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part 2 is done #172

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part 2 is done #172

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19 changes: 14 additions & 5 deletions src/test/java/lambda/part2/exercise/ArrowNotationExercise.java
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@ 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)));
}
Expand All @@ -23,26 +23,35 @@ public void getAge() {
public void compareAges() {
// TODO use BiPredicate
// compareAges: (Person, Person) -> boolean
BiPredicate<Person,Person> compareAges = ((person, person2) ->
person.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) -> function.apply(p1).compareTo(function.apply(p2)) > 0
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Why not function.apply(p1) > function.apply(p2)?

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@ElenaFedorovskaia ElenaFedorovskaia Jul 7, 2017 •
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Because i compare two strings. Or did you mean function.apply(p1).length > function.apply(p2).length?

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Yeap

? p1.getAge() : p2.getAge();
}

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

// (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
28 changes: 10 additions & 18 deletions src/test/java/lambda/part2/exercise/FunctionCombinationExercise.java
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Original file line number Diff line number Diff line change
Expand Up @@ -22,19 +22,13 @@ public void personHasNotEmptyLastNameAndFirstName0() {
// 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 @@ -55,26 +49,24 @@ public void personHasNotEmptyLastNameAndFirstName1() {
// 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); // TODO use negate
final Predicate<Person> validateLastName = negate(hasEmptyLastName); // TODO use negate

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

assertEquals(true, validate.test(new Person("a", "b", 0)));
assertEquals(false, validate.test(new Person("", "b", 0)));
Expand All @@ -86,10 +78,10 @@ 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(); // TODO use Predicate::negate
final Predicate<Person> validateLastName = hasEmptyLastName.negate(); // TODO use Predicate::negate

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

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