docs: public Object stringToKey(String s) {
        char type = s.charAt(0);
        switch (type) {
           case 'S':
              // this is a String, NOT a Short. For Short see case 'X'.
              return s.substring(2);
           case 'I':
              // This is an Integer
              return Integer.valueOf(s.substring(2));
           case 'Y':
              // This is a BYTE
              return Byte.valueOf(s.substring(2));
           case 'L':
              // This is a Long
              return Long.valueOf(s.substring(2));
           case 'X':
              // This is a SHORT
              return Short.valueOf(s.substring(2));
           case 'D':
              // This is a Double
              return Double.valueOf(s.substring(2));
           case 'F':
              // This is a Float
              return Float.valueOf(s.substring(2));
           case 'B':
              // This is a Boolean, NOT a Byte. For Byte see case 'Y'.
              return Boolean.valueOf(s.substring(2));
           case 'C':
              // This is a Character
              return Character.valueOf(s.charAt(2));
           case 'U':
              // This is a java.util.UUID
              return UUID.fromString(s.substring(2));
           case 'A':
              // This is an array of bytes encoded as a Base64 string
              return Base64.getDecoder().decode(s.substring(2));
           case 'T':
              // this is a custom Transformable or a type with a registered Transformer
              int indexOfSecondDelimiter = s.indexOf(':', 2);
              String keyClassName = s.substring(2, indexOfSecondDelimiter);
              String keyAsString = s.substring(indexOfSecondDelimiter + 1);
              Transformer t = getTransformer(keyClassName);
              if (t != null) {
                 return t.fromString(keyAsString);
              } else {
                 throw log.noTransformerForKey(keyClassName);
              }
        }
        throw new CacheException("Unknown key type metadata: " + type);
     }