Refactoring for DRY (original) (raw)

Sam Pullara spullara at gmail.com
Mon Apr 8 19:30:50 PDT 2013

So as a first pass, I would do normal refactoring to use the API more effectively:

Predicate<Person> ageRange = p -> p.getAge() >= 12 && p.getAge() < 65;

people.parallelStream()
        .filter(ageRange)
        .forEach(p -> {
          p.setPrice(9.25);
        });

people.parallelStream()
        .filter(ageRange.and(Person::hasCoupon))
        .forEach(p -> {
          p.setPrice(p.getPrice() - 2.00);
        });

people.parallelStream()
        .filter(ageRange.negate())
        .forEach(p -> {
          p.setPrice(5.25);
        });

people.stream()
        .forEach(p -> {
          p.display();
        });

double sum = people.stream().map(p -> p.getPrice()).collect(Collectors.toDoubleSummaryStatistics(d -> d)).getSum();

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();

But that doesn't really address the larger issue of the multiple passes. I think this would be most effectively done with tee() On Apr 8, 2013, at 4:35 PM, "Barry Burd" <bburd at drew.edu> wrote:

The following code seems very repetitious to me. Ss there a recommended way to refactor this code?

people.parallelStream() .filter(p -> p.getAge() >= 12) .filter(p -> p.getAge() < 65)_ _.forEach(p -> { p.setPrice(9.25); }); people.parallelStream() .filter(p -> p.getAge() >= 12) .filter(p -> p.getAge() < 65)_ _.filter(p -> p.hasCoupon()) .forEach(p -> { p.setPrice(p.getPrice() - 2.00); }); people.parallelStream() .filter(p -> (p.getAge() < 12 || p.getAge() >= 65)) .forEach(p -> { p.setPrice(5.25); }); people.stream() .forEach(p -> { p.display(); }); people.stream().map(p -> p.getPrice()).forEach(amount -> total += amount);

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