Кружок про ООП и дизайн / archived / read-only

© Rich Hickey: SimpleMadeEasy

• What kind of runner can run as fast as they possibly can from the very start of a race? Right, only somebody who runs really short races, okay? [Audience reply: Sprinter] But of course, we are programmers, and we are smarter than runners, apparently, because we know how to fix that problem, right? We just fire the starting pistol every hundred yards and call it a new sprint.

```java storage.write(file); // я говорю, что я хочу

class Hdd implements Storage { void write(File file) { while (file.hasNext()) { write(file.readNext(BLOCK_SIZE)); } }

void write(byte[] bytes) {
    // assertBlockSize
    head.setPosition(...);
    currentBlock.write(bytes);
}

}

class File { boolean hasNext(); byte[] readNext(int numOfBytes); }

```

• От стандартной библиотеки зависеть можно
• От фреймворка тоже, если очень уверены, что не соберётесь его поменять

• Сделайте обёртку со стабильным интерфейсом

```java class FraudConfirmationService { private SmartcallsClient smartcalls;

void confirmOrder(Long orderId) {
    Order order = getOrder(orderId);

    SmartcallsResult res = smartcalls.appendToCampaign(PhoneNormalizer.normalizeWithoutPlus(order.phone));
    if (res.getAttempt().isSuccess()) {
    }
}

} ```

• ```java class FraudConfirmationService { private ClientConfirmationService clientConfirmationService;

  void confirmOrder(Long orderId) {
      if (clientConfirmationService.askConfirmation(new Phone(order.phone))) {
      }
      orderService.confirm();
      ticket.resolve();
  }
  

  }

  interface ClientConfirmationService { boolean askConfirmation(Phone phone); }

  class SmartcallsCallService implements ClientConfirmationService { boolean askConfirmation(Phone phone) { return smartcalls.appendToCampaign(phone.withoutPlus()).getAttempt().isSuccess(); } } ```

• ```java class BackupService { private MdsService mds;

  public String backup(List<String> filenames) {
      String zipPath = zipFiles(filenames);
      return mds.write(zipPath);
  }
  
  private String zipFiles(List<String> filenames) {
      File tempFile = File.createTempFile("blabla");
      var zip = new Zip(tempFile);
      for (var f : filenames) {
          zip.add("/", f);
      }
      return tempFile.getName();
  }
  

  } ```