@FunctionalInterface标记在接口上,“函数式接口”是指仅仅只包含一个抽象方法的接口。 如果一个接口中包含不止一个抽象方法,那么不能使用@FunctionalInterface,编译会报错。 比如下面这个接口就是一个正确的函数式接口:
Interface Comparator<T> Type Parameters: T- the type of objects that may be compared by this comparator All Known Implementing Classes: Collator,RuleBasedCollator Functional Interface: This is a functional interface and can therefore be used as the assignment target for a lambda expression or method...
@FunctionalInterface publicinterfaceComparator{ /** *Comparesitstwoargumentsfororder.Returnsanegativeinteger, *zero,orapositiveintegerasthefirstargumentislessthan,equal *to,orgreaterthanthesecond. * *Intheforegoingdescription,thenotation *sgn(expression)designatesthemathematical *signumfunction,whichisdefinedtore...
其中 equals为Object的方法，不算入内，所以Comparator可以作为函数式接口。FunctionalInterface (Java Platfo...
Comparator 是一个函数式接口,这个可以从它的定义上看出来。它具有这个注解:@FunctionalInterface。 这个注解标注此接口属于函数式接口,意味着只能有一个抽象方法,但是带你进去看,你会发现两个抽象方法! intcompare(T o1, T o2);booleanequals(Object obj); ...
Functional Interface: This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference. @FunctionalInterface public interface Comparator<T> A comparison function, which imposes a total ordering on some collection of objects. Comparators can ...
Java 8 Comparator interface is a functional interface that contains only one abstract method. Now, we can use the Comparator interface as the assignment target for a lambda expression or method reference. Methods of Java 8 Comparator InterfaceMethod...
Comparator是一个函数式接口(@FunctionalInterface).所谓的函数式接口,当然首先是一个接口,然后就是在这个接口里面只能有一个抽象方法。加不加@FunctionalInterface对于接口是不是函数式接口没有影响,该注解只是提醒编译器去检查该接口是否仅包含一个抽象方法。Comparator接口中定义了一个抽象方法int compare(T o1, T o2...
because it's an old interface and may not implement functional interface annotated with @FunctionalInterface annotation?The answer to that question is Yes, you can use a lambda expression to implement Comparator and Comparable interface in Java, and not just these two interfaces but to implement an...
Comparator 是一个函数式接口,这个可以从它的定义上看出来。它具有这个注解:@FunctionalInterface。 这个注解标注此接口属于函数式接口,意味着只能有一个抽象方法,但是带你进去看,你会发现两个抽象方法! intcompare(T o1, T o2);booleanequals(Object obj); ...