package lambda;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.function.BiFunction;
import java.util.stream.Stream;
public final class Lambda {
private Lambda() {
}
static class Person implements Named, EchoName {
private String name;
Person(String name) {
this.name = name;
}
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
public String toString() {
return String.format("My name is %s", this.name);
}
@Override
public String echoName() {
return Named.super.echoName(); // é‡å了必须è¦æ‰‹åŠ¨æŒ‡å®šå®žçŽ°
}
}
static interface Named {
default String echoName() { // 默认方法的实现
return "SamChi";
}
}
static interface EchoName {
default String echoName() {
return "James";
}
}
public static void main(String[] args) {
List strList =
Arrays.asList("Sam", "Jack", "Peter", "Tom", "Lucy", "Anders", "James", "Lily");
System.out.println("before sort:" + strList);
strList.sort((str1, str2) -> Integer.compare(str1.length(), str2.length())); // æ ¹æ®æ³›åž‹æ¥è‡ªåŠ¨æŽ¨å¯¼
System.out.println("after sort:" + strList);
strList.forEach(str -> System.out.println(String.format("= %s =", str))); // å¯ç±»åž‹æŽ¨å¯¼çš„å•ä¸ªå‚æ•°æ— éœ€åŠ å°æ‹¬å·
strList.forEach((final String str) -> System.out.println(String.format("= %s =", str))); // å¯ä»¥åŠ final修饰符
// java.util.function包ä¸çš„函数å¼æŽ¥å£
BiFunction comparator =
(str1, str2) -> Integer.compare(str1.length(), str2.length());
System.out.println(comparator instanceof Object);
System.out.println(comparator.getClass().getCanonicalName());
Object obj = comparator;
System.out.println(obj.getClass().getCanonicalName());
// obj = (String str1, String str2) -> Integer.compare(str1.length(), str2.length()); è¿™æ ·å¼•ç”¨å°±ä¸å¯ä»¥äº†ã€‚
Runnable sleeper = () -> {
System.out.println("Zzzzzz");
try {
TimeUnit.SECONDS.sleep(1L);
} catch (InterruptedException e) {
e.printStackTrace(); // 在Lambda表达å¼ä¸æ•èŽ·å¼‚常
}
};
Thread t = new Thread(sleeper);
t.start();
strList.forEach(str -> System.out.println(str));
strList.forEach(System.out::println);
strList.sort(String::compareToIgnoreCase);
Stream personsStream = strList.stream().map(Person::new);
personsStream.forEach(System.out::println);
int a = 0, b = 1;
new Thread(() -> {
System.out.println("a is :" + a);
System.out.println("b is :" + b);
// a++; ä¸å¯ä»¥æ”¹å˜å¤–围作用域的值
// int a = 3; ä¸å¯ä»¥è¦†ç›–定义外围作用域的值
}).start();
Person p = new Person("Jack");
System.out.println(">>>>>" + p.getName());
}
}