package com.github.andbed.cleanarch.learningtest.java8;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Collectors;
public class Example1 {
public static void main(String[] args) {
}
public static void oldFashionedSimpleFor() {
List<Integer> ints = Arrays.asList(1, 2, 3, 4, 5, 6);
int total = 0;
for (int i=0; i<ints.size(); i++) {
total += ints.get(i);
}
System.out.println(total);
}
public static void oldFashionedComplexFor() {
List<Integer> ints = Arrays.asList(1, 2, 3, 4, 5, 6);
List<Integer> evenDoubles = new ArrayList<>();
for (int i=0; i<ints.size(); i++) {
if (ints.get(i) % 2 == 0) {
Integer doubled = ints.get(i) * 2;
evenDoubles.add(doubled);
}
}
System.out.println(evenDoubles);
}
public static void functionalSimpleFor() {
List<Integer> ints = Arrays.asList(1, 2, 3, 4, 5, 6);
Integer total = ints.stream()
.mapToInt(e -> e * 2)
.sum();
System.out.println(total);
}
public static void functionalComplexFor() {
List<Integer> ints = Arrays.asList(1, 2, 3, 4, 5, 6);
List<Integer> evenDoubles = ints.stream()
.filter(e -> e % 2 == 0)
.map(e -> e * 2)
.collect(Collectors.toList());
System.out.println(evenDoubles);
universalListProcessor(e -> e * 2, e -> e % 2 == 0);
}
public static void universalListProcessor(Function<Integer, Integer> func, Predicate<Integer> pred) {
List<Integer> collection = Arrays.asList(1, 2, 3, 4, 5, 6);
List<Integer> col = collection.stream()
.filter(pred)
.map(func)
.collect(Collectors.toList());
System.out.println(col);
}
}
