code: private static void addProcessor(final String key, final Processor processor) throws IllegalStateException {
          if (!ARCH_TO_PROCESSOR.containsKey(key)) {
              ARCH_TO_PROCESSOR.put(key, processor);
          } else {
              final String msg = "Key " + key + " already exists in processor map";
              throw new IllegalStateException(msg);
          }
      }
docs: Adds the given {@link Processor} with the given key {@link String} to the map.
  
  @param key The key as {@link String}.
  @param processor The {@link Processor} to add.
  @throws IllegalStateException If the key already exists.