Untitled 20

 
public class Calculator {  
  
    private static final List<NewArithmeticOperator> arithmeticOperators = List.of(new AddithionOperator(),  
       new SubtractionOperator(), new MultiplicationOperator(), new DivisionOperator());  
  
    public static int calculator(PositiveNumber operand1, String operator, PositiveNumber operand2) {  
       return arithmeticOperators.stream()  
          .filter(arithmeticOperators -> arithmeticOperators.supports(operator))  
          .map(arithmeticOperators -> arithmeticOperators.calculate(operand1, operand2))  
          .findFirst()  
          .orElseThrow(() -> new IllegalArgumentException("올바른 사칙연산이 아닙니다."));  
    }  
}

package com.gooot;  
  
import java.util.Arrays;  
  
public enum ArithmeticOperator {  
    ADDITION("+") {  
       @Override  
       public int arithmeticCalculate(int operand1, int operand2) {  
          return operand1 + operand2;  
       }  
    }, SUBTRACTION("-") {  
       @Override  
       public int arithmeticCalculate(int operand1, int operand2) {  
          return operand1 - operand2;  
       }  
    }, MULTIPLICATION("*") {  
       @Override  
       public int arithmeticCalculate(int operand1, int operand2) {  
          return operand1 * operand2;  
       }  
    }, DIVISION("/") {  
       @Override  
       public int arithmeticCalculate(int operand1, int operand2) {  
          return operand1 / operand2;  
       }  
    };  
  
    private final String operator;  
  
  
    ArithmeticOperator(String operator) {  
       this.operator = operator;  
    }  
  
    public abstract  int arithmeticCalculate(final int operand1, final int operand2);  
  
    public static int calculate(int operand1,String operator, int operand2) {  
       ArithmeticOperator arithmeticOperator = Arrays.stream(values())  
          .filter(v->v.operator.equals(operator))  
          .findFirst()  
          .orElseThrow(()-> new IllegalArgumentException(operator+" is not supported"));  
  
       return arithmeticOperator.arithmeticCalculate(operand1,operand2);  
    }  
}

package com.gooot.calculate;  
  
public class PositiveNumber {  
  
    private final int value;  
  
    public PositiveNumber(int value) {  
       validate(value);  
       this.value = value;  
    }  
  
    private void validate(int value) {  
       if(isNegativeNumber(value)){  
          throw new IllegalArgumentException("0 또는 음수를 전달 할 수 없습니다.");  
       }  
    }  
  
    private boolean isNegativeNumber(int value) {  
       return value <= 0;  
    }  
  
    public int toInt(){  
       return value;  
    }  
  
}

package com.gooot.calculate;  
  
public interface NewArithmeticOperator {  
    boolean supports(String operator);  
    int calculate(PositiveNumber operand1, PositiveNumber operand2);  
}

package com.gooot.calculate;  
  
public class AddithionOperator implements NewArithmeticOperator {  
  
    @Override  
    public boolean supports(String operator) {  
       return "+".equals(operator);  
    }  
  
    @Override  
    public int calculate(PositiveNumber operand1, PositiveNumber operand2) {  
       return operand1.toInt() + operand2.toInt();  
    }  
}