function 응용

public class FunctionRef {

  public static void ifFalseThen(boolean bool, Runnable runnable) {
    if ( !bool ) runnable.run();
  }

  public static void ifTrueThen(boolean bool, Runnable runnable) {
    if ( bool ) runnable.run();
  }

  public static  T ifFalseApply(boolean bool, Supplier runnable) {
    if ( !bool ) return runnable.get(); else return null;
  }

  public static  T ifTrueApply(boolean bool, Supplier runnable) {
    if ( bool ) return runnable.get(); else return null;
  }

  public static  T ifApply(boolean bool, Supplier runnable, Supplier falseSupply) {
    if ( bool ) return runnable.get(); else return falseSupply.get();
  }

  public static void ifThen(boolean bool, Runnable trueRun, Runnable falseRun) {
    if ( bool ) trueRun.run(); else falseRun.run();
  }

  public static void ifTrueThen(Supplier supplier, Runnable runnable) {
    if ( supplier.get() ) runnable.run();
  }

  public static void ifFalseThen(Supplier supplier, Runnable runnable) {
    if ( !supplier.get() ) runnable.run();
  }

  public static void ifThen(Supplier supplier, Runnable trueThen, Runnable falseThen) {
    if ( supplier.get() ) trueThen.run(); else falseThen.run();
  }

  public static void ifTrueThrow(boolean bool, Exception e) throws Exception {
    if (bool) throw e;
  }
}

static 메서드로 condition, successFunction, failFunction 등을 선언해놓은 것은 매우 재미있는 것 같다.

덕분에 메서드 체이닝도 되고