This plugin adds mapping to Kotlin classes anywhere a ResultSet is used.

It supports data classes where all fields are present in the constructor as well as classes with writable properties. Any fields not present in the constructor will be set after the constructor call. The mapper supports nullable types. It also uses default parameter values in the constructor if the parameter type is not nullable and the value absent in the result set.

The Kotlin mapper also supports the @ColumnName annotation that allows to specify name for a property or parameter explicitly, as well as the @Nested annotation that allows mapping nested Kotlin objects.

Install the plugin using Jdbi.installPlugin(KotlinPlugin()).

An example from the test class:

    data class IdAndName(val id: Int, val name: String)
    data class Thing(@Nested val idAndName: IdAndName,
                     val nullable: String?,
                     val nullableDefaultedNull: String? = null,
                     val nullableDefaultedNotNull: String? = "not null",
                     val defaulted: String = "default value")

     @Test fun testFindById() {
        val qry = db.sharedHandle.createQuery("select id, name from something where id = :id")
        val things: List<Thing> = qry.bind("id", brian.idAndName.id).mapTo<Thing>().list()
        assertEquals(1, things.size)
        assertEquals(brian, things[0])
     } 

There are two extensions to help:

• <reified T : Any>ResultBearing.mapTo()
• <T : Any>ResultIterable<T>.useSequence(block: (Sequence<T>)->Unit)

Allowing code like:

val qry = handle.createQuery("select id, name from something where id = :id")
val things = qry.bind("id", brian.idAndName.id).mapTo<Thing>.list()

and for using a Sequence that is auto closed:

qryAll.mapTo<Thing>.useSequence {
    it.forEach(::println)
}