java-design-patterns/data-transfer-object/src/main/java/com/iluwatar/datatransfer/App.java

/*
 * The MIT License
 * Copyright © 2014-2019 Ilkka Seppälä
 *
 * 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;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * 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 App}) 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 App {

  private static final Logger LOGGER = LoggerFactory.getLogger(App.class);

  /**
   * Method as act client and request to server for details.
   *
   * @param args program argument.
   */
  public static void main(String[] args) {
    var customerOne = new CustomerDto("1", "Kelly", "Brown");
    var customerTwo = new CustomerDto("2", "Alfonso", "Bass");
    var customers = new ArrayList<>(List.of(customerOne, customerTwo));

    var customerResource = new CustomerResource(customers);

    LOGGER.info("All customers:-");
    var allCustomers = customerResource.getAllCustomers();
    printCustomerDetails(allCustomers);

    LOGGER.info("----------------------------------------------------------");

    LOGGER.info("Deleting customer with id {1}");
    customerResource.delete(customerOne.getId());
    allCustomers = customerResource.getAllCustomers();
    printCustomerDetails(allCustomers);

    LOGGER.info("----------------------------------------------------------");

    LOGGER.info("Adding customer three}");
    var customerThree = new CustomerDto("3", "Lynda", "Blair");
    customerResource.save(customerThree);
    allCustomers = customerResource.getAllCustomers();
    printCustomerDetails(allCustomers);
  }

  private static void printCustomerDetails(List<CustomerDto> allCustomers) {
    allCustomers.forEach(customer -> LOGGER.info(customer.getFirstName()));
  }
}