Refactoring for DRY

[Sam Pullara]

Sorry, that was the version forgoing all other considerations...

Sam

All my photos are panoramas.

On Apr 9, 2013, at 6:20 AM, Brian Goetz <brian.goetz at oracle.com> wrote:

> Richard is absolutely right.  Putting side-effects inside a lambda passed to map, flatMap, etc, is a Bad Idea -- regardless of whether you can prove that *in this particular case* it might be safe.  Don't code like this, and please don't write examples like this in books :)
>
> DRY is a good principle, but that doesn't mean it necessarily trumps all other good principles.
>
> On 4/9/2013 6:02 AM, Richard Warburton wrote:
>>> But aggressively I might optimize by only doing a single pass:
>>>
>>>     double sum = people.parallelStream().flatMap( (Person p,
>>> Consumer<Person> c) -> {
>>>       if (p.getAge() >= 12 && p.getAge() < 65) {
>>>         if (p.hasCoupon()) {
>>>           p.setPrice(9.25);
>>>         } else {
>>>           p.setPrice(7.25);
>>>         }
>>>       } else {
>>>         p.setPrice(5.25);
>>>       }
>>>       p.display();
>>>       c.accept(p);
>>>     }).map(Person::getPrice)
>>>             .collect(Collectors.toDoubleSummaryStatistics(d ->
>>> d)).getSum();
>>
>> Even leaving aside the question of tee()/peek() is this code really a good
>> candidate to be run in parallel?
>>
>> Its pretty unreasonable to expect display to not have side effects, does
>> their ordering matter, and the consumer needs to be thread-safe.  Does this
>> not get people away from the driving motivation of minimising and
>> controlling side effects in order to make safe concurrent code easier to
>> write?
>>
>> I'm really wondering because to my mind this is the kind of code I'd
>> recommend people don't write with lambdas.
>>
>> regards,
>>
>>   Richard Warburton
>>
>>   http://insightfullogic.com
>>   @RichardWarburto <http://twitter.com/richardwarburto>
>>