Type Cast String to Enum giving error in Apex

Question

I am trying to convert String to an enum value. but I am getting null pointer exception. Below is the code which I have tried to convert. (I have checked other stackoverflow questions before asking the question)

public static Object parseEnum(String enumString, Type enumType) {
    Type cType = Type.forName(
        String.format('List<{0}>', new List<String>{ enumType.getName() })
    );
    System.debug('cType ' + cType); // throws null pointer exception
    return ((List<Object>) JSON.deserialize(
        String.format('["{0}"]', new List<String>{ enumString }),
        cType
    ))[0];
}

public enum Markup_Category {
    Admin,
    DC,
    Frozen
}

this is my methods which I am using to convert from String to Enum type. I am calling below code in the anonymous window for testing.

String markupCategory = 'Admin';
Markup_Category enumBoniMarkupCategory = (Markup_Category) parseEnum(
            markupCategory,
            Markup_Category.class
);

It is throwing null pointer exception at System.debug();. If someone can help me what I am doing wrong or any other suggestions would be great.

PS: Please ignore any typo mistake as code is compelling correctly.

Answer 1

In testing this myself, I found that enumerations and classes declared inside of Anonymous Apex do not work with Type.forName() on any level. The following all return null:

• Type.forName(String.format('List<{0}>', new List<Object>{MyEnum.class.getName()}));
• Type.forName('List<MyEnum>');
• Type.forName('MyEnum');

If you save that enum as a proper class, the parseEnum method you provided should work as you expect when testing it from anonymous apex (even if parseEnum is itself defined in the anonymous apex window) ...provided the enum itself is visible (i.e. not private and being called from outside the class that would have visibility of it)