Does Java 8 lack a Stream.concat working on a varags of streams?

Question

Currently we have the following Stream.concat in Java 8:

public static <T> Stream<T> concat(Stream<? extends T> a, Stream<? extends T> b); 

I am surprised as to why there is no version taking a varargs of Stream<? extends T>?

Currently I have code written like:

Stream<Integer> resultStream = Stream.concat(stream1, Stream.concat(stream2, Stream.of(element)))         .filter(x -> x != 0)         .filter(x -> x != 1)         .filter(x -> x != 2); 

If a varargs of this signature were available:

public static <T> Stream<T> concat(Stream<? extends T>... streams); 

Then I could write it much more clearly as:

Stream<Integer> resultStream = Stream.concat(                 stream1,                 stream2,                 Stream.of(element)         )         .filter(x -> x != 0)         .filter(x -> x != 1)         .filter(x -> x != 2); 

Without all kinds of nested Stream.concat calls.

Or are there other reasons why it is not provided?
I cannot think of such reasons, as we end up doing the job of a varargs call anyway now.

Answer 1

Just flatMap it:

public static void main(final String[] args) throws Exception {     final Stream<String> stream1 = /*some stream*/     final Stream<String> stream2 = /*some stream*/     final Stream<String> stream3 = /*some stream*/     final Stream<String> stream4 = /*some stream*/     final Stream<String> stream5 = /*some stream*/      final Stream<String> stream = Stream.of(stream1, stream2, stream3, stream4, stream5).flatMap(Function.identity()); } 

In your example:

Stream<Integer> resultStream = Stream.of(stream1, stream2, Stream.of(element))         .flatMap(identity())         .filter(x -> x != 0)         .filter(x -> x != 1)         .filter(x -> x != 2);