Predicate를 이용한 리팩토링

To be

 

import java.util.Arrays;
import java.util.function.Predicate;

public enum Ranking {
    FIRST(2000_000_000,6,false),
    SECOND(30_000_000,5, true),
    THIRD(1_500_000,5,false),
    FOURTH(50_000,4,false),
    FIFTH(5_000,3,false),
    NONE(0,0,false);
    private  final  int prize;
    private final  int count;
    private final boolean hasBonusNumber;
    
    Ranking(int prize,int count,boolean hasBonusNumber){
        this.prize=prize;
        this.count=count;
        this.hasBonusNumber= hasBonusNumber;
    }
    public static Ranking findRanking(int cnt, boolean hasBonusNumber){
        return Arrays.stream(Ranking.values()).filter(ranking -> ranking.count == cnt && ranking.hasBonusNumber == hasBonusNumber).findAny().orElse(NONE);
    }

}

•  Predicate : Type T 인자를 하나만 받아 boolean을 return
•  BiPredicate : T, U 인자 두개를 받아 boolean을 return

import java.util.Arrays;
import java.util.function.BiPredicate;
import java.util.function.Predicate;

public enum Ranking {
    FIRST(2000_000_000, (count, bonus) -> count == 6),
    SECOND(30_000_000, (count, bonus) -> count == 5 && bonus),
    THIRD(1_500_000, (count, bonus) -> count == 5 && !bonus),
    FOURTH(50_000, (count, bonus) -> count == 4),
    FIFTH(5_000, (count, bonus) -> count == 3),
    NONE(0, (count, bonus) -> count < 3);
    
    
    private  final  int prize;
   
    BiPredicate<Integer,Boolean> condition;
    
    
    Ranking(int prize, BiPredicate<Integer,Boolean> condition){
        this.prize=prize;
        this.condition=condition;
    }
    
    public static Ranking findRanking(int cnt, boolean hasBonusNumber){
        return Arrays.stream(Ranking.values()).filter(ranking -> ranking.condition.test(cnt,hasBonusNumber))
            .findAny().orElse(NONE);
    }

}