tadams

package com.tom;

import org.hamcrest.Description;
import org.hamcrest.TypeSafeMatcher;

import java.util.function.BiConsumer;
import java.util.function.Consumer;
import java.util.function.Predicate;

public class FuncTypeSafeMatcher<T> extends TypeSafeMatcher<T> {

tadams

public class StoryTest3 {
    @Test
    public void shouldReturnHobbitCharacters() {
        List<Character> characters = new TestCharacterData().fellowshipOfTheRing();
        Story story = Story.builder().characters(characters).build();
        Set<Character> fellowshipOfRingHobbits = story.charactersOf(Race.HOBBIT);
        assertThat(fellowshipOfRingHobbits).containsOnly(FRODO, SAM, MERRY, PIPPIN)
                                           .extracting(Character::getRace)
                                           .containsOnly(Race.HOBBIT);
    }

tadams

public class StoryTest2 {
    @Test
    public void shouldReturnHobbitCharacters() {
        List<Character> characters = Arrays.asList(BILBO, SAM, ARAGORN, GANDALF, FRODO);
        Story story = Story.builder().characters(characters).build();
        Set<Character> storyHobbits = story.charactersOf(Race.HOBBIT);
        assertThat(storyHobbits).containsOnly(BILBO, FRODO, SAM)
                                .extracting(Character::getRace)
                                .containsOnly(Race.HOBBIT);
    }

tadams

public class StoryTest1 {
    @Test
    public void shouldReturnHobbitCharacters() {
        List<Character> characters = new TestCharacterData().createList();
        Story story = Story.builder().characters(characters).build();
        Set<Character> storyHobbits = story.charactersOf(Race.HOBBIT);
        assertThat(storyHobbits).containsOnly(BILBO, FRODO, SAM)
                                .extracting(Character::getRace)
                                .containsOnly(Race.HOBBIT);
    }

tadams

// Product class
public Integer getPackageQuantity2() {
    return firstNonNull(quantity, innerPackQuantity, DEFAULT_QUANTITY);
}

// Utils class
public static <T> T firstNonNull(T... args) {
    return Stream.of(args)
                 .filter(Objects::nonNull)
                 .findFirst()

tadams

public Integer getPackageQuantity() {
    return ObjectUtils.firstNonNull(quantity, innerPackQuantity, DEFAULT_QUANTITY);
}

tadams

import static java.util.Objects.requireNonNull;
...

// throws a NullPointerException when null
requireNonNull(employee);

// throws a NullPointerException with a message
requireNonNull(employee, "employee reference is null");

// throws a NullPointerException with a message from a supplier function

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    public void generatePaycheck(@NonNull Employee employee) {
        // do paycheck stuff ...
    }

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public void optionalCreationExamples() {

    // city can be null
    Optional<City> optionalCity = Optional.ofNullable(city);

    // cannot be null or NullPointerException is thrown        
    Optional<City> presentCity = Optional.of(city);
    
    // creates a empty or not present instance of optional
    Optional<City> absentCity = Optional.empty();

tadams

  public void validateCity(String cityCode) {
        Optional<City> city = findCity(cityCode);
        if (city.isPresent()) {
            return;
        }
        setError(CITY_INVALID, cityCode);
    }

    public Optional<City> findCity(String cityCode) {
        City city = cityRepository.get(cityCode);