iluwatar#348 - Data Tranfer Object : customer client request customer details to server at one shot.

Author: Gopinath Langote

data-transfer-object/etc/data-transfer-object.urm.png

@@ -1,5 +1,10 @@
 @startuml
 package com.iluwatar.datatransfer {
+  class CustomerClientApp {
+    + CustomerClientApp()
+    + main(args : String[]) {static}
+    - printCustomerDetails(allCustomers : List<CustomerDto>) {static}
+  }
   class CustomerDto {
     - firstName : String
     - id : String

data-transfer-object/etc/data-transfer-object.urm.puml

@@ -0,0 +1,78 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Gopinath Langote
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package com.iluwatar.datatransfer;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * The Data Transfer Object pattern is a design pattern in which an data transfer object is used to serve related
+ * information together to avoid multiple call for each piece of information.
+ * <p>
+ * In this example, ({@link CustomerClientApp}) as as customer details consumer i.e. client to request for
+ * customer details to server.
+ * <p>
+ * CustomerResource ({@link CustomerResource}) act as server to serve customer information.
+ * And The CustomerDto ({@link CustomerDto} is data transfer object to share customer information.
+ */
+public class CustomerClientApp {
+  /**
+   * Method as act client and request to server for details.
+   *
+   * @param args program argument.
+   */
+  public static void main(String[] args) {
+    List<CustomerDto> customers = new ArrayList<>();
+    CustomerDto customerOne = new CustomerDto("1", "Kelly", "Brown");
+    CustomerDto customerTwo = new CustomerDto("2", "Alfonso", "Bass");
+    customers.add(customerOne);
+    customers.add(customerTwo);
+
+    CustomerResource customerResource = new CustomerResource(customers);
+
+    System.out.println("All customers:-");
+    List<CustomerDto> allCustomers = customerResource.getAllCustomers();
+    printCustomerDetails(allCustomers);
+
+    System.out.println("----------------------------------------------------------");
+
+    System.out.println("Deleting customer with id {1}");
+    customerResource.delete(customerOne.getId());
+    allCustomers = customerResource.getAllCustomers();
+    printCustomerDetails(allCustomers);
+
+    System.out.println("----------------------------------------------------------");
+
+    System.out.println("Adding customer three}");
+    CustomerDto customerThree = new CustomerDto("3", "Lynda", "Blair");
+    customerResource.save(customerThree);
+    allCustomers = customerResource.getAllCustomers();
+    printCustomerDetails(allCustomers);
+  }
+
+  private static void printCustomerDetails(List<CustomerDto> allCustomers) {
+    allCustomers.forEach(customer -> System.out.println(customer.getFirstName()));
+  }
+}

data-transfer-object/src/main/java/com/iluwatar/datatransfer/CustomerClientApp.java

@@ -37,7 +37,7 @@
 public class CustomerResourceTest {
   @Test
   public void shouldGetAllCustomers() {
-    CustomerDto customer = new CustomerDto("1", "David", "Roy");
+    CustomerDto customer = new CustomerDto("1", "Melody", "Yates");
     List<CustomerDto> customers = new ArrayList<>();
     customers.add(customer);
 
@@ -47,26 +47,26 @@ public void shouldGetAllCustomers() {
 
     assertEquals(allCustomers.size(), 1);
     assertEquals(allCustomers.get(0).getId(), "1");
-    assertEquals(allCustomers.get(0).getFirstName(), "David");
-    assertEquals(allCustomers.get(0).getLastName(), "Roy");
+    assertEquals(allCustomers.get(0).getFirstName(), "Melody");
+    assertEquals(allCustomers.get(0).getLastName(), "Yates");
   }
 
   @Test
   public void shouldSaveCustomer() {
-    CustomerDto customer = new CustomerDto("1", "David", "Roy");
+    CustomerDto customer = new CustomerDto("1", "Rita", "Reynolds");
     CustomerResource customerResource = new CustomerResource(new ArrayList<>());
 
     customerResource.save(customer);
 
     List<CustomerDto> allCustomers = customerResource.getAllCustomers();
     assertEquals(allCustomers.get(0).getId(), "1");
-    assertEquals(allCustomers.get(0).getFirstName(), "David");
-    assertEquals(allCustomers.get(0).getLastName(), "Roy");
+    assertEquals(allCustomers.get(0).getFirstName(), "Rita");
+    assertEquals(allCustomers.get(0).getLastName(), "Reynolds");
   }
 
   @Test
   public void shouldDeleteCustomer() {
-    CustomerDto customer = new CustomerDto("1", "David", "Roy");
+    CustomerDto customer = new CustomerDto("1", "Terry", "Nguyen");
     List<CustomerDto> customers = new ArrayList<>();
     customers.add(customer);