Add examples with long lambdas

aplotnikov · aplotnikov · commit d66309760e1c · 2018-12-26T20:36:21.000+01:00
diff --git a/src/main/java/io/github/aplotnikov/java_8_misuses/domain/Client.java b/src/main/java/io/github/aplotnikov/java_8_misuses/domain/Client.java
@@ -16,10 +16,16 @@ public class Client {
 
     long id;
 
+    String name;
+
+    String surname;
+
     List<Loan> loans;
 
-    public Client(long id, List<Loan> loans) {
+    public Client(long id, String name, String surname, List<Loan> loans) {
         this.id = id;
+        this.name = name;
+        this.surname = surname;
         this.loans = loans;
         loans.forEach(loan -> loan.setClient(Client.this));
     }
diff --git a/src/main/java/io/github/aplotnikov/java_8_misuses/lambda/AvoidLongLambdas.java b/src/main/java/io/github/aplotnikov/java_8_misuses/lambda/AvoidLongLambdas.java
@@ -0,0 +1,63 @@
+package io.github.aplotnikov.java_8_misuses.lambda;
+
+import io.github.aplotnikov.java_8_misuses.domain.Client;
+import lombok.Data;
+import lombok.experimental.FieldDefaults;
+
+import java.util.List;
+import java.util.function.Function;
+
+import static io.github.aplotnikov.java_8_misuses.utils.Annotations.Good;
+import static io.github.aplotnikov.java_8_misuses.utils.Annotations.Ugly;
+import static java.util.stream.Collectors.toList;
+import static lombok.AccessLevel.PRIVATE;
+
+class AvoidLongLambdas {
+
+    @Ugly
+    class LongLambdaInPlace {
+        List<ClientDto> convertToDto(List<Client> clients) {
+            return clients.stream()
+                          .map(client -> {
+                              ClientDto dto = new ClientDto();
+                              dto.setId(client.getId());
+                              dto.setName(client.getName());
+                              dto.setSurname(client.getSurname());
+                              return dto;
+                          })
+                          .collect(toList());
+        }
+    }
+
+    @Good
+    class MethodReferenceInsteadOfLambda {
+        //particular toDto could be implemented as a separate class or as a lambda function
+        private final Function<Client, ClientDto> toDto = this::convertToDto;
+
+        List<ClientDto> convertToDto(List<Client> clients) {
+            return clients.stream()
+                          .map(toDto)
+                          .collect(toList());
+        }
+
+        private ClientDto convertToDto(Client client) {
+            ClientDto dto = new ClientDto();
+            dto.setId(client.getId());
+            dto.setName(client.getName());
+            dto.setSurname(client.getSurname());
+            return dto;
+        }
+    }
+
+    @Data
+    @FieldDefaults(level = PRIVATE)
+    private static class ClientDto {
+
+        long id;
+
+        String name;
+
+        String surname;
+
+    }
+}
