Clean Code add Context

來源：https://github.com/EQuimper/Tutorial-And-Programming-Books-Notes/blob/master/clean-code/02-Meaningful Names/Add-Meaningful-Context.java

比較一下上下兩個差別：

private void printGuessStatistics(char candidate, int count) {
  String number;
  String verb;
  String pluralModifier;

  if (count == 0) {
    number = "no";
    verb = "are";
    pluralModifier = "s";
  } else if (count == 1) {
    number = "1";
    verb = "is";
    pluralModifier = "";
  } else {
    number = Integer.toString(count);
    verb = "are";
    pluralModifier = "s";
  }

  String guessMessage = String.format(
    "There %s %s %s%s", verb, number, candidate, pluralModifier
  );
  print(guessMessage);
}

加入 context class:

public class GuessStatisticsMessage {
  private String number;
  private String verb;
  private String pluralModifier;

  public String make(char candidate, int count) {
    createPluralDependentMessageParts(count);
    return String.format(
      "There %s %s %s%s",
      verb, number, candidate, pluralModifier
    );
  }

  private void createPluralDependentMessageParts(int count) {
    if (count == 0) {
      thereAreNoLetters();
    } else if (count == 1) {
      thereIsOneLetter();
    } else {
      thereAreManyLetters(count);
    }
  }

  private void thereAreManyLetters(int count) {
    number = Integer.toString(count);
    verb = "are";
    pluralModifier = "s";
  }

  private void thereIsOneLetter() {
    number = "1";
    verb = "is";
    pluralModifier = "";
  }

  private void thereAreNoLetters() {
    number = "no";
    verb = "are";
    pluralModifier = "s";
  }
}