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mperormperor
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Add example of chain builders with tests (#39)
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‎DesignPatterns/src/main/java/pl/mperor/lab/java/design/pattern/creational/builder/chain/inner/Task.java‎

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package pl.mperor.lab.java.design.pattern.creational.builder.chain.inner;
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import java.util.concurrent.atomic.AtomicInteger;
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public class Task {
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private static final AtomicInteger ID_GENERATOR = new AtomicInteger(1);
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private int id;
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private String description;
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private boolean done;
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private Task() {
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}
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private Task(Task task) {
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this.id = ID_GENERATOR.getAndIncrement();
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// Deep copy is required here!
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this.description = task.description;
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this.done = task.done;
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}
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public int getId() {
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return id;
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}
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public String getDescription() {
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return description;
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}
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public boolean isDone() {
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return done;
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}
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public static Builder builder() {
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return new Task().new Builder();
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}
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public class Builder {
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private Builder() {
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}
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public Builder description(String description) {
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Task.this.description = description;
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return this;
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}
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public Builder done(boolean done) {
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Task.this.done = done;
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return this;
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}
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public Task build() {
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return new Task(Task.this);
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}
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}
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}

‎DesignPatterns/src/main/java/pl/mperor/lab/java/design/pattern/creational/builder/chain/nested/User.java‎

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package pl.mperor.lab.java.design.pattern.creational.builder.chain.nested;
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import java.util.concurrent.atomic.AtomicInteger;
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public class User {
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private static final AtomicInteger ID_GENERATOR = new AtomicInteger(1);
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private int id;
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private String name;
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private String password;
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private String email;
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private User() {
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}
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private User(User user) {
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this.id = ID_GENERATOR.getAndIncrement();
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// Deep copy is required here!
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this.name = user.name;
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this.password = user.password;
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this.email = user.email;
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}
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int getId() {
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return id;
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}
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public String getName() {
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return name;
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}
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public String getPassword() {
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return password;
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}
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public String getEmail() {
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return email;
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}
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public static Builder builder() {
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return new Builder();
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}
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public static class Builder {
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private final User user;
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private Builder() {
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this.user = new User();
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}
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public Builder name(String name) {
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this.user.name = name;
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return this;
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}
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public Builder password(String password) {
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user.password = password;
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return this;
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}
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public Builder email(String email) {
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user.email = email;
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return this;
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}
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public User build() {
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return new User(user);
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}
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}
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}

‎DesignPatterns/src/main/java/pl/mperor/lab/java/design/pattern/creational/builder/chain/outer/Person.java‎

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package pl.mperor.lab.java.design.pattern.creational.builder.chain.outer;
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import java.time.LocalDate;
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public class Person {
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private final String firstName;
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private final String lastName;
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private final LocalDate dateOfBirth;
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private final String address;
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private Person(PersonBuilder builder) {
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this.firstName = builder.getFirstName();
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this.lastName = builder.getLastName();
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this.dateOfBirth = builder.getDateOfBirth();
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this.address = builder.getAddress();
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}
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public String getFirstName() {
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return firstName;
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}
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public String getLastName() {
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return lastName;
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}
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public LocalDate getDateOfBirth() {
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return dateOfBirth;
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}
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public String getAddress() {
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return address;
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}
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public static Person build(PersonBuilder builder) {
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return new Person(builder);
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}
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}

‎DesignPatterns/src/main/java/pl/mperor/lab/java/design/pattern/creational/builder/chain/outer/PersonBuilder.java‎

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package pl.mperor.lab.java.design.pattern.creational.builder.chain.outer;
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import java.time.LocalDate;
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public class PersonBuilder {
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private String firstName;
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private String lastName;
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private LocalDate dateOfBirth;
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private String address;
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public PersonBuilder firstName(String name) {
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this.firstName = name;
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return this;
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}
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public PersonBuilder lastName(String name) {
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this.lastName = name;
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return this;
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}
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public PersonBuilder dateOfBirth(LocalDate date) {
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this.dateOfBirth = date;
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return this;
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}
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public PersonBuilder address(String address) {
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this.address = address;
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return this;
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}
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public String getFirstName() {
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return firstName;
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}
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public String getLastName() {
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return lastName;
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}
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public LocalDate getDateOfBirth() {
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return dateOfBirth;
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}
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public String getAddress() {
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return address;
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}
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}

‎DesignPatterns/src/test/java/pl/mperor/lab/java/design/pattern/creational/builder/chain/inner/TaskInnerBuilderTest.java‎

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package pl.mperor.lab.java.design.pattern.creational.builder.chain.inner;
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import org.junit.jupiter.api.Assertions;
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import org.junit.jupiter.api.Test;
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public class TaskInnerBuilderTest {
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@Test
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public void builderShouldAllowToBuildTask() {
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Task task = Task.builder()
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.build();
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Assertions.assertNotNull(task);
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Assertions.assertTrue(task.getId() >= 1);
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Assertions.assertNull(task.getDescription());
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Assertions.assertFalse(task.isDone());
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}
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@Test
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public void builderShouldAllowToBuildDoneTasks() {
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var builder = Task.builder()
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.done(true);
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Task t1 = builder
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.description("First task")
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.build();
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Task t2 = builder
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.description("Second task")
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.build();
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Assertions.assertEquals("First task", t1.getDescription());
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Assertions.assertEquals("Second task", t2.getDescription());
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Assertions.assertTrue(t1.isDone() && t2.isDone());
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Assertions.assertNotEquals(t1.getId(), t2.getId());
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}
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}

‎DesignPatterns/src/test/java/pl/mperor/lab/java/design/pattern/creational/builder/chain/nested/UserNestedStaticBuilderTest.java‎

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package pl.mperor.lab.java.design.pattern.creational.builder.chain.nested;
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import org.junit.jupiter.api.Assertions;
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import org.junit.jupiter.api.Test;
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public class UserNestedStaticBuilderTest {
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@Test
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public void userBuilderShouldAllowToBuildUser() {
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User user = User.builder().build();
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Assertions.assertNotNull(user);
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Assertions.assertTrue(user.getId() >= 1);
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Assertions.assertNull(user.getName());
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Assertions.assertNull(user.getPassword());
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}
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@Test
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public void userBuilderShouldAllowToBuildCustomUser() {
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User custom = User.builder()
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.name("user")
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.password("{noop}password")
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.email("[email protected]")
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.build();
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Assertions.assertTrue(custom.getId() >= 1);
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Assertions.assertEquals("user", custom.getName());
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Assertions.assertNotNull(custom.getPassword());
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Assertions.assertEquals("[email protected]", custom.getEmail());
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}
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@Test
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public void userBuilderShouldAllowToBuildGroupOfUsers() {
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var builder = User.builder();
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User u1 = builder
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.name("Anonymous")
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.email("[email protected]")
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.build();
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Assertions.assertEquals("Anonymous", u1.getName());
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Assertions.assertEquals("[email protected]", u1.getEmail());
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User u2 = builder
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.email("[email protected]")
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.build();
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Assertions.assertEquals("Anonymous", u2.getName());
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Assertions.assertEquals("[email protected]", u2.getEmail());
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User u3 = User.builder()
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.email("[email protected]")
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.build();
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Assertions.assertNull(u3.getName());
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Assertions.assertEquals("[email protected]", u3.getEmail());
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Assertions.assertTrue(u1.getId() < u2.getId() && u2.getId() < u3.getId());
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}
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}

‎DesignPatterns/src/test/java/pl/mperor/lab/java/design/pattern/creational/builder/chain/outer/PersonOuterBuilderTest.java‎

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package pl.mperor.lab.java.design.pattern.creational.builder.chain.outer;
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import org.junit.jupiter.api.Assertions;
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import org.junit.jupiter.api.Test;
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import java.time.LocalDate;
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import java.time.Month;
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public class PersonOuterBuilderTest {
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@Test
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public void personShouldBeCreatedByPersonBuilder() {
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Person person = Person.build(new PersonBuilder()
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.firstName("Jack")
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.lastName("Bell")
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.address("New York")
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.dateOfBirth(LocalDate.of(1990, Month.JANUARY, 1)));
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Assertions.assertNotNull(person);
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Assertions.assertEquals("Jack", person.getFirstName());
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Assertions.assertEquals("Bell", person.getLastName());
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Assertions.assertEquals("New York", person.getAddress());
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Assertions.assertEquals("1990-01-01", person.getDateOfBirth().toString());
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}
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}

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