在Java中如何使用lambda实现LongUnaryOperator？
LongUnaryOperator是一个java.util.function函数接口。此函数接口接受单个长值操作数并生成长值结果。LongUnaryOperator接口可以用作lambda表达式和方法引用的赋值目标。它包含一个抽象方法：applyAsLong()、一个静态方法identity()和两个默认方法：andThen()和compose()。
语法
@FunctionalInterface public interface LongUnaryOperator long applyAsLong(long operand); }
示例
import java.util.function.LongUnaryOperator;
public class LongUnaryOperatorTest {
public static void main(String args[]) {
LongUnaryOperator getSquare = longValue -> { // lambda
long result = longValue * longValue;
System.out.println("Getting square: " + result);
return result;
};
LongUnaryOperator getNextValue = longValue -> { // lambda
long result = longValue + 1;
System.out.println("Getting Next value: " + result);
return result;
};
LongUnaryOperator getSquareOfNext = getSquare.andThen(getNextValue);
LongUnaryOperator getNextOfSquare = getSquare.compose(getNextValue);
long input = 10L;
System.out.println("Input long value: " + input);
System.out.println();
long squareOfNext = getSquareOfNext.applyAsLong(input);
System.out.println("Square of next value: " + squareOfNext);
System.out.println();
long nextOfSquare = getNextOfSquare.applyAsLong(input);
System.out.println("Next to square of value: " + nextOfSquare);
}
}输出结果
Input long value: 10 Getting square: 100 Getting Next value: 101 Square of next value: 101 Getting Next value: 11 Getting square: 121 Next to square of value: 121