Github user drewrobb commented on a diff in the pull request: https://github.com/apache/spark/pull/23062#discussion_r234844306 --- Diff: sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/ScalaReflection.scala --- @@ -788,12 +788,37 @@ object ScalaReflection extends ScalaReflection { } /** - * Finds an accessible constructor with compatible parameters. This is a more flexible search - * than the exact matching algorithm in `Class.getConstructor`. The first assignment-compatible - * matching constructor is returned. Otherwise, it returns `None`. + * Finds an accessible constructor with compatible parameters. This is a more flexible search than + * the exact matching algorithm in `Class.getConstructor`. The first assignment-compatible + * matching constructor is returned if it exists. Otherwise, we check for additional compatible + * constructors defined in the companion object as `apply` methods. Otherwise, it returns `None`. */ - def findConstructor(cls: Class[_], paramTypes: Seq[Class[_]]): Option[Constructor[_]] = { - Option(ConstructorUtils.getMatchingAccessibleConstructor(cls, paramTypes: _*)) + def findConstructor(cls: Class[_], paramTypes: Seq[Class[_]]): Option[Seq[AnyRef] => Any] = { + Option(ConstructorUtils.getMatchingAccessibleConstructor(cls, paramTypes: _*)) match { + case Some(c) => Some((x: Seq[AnyRef]) => c.newInstance(x: _*)) + case None => + val companion = mirror.staticClass(cls.getName).companion + val moduleMirror = mirror.reflectModule(companion.asModule) + val applyMethods = companion.asTerm.typeSignature + .member(universe.TermName("apply")).asTerm.alternatives + applyMethods.find { method => + val params = method.typeSignature.paramLists.head + // Check that the needed params are the same length and of matching types + params.size == paramTypes.tail.size && + params.zip(paramTypes.tail).forall { case(ps, pc) => + ps.typeSignature.typeSymbol == mirror.classSymbol(pc) + } + }.map { applyMethodSymbol => + val expectedArgsCount = applyMethodSymbol.typeSignature.paramLists.head.size + val instanceMirror = mirror.reflect(moduleMirror.instance) + val method = instanceMirror.reflectMethod(applyMethodSymbol.asMethod) + (_args: Seq[AnyRef]) => { + // Drop the "outer" argument if it is provided + val args = if (_args.size == expectedArgsCount) _args else _args.tail --- End diff -- You would still have to check the length, in case the first actual argument was for some reason also a class.
--- --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org