Java Java.util.function.LongPredicate用法及代码示例

LongPredicate接口被引入JDK 8。该接口封装在java.util.function包。它对long值进行操作并根据条件返回谓词值。它是一个函数接口因此可以用于拉姆达表达式还。

public interface LongPredicate

方法

test()：此函数对 long 值进行条件检查，并返回一个表示结果的布尔值。

boolean test(long value)

and()：该函数对当前对象和作为参数接收的对象进行 AND 运算，并返回新形成的谓词。该方法有一个默认实现。

default LongPredicate and(LongPredicate other)

negate()：该函数返回当前谓词的逆，即反转测试条件。该方法有一个默认实现。

default LongPredicate negate()

or()：该函数对当前对象和作为参数接收的对象进行 OR 运算，并返回新形成的谓词。该方法有一个默认实现。

default LongPredicate or(LongPredicate other)

例子：

Java


// Java example to demonstrate LongPredicate interface
import java.util.function.LongPredicate;
public class LongPredicateDemo {
    public static void main(String[] args)
    {
        // Predicate to check for equal to 500000
        LongPredicate longPredicate = (x) ->
        {
            return (x == 500000);
        };
        System.out.println("499999 is equal to 500000 "
                           + longPredicate.test(499999));
        // Predicate to check for less than equal to 500000
        LongPredicate longPredicate1 = (x) ->
        {
            return (x <= 500000);
        };
        System.out.println("499999 is less than equal to 500000 "
                           + longPredicate1.test(499999));
        // ANDing the two predicates
        LongPredicate longPredicate2
            = longPredicate.and(longPredicate1);
        System.out.println("500000 is equal to 500000 "
                           + longPredicate2.test(500000));
        // ORing the two predicates
        longPredicate2 = longPredicate.or(longPredicate1);
        System.out.println("500001 is less than equal to 500000 "
                           + longPredicate2.test(500001));
        // Negating the predicate
        longPredicate2 = longPredicate1.negate();
        System.out.println("499999 is greater than 500000 "
                           + longPredicate2.test(499999));
    }
}

输出：

499999 is equal to 500000 false
499999 is less than equal to 500000 true
500000 is equal to 500000 true
500001 is less than equal to 500000 false
499999 is greater than 500000 false

参考： https://docs.oracle.com/javase/8/docs/api/java/util/function/LongPredicate.html

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注：本文由纯净天空筛选整理自CharchitKapoor大神的英文原创作品 Java.util.function.LongPredicate interface in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。