Merge data transfer object examples (#1635)

* #1617 merge dto pattern examples

* #1617 update license headers

Co-authored-by: Subhrodip Mohanta <subhrodipmohanta@gmail.com>

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

@@ -0,0 +1,70 @@
+/*
+ * 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.customer;
+
+import java.util.List;
+
+/**
+ * The resource class which serves customer information. This class act as server in the demo. Which
+ * has all customer details.
+ */
+public class CustomerResource {
+  private final List<CustomerDto> customers;
+
+  /**
+   * Initialise resource with existing customers.
+   *
+   * @param customers initialize resource with existing customers. Act as database.
+   */
+  public CustomerResource(List<CustomerDto> customers) {
+    this.customers = customers;
+  }
+
+  /**
+   * Get all customers.
+   *
+   * @return : all customers in list.
+   */
+  public List<CustomerDto> getAllCustomers() {
+    return customers;
+  }
+
+  /**
+   * Save new customer.
+   *
+   * @param customer save new customer to list.
+   */
+  public void save(CustomerDto customer) {
+    customers.add(customer);
+  }
+
+  /**
+   * Delete customer with given id.
+   *
+   * @param customerId delete customer with id {@code customerId}
+   */
+  public void delete(String customerId) {
+    customers.removeIf(customer -> customer.getId().equals(customerId));
+  }
+}