java_upgrade/src/main/java/CollectorsDemo.java at main · MikeLaptev/java_upgrade · GitHub

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import java.util.List;

import java.util.Map;

import java.util.Set;

import java.util.concurrent.ConcurrentSkipListSet;

import java.util.function.Function;

import java.util.stream.Collectors;

import java.util.stream.Stream;

public class CollectorsDemo {

public static void main(String[] args) {

var nums = Stream.of("this", "is", "a", "collection", "of", "strings")

.parallel()

.map(String::length)

// .map(n -> {

// System.out.println(n);

// return n;

// })

// equivalent to:

.peek(n -> {

System.out.println("On " + Thread.currentThread().getName()

+ ", the value of n before the filter is " + n);

})

.filter(n -> n % 2 == 0)

.peek(n -> System.out.println("On " + Thread.currentThread().getName()

+ ", the value of n after the filter is " + n))

.toList();

System.out.println(nums);

var set = Stream.of("this is a is a collection of strings".split(" "))

.collect(Collectors.toSet());

System.out.println(set);

System.out.println(set.getClass().getName());

var collection =

Stream.of("this is a is a collection of strings".split(" "))

.collect(Collectors.toCollection(ConcurrentSkipListSet::new));

var stringMap =

Stream.of("this is a collection of strings".split(" "))

.collect(Collectors.toMap(Function.identity(), String::length));

System.out.println(stringMap);

}

java_upgrade/src/main/java/CollectorsDemo.java at main · MikeLaptev/java_upgrade · GitHub

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