package Java8Study.stream3;

import Java8Study.lambda1.Employee;

import org.junit.Test;

import java.util.Arrays;

import java.util.Comparator;

import java.util.List;

import java.util.Optional;

public class TestStreamAPI3 {

/**

* 给定一个数字列表，返回由每个数字平方组成的列表

* 1,2,3,4 -> 1,4,9,16

*/

@Test

public void test1(){

//map做法

int[] arr ={1,2,3,4};

Arrays.stream(arr).map(x -> x*x).forEach(System.out::println);

}

/**

* 用map和reduce得到流中有多少employee

*/

List<Employee> employees = Arrays.asList(

new Employee("jerry",18,9999.1, Employee.Status.FREE),

new Employee("tom",23,1000,Employee.Status.BUSY),

new Employee("amy",26,1234, Employee.Status.VACATION),

new Employee("pony",45,12442.1, Employee.Status.FREE),

new Employee("tony",50,1232, Employee.Status.VACATION)

);

/**

* 用map和reduce得到流中有多少employee

*/

@Test

public void test2(){

Optional<Integer> sum = employees.stream().map(e -> 1).reduce(Integer::sum);

System.out.println(sum);

}

/**

* 找出工作状态为 FREE，且年龄最大的

*/

@Test

public void test3(){

Optional<Employee> freeOldest = employees.stream()

.filter( e -> e.getStatus().equals(Employee.Status.FREE))

.max(Comparator.comparingInt(Employee::getAge));

System.out.println("工作状态为 FREE，且年龄最大的 : "+ freeOldest.get());

}

/**

* 找出

*/

}