pass reflected enum to method.invoke java

Question

If you have an enum that you are accessing via reflection how would you pass it's value into method.invoke call.

Would it be something like (shown as a static method for simplicity)

    Class enumClazz = Class.forName("mypkg.MyEnum",true,MyClassLoader);
    Class myReflectedClazz = Class.forName("mypkg.MyClass",true,MyClassLoader);
    Field f = enumClazz.getField("MyEnumValue");

    Method m = myReflectedClazz.getMethod("myMethod",enumClazz);
    m.invoke(null,f.get(null));

Answer 1

You should probably do:

Enum e = Enum.valueOf(enumClazz, "MyEnumValue");

You will get unchecked warnings as you are using raw types but this will compile and run.

Using reflection, you would need to pass an instance to access a Field - however in the case of static methods, you can pass in null to Field's get method as follows:

m.invoke(null,f.get(null));

Also - is myMethod a static method as you are calling this with no instance as well?

Answer 2

You have an enum definition:

public enum MyEnum {
    MY_SAMPLE_ENUM
}

And a class which has a method that has an enum parameter:

public class SampleClass {
    public static void myMethod(MyEnum myEnumParam) {
        // some logic here
    }
}

Invoke SampleClass.myMethod(MyEnum.MY_SAMPLE_ENUM) by reflection:

Class clazzMyEnum= Class.forName("mypkg.MyEnum", true, myClassLoader);
Enum enum_MY_SAMPLE_ENUM = Enum.valueOf(clazzMyEnum, "MY_SAMPLE_ENUM");

Class clazzSampleClass = Class.forName("mypkg.SampleClass", true, myClassLoader);
Method methodMyMethod = clazzSampleClass.getMethod("myMethod", clazzMyEnum);
methodMyMethod.invoke(null, enum_MY_SAMPLE_ENUM);