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Part 2 (Vasilii Bobkov) #165

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28 changes: 17 additions & 11 deletions src/test/java/lambda/part2/exercise/ArrowNotationExercise.java
Original file line number Diff line number Diff line change
Expand Up @@ -14,35 +14,41 @@ public class ArrowNotationExercise {
@Test
public void getAge() {
// Person -> Integer
final Function<Person, Integer> getAge = null; // TODO
final Function<Person, Integer> getAge = Person::getAge;

assertEquals(Integer.valueOf(33), getAge.apply(new Person("", "", 33)));
}

@Test
public void compareAges() {
// TODO use BiPredicate
// compareAges: (Person, Person) -> boolean
BiPredicate<Person, Person> compareAges = (person1, person2) -> person1.getAge() <= person2.getAge();

throw new UnsupportedOperationException("Not implemented");
//assertEquals(true, compareAges.test(new Person("a", "b", 22), new Person("c", "d", 22)));
assertEquals(true, compareAges.test(new Person("a", "b", 22), new Person("c", "d", 22)));
}

// TODO
// getFullName: Person -> String
private String getFullName(Person person) {
return person.getFirstName() + " " + person.getLastName();
}

// TODO
// ageOfPersonWithTheLongestFullName: (Person -> String) -> (Person, Person) -> int
//
private BiFunction<Person, Person, Integer> ageOfPersonWithTheLongestFullName(Function<Person, String> function) {
return (p1, p2) -> {
if (function.apply(p1).compareTo(function.apply(p2)) > 0) {
return p1.getAge();
} else {
return p2.getAge();
}
};
}

@Test
public void getAgeOfPersonWithTheLongestFullName() {
// Person -> String
final Function<Person, String> getFullName = null; // TODO

final Function<Person, String> getFullName = this::getFullName;
// (Person, Person) -> Integer
// TODO use ageOfPersonWithTheLongestFullName(getFullName)
final BiFunction<Person, Person, Integer> ageOfPersonWithTheLongestFullName = null;
final BiFunction<Person, Person, Integer> ageOfPersonWithTheLongestFullName = ageOfPersonWithTheLongestFullName(getFullName);

assertEquals(
Integer.valueOf(1),
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -19,22 +19,14 @@ public void personHasNotEmptyLastNameAndFirstName0() {
assertEquals(false, validate.test(new Person("a", "", 0)));
}

// TODO
// negate1: (Person -> boolean) -> (Person -> boolean)
private Predicate<Person> negate1(Predicate<Person> test) {
return p -> {
// TODO
throw new UnsupportedOperationException();
};
return p -> !test.test(p);
}

// TODO
// validateFirstNameAndLastName: (Person -> boolean, Person -> boolean) -> (Person -> boolean)
private Predicate<Person> validateFirstNameAndLastName(Predicate<Person> t1, Predicate<Person> t2) {
return p -> {
// TODO
throw new UnsupportedOperationException();
};
return p -> t1.test(p) && t2.test(p);
}

@Test
Expand All @@ -52,29 +44,25 @@ public void personHasNotEmptyLastNameAndFirstName1() {
assertEquals(false, validate.test(new Person("a", "", 0)));
}

// TODO
// negate: (T -> boolean) -> (T -> boolean)
private <T> Predicate<T> negate(Predicate<T> test) {
// TODO
throw new UnsupportedOperationException();
return T -> !test.test(T);
}

// TODO
// and: (T -> boolean, T -> boolean) -> (T -> boolean)
private <T> Predicate<T> and(Predicate<T> t1, Predicate<T> t2) {
// TODO
throw new UnsupportedOperationException();
return T -> t1.test(T) && t2.test(T);
}

@Test
public void personHasNotEmptyLastNameAndFirstName2() {
final Predicate<Person> hasEmptyFirstName = p -> p.getFirstName().isEmpty();
final Predicate<Person> hasEmptyLastName = p -> p.getLastName().isEmpty();

final Predicate<Person> validateFirstName = null; // TODO use negate
final Predicate<Person> validateLastName = null; // TODO use negate
final Predicate<Person> validateFirstName = negate(hasEmptyFirstName);
final Predicate<Person> validateLastName = negate(hasEmptyLastName);

final Predicate<Person> validate = null; // TODO use and
final Predicate<Person> validate = and(validateFirstName,validateLastName);

assertEquals(true, validate.test(new Person("a", "b", 0)));
assertEquals(false, validate.test(new Person("", "b", 0)));
Expand All @@ -86,10 +74,10 @@ public void personHasNotEmptyLastNameAndFirstName3() {
final Predicate<Person> hasEmptyFirstName = p -> p.getFirstName().isEmpty();
final Predicate<Person> hasEmptyLastName = p -> p.getLastName().isEmpty();

final Predicate<Person> validateFirstName = null; // TODO use Predicate::negate
final Predicate<Person> validateLastName = null; // TODO use Predicate::negate
final Predicate<Person> validateFirstName = hasEmptyFirstName.negate();
final Predicate<Person> validateLastName = hasEmptyLastName.negate();

final Predicate<Person> validate = null; // TODO use Predicate::and
final Predicate<Person> validate = validateFirstName.and(validateLastName);

assertEquals(true, validate.test(new Person("a", "b", 0)));
assertEquals(false, validate.test(new Person("", "b", 0)));
Expand Down