Class Filtering

src/test/java/com/amigoscode/examples/Filtering.java:15–90

import java.util.stream.Stream;

public class Filtering {

    @Test
    public void filter() throws Exception {
        List<Car> cars = MockData.getCars();

        Predicate<Car> carPredicate = car -> car.getPrice() < 20_000.00;
        Predicate<Car> yellow = car -> car.getColor().equals("Yellow");

        List<Car> carsLessThan20k = cars.stream()
                .filter(carPredicate)
                .filter(yellow)
                .collect(Collectors.toList());

        carsLessThan20k.forEach(System.out::println);
    }

    @Test
    public void dropWhile() throws Exception {
        System.out.println("using filter");
        Stream.of(2, 4, 6, 8, 9, 10, 12).filter(n -> n % 2 == 0)
                .forEach(n -> System.out.print(n + " "));
        System.out.println();
        System.out.println("using dropWhile");
        Stream.of(2, 4, 6, 8, 9, 10, 12).dropWhile(n -> n % 2 == 0)
                .forEach(n -> System.out.print(n + " "));

    }

    @Test
    public void takeWhile() throws Exception {
        // using filter
        System.out.println("using filter");
        Stream.of(2, 4, 6, 8, 9, 10, 12).filter(n -> n % 2 == 0)
                .forEach(n -> System.out.print(n + " "));

        System.out.println();
        System.out.println("using take while");
        Stream.of(2, 4, 6, 8, 9, 10, 12).takeWhile(n -> n % 2 == 0)
                .forEach(n -> System.out.print(n + " "));
    }

    @Test
    public void findFirst() throws Exception {
        int[] numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
        int result = Arrays.stream(numbers).filter(n -> n == 50)
                .findFirst()
                .orElse(-1);
        System.out.println(result);

    }

    @Test
    public void findAny() throws Exception {
        int[] numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9, 9, 10};
        int result = Arrays.stream(numbers).filter(n -> n == 9)
                .findAny()
                .orElse(-1);