通用枚举解析器，没有未经检查的警告

Question

How to remove @SuppressWarnings("unchecked") in the following code?

public <T extends Enum<T>> T getEnum( String key, T dflt ) {
   final String value = properties.getProperty( key, dflt.name());
   @SuppressWarnings("unchecked")
   final Class<T> clazz = (Class<T>)dflt.getClass();
   return Enum.valueOf( clazz, value );
}

Answer 1

All Enum<E> subclasses have a method that returns its Class that is properly parameterized.

public <T extends Enum<T>> T getEnum(String key, T dflt) {
    final String value = properties.getProperty(key, dflt.name());
    final Class<T> clazz = dflt.getDeclaringClass();
    return Enum.valueOf(clazz, value);
}

EDIT: Your previous solution is WRONG, not just bad style.

 public final Class<E> getDeclaringClass() 

Returns the Class object corresponding to this enum constant's enum type. Two enum constants e1 and e2 are of the same enum type if and only if e1.getDeclaringClass() == e2.getDeclaringClass(). (The value returned by this method may differ from the one returned by the Object.getClass() method for enum constants with constant-specific class bodies.)

Enum.valueOf(Class, String) may complain if the Class passed in is the Class for "enum constants with constant-specific class bodies". Class.isEnum() will return false for those classes.