On 11/20/17 10:34 AM, Paul Sandoz wrote:
On 17 Nov 2017, at 17:18, Stuart Marks <stuart.ma...@oracle.com> wrote:
The normative text about binding to the source and subsequent modifications to
the source possibly not being reflected in the stream makes sense.
I'm having trouble understanding the API note though. What does "optimal" mean?
What about concatenating multiple streams would not be optimal?
I updated to:
* @apiNote
* To preserve optimization opportunities this method binds each stream to
* its source and accepts only two streams as parameters. For example, the
* exact size of the concatenated stream source can be computed if the exact
* size of each input stream source is known.
* To concatenate more streams without binding, or nested calls to this
* method, try creating a stream of streams and flat-mapping with the
* identity function, for example:
* <pre>{@code
* Stream<T> concat = Stream.of(s1, s2, s3, s4).flatMap(s -> s);
* }</pre>
We could support three or more streams while preserving some characteristics,
that complicates the concatenating spliterator a little bit. Each stream would
still need to be bound.
Patch updated to include the primitive streams:
http://cr.openjdk.java.net/~psandoz/jdk10/JDK-8181175-concat-eager-binding/webrev/
OK, this makes a lot more sense. Just a small wording change:
1361 * To concatenate more streams without binding, or nested calls to this
1362 * method, try creating a stream of streams and flat-mapping with the
1363 * identity function, for example:
I think this would read more clearly if it were changed to "... without binding,
or without nested calls to this method, ...." I think this applies in all four
occurrences.
Thanks,
s'marks
