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homework part2 (Olga Li) #169

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29 changes: 19 additions & 10 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 @@ -3,6 +3,7 @@
import data.Person;
import org.junit.Test;

import java.util.Comparator;
import java.util.function.BiFunction;
import java.util.function.BiPredicate;
import java.util.function.Function;
Expand All @@ -14,35 +15,43 @@ public class ArrowNotationExercise {
@Test
public void getAge() {
// Person -> Integer
final Function<Person, Integer> getAge = null; // TODO
final Function<Person, Integer> getAge = person -> person.getAge(); // TODO - done

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

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

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

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

// TODO
// TODO - done
// getFullName: Person -> String
private static String getFullName(Person p){
return String.format("%s %s",p.getFirstName(),p.getLastName());
}

// TODO
// TODO - done
//lambda BiFunction
// ageOfPersonWithTheLongestFullName: (Person -> String) -> (Person, Person) -> int
//
private static BiFunction<Person,Person,Integer> ageOfPersonWithTheLongestFullName(Function<Person,String> function) {
return (person, person2) -> function.apply(person).length()<=function.apply(person2).length() ? person2.getAge() : person.getAge();
}

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

// (Person, Person) -> Integer
// TODO use ageOfPersonWithTheLongestFullName(getFullName)
final BiFunction<Person, Person, Integer> ageOfPersonWithTheLongestFullName = null;
// TODO use ageOfPersonWithTheLongestFullName(getFullName) - done
final BiFunction<Person, Person, Integer> ageOfPersonWithTheLongestFullName = ageOfPersonWithTheLongestFullName(getFullName);

assertEquals(
Integer.valueOf(1),
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28 changes: 11 additions & 17 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 @@ -21,20 +21,14 @@ public void personHasNotEmptyLastNameAndFirstName0() {

// TODO
// negate1: (Person -> boolean) -> (Person -> boolean)
private Predicate<Person> negate1(Predicate<Person> test) {
return p -> {
// TODO
throw new UnsupportedOperationException();
};
private Predicate<Person> negate1(Predicate<Person> t) {
return p -> !t.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 @@ -56,25 +50,25 @@ public void personHasNotEmptyLastNameAndFirstName1() {
// 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 +80,10 @@ 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