A DESCRIPTION OF THE REQUEST :
Especially for larger-size enums (more than ten elements), the valueOf method implementation is slow, iterating over all elements of the $VALUES array until an element with matching name is found.

The request is to change the code generated for this method to a hashmap-based lookup, at least for "large" enums.

JUSTIFICATION :
Performance. Example: for an enumeration of 192 countries, the average access times on my machine are as follows:

Generated valueOf method                           2,510 nanoseconds
Hashmap-based getInstance method             92 nanoseconds

For a 64-element enum, the corresponding times are 781 and 87 nanoseconds.
For a 10-element enum, the times are 157 and 76 nanoseconds.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Cache name-element pairs in unmodifiable HashMap.
ACTUAL -
See above.

---------- BEGIN SOURCE ----------
For enum E {...}:

public static E valueOf(String elmName) {
   E elm = _cachedRefs.get(elmName);
   if (elm == null) throw new IllegalArgumentException(...);
   return elm;
}

private static final Map<String, E> _cachedRefs;
static {
   // populate map
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Write getInstance method for each enum.