如何使用Java-Reflection设置scala.Enumeration类型的值

Question

I have a complicated reflection-based Java-Application which I now translated partly into scala. Howerver, the reflection-based part is still in Java ...

Now I have a scala enumeration type, for instance:

object DayType extends Enumeration {
  type DayType = Value

  val Monday = Value("Monday")
  val Tuesday = Value("Tuesday")
  ...
}

Now I use Java Reflection in a following way:

public static void setFieldValue(Object o, String fieldName, String value) {

  Field field;
  try {
    field = o.getClass().getField(fieldName);
  } catch (NoSuchFieldException e) {
    // in Scala EVERY field is private.
    field = o.getClass().getDeclaredField(fieldName);
    field.setAccessible(true);
  }

  Class type = field.getType();
  if (type == Float.TYPE) {
    field.setFloat(o, Float.parseFloat(value));
  } 
  if (type == Integer.TYPE) {
    field.setInt(o, Integer.parseInt(value));
  }

  ...

  if (type.getName().equals("scala.Enumeration$Value")) {
    System.out.println("fieldname: " + field.getName());
    System.out.println("fieldtype: " + field.getType());
    try {
      field.set(o, ???);
    } catch (Exception e) {
      System.out.println(e.getMessage());
    }

  ...

At least the type recognition works correctly, however, two questions remain: 1. Is there a way to recognize the type without going via the name? if (type == Enumeration.class) does not work, if (type == Enumeration) also not (the second solution does not even compile) 2. How to set the value? How to replace "???" Simply doing field.set(o, value) leads to a "Can not set scala.Enumeration$Value field diva.module.AdaptationFloodingNew.adaptMode to java.lang.String" exception (which is reasonable).

Answer 1

What is missing from the code is a way to convert the value from a string to a DayType. Kind of like the way the Integer is handled... Integer.parseInt(value). Try using the Value construct that is used in the DayType Enumeration.