From 8d7d98a144b2af7038efa1a266a284df92b9b7d9 Mon Sep 17 00:00:00 2001
From: Sasa M <sasam0320@gmail.com>
Date: Sun, 26 Apr 2020 18:37:31 +0200
Subject: [PATCH] Customizing Java 8 code in modemmapper package

---
 .../com/baeldung/modelmapper/MapperUtil.java     | 16 +++++++---------
 .../baeldung/modelmapper/UserPropertyMap.java    | 13 +++++++------
 .../modelmapper/UsersListMappingUnitTest.java    | 12 ++++++------
 3 files changed, 20 insertions(+), 21 deletions(-)

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
index 60af44cc76..9c6a5a0320 100644
--- 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
@@ -2,11 +2,11 @@ package com.baeldung.modelmapper;
 
 import org.modelmapper.ModelMapper;
 
-import java.util.ArrayList;
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
- * This is a helper class that contains methods for generic mapping of the users list.
+ * This is a helper class that contains method for generic mapping of the users list.
  * Initially, an instance of ModelMapper was created.
  *
  * @author Sasa Milenkovic
@@ -21,14 +21,12 @@ public class MapperUtil {
 
     }
 
-    public static <S, T> List<T> mapList(List<S> sourceList, Class<T> target) {
-        List<T> targetList = new ArrayList<T>();
+    public static <S, T> List<T> mapList(List<S> source, Class<T> targetClass) {
 
-        for (S source : sourceList) {
-            targetList.add(modelMapper.map(source, target));
-        }
-
-        return targetList;
+        return source
+                .stream()
+                .map(element -> modelMapper.map(element, targetClass))
+                .collect(Collectors.toList());
     }
 
 }
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
index 0d2ebf7b4c..5b2942b158 100644
--- 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
@@ -4,11 +4,11 @@ import org.modelmapper.AbstractConverter;
 import org.modelmapper.Converter;
 import org.modelmapper.PropertyMap;
 
-import java.util.ArrayList;
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
- * UserPropertyMap class instantiates the converter to map the data from the user list to the user name list.
+ * UserPropertyMap class instantiates the converter to map the data from the UserList to the UsersLisDTO.
  * In the configuration method, we call a converter to do the mapping.
  *
  * @author Sasa Milenkovic
@@ -18,19 +18,20 @@ public class UserPropertyMap extends PropertyMap<UserList, UserListDTO> {
 
     Converter<List<User>, List<String>> converter = new AbstractConverter<List<User>, List<String>>() {
 
-        protected List<String> usernames;
 
         @Override
         protected List<String> convert(List<User> users) {
 
-            usernames = new ArrayList<String>();
-            users.forEach(user -> usernames.add(user.getUsername()));
-            return usernames;
+            return users
+                    .stream()
+                    .map(User::getUsername)
+                    .collect(Collectors.toList());
         }
     };
 
     @Override
     protected void configure() {
+
         using(converter).map(source.getUsers(), destination.getUsernames());
     }
 }
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
index aaeb8711a8..982622e1f5 100644
--- 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
@@ -59,7 +59,7 @@ public class UsersListMappingUnitTest {
     @Test
     public void givenUsersList_whenUseGenericType_thenMapToDto() {
 
-        // Mapping lists using generic type methods
+        // Mapping lists using custom type methods
 
         List<UserDTO> userDtoList = MapperUtil.mapList(users, UserDTO.class);
 
@@ -72,12 +72,12 @@ public class UsersListMappingUnitTest {
 
         UserList userList = new UserList();
         userList.setUsers(users);
-        UserListDTO dto = new UserListDTO();
-        modelMapper.map(userList, dto);
+        UserListDTO dtos = new UserListDTO();
+        modelMapper.map(userList, dtos);
 
-        assertNotNull(dto);
-        assertThat(dto, Matchers.hasProperty("usernames"));
-        assertThat(dto.getUsernames(), hasSize(3));
+        assertNotNull(dtos);
+        assertThat(dtos, Matchers.hasProperty("usernames"));
+        assertThat(dtos.getUsernames(), hasSize(3));
 
     }