return Math.abs(Anonymous1.this.getValue()); // compilation error - Anonymous1 is not an enclosing class
                    }
                };
            }
        };
    }
}

abstract class Anonymous1 {
    abstract void validate();

    int getValue() {
        return 0;
    }
}

abstract class Anonymous2 {
    abstract int calculate();
}

I know that it looks complicated and unusable, but I am just wonder is it possible to point to Anonymous1 class from Anonymous2 using .this pointer, or in any else way.

The problem is, `Anonymous1` and `Anonymous2` are not the names of those inner classes. `Anonymous1` and `Anonymous2` are the *superclasses* of those inner classes. You need to use the actual name of the class for `Something.this`, but there is no name because they are anonymous. — newacct, Mar 15 '16 at 00:48

score 4 · Accepted Answer · answered Mar 11 '16 at 08:27

You need to do it in the class.

public Test() {
    new Anonymous1() {
        void validate() {
            final Object this1 = this;
            new Anonymous2() {
                int calculate() {
                    return Math.abs(this1.getValue()); 
                }
            }
        }
    }
}

or even better, extract the things you need first and use effectively final added in Java 8.

public Test() {
    new Anonymous1() {
        void validate() {
            int value = getValue();
            new Anonymous2() {
                int calculate() {
                    return Math.abs(value); 
                }
            }
        }
    }
}

if Anonymous1 and Anonymous2 were interfaces you could use lambdas in Java 8.

public Test() {
   Anonymous1 a = () -> {
      int v = getValue();
      Anonymous2 = a2 = () -> Math.abs(v);
   };

}

Is it possible to point to anonymous class by .THIS keyword?

1 Answers1