Cache enum's value array for a speed increase

Author: oschwald

src/main/java/com/maxmind/maxminddb/Decoder.java

@@ -33,14 +33,16 @@ final class Decoder {
     static enum Type {
         EXTENDED, POINTER, UTF8_STRING, DOUBLE, BYTES, UINT16, UINT32, MAP, INT32, UINT64, UINT128, ARRAY, CONTAINER, END_MARKER, BOOLEAN, FLOAT;
 
+        // Java clones the array when you call values(). Caching it increased
+        // the speed by about 5000 requests per second on my machine.
+        final static Type[] values = Type.values();
+
         public static Type get(int i) {
-            // XXX - Type.values() might be expensive. Consider caching it.
-            return Type.values()[i];
+            return Type.values[i];
         }
 
         private static Type get(byte b) {
             // bytes are signed, but we want to treat them as unsigned here
-            // XXX - Type.values() might be expensive. Consider caching it.
             return Type.get(b & 0xFF);
         }