Java8-Lambda-No.03

import java.util.Comparator; import java.util.Objects; import java.util.UUID; import java.util.concurrent.Callable; import java.util.function.Consumer; import java.util.function.Function; import java.util.function.Predicate; import java.util.function.Supplier; public class Lambda3 { @FunctionalInterface interface Fun { void foo(); } public static void main(String[] args) throws Exception { // Predicates Predicate<String> predicate = (s) -> s.length() > 0; predicate.test("foo"); // true predicate.negate().test("foo"); // false Predicate<Boolean> nonNull = Objects::nonNull; Predicate<Boolean> isNull = Objects::isNull; Predicate<String> isEmpty = String::isEmpty; Predicate<String> isNotEmpty = isEmpty.negate(); // Functions Function<String, Integer> toInteger = Integer::valueOf; Function<String, String> backToString = toInteger.andThen(String::valueOf); backToString.apply("123"); // "123" // Suppliers Supplier<Person> personSupplier = Person::new; personSupplier.get(); // new Person // Consumers Consumer<Person> greeter = (p) -> System.out.println("Hello, " + p.firstName); greeter.accept(new Person("Luke", "Skywalker")); // Comparators Comparator<Person> comparator = (p1, p2) -> p1.firstName.compareTo(p2.firstName); Person p1 = new Person("John", "Doe"); Person p2 = new Person("Alice", "Wonderland"); comparator.compare(p1, p2); // > 0 comparator.reversed().compare(p1, p2); // < 0 // Runnables Runnable runnable = () -> System.out.println(UUID.randomUUID()); runnable.run(); // Callables Callable<UUID> callable = UUID::randomUUID; callable.call(); } }

转载于:https://www.cnblogs.com/bilaisheng/p/10210915.html