Using Spring IoC to set up enum values

Question

Is there a way to set up such enum values via Spring IoC at construction time?

What I would like to do is to inject, at class load time, values that are hard-coded i

Answer 1

All right, this is a bit complex but you may find a way to integrate it. Enums are not meant to change at runtime, so this is a reflection hack. Sorry I don't have the Spring implementation part, but you could just build a bean to take in the enum class or object, and another field that would be the new value or values.

Constructor con = MyEnum.class.getDeclaredConstructors()[0];
Method[] methods = con.getClass().getDeclaredMethods();
for (Method m : methods) {
  if (m.getName().equals("acquireConstructorAccessor")) {
    m.setAccessible(true);
    m.invoke(con, new Object[0]);
  }
}
Field[] fields = con.getClass().getDeclaredFields();
Object ca = null;
for (Field f : fields) {
  if (f.getName().equals("constructorAccessor")) {
    f.setAccessible(true);
    ca = f.get(con);
  }
}
Method m = ca.getClass().getMethod(
  "newInstance", new Class[] { Object[].class });
m.setAccessible(true);
MyEnum v = (MyEnum) m.invoke(ca, new Object[] { 
  new Object[] { "MY_NEW_ENUM_VALUE", Integer.MAX_VALUE } });
  System.out.println(v.getClass() + ":" + v.name() + ":" + v.ordinal());

This is taken from this site.