import java.util.Arrays;
import java.util.List;
public
class Streams11 {
static
class Person {
String name;
int age;
Person(String name, int age) {
this.name = name;
this.age = age;
}
@Override
public String toString() {
return name;
}
}
public static
void main(String[] args) {
List<Person> persons =
Arrays.asList(
new Person(
"Max",
18),
new Person(
"Peter",
23),
new Person(
"Pamela",
23),
new Person(
"David",
12));
// test1(persons);
// test2(persons);
// test3(persons);
// test4(persons);
// test5(persons);
test6(persons);
}
private static
void test1(List<Person> persons) {
persons
.stream()
.reduce
((p1, p2) -> p1.age > p2.age ? p1 : p2)
.ifPresent(System.out::println); // Pamela
}
private static void test2(List<Person> persons) {
Person result =
persons
.stream()
.reduce(new Person("", 0), (p1, p2) -> {
p1.age += p2.age;
p1.name += p2.name;
return p1;
});
System.out.format("name=%s; age=%s", result.name, result.age);
}
private static void test3(List<Person> persons) {
Integer ageSum = persons
.stream()
.reduce(0, (sum, p) -> sum += p.age, (sum1, sum2) -> sum1 + sum2);
System.out.println(ageSum);
}
private static void test4(List<Person> persons) {
Integer ageSum = persons
.stream()
.reduce(0,
(sum, p) -> {
System.out.format("accumulator: sum=%s; person=%s\n", sum, p);
return sum += p.age;
},
(sum1, sum2) -> {
System.out.format("combiner: sum1=%s; sum2=%s\n", sum1, sum2);
return sum1 + sum2;
});
System.out.println(ageSum);
}
private static void test5(List<Person> persons) {
Integer ageSum = persons
.parallelStream()
.reduce(0,
(sum, p) -> {
System.out.format("accumulator: sum=%s; person=%s\n", sum, p);
return sum += p.age;
},
(sum1, sum2) -> {
System.out.format("combiner: sum1=%s; sum2=%s\n", sum1, sum2);
return sum1 + sum2;
});
System.out.println(ageSum);
}
private static void test6(List<Person> persons) {
Integer ageSum = persons
.parallelStream()
.reduce(0,
(sum, p) -> {
System.out.format("accumulator: sum=%s; person=%s; thread=%s\n",
sum, p, Thread.currentThread().getName());
return sum += p.age;
},
(sum1, sum2) -> {
System.out.format("combiner: sum1=%s; sum2=%s; thread=%s\n",
sum1, sum2, Thread.currentThread().getName());
return sum1 + sum2;
});
System.out.println(ageSum);
}
}
转载于:https://www.cnblogs.com/bilaisheng/p/10210927.html
