Hello, Im looking for a way to clean this code. I dont like this part of init empty String, is there...

# codereview

[Dipendra Singh]

Hello, Im looking for a way to clean this code.
I dont like this part of init empty String, is there other way write this?

fun getStreetNameByStreetId(id: String): String {
        val query = Query()
        query.fields().include("name")
        query.addCriteria(Criteria.where("_id").`is`(id))
        var streetName = ""
        mongoTemplate.executeQuery(
            query, STREET_COLLECTION
        ) { document: Document ->
            streetName = document.getValue("name").toString()
        }
        return streetName
    }

[sbyrne]

I would probably write an extension function on MongoTemplate that uses a sequence builder to return a Sequence<T>, and in your case where you only want one value, do val streetName = mongoTemplate.executeQueryToSequence(query,STREET_COLLECTION) { document -> document.getValue("name").toString() }.firstOrNull().

[sbyrne]

(executeQueryToSequence is the extension function I would write.)

[Paul Griffith]

it looks like findOne already exists and is nullable, so something like this would probably be more idiomatic. As a sidenote, this function should probably return String? since the lookup is fallible

Untitled.txt

[Paul Griffith]

cribbing from https://docs.spring.io/spring-data/data-mongodb/docs/current/reference/html/#mongo-template.save-update-remove

[todd.ginsberg]

An apply might make things a bit cleaner:

fun getStreeNameByStreetId(id: String): String {
    val query = Query().apply {
        fields().include("name")
        addCriteria(Criteria.where("_id").`is`(id))
    }
    return mongoTemplate...
}

[Paul Griffith]

https://docs.spring.io/spring-data/data-mongodb/docs/current/reference/html/#mongo.query.kotlin-support
it looks like there's already a nicer API for Kotlin, even

[Paul Griffith]

e.g.

Untitled.kt

[Dipendra Singh]

@Paul Griffith findOne will shout "None of the following functions can be called with the arguments supplied."
and Document: id
Unresolved reference: _id
Im trying to rewrite it somehow but always coming with errors

[Paul Griffith]

🤷 I don't have Spring, MongoDB, or your internal classes in front of me, so I'm just guessing. Your original query syntax may work, it's just not very 'nice' Kotlin