Mongojack: invalid hexadecimal representation of an ObjectId

Question

Goal

I am trying to push some data to a mongo db using mongojack . I expect the result to be something like this in the db:

{
 "_id": "840617013772681266",
 "messageCount": 69420,
 "seedCount": 18,
 "prefix": "f!",
 "language": "en"
}

Problem

Instead, I get this error in my console.

Caused by: java.lang.IllegalArgumentException: invalid hexadecimal representation of an ObjectId: [840617013772681266]
    at org.bson.types.ObjectId.parseHexString(ObjectId.java:390)
    at org.bson.types.ObjectId.<init>(ObjectId.java:193)
    at org.mongojack.internal.ObjectIdSerializer.serialiseObject(ObjectIdSerializer.java:66)
    at org.mongojack.internal.ObjectIdSerializer.serialize(ObjectIdSerializer.java:49)
    at com.fasterxml.jackson.databind.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:728)
    at com.fasterxml.jackson.databind.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:770)
    ... 59 more

Code

This is the code that gets called when I try to create a new Guild in the db:

    public static Guild getGuild(String id) throws ExecutionException {
        return cache.get(id);
    }

cache is the following (load get executed):

    private static LoadingCache<String, Guild> cache = CacheBuilder.newBuilder()
            .expireAfterAccess(10, TimeUnit.MINUTES)
            .build(
                    new CacheLoader<>() {
                        @Override
                        public Guild load(@NotNull String id) {
                            return findGuild(id).orElseGet(() -> new Guild(id, "f!"));
                        }
                    });

The findGuild method that gets called first:

    public static Optional<Guild> findGuild(String id) {
        return Optional.ofNullable(guildCollection.find()
                .filter(Filters.eq("_id", id)).first());
    }

And finally the Guild document.

@Getter
@Setter
public class Guild implements Model {

    public Guild(String id, String prefix) {
        this.id = id;
        this.prefix = prefix;
    }

    public Guild() {
    }

    private String id;

    /*
    If a Discord guild sent 1,000,000,000 messages per second,
    it would take roughly 292471 years to reach the long primitive limit.
     */
    private long messageCount;

    private long seedCount;

    // The default language is specified in BotValues.java's bot.yaml.
    private String language;

    private String prefix;

    @ObjectId
    @JsonProperty("_id")
    public String getId() {
        return id;
    }

    @ObjectId
    @JsonProperty("_id")
    public void setId(String id) {
        this.id = id;
    }
}

What I've tried

I've tried multiple things, such as doing Long.toHexString(Long.parseLong(id)) truth is I don't understand the error completely and after seeing documentation I'm left with more questions than answers.

Answer 1

ObjectId is a 12-byte value that is commonly represented as a sequence of 24 hex digits. It is not an integer.

You can either create ObjectId values using the appropriate ObjectId constructor or parse a 24-hex-digit string. You appear to be trying to perform an integer conversion to ObjectId which generally isn't a supported operation.

You can technically convert the integer 840617013772681266 to an ObjectId by zero-padding it to 12 bytes, but standard MongoDB driver tooling doesn't do that for you and considers this invalid input (either as an integer or as a string) for conversion to ObjectId.

Example in Ruby:

irb(main):011:0> (v = '%x' % 840617013772681266) + '0' * (24 - v.length)
=> "baa78b862120032000000000"

Note that while the resulting value would be parseable as an ObjectId, it isn't constructed following the ObjectId rules and thus the value cannot be sensibly decomposed into the ObjectId components (machine id, counter and a random value).