Java中的BiPredicate

介绍

是一个函数式接口，表示接受两和变量返回一个boolean类型的值。与Predicate类似，只不过Predicate返回的是一个值

@FunctionalInterface
public interface BiPredicate<T, U> {
    boolean test(T t, U u);
    
    default BiPredicate<T, U> and(BiPredicate<? super T, ? super U> other) {
        Objects.requireNonNull(other);
        return (T t, U u) -> test(t, u) && other.test(t, u);
    }  
    default BiPredicate<T, U> negate() {
        return (T t, U u) -> !test(t, u);
    }
    default BiPredicate<T, U> or(BiPredicate<? super T, ? super U> other) {
        Objects.requireNonNull(other);
        return (T t, U u) -> test(t, u) || other.test(t, u);
    }
}

package cn.caigen.bipredicate;

import java.util.HashMap;
import java.util.Map;
import java.util.function.BiFunction;
import java.util.function.BiPredicate;

public class BiPredicateEx1 {
    public static void main(String[] args) {
        BiPredicate<String, Integer> biPredicate = (name, length) -> name.length() == length;
        Map<String, Integer> localTest = new HashMap<>();

        localTest.put("Google", 6);
        localTest.put("Tencent", 7);
        localTest.put("Alibaba",6);

        localTest.entrySet()
                .stream()
                .filter(entry -> biPredicate.test(entry.getKey(), entry.getValue()))
                .forEach(System.out::println);
    }
}

BiPredicate + 方法

如果一个静态函数接受两个变量且返回一个Boolean类型的值，则可以是BiPredicate

package cn.caigen.bipredicate;

import java.util.HashMap;
import java.util.Map;
import java.util.function.BiPredicate;

public class BiPredicateEx2 {
    public static void main(String[] args) {
        PreinEx preinEx = new PreinEx();
        BiPredicate<String, String> biPredicate = preinEx::isSameOne;

        Map<String, String> conMap = new HashMap<>();
        conMap.put("Bill", "Bill");
        conMap.put("Caigen", "Caigen");
        conMap.put("ali", "tencent");

        conMap.entrySet()
                .stream().filter(stringStringEntry ->
                        biPredicate.test(stringStringEntry.getKey(), stringStringEntry.getValue()))
                .forEach(System.out::println);
        
        boolean res = biPredicate.test("123","123");
        System.out.println(res);
    }
}

class PreinEx{

    public boolean isSameOne(String Fname,String Mname) {
        return Fname.equals(Mname);
    }
}

其余同Predicate方法，略！