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public class StreamTest {
private final Stream<Dish> menu = Arrays.asList(
new Dish("pork", false, 800, Dish.Type.MEAT),
new Dish("beef", false, 700, Dish.Type.MEAT),
new Dish("chicken", false, 400, Dish.Type.MEAT),
new Dish("french fries", true, 530, Dish.Type.OTHER),
new Dish("rice", true, 350, Dish.Type.OTHER),
new Dish("season fruit", true, 120, Dish.Type.OTHER),
new Dish("pizza", true, 550, Dish.Type.OTHER),
new Dish("prawns", false, 300, Dish.Type.FISH),
new Dish("salmon", false, 450, Dish.Type.FISH)
).stream();
@Test
public void testGp() {
final Map<Boolean,Long> allQueryParam = menu.collect(Collectors.groupingBy(Dish::isVegatarian, Collectors.counting()));
allQueryParam.forEach((vegatarian, total)->{
System.out.println("Dish vegatarian: "+vegatarian+", total: "+total);
});
//output:
//Dish vegatarian: false, total: 5
//Dish vegatarian: true, total: 4
}