[BAEL-3077] Add examples for mapstruct with multiple source objects (#7724)

* [BAEL-3077] Add examples for mapstruct with multiple source objects

* [BAEL-3077] Add unit tests for mappers added by examples

mapstruct/src/main/java/com/baeldung/dto/CustomerDto.java

@@ -0,0 +1,25 @@
+package com.baeldung.dto;
+
+public class CustomerDto {
+
+    private String forename;
+    private String surname;
+
+    public String getForename() {
+        return forename;
+    }
+
+    public CustomerDto setForename(String forename) {
+        this.forename = forename;
+        return this;
+    }
+
+    public String getSurname() {
+        return surname;
+    }
+
+    public CustomerDto setSurname(String surname) {
+        this.surname = surname;
+        return this;
+    }
+}

mapstruct/src/main/java/com/baeldung/entity/Address.java

@@ -0,0 +1,35 @@
+package com.baeldung.entity;
+
+public class Address {
+
+    private String street;
+    private String postalcode;
+    private String county;
+
+    public String getStreet() {
+        return street;
+    }
+
+    public Address setStreet(String street) {
+        this.street = street;
+        return this;
+    }
+
+    public String getPostalcode() {
+        return postalcode;
+    }
+
+    public Address setPostalcode(String postalcode) {
+        this.postalcode = postalcode;
+        return this;
+    }
+
+    public String getCounty() {
+        return county;
+    }
+
+    public Address setCounty(String county) {
+        this.county = county;
+        return this;
+    }
+}

mapstruct/src/main/java/com/baeldung/entity/Customer.java

@@ -0,0 +1,25 @@
+package com.baeldung.entity;
+
+public class Customer {
+
+    private String firstName;
+    private String lastName;
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public Customer setFirstName(String firstName) {
+        this.firstName = firstName;
+        return this;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public Customer setLastName(String lastName) {
+        this.lastName = lastName;
+        return this;
+    }
+}

mapstruct/src/main/java/com/baeldung/entity/DeliveryAddress.java

@@ -0,0 +1,55 @@
+package com.baeldung.entity;
+
+public class DeliveryAddress {
+
+    private String forename;
+    private String surname;
+    private String street;
+    private String postalcode;
+    private String county;
+
+    public String getForename() {
+        return forename;
+    }
+
+    public DeliveryAddress setForename(String forename) {
+        this.forename = forename;
+        return this;
+    }
+
+    public String getSurname() {
+        return surname;
+    }
+
+    public DeliveryAddress setSurname(String surname) {
+        this.surname = surname;
+        return this;
+    }
+
+    public String getStreet() {
+        return street;
+    }
+
+    public DeliveryAddress setStreet(String street) {
+        this.street = street;
+        return this;
+    }
+
+    public String getPostalcode() {
+        return postalcode;
+    }
+
+    public DeliveryAddress setPostalcode(String postalcode) {
+        this.postalcode = postalcode;
+        return this;
+    }
+
+    public String getCounty() {
+        return county;
+    }
+
+    public DeliveryAddress setCounty(String county) {
+        this.county = county;
+        return this;
+    }
+}

mapstruct/src/main/java/com/baeldung/mapper/CustomerDtoMapper.java

@@ -0,0 +1,15 @@
+package com.baeldung.mapper;
+
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+
+import com.baeldung.dto.CustomerDto;
+import com.baeldung.entity.Customer;
+
+@Mapper
+public interface CustomerDtoMapper {
+
+    @Mapping(source = "firstName", target = "forename")
+    @Mapping(source = "lastName", target = "surname")
+    CustomerDto from(Customer customer);
+}

mapstruct/src/main/java/com/baeldung/mapper/DeliveryAddressMapper.java

@@ -0,0 +1,24 @@
+package com.baeldung.mapper;
+
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+import org.mapstruct.MappingTarget;
+
+import com.baeldung.entity.Address;
+import com.baeldung.entity.Customer;
+import com.baeldung.entity.DeliveryAddress;
+
+@Mapper
+public interface DeliveryAddressMapper {
+
+    @Mapping(source = "customer.firstName", target = "forename")
+    @Mapping(source = "customer.lastName", target = "surname")
+    @Mapping(source = "address.street", target = "street")
+    @Mapping(source = "address.postalcode", target = "postalcode")
+    @Mapping(source = "address.county", target = "county")
+    DeliveryAddress from(Customer customer, Address address);
+
+    @Mapping(source = "address.postalcode", target = "postalcode")
+    @Mapping(source = "address.county", target = "county")
+    DeliveryAddress updateAddress(@MappingTarget DeliveryAddress deliveryAddress, Address address);
+}

mapstruct/src/test/java/com/baeldung/mapper/CustomerDtoMapperUnitTest.java

@@ -0,0 +1,29 @@
+package com.baeldung.mapper;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.jupiter.api.Test;
+import org.mapstruct.factory.Mappers;
+
+import com.baeldung.dto.CustomerDto;
+import com.baeldung.entity.Customer;
+
+public class CustomerDtoMapperUnitTest {
+
+    private CustomerDtoMapper customerDtoMapper = Mappers.getMapper(CustomerDtoMapper.class);
+
+    @Test
+    void testGivenCustomer_mapsToCustomerDto() {
+
+        // given
+        Customer customer = new Customer().setFirstName("Max")
+            .setLastName("Powers");
+
+        // when
+        CustomerDto customerDto = customerDtoMapper.from(customer);
+
+        // then
+        assertEquals(customerDto.getForename(), customer.getFirstName());
+        assertEquals(customerDto.getSurname(), customer.getLastName());
+    }
+}

mapstruct/src/test/java/com/baeldung/mapper/DeliveryAddressMapperUnitTest.java

@@ -0,0 +1,64 @@
+package com.baeldung.mapper;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertSame;
+
+import org.junit.Test;
+import org.mapstruct.factory.Mappers;
+
+import com.baeldung.entity.Address;
+import com.baeldung.entity.Customer;
+import com.baeldung.entity.DeliveryAddress;
+
+public class DeliveryAddressMapperUnitTest {
+
+    private DeliveryAddressMapper deliveryAddressMapper = Mappers.getMapper(DeliveryAddressMapper.class);
+
+    @Test
+    public void testGivenCustomerAndAddress_mapsToDeliveryAddress() {
+
+        // given
+        Customer customer = new Customer().setFirstName("Max")
+            .setLastName("Powers");
+
+        Address homeAddress = new Address().setStreet("123 Some Street")
+            .setCounty("Nevada")
+            .setPostalcode("89123");
+
+        // when
+        DeliveryAddress deliveryAddress = deliveryAddressMapper.from(customer, homeAddress);
+
+        // then
+        assertEquals(deliveryAddress.getForename(), customer.getFirstName());
+        assertEquals(deliveryAddress.getSurname(), customer.getLastName());
+        assertEquals(deliveryAddress.getStreet(), homeAddress.getStreet());
+        assertEquals(deliveryAddress.getCounty(), homeAddress.getCounty());
+        assertEquals(deliveryAddress.getPostalcode(), homeAddress.getPostalcode());
+    }
+
+    @Test
+    public void testGivenDeliveryAddressAndSomeOtherAddress_updatesDeliveryAddress() {
+
+        // given
+        Customer customer = new Customer().setFirstName("Max")
+            .setLastName("Powers");
+
+        DeliveryAddress deliveryAddress = new DeliveryAddress().setStreet("123 Some Street")
+            .setCounty("Nevada")
+            .setPostalcode("89123");
+
+        Address otherAddress = new Address().setStreet("456 Some other street")
+            .setCounty("Arizona")
+            .setPostalcode("12345");
+
+        // when
+        DeliveryAddress updatedDeliveryAddress = deliveryAddressMapper.updateAddress(deliveryAddress, otherAddress);
+
+        // then
+        assertSame(deliveryAddress, updatedDeliveryAddress);
+
+        assertEquals(deliveryAddress.getStreet(), otherAddress.getStreet());
+        assertEquals(deliveryAddress.getCounty(), otherAddress.getCounty());
+        assertEquals(deliveryAddress.getPostalcode(), otherAddress.getPostalcode());
+    }
+}