playframework 2.4 - Unspecified value parameter headers error - scala

Question

I am upgrading playframework 2.4 from 2.3, I changed versions then if I compile same code, I see following error. Since I am novice at Scala, I am trying to learn Scala to solve this issue but still don't know what is the problem. What I want to do is adding a request header value from original request headers. Any help will be appreciated.
[error] /mnt/garner/project/app-service/app/com/company/playframework/filters/LoggingFilter.scala:26: not enough arguments for constructor Headers: (headers: Seq[(String, String)])play.api.mvc.Headers.
[error] Unspecified value parameter headers.
[error] val newHeaders = new Headers { val data = (requestHeader.headers.toMap
The LoggingFilter class
class LoggingFilter extends Filter {
val logger = AccessLogger.getInstance();
def apply(next: (RequestHeader) => Future[Result])(requestHeader: RequestHeader): Future[Result] = {
val startTime = System.currentTimeMillis
val requestId = logger.createLog();
val newHeaders = new Headers { val data = (requestHeader.headers.toMap
+ (AccessLogger.X_HEADER__REQUEST_ID -> Seq(requestId))).toList }
val newRequestHeader = requestHeader.copy(headers = newHeaders)
next(newRequestHeader).map { result =>
val endTime = System.currentTimeMillis
val requestTime = endTime - startTime
val bytesToString: Enumeratee[ Array[Byte], String ] = Enumeratee.map[Array[Byte]]{ bytes => new String(bytes) }
val consume: Iteratee[String,String] = Iteratee.consume[String]()
val resultBody : Future[String] = result.body |>>> bytesToString &>> consume
resultBody.map {
body =>
logger.finish(requestId, result.header.status, requestTime, body)
}
result;
}
}
}
Edit
I updated codes as following and it compiled well
following codes changed
val newHeaders = new Headers { val data = (requestHeader.headers.toMap
+ (AccessLogger.X_HEADER__REQUEST_ID -> Seq(requestId))).toList }
to
val newHeaders = new Headers((requestHeader.headers.toSimpleMap
+ (AccessLogger.X_HEADER__REQUEST_ID -> requestId)).toList)

Answer 1

It simply states that if you want to construct Headers you need to supply a field named headers which is of type Seq[(String, String)]. If you omit the inital new you will be using the apply function of the corresponding object for Headers which will just take a parameter of a vararg of (String, String) and your code should work. If you look at documentation https://www.playframework.com/documentation/2.4.x/api/scala/index.html#play.api.mvc.Headers and flip between the docs for object and class it should become clear.