java8 stream

stream_ex.java

package com.company;

import java.util.Arrays;
import java.util.List;
import java.util.stream.Stream;

public class Main {

    public static void main(String[] args) {
	// write your code here
		List<Integer> list = Arrays.asList(1,2,3,4,5);
		Stream<Integer> stream1 = list.stream();

		Integer ab = stream1.reduce(0, (a,b) -> a + b);
		System.out.println(ab);

		// can not use stream1, because stream1 has already consumed.
		Stream<Integer> stream2 = list.stream();
		Stream<String> s2 = stream2.map(x -> x.toString());
		s2.forEach(System.out::println);

		// peek can show consumed elements
		Stream<Integer> stream3 = list.stream();
		stream3.filter(x -> x < 3)
				.peek(e -> {System.out.println(e);})
				.forEach(System.out::println);
    }
}