java Predicate 问题

[anakin_feng]

看到java1.8 Predicate 这个接口，看不明白有点，为什么能够返回Predicate类型的对象

    default Predicate<T> and(Predicate<? super T> other) {
        Objects.requireNonNull(other);
        //为什么能够返回Predicate类型的对象
        return (t) -> test(t) && other.test(t);
    }

[soton_dolphin]

Predicate<String> egg = s -> s.contains("egg"); Predicate<String> brown = s -> s.contains("brown"); Predicate<String> brownEggs = egg.and(brown); Predicate<String> otherEggs = egg.and(brown.negate());

[soton_dolphin]

相当于

default Predicate<T> and(Predicate<T> other) {
        Objects.requireNonNull(other);
        //为什么能够返回Predicate类型的对象
        //return (t) -> test(t) && other.test(t);
        return new Predicate(){

			@Override
			public boolean test(Object o) {
				return this.test(o) && other.test(o);
			}
        };
    }

[soton_dolphin]

相当于

 default Predicate<T> and(Predicate<? super T> other) {
        Objects.requireNonNull(other);
        //return (t) -> test(t) && other.test(t);
        
        return new Predicate<T>(){

			@Override
			public boolean test(T t) {
				// TODO Auto-generated method stub
				return this.test(t) && other.test(t);
			}
        	
        };
    }

[anakin_feng]

原来我看错了,是这个逻辑

return (t) -> (test(t) && other.test(t));