public <SerializationT extends Serialization> boolean hasParserForKey(
      SerializationT serializedKey) {
    ParserIndex index =
        new ParserIndex(serializedKey.getClass(), serializedKey.getObjectIdentifier());
    return keyParserMap.containsKey(index);
  }
Returns true if a parser for this {@code serializedKey} has been registered.
java_src/src/main/java/com/google/crypto/tink/internal/SerializationRegistry.java