Helper methods and extensions to improve kotlin interop.

[rozza]

Based on kmongo-property but provides both infix and nested helpers.

Adds a new package org.mongodb.mongodb-driver-kotlin-extensions. Its both kotlin drivers and bson kotlin implementations agnostic. So can be used with any combination of bson-kotlin, bson-kotlinx, mongodb-driver-kotlin-sync and mongodb-driver-kotlin-coroutine.

Initial Filters extensions support, with both inflix and nested helpers eg:

import com.mongodb.kotlin.client.model.Filters.eq

// infix
Person::name.eq(person.name)

// nested
val bson = eq(Person::name, person.name)

Also adds path based support which works with vairous annotations on the data class: @SerialName("_id"), @BsonId, @BsonProperty("_id"):

(Restaurant::reviews / Review::score).path() == "reviews.rating"

JAVA-5308 JAVA-5484

[vbabanin]

Looks good overall! Just a couple of questions.

NOTE: I am still reviewing some of the files before LGTM.

[vbabanin]

LGTM, noting that I'm not deeply versed in Kotlin!

[nhachicha]

LGTM some minor comments 👍

[nhachicha]

Note that driver-core defines the same overloads for String property name
so if a user combines both filters they need to FQN the second one.

       val bsonExt = eq(Person::name, person.name)
       val bson = com.mongodb.client.model.Filters.eq(Person::name.name, person.name)

Extension functions can reside as top methods on a Kotlin file, the suggested approach below might offer IDE help when importing (although you still need 2 static imports for both)

• FiltersExt.kt

package com.mongodb.client.model.ext

import com.mongodb.client.model.Filters
import com.mongodb.kotlin.client.model.path
import org.bson.conversions.Bson
import kotlin.internal.OnlyInputTypes
import kotlin.reflect.KProperty

@JvmName("eqExt")
public infix fun <@OnlyInputTypes T> KProperty<T?>.eq(value: T?): Bson = Filters.eq(path(), value)
public fun <@OnlyInputTypes T> eq(property: KProperty<T?>, value: T?): Bson = property.eq(value)

and in the

• FiltersTes.kt

import com.mongodb.client.model.Filters.eq
import com.mongodb.client.model.ext.eq

  val bson = eq(Person::name, person.name)
  val bson2 = eq(Person::name.name, person.name)
  assertEquals(expected, bson.document)

  val kmongoDsl = Person::name eq person.name

[rozza]

As the namespaces are different they can import both methods:

import com.mongodb.client.model.Filters.eq
import com.mongodb.kotlin.client.model.Filters.eq

...

    @Test
    fun testEqSupport() {
        val expected = BsonDocument.parse("""{"name": "Ada"}""")
        val bson = eq(Person::name, person.name)
        assertEquals(expected, bson.document)

        val bson2 = eq(Person::name.name, person.name)
        assertEquals(expected, bson2.document)

        val kmongoDsl = Person::name eq person.name
        assertEquals(expected, kmongoDsl.document)
    }

[rozza]

@nhachicha thanks for the review - I think I've responded to everything or have asked follow questions.

[nhachicha]

Nice one 🎉
Should this still target master or a feature branch?

[rozza]

@nhachicha merged into: https://github.com/mongodb/mongo-java-driver/tree/kotlin-extensions

CI: https://spruce.mongodb.com/commits/java-driver-kotlin-extensions