[Ch10b] Examples for generic methods (3418a3d1) · Commits · examples / Head First Java 3rd Edition

src/main/java/ch10b/TestGenerics3.java

+13 −0

Changes for src/main/java/ch10b/TestGenerics3.java: 13 added lines, 0 removed lines.
Original line number	Diff line number	Diff line
		@@ -13,6 +13,11 @@ public class TestGenerics3 {

		List<Dog> dogs = List.of(new Dog(), new Dog());
		takeAnimals(dogs);

		List<Dog> vaccinatedDogs = getUniqueAnimals(dogs);
		System.out.println(vaccinatedDogs);
		List<? extends Animal> uniqueAnimals2 = getUniqueAnimals2(dogs);
		System.out.println(uniqueAnimals2);
		}

		public void takeAnimals(List<? extends Animal> animals) {
		@@ -26,6 +31,14 @@ public class TestGenerics3 {
		a.eat();
		}
		}

		public <T extends Animal> List<T> getUniqueAnimals(List<T> animals) {
		return new ArrayList<>(animals);
		}

		public List<? extends Animal> getUniqueAnimals2(List<? extends Animal> animals) {
		return List.of(new Cat());
		}
		}

0 → 100644

+33 −0

Changes for src/main/java/ch10b/TestGenerics4.java: 33 added lines, 0 removed lines.
Original line number	Diff line number	Diff line
		package ch10b;

		import java.util.*;

		public class TestGenerics4 {
		public static void main(String[] args) {
		new TestGenerics4().go();
		}

		public void go() {
		List<Dog> dogs = List.of(new Dog(), new Dog());
		List<Dog> vaccinatedDogs = takeAnimals(dogs);
		System.out.println(vaccinatedDogs);

		List<Animal> animals = List.of(new Dog(), new Cat(), new Dog());
		List<Animal> vaccinatedAnimals = takeAnimals(animals);
		System.out.println(vaccinatedAnimals);

		List<? extends Animal> vaccinatedSomethings = takeAnimals2(dogs);
		System.out.println(vaccinatedSomethings);
		}

		public <T extends Animal> List<T> takeAnimals(List<T> animals) {
		return new ArrayList<>(animals);
		}

		public List<? extends Animal> takeAnimals2(List<? extends Animal> animals) {
		return List.of(new Cat());
		}
		}