initial commit

Author: mluckam

.gitignore

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+/target/
+.classpath
+.project
+.settings/

pom.xml

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+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>example</groupId>
+    <artifactId>builder</artifactId>
+    <version>1.0</version>
+
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>11</maven.compiler.source>
+        <maven.compiler.target>11</maven.compiler.target>
+
+        <commons.lang3.version>3.9</commons.lang3.version>
+        <junit.jupiter.engine.version>5.5.2</junit.jupiter.engine.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+            <version>${junit.jupiter.engine.version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons.lang3.version}</version>
+        </dependency>
+    </dependencies>
+
+</project>

src/main/java/example/builder/Name.java

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+package example.builder;
+
+public class Name {
+
+    private final String firstName;
+    private final String middleName;
+    private final String lastName;
+
+    public Name(String firstName, String middleName, String lastName) {
+        super();
+        this.firstName = firstName;
+        this.middleName = middleName;
+        this.lastName = lastName;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public String getMiddleName() {
+        return middleName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+}

src/main/java/example/builder/Person.java

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+package example.builder;
+
+import org.apache.commons.lang3.builder.EqualsBuilder;
+import org.apache.commons.lang3.builder.HashCodeBuilder;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+
+public class Person {
+
+    private String firstName;
+    private String middleName;
+    private String lastName;
+    private int age;
+
+    // default constructor so the builder can create an empty version
+    private Person() {
+    }
+
+    private Person(Person person) {
+        this.firstName = person.getFirstName();
+        this.middleName = person.getMiddleName();
+        this.lastName = person.getLastName();
+        this.age = person.getAge();
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public String getMiddleName() {
+        return middleName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        return EqualsBuilder.reflectionEquals(this, o);
+    }
+
+    @Override
+    public int hashCode() {
+        return HashCodeBuilder.reflectionHashCode(this);
+    }
+
+    @Override
+    public String toString() {
+        return ToStringBuilder.reflectionToString(this);
+    }
+
+    public static Builder getBuilder() {
+        return new Builder();
+    }
+
+    public static final class Builder {
+
+        private final Person person = new Person();
+
+        public Builder firstName(String firstName) {
+            this.person.firstName = firstName;
+            return this;
+        }
+
+        public Builder middleName(String middleName) {
+            this.person.middleName = middleName;
+            return this;
+        }
+
+        public Builder lastName(String lastName) {
+            this.person.lastName = lastName;
+            return this;
+        }
+
+        public Builder age(int age) {
+            this.person.age = age;
+            return this;
+        }
+
+        public Builder name(Name name) {
+            this.person.firstName = name.getFirstName();
+            this.person.middleName = name.getMiddleName();
+            this.person.lastName = name.getLastName();
+            return this;
+        }
+
+        //a new person is created here so that if a method in this instance of the Builder is called it will not change the value of the Person being returned.
+        public Person build() {
+            return new Person(person);
+        }
+    }
+}

src/test/java/builder/PersonTest.java

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+package builder;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+import example.builder.Person;
+
+class PersonTest {
+
+    @Test
+    void testBuilder() {
+        String firstName = "foo";
+        String middleName = "bar";
+        String lastName = "baz";
+        int age = 50;
+
+        Person person1 = Person.getBuilder()
+                .firstName(firstName)
+                .middleName(middleName)
+                .lastName(lastName)
+                .age(age)
+                .build();
+
+        assertEquals(firstName, person1.getFirstName());
+        assertEquals(middleName, person1.getMiddleName());
+        assertEquals(lastName, person1.getLastName());
+        assertEquals(age, person1.getAge());
+
+    }
+
+}