Merge pull request #7327 from dev-chirag/master

BAEL-2990 Automatic generation of the Builder pattern with FreeBuilder

patterns/design-patterns-2/pom.xml

@@ -30,6 +30,17 @@
             <groupId>org.apache.commons</groupId>
             <artifactId>commons-lang3</artifactId>
             <version>${commons-lang3.version}</version>
+        </dependency>
+   		<dependency>
+            <groupId>org.inferred</groupId>
+            <artifactId>freebuilder</artifactId>
+            <version>${freebuilder.version}</version>
+            <optional>true</optional>
+        </dependency>
+        <dependency>
+            <groupId>com.google.code.findbugs</groupId>
+            <artifactId>jsr305</artifactId>
+            <version>${javax.annotations.version}</version>
         </dependency>
     </dependencies>
     
@@ -38,5 +49,7 @@
         <maven.compiler.source>1.8</maven.compiler.source>
         <maven.compiler.target>1.8</maven.compiler.target>
         <intellij.annotations.version>16.0.2</intellij.annotations.version>
+        <freebuilder.version>2.4.1</freebuilder.version>
+        <javax.annotations.version>3.0.2</javax.annotations.version>
     </properties>
 </project>

patterns/design-patterns-2/src/main/java/com/baeldung/freebuilder/Address.java

@@ -0,0 +1,25 @@
+package com.baeldung.freebuilder;
+
+import org.inferred.freebuilder.FreeBuilder;
+
+import java.util.Optional;
+
+@FreeBuilder
+public interface Address {
+
+    Optional<String> getAddressLine1();
+
+    Optional<String> getAddressLine2();
+
+    Optional<String> getAddressLine3();
+
+    String getCity();
+
+    Optional<String> getState();
+
+    Optional<Long> getPinCode();
+
+    class Builder extends Address_Builder {
+
+    }
+}

patterns/design-patterns-2/src/main/java/com/baeldung/freebuilder/Employee.java

@@ -0,0 +1,65 @@
+package com.baeldung.freebuilder;
+
+import org.inferred.freebuilder.FreeBuilder;
+
+import javax.annotation.Nullable;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+@FreeBuilder
+public interface Employee {
+
+    String getName();
+
+    int getAge();
+
+    String getDepartment();
+
+    String getRole();
+
+    String getSupervisorName();
+
+    String getDesignation();
+
+    String getEmail();
+
+    long getPhoneNumber();
+
+    Optional<Boolean> getPermanent();
+
+    Optional<String> getDateOfJoining();
+
+    @Nullable
+    String getCurrentProject();
+
+    Address getAddress();
+
+    List<Long> getAccessTokens();
+
+    Map<String, Long> getAssetsSerialIdMapping();
+
+    Optional<Double> getSalaryInUSD();
+
+
+    class Builder extends Employee_Builder {
+
+        public Builder() {
+            // setting default value for department
+            setDepartment("Builder Pattern");
+        }
+
+        @Override
+        public Builder setEmail(String email) {
+            if (checkValidEmail(email))
+                return super.setEmail(email);
+            else
+                throw new IllegalArgumentException("Invalid email");
+
+        }
+
+        private boolean checkValidEmail(String email) {
+            return email.contains("@");
+        }
+    }
+}

patterns/design-patterns-2/src/main/java/com/baeldung/freebuilder/builder/Employee.java

@@ -0,0 +1,53 @@
+package com.baeldung.freebuilder.builder;
+
+public class Employee {
+
+    private final String name;
+    private final int age;
+    private final String department;
+
+    private Employee(String name, int age, String department) {
+        this.name = name;
+        this.age = age;
+        this.department = department;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public int getAge() {
+        return age;
+    }
+
+    public String getDepartment() {
+        return department;
+    }
+
+    public static class Builder {
+
+        private String name;
+        private int age;
+        private String department;
+
+        public Builder setName(String name) {
+            this.name = name;
+            return this;
+        }
+
+        public Builder setAge(int age) {
+            this.age = age;
+            return this;
+        }
+
+        public Builder setDepartment(String department) {
+            this.department = department;
+            return this;
+        }
+
+        public Employee build() {
+            return new Employee(name, age, department);
+        }
+    }
+
+}

patterns/design-patterns-2/src/test/java/com/baeldung/freebuilder/EmployeeBuilderUnitTest.java

@@ -0,0 +1,226 @@
+package com.baeldung.freebuilder;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.Optional;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class EmployeeBuilderUnitTest {
+
+    private static final int PIN_CODE = 223344;
+    public static final String CITY_NAME = "New York";
+    public static final int INPUT_SALARY_EUROS = 10000;
+    public static final double EUROS_TO_USD_RATIO = 0.6;
+
+    @Test
+    public void whenBuildEmployeeWithAddress_thenReturnEmployeeWithValidAddress() {
+
+        // when
+        Address.Builder addressBuilder = new Address.Builder();
+        Address address = addressBuilder.setCity(CITY_NAME).build();
+
+        Employee.Builder builder = new Employee.Builder();
+
+        Employee employee = builder.setName("baeldung")
+          .setAge(10)
+          .setDesignation("author")
+          .setEmail("abc@xyz.com")
+          .setSupervisorName("Admin")
+          .setPhoneNumber(4445566)
+          .setPermanent(true)
+          .setRole("developer")
+          .setAddress(address)
+          .build();
+
+        // then
+        assertTrue(employee.getAddress().getCity().equalsIgnoreCase(CITY_NAME));
+
+    }
+
+    @Test
+    public void whenMapSalary_thenReturnEmployeeWithSalaryInUSD() {
+
+        // when
+        Address.Builder addressBuilder = new Address.Builder();
+        Address address = addressBuilder.setCity(CITY_NAME).setPinCode(PIN_CODE).build();
+
+        long salaryInEuros = INPUT_SALARY_EUROS;
+        Employee.Builder builder = new Employee.Builder();
+
+        Employee employee = builder
+          .setName("baeldung")
+          .setAge(10)
+          .setDesignation("author")
+          .setEmail("abc@xyz.com")
+          .setSupervisorName("Admin")
+          .setPhoneNumber(4445566)
+          .setPermanent(true)
+          .setRole("developer")
+          .setAddress(address)
+          .mapSalaryInUSD(sal -> salaryInEuros * EUROS_TO_USD_RATIO)
+          .build();
+
+        // then
+        assertTrue(employee.getAddress().getPinCode().get() == PIN_CODE);
+
+    }
+
+    @Test
+    public void whenOptionalFields_thenReturnEmployeeWithEmptyValues() {
+
+        // when
+        Address.Builder addressBuilder = new Address.Builder();
+        Address address = addressBuilder.setCity(CITY_NAME).build();
+
+        Employee.Builder builder = new Employee.Builder();
+
+        Employee employee = builder.setName("baeldung")
+          .setAge(10)
+          .setDesignation("author")
+          .setEmail("abc@xyz.com")
+          .setSupervisorName("Admin")
+          .setPhoneNumber(4445566)
+          .setPermanent(true)
+          .setRole("developer")
+          .setAddress(address)
+          .build();
+
+        // then
+        assertTrue(employee.getPermanent().isPresent());
+        assertTrue(employee.getPermanent().get());
+        assertFalse(employee.getDateOfJoining().isPresent());
+
+    }
+
+    @Test
+    public void whenNullableFields_thenReturnEmployeeWithNullValueForField() {
+
+        // when
+        Address.Builder addressBuilder = new Address.Builder();
+        Address address = addressBuilder.setCity(CITY_NAME).build();
+
+        Employee.Builder builder = new Employee.Builder();
+
+        Employee employee = builder.setName("baeldung")
+          .setAge(10)
+          .setDesignation("author")
+          .setEmail("abc@xyz.com")
+          .setSupervisorName("Admin")
+          .setPhoneNumber(4445566)
+          .setNullablePermanent(null)
+          .setDateOfJoining(Optional.empty())
+          .setRole("developer")
+          .setAddress(address)
+          .build();
+
+        // then
+        assertNull(employee.getCurrentProject());
+
+    }
+
+    @Test
+    public void whenCollectionFields_thenReturnEmployeeWithValues() {
+
+        // when
+        Address.Builder addressBuilder = new Address.Builder();
+        Address address = addressBuilder.setCity(CITY_NAME).build();
+
+        Employee.Builder builder = new Employee.Builder();
+
+        Employee employee = builder.setName("baeldung")
+          .setAge(10)
+          .setDesignation("author")
+          .setEmail("abc@xyz.com")
+          .setSupervisorName("Admin")
+          .setPhoneNumber(4445566)
+          .setNullablePermanent(null)
+          .setDateOfJoining(Optional.empty())
+          .setRole("developer")
+          .addAccessTokens(1221819L)
+          .addAccessTokens(1223441L, 134567L)
+          .setAddress(address)
+          .build();
+
+        // then
+        assertTrue(employee.getAccessTokens().size() == 3);
+
+    }
+
+    @Test
+    public void whenMapFields_thenReturnEmployeeWithValues() {
+
+        // when
+        Address.Builder addressBuilder = new Address.Builder();
+        Address address = addressBuilder.setCity(CITY_NAME).build();
+
+        Employee.Builder builder = new Employee.Builder();
+
+        Employee employee = builder.setName("baeldung")
+          .setAge(10)
+          .setDesignation("author")
+          .setEmail("abc@xyz.com")
+          .setSupervisorName("Admin")
+          .setPhoneNumber(4445566)
+          .setNullablePermanent(null)
+          .setDateOfJoining(Optional.empty())
+          .setRole("developer")
+          .addAccessTokens(1221819L)
+          .addAccessTokens(1223441L, 134567L)
+          .putAssetsSerialIdMapping("Laptop", 12345L)
+          .setAddress(address)
+          .build();
+
+        // then
+        assertTrue(employee.getAssetsSerialIdMapping().size() == 1);
+
+    }
+
+    @Test
+    public void whenNestedBuilderTypes_thenReturnEmployeeWithValues() {
+
+        // when
+        Address.Builder addressBuilder = new Address.Builder();
+        Address address = addressBuilder.setCity(CITY_NAME).build();
+
+        Employee.Builder builder = new Employee.Builder();
+
+        Employee employee = builder.setName("baeldung")
+          .setAge(10)
+          .setDesignation("author")
+          .setEmail("abc@xyz.com")
+          .setSupervisorName("Admin")
+          .setPhoneNumber(4445566)
+          .setNullablePermanent(null)
+          .setDateOfJoining(Optional.empty())
+          .setRole("developer")
+          .addAccessTokens(1221819L)
+          .addAccessTokens(1223441L, 134567L)
+          .putAssetsSerialIdMapping("Laptop", 12345L)
+          .setAddress(address)
+          .mutateAddress(a -> a.setPinCode(112200))
+          .build();
+
+        // then
+        assertTrue(employee.getAssetsSerialIdMapping().size() == 1);
+
+    }
+
+    @Test()
+    public void whenPartialEmployeeWithValidEmail_thenReturnEmployeeWithEmail() {
+
+        // when
+        Employee.Builder builder = new Employee.Builder();
+
+        Employee employee = builder.setName("baeldung")
+          .setAge(10)
+          .setEmail("abc@xyz.com")
+          .buildPartial();
+
+        assertNotNull(employee.getEmail());
+    }
+
+}

patterns/design-patterns-2/src/test/java/com/baeldung/freebuilder/builder/EmployeeBuilderUnitTest.java

@@ -0,0 +1,27 @@
+package com.baeldung.freebuilder.builder;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+
+class EmployeeBuilderUnitTest {
+
+    public static final String NAME = "baeldung";
+
+    @Test
+    public void whenBuildEmployee_thenReturnValidEmployee() {
+
+        // when
+        Employee.Builder emplBuilder = new Employee.Builder();
+
+        Employee employee = emplBuilder
+          .setName(NAME)
+          .setAge(12)
+          .setDepartment("Builder Pattern")
+          .build();
+
+        //then
+        Assertions.assertTrue(employee.getName().equalsIgnoreCase(NAME));
+    }
+
+}