hg: lambda/lambda/jdk: - implement IntStream.average (arithemtic mean).

[Paul Sandoz]

On Nov 20, 2012, at 4:51 PM, Brian Goetz <brian.goetz at Oracle.COM> wrote:

> Rather than reduce with Integer::sum, should sum() use a reducing sink that internally does computation in long so as to be less sensitive to overflow when adding BIG + BIG + NEGATIVE_BIG?
> 

I was wondering about whether IntStream.sum() should return long or not, and also what to do on overflows, i suppose one such answer would be for developers to do:

  s.reduce(0, Math::addExact)

and catch the ArithmeticException.

Perhaps another solution is to widen the stream?

 s.asLongs().sum()

Not as efficient though.

Paul.


> On 11/20/2012 10:34 AM, paul.sandoz at oracle.com wrote:
>> Changeset: 932b4939d7c8
>> Author:    psandoz
>> Date:      2012-11-20 16:34 +0100
>> URL:       http://hg.openjdk.java.net/lambda/lambda/jdk/rev/932b4939d7c8
>> 
>> - implement IntStream.average (arithemtic mean).
>> 
>> + src/share/classes/java/util/stream/primitive/IntAverageOp.java
>> ! src/share/classes/java/util/stream/primitive/IntPipeline.java
>> ! src/share/classes/java/util/stream/primitive/IntStream.java
>> + test-ng/tests/org/openjdk/tests/java/util/stream/primitive/IntAverageOpTest.java
>> 
>>