Creating TypeMap to use property mapping and converter class

Sasa M · sasam0320 · commit 67982c7ecf18 · 2020-04-29T21:55:30.000+02:00
diff --git a/java-collections-conversions-2/src/main/java/com/baeldung/modelmapper/MapperUtil.java b/java-collections-conversions-2/src/main/java/com/baeldung/modelmapper/MapperUtil.java
@@ -6,7 +6,7 @@
 import java.util.stream.Collectors;
 
 /**
- * This is a helper class that contains method for generic mapping of the users list.
+ * This is a helper class that contains method for custom mapping of the users list.
  * Initially, an instance of ModelMapper was created.
  *
  * @author Sasa Milenkovic
diff --git a/java-collections-conversions-2/src/main/java/com/baeldung/modelmapper/UserPropertyMap.java b/java-collections-conversions-2/src/main/java/com/baeldung/modelmapper/UserPropertyMap.java
diff --git a/java-collections-conversions-2/src/main/java/com/baeldung/modelmapper/UsersListConverter.java b/java-collections-conversions-2/src/main/java/com/baeldung/modelmapper/UsersListConverter.java
@@ -0,0 +1,23 @@
+package com.baeldung.modelmapper;
+
+import org.modelmapper.AbstractConverter;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * UsersListConverter class map the property data from the list of users into the list of user names.
+ *
+ * @author Sasa Milenkovic
+ */
+public class UsersListConverter extends AbstractConverter<List<User>, List<String>> {
+
+    @Override
+    protected List<String> convert(List<User> users) {
+
+        return users
+                .stream()
+                .map(User::getUsername)
+                .collect(Collectors.toList());
+    }
+}
diff --git a/java-collections-conversions-2/src/test/java/com/baeldung/modelmapper/UsersListMappingUnitTest.java b/java-collections-conversions-2/src/test/java/com/baeldung/modelmapper/UsersListMappingUnitTest.java
@@ -4,6 +4,7 @@
 import org.junit.Before;
 import org.junit.Test;
 import org.modelmapper.ModelMapper;
+import org.modelmapper.TypeMap;
 import org.modelmapper.TypeToken;
 
 import java.util.ArrayList;
@@ -12,14 +13,12 @@
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.hasItems;
 import static org.hamcrest.Matchers.hasProperty;
-import static org.hamcrest.collection.IsCollectionWithSize.hasSize;
-import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertThat;
 
 
 /**
  * This class has test methods of mapping Integer to Character list,
- * mapping user list to DTO list using MapperUtil generic methods and Converter
+ * mapping users list to DTO list using MapperUtil custom type method and property mapping using converter class
  *
  * @author Sasa Milenkovic
  */
@@ -32,7 +31,12 @@ public class UsersListMappingUnitTest {
     public void init() {
 
         modelMapper = new ModelMapper();
-        modelMapper.addMappings(new UserPropertyMap());
+
+        TypeMap<UserList, UserListDTO> typeMap = modelMapper.createTypeMap(UserList.class, UserListDTO.class);
+
+        typeMap.addMappings(mapper -> mapper.using(new UsersListConverter())
+                .map(UserList::getUsers, UserListDTO::setUsernames));
+
         users = new ArrayList();
         users.add(new User("b100", "user1", "user1@baeldung.com", "111-222", "USER"));
         users.add(new User("b101", "user2", "user2@baeldung.com", "111-333", "USER"));
@@ -41,7 +45,7 @@ public void init() {
     }
 
     @Test
-    public void whenMapIntegerToCharList() {
+    public void whenInteger_thenMapToCharacter() {
 
         List<Integer> integers = new ArrayList<Integer>();
 
@@ -57,9 +61,9 @@ public void whenMapIntegerToCharList() {
     }
 
     @Test
-    public void givenUsersList_whenUseGenericType_thenMapToDto() {
+    public void givenUsersList_whenUseGenericType_thenMapToUserDTO() {
 
-        // Mapping lists using custom type methods
+        // Mapping lists using custom (generic) type mapping
 
         List<UserDTO> userDtoList = MapperUtil.mapList(users, UserDTO.class);
 
@@ -68,16 +72,20 @@ public void givenUsersList_whenUseGenericType_thenMapToDto() {
                         .and(hasProperty("email", equalTo("user1@baeldung.com")))
                         .and(hasProperty("username", equalTo("user1")))));
 
-        // Mapping lists using PropertyMap and Converter
+
+    }
+
+    @Test
+    public void givenUsersList_whenUseConverter_thenMapToUsernames() {
+
+        // Mapping lists using property mapping and converter
 
         UserList userList = new UserList();
         userList.setUsers(users);
         UserListDTO dtos = new UserListDTO();
         modelMapper.map(userList, dtos);
 
-        assertNotNull(dtos);
-        assertThat(dtos, Matchers.hasProperty("usernames"));
-        assertThat(dtos.getUsernames(), hasSize(3));
+        assertThat(dtos.getUsernames(), hasItems("user1", "user2", "user3"));
 
     }
 

Original file line number	Diff line number	Diff line change
`@@ -6,7 +6,7 @@`
`6`	`6`	`import java.util.stream.Collectors;`
`7`	`7`
`8`	`8`	`/**`
`9`		`- * This is a helper class that contains method for generic mapping of the users list.`
	`9`	`+ * This is a helper class that contains method for custom mapping of the users list.`
`10`	`10`	`* Initially, an instance of ModelMapper was created.`
`11`	`11`	`*`
`12`	`12`	`* @author Sasa Milenkovic`