Criteria/Restrictions: lack of operators?

[eskamuc]

Hi,
first of all, I'd like to thank you for providing MongoLink on GitHub.
When trying out the criteria API I was wondering, why there is a method Restrictions.greaterThanOrEqual but no "greaterThan" or even "lessThan" respectively "lessThanEqual". The MongoDB QueryBuilder has all these methods (see http://api.mongodb.org/java/2.2/com/mongodb/QueryBuilder.html#lessThanEquals%28java.lang.Object%29 respectively http://api.mongodb.org/java/2.2/com/mongodb/QueryBuilder.html#lessThan%28java.lang.Object%29 )

So for me there are three questions:

1. Are there plans to extend the Restrictions/RestrictionFactory for the missing operators like "lessThan", "lessThanEquals" or others?
2. Is there a workaround for the issue?
3. Is it possible to use a query built with MongoDB QueryBuilder to retrieve objects using MongoLink?

Regards,
Stefan

[BodySplash]

Hi Stefan,

First of all, thank you for your interest in MongoLink :)
The reason we don't support (yet) every operators is quite simple. We only add them when we or the community need them.

On the other hand, we started MongoLink when they were no QueryBuilder, so we still need to figure if we want to use it or not. Theoretically, we don't want to expose any driver objects, so you won't be couple to it, but the QueryBuilder is quite simple, it makes me wonder.

So :

• There is a plan do add restrictions when someone need one. There are simple enough so you can fork mongolink, add them, make a pull request; or you can wait for my next development slot for mongolink :)
• You can create your own CriteriaFactory, pass it to the initial Settings. Then your own criteria just have to inherit from Criteria, and you have to override createQuery and make use of QueryBuilder. It's a bit hacky, since you'll have to cast Criteria with your own implementation, but it's possible.
• We could use QueryBuilder instead of our own restrictions to support all operators and future operators right now.

[eskamuc]

Hello Jean-Baptiste,
thanks for your really quick response. Since I've already implemented two implementations of a query builder (one using MongoLinks Criteria API and one using MongoDBs QueryBuilder API), so I'll try to override the createQuery. Thank you very much.
Regards,
Stefan

[eskamuc]

Hello,
I've subclassed now - as suggested - Criteria and CriteriaFactory and it works fine so far with the standard MongoDB QueryBuilder.
One additional hint: MongoLinkRule (see https://github.com/MongoLink/mongolink/blob/master/mongolink-testtools/src/main/java/org/mongolink/test/MongolinkRule.java ) cannot be used with this approach, because Settings is not exposed by MongoLinkRule. MongoLinkRule also cannot be subclassed, so I had to reimplement it (which btw is not such a big deal).
Thanks again and best regards,
Stefan

[BodySplash]

Glad to here it worked :) We definitely need to enhance the criteria api one way or another.
I keep this issue open.