[Lambda] 기본형 함수형 인터페이스 : AToBFunction

AToBFunction 

A : 입력타입 B: 출력타입 

 

IntToDoubleFunction :  : public double applyAsDouble(int value)

IntToLongFunction : public long applyAsDouble(int value)

 

DoubleToIntFunction : public int applyAsDouble(double value)

DoubleToLongFunction : public long applyAsDouble(double value)

 

LongToIntFunction : public int applyAsDouble(long value)

LongToDoubleFunction : public double applyAsDouble(long value)

import java.util.function.*;

public class AToBFunctionExam {

    public static void main(String[] args) {

        IntToDoubleFunction intToDoubleFunction = new IntToDoubleFunction() {
            @Override
            public double applyAsDouble(int value) {
                return value;
            }
        };

        // 타입 검사
        boolean result = Double.class.isInstance(intToDoubleFunction.applyAsDouble(10));
        System.out.println(result);

        IntToLongFunction intToLongFunction = new IntToLongFunction() {
            @Override
            public long applyAsLong(int value) {
                return value;
            }
        };

        // 타입검사
        result = Long.class.isInstance(intToLongFunction.applyAsLong(10));
        System.out.println(result);

    }
}

/* 람다 */
import java.util.function.*;

public class AToBFunctionExam {

    public static void main(String[] args) {

        IntToDoubleFunction intToDoubleFunction = value -> value;

        // 타입 검사
        boolean result = Double.class.isInstance(intToDoubleFunction.applyAsDouble(10));
        System.out.println(result);

        IntToLongFunction intToLongFunction = value -> value;

        // 타입검사
        result = Long.class.isInstance(intToLongFunction.applyAsLong(10));
        System.out.println(result);

    }


}