[java] Java: using switch statement with enum under subclass

First I'll state that I'm much more familiar with enums in C# and it seems like enums in java is a quite mess.

As you can see, I'm trying to use a switch statement @ enums in my next example but I always get an error no matter what I'm doing.

The error I receive is:

The qualified case label SomeClass.AnotherClass.MyEnum.VALUE_A must be replaced with the unqualified enum constant VALUE_A

The thing is I quite understand the error but I can't just write the VALUE_A since the enum is located in another sub-class. Is there a way to solve this problem? And why is it happening in Java?

//Main Class
public class SomeClass {

    //Sub-Class
    public static class AnotherClass {
        public enum MyEnum {
            VALUE_A, VALUE_B
        }    
        public MyEnum myEnum;
    }

    public void someMethod() { 
        MyEnum enumExample //...

        switch (enumExample) {
            case AnotherClass.MyEnum.VALUE_A: { <-- error on this line
                //..
                break;
            }
        }
    }
}

This question is related to java enums switch-statement

The answer is


Write someMethod() in this way:

public void someMethod() {

    SomeClass.AnotherClass.MyEnum enumExample = SomeClass.AnotherClass.MyEnum.VALUE_A;

    switch (enumExample) {
    case VALUE_A:
        break;
    }

}

In switch statement you must use the constant name only.


This is how I am using it. And it is working fantastically -

public enum Button {
        REPORT_ISSUES(0),
        CANCEL_ORDER(1),
        RETURN_ORDER(2);

        private int value;

        Button(int value) {
            this.value = value;
        }

        public int getValue() {
            return value;
        }
    }

And the switch-case as shown below

@Override
public void onClick(MyOrderDetailDelgate.Button button, int position) {
    switch (button) {
        case REPORT_ISSUES: {
            break;
        }
        case CANCEL_ORDER: {
            break;
        }
        case RETURN_ORDER: {
            break;
        }
    }
}

Wrong:

case AnotherClass.MyEnum.VALUE_A

Right:

case VALUE_A:

Java infers automatically the type of the elements in case, so the labels must be unqualified.

int i;
switch(i) {
   case 5: // <- integer is expected
}
MyEnum e;
switch (e) {
   case VALUE_A: // <- an element of the enumeration is expected
}

this should do:

//Main Class
public class SomeClass {

    //Sub-Class
    public static class AnotherClass {
        public enum MyEnum {
            VALUE_A, VALUE_B
        }    
        public MyEnum myEnum;
    }

    public void someMethod() { 
        AnotherClass.MyEnum enumExample = AnotherClass.MyEnum.VALUE_A; //...

        switch (enumExample) {
            case VALUE_A: { //<-- error on this line
            //..
            break;
            }
        }
    }
}

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