Good morning. I have this stupid problem with gene...

# announcements

[Jakub Gwóźdź]

Good morning. I have this stupid problem with generics-vs-overloading-vs-varargs in JOOQ. While following code:

public class GenericsJava {
  public static Condition testJooqGenerics(Table<?> table, List<Object> list) {
    Field<Object> myColumn = table.field("MY_COLUMN", Object.class);
    return <http://myColumn.in|myColumn.in>(list);
  }
}

works well in Java, the Kotlin version

object GenericsKotlin {
    fun testJooqGenerics(table: Table<*>, list: List<Any?>?): Condition {
        val myColumn: Field<Any> = table.field("MY_COLUMN", Any::class.java)
        return myColumn.`in`(list)
    }
}

yelds Overload resolution ambiguity:

@Support public abstract fun `in`(vararg p0: Any!): Condition! defined in org.jooq.Field
@Support public abstract fun `in`(p0: (Mutable)Collection<*>!): Condition! defined in org.jooq.Field

Is there any way to work around this API issue?

[Jakub Gwóźdź]

(obviously, when the type is anything but Any, e.g. Field<String>, it works great)

[henrik]

Can you add your import statements?

[Jakub Gwóźdź]

sure, it's

package test.generics

import org.jooq.Condition
import org.jooq.Field
import org.jooq.Table

plus java.util.List and semicolons in java version 🙂

[Jakub Gwóźdź]

Ok, I found the solution in case anyone needs it sometime in the future: reified generics.

object GenericsKotlin {
    inline fun <reified T> testJooqGenericsInline(table: Table<*>, list: List<T>): Condition {
        val myColumn: Field<T> = table.field("MY_COLUMN", T::class.java)
        return myColumn.`in`(list)
    }

    fun testJooqGenerics(table: Table<*>, list: List<Any>): Condition {
        return testJooqGenericsInline(table, list)
    }
}