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Merge data transfer object examples (#1635)

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* #1617 merge dto pattern examples

* #1617 update license headers

Co-authored-by: Subhrodip Mohanta <subhrodipmohanta@gmail.com>
This commit is contained in:
Ilkka Seppälä
2021-01-25 05:35:04 +02:00
committed by GitHub
parent 3adc3cda05
commit 0010fb55c5
37 changed files with 674 additions and 358 deletions
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69
data-transfer-object/src/main/java/com/iluwatar/datatransfer/App.java
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@ -23,7 +23,13 @@
package com.iluwatar.datatransfer;
import com.iluwatar.datatransfer.customer.CustomerDto;
import com.iluwatar.datatransfer.customer.CustomerResource;
import com.iluwatar.datatransfer.product.Product;
import com.iluwatar.datatransfer.product.ProductDto;
import com.iluwatar.datatransfer.product.ProductResource;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@ -32,11 +38,17 @@ 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>In the first example, {@link App} is a customer details consumer i.e. client to
* request for customer details to server. {@link CustomerResource} act as server to serve customer
* information. {@link CustomerDto} is data transfer object to share customer information.
*
* <p>In the second example, {@link App} is a product details consumer i.e. client to
* request for product details to server. {@link ProductResource} acts as server to serve
* product information. {@link ProductDto} is data transfer object to share product information.
*
* <p>The pattern implementation is a bit different in each of the examples. The first can be
* thought as a traditional example and the second is an enum based implementation.
*
* <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 {
@ -48,6 +60,8 @@ public class App {
* @param args program argument.
*/
public static void main(String[] args) {
// Example 1: Customer DTO
var customerOne = new CustomerDto("1", "Kelly", "Brown");
var customerTwo = new CustomerDto("2", "Alfonso", "Bass");
var customers = new ArrayList<>(List.of(customerOne, customerTwo));
@ -72,6 +86,53 @@ public class App {
customerResource.save(customerThree);
allCustomers = customerResource.getAllCustomers();
printCustomerDetails(allCustomers);
// Example 2: Product DTO
Product tv =
new Product().setId(1L).setName("TV").setSupplier("Sony").setPrice(1000D).setCost(1090D);
Product microwave =
new Product()
.setId(2L)
.setName("microwave")
.setSupplier("Delonghi")
.setPrice(1000D)
.setCost(1090D);
Product refrigerator =
new Product()
.setId(3L)
.setName("refrigerator")
.setSupplier("Botsch")
.setPrice(1000D)
.setCost(1090D);
Product airConditioner =
new Product()
.setId(4L)
.setName("airConditioner")
.setSupplier("LG")
.setPrice(1000D)
.setCost(1090D);
List<Product> products =
new ArrayList<>(Arrays.asList(tv, microwave, refrigerator, airConditioner));
ProductResource productResource = new ProductResource(products);
LOGGER.info(
"####### List of products including sensitive data just for admins: \n {}",
Arrays.toString(productResource.getAllProductsForAdmin().toArray()));
LOGGER.info(
"####### List of products for customers: \n {}",
Arrays.toString(productResource.getAllProductsForCustomer().toArray()));
LOGGER.info("####### Going to save Sony PS5 ...");
ProductDto.Request.Create createProductRequestDto =
new ProductDto.Request.Create()
.setName("PS5")
.setCost(1000D)
.setPrice(1220D)
.setSupplier("Sony");
productResource.save(createProductRequestDto);
LOGGER.info(
"####### List of products after adding PS5: {}",
Arrays.toString(productResource.getProducts().toArray()));
}
private static void printCustomerDetails(List<CustomerDto> allCustomers) {

2
data-transfer-object/src/main/java/com/iluwatar/datatransfer/CustomerDto.java → data-transfer-object/src/main/java/com/iluwatar/datatransfer/customer/CustomerDto.java
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@ -21,7 +21,7 @@
* THE SOFTWARE.
*/
package com.iluwatar.datatransfer;
package com.iluwatar.datatransfer.customer;
/**
* {@link CustomerDto} is a data transfer object POJO. Instead of sending individual information to

2
data-transfer-object/src/main/java/com/iluwatar/datatransfer/CustomerResource.java → data-transfer-object/src/main/java/com/iluwatar/datatransfer/customer/CustomerResource.java
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@ -21,7 +21,7 @@
* THE SOFTWARE.
*/
package com.iluwatar.datatransfer;
package com.iluwatar.datatransfer.customer;
import java.util.List;

114
data-transfer-object/src/main/java/com/iluwatar/datatransfer/product/Product.java Normal file
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@ -0,0 +1,114 @@
/*
* 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.product;
/**
* {@link Product} is a entity class for product entity. This class act as entity in the demo.
*/
public final class Product {
private Long id;
private String name;
private Double price;
private Double cost;
private String supplier;
/**
* Constructor.
*
* @param id product id
* @param name product name
* @param price product price
* @param cost product cost
* @param supplier product supplier
*/
public Product(Long id, String name, Double price, Double cost, String supplier) {
this.id = id;
this.name = name;
this.price = price;
this.cost = cost;
this.supplier = supplier;
}
/**
* Constructor.
*/
public Product() {
}
public Long getId() {
return id;
}
public Product setId(Long id) {
this.id = id;
return this;
}
public String getName() {
return name;
}
public Product setName(String name) {
this.name = name;
return this;
}
public Double getPrice() {
return price;
}
public Product setPrice(Double price) {
this.price = price;
return this;
}
public Double getCost() {
return cost;
}
public Product setCost(Double cost) {
this.cost = cost;
return this;
}
public String getSupplier() {
return supplier;
}
public Product setSupplier(String supplier) {
this.supplier = supplier;
return this;
}
@Override
public String toString() {
return "Product{"
+ "id=" + id
+ ", name='" + name + '\''
+ ", price=" + price
+ ", cost=" + cost
+ ", supplier='" + supplier + '\''
+ '}';
}
}

287
data-transfer-object/src/main/java/com/iluwatar/datatransfer/product/ProductDto.java Normal file
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@ -0,0 +1,287 @@
/*
* 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.product;
/**
* {@link ProductDto} is a data transfer object POJO.
* Instead of sending individual information to
* client We can send related information together in POJO.
*
* <p>Dto will not have any business logic in it.
*/
public enum ProductDto {
;
/**
* This is Request class which consist of Create or any other request DTO's
* you might want to use in your API.
*/
public enum Request {
;
/**
* This is Create dto class for requesting create new product.
*/
public static final class Create implements Name, Price, Cost, Supplier {
private String name;
private Double price;
private Double cost;
private String supplier;
@Override
public String getName() {
return name;
}
public Create setName(String name) {
this.name = name;
return this;
}
@Override
public Double getPrice() {
return price;
}
public Create setPrice(Double price) {
this.price = price;
return this;
}
@Override
public Double getCost() {
return cost;
}
public Create setCost(Double cost) {
this.cost = cost;
return this;
}
@Override
public String getSupplier() {
return supplier;
}
public Create setSupplier(String supplier) {
this.supplier = supplier;
return this;
}
}
}
/**
* This is Response class which consist of any response DTO's
* you might want to provide to your clients.
*/
public enum Response {
;
/**
* This is Public dto class for API response with the lowest data security.
*/
public static final class Public implements Id, Name, Price {
private Long id;
private String name;
private Double price;
@Override
public Long getId() {
return id;
}
public Public setId(Long id) {
this.id = id;
return this;
}
@Override
public String getName() {
return name;
}
public Public setName(String name) {
this.name = name;
return this;
}
@Override
public Double getPrice() {
return price;
}
public Public setPrice(Double price) {
this.price = price;
return this;
}
@Override
public String toString() {
return "Public{"
+ "id="
+ id
+ ", name='"
+ name
+ '\''
+ ", price="
+ price
+ '}';
}
}
/**
* This is Private dto class for API response with the highest data security.
*/
public static final class Private implements Id, Name, Price, Cost {
private Long id;
private String name;
private Double price;
private Double cost;
@Override
public Long getId() {
return id;
}
public Private setId(Long id) {
this.id = id;
return this;
}
@Override
public String getName() {
return name;
}
public Private setName(String name) {
this.name = name;
return this;
}
@Override
public Double getPrice() {
return price;
}
public Private setPrice(Double price) {
this.price = price;
return this;
}
@Override
public Double getCost() {
return cost;
}
public Private setCost(Double cost) {
this.cost = cost;
return this;
}
@Override
public String toString() {
return "Private{"
+
"id="
+ id
+
", name='"
+ name
+ '\''
+
", price="
+ price
+
", cost="
+ cost
+
'}';
}
}
}
/**
* Use this interface whenever you want to provide the product Id in your DTO.
*/
private interface Id {
/**
* Unique identifier of the product.
*
* @return : id of the product.
*/
Long getId();
}
/**
* Use this interface whenever you want to provide the product Name in your DTO.
*/
private interface Name {
/**
* The name of the product.
*
* @return : name of the product.
*/
String getName();
}
/**
* Use this interface whenever you want to provide the product Price in your DTO.
*/
private interface Price {
/**
* The amount we sell a product for.
* <b>This data is not confidential</b>
*
* @return : price of the product.
*/
Double getPrice();
}
/**
* Use this interface whenever you want to provide the product Cost in your DTO.
*/
private interface Cost {
/**
* The amount that it costs us to purchase this product
* For the amount we sell a product for, see the {@link Price Price} parameter.
* <b>This data is confidential</b>
*
* @return : cost of the product.
*/
Double getCost();
}
/**
* Use this interface whenever you want to provide the product Supplier in your DTO.
*/
private interface Supplier {
/**
* The name of supplier of the product or its manufacturer.
* <b>This data is highly confidential</b>
*
* @return : supplier of the product.
*/
String getSupplier();
}
}

94
data-transfer-object/src/main/java/com/iluwatar/datatransfer/product/ProductResource.java Normal file
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@ -0,0 +1,94 @@
/*
* 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.product;
import java.util.List;
import java.util.stream.Collectors;
/**
* The resource class which serves product information. This class act as server in the demo. Which
* has all product details.
*/
public class ProductResource {
private final List<Product> products;
/**
* Initialise resource with existing products.
*
* @param products initialize resource with existing products. Act as database.
*/
public ProductResource(final List<Product> products) {
this.products = products;
}
/**
* Get all products.
*
* @return : all products in list but in the scheme of private dto.
*/
public List<ProductDto.Response.Private> getAllProductsForAdmin() {
return products
.stream()
.map(p -> new ProductDto.Response.Private().setId(p.getId()).setName(p.getName())
.setCost(p.getCost())
.setPrice(p.getPrice()))
.collect(Collectors.toList());
}
/**
* Get all products.
*
* @return : all products in list but in the scheme of public dto.
*/
public List<ProductDto.Response.Public> getAllProductsForCustomer() {
return products
.stream()
.map(p -> new ProductDto.Response.Public().setId(p.getId()).setName(p.getName())
.setPrice(p.getPrice()))
.collect(Collectors.toList());
}
/**
* Save new product.
*
* @param createProductDto save new product to list.
*/
public void save(ProductDto.Request.Create createProductDto) {
products.add(new Product()
.setId((long) (products.size() + 1))
.setName(createProductDto.getName())
.setSupplier(createProductDto.getSupplier())
.setPrice(createProductDto.getPrice())
.setCost(createProductDto.getCost()));
}
/**
* List of all products in an entity representation.
*
* @return : all the products entity that stored in the products list
*/
public List<Product> getProducts() {
return products;
}
}

5
data-transfer-object/src/test/java/com/iluwatar/datatransfer/CustomerResourceTest.java → data-transfer-object/src/test/java/com/iluwatar/datatransfer/customer/CustomerResourceTest.java
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@ -21,13 +21,16 @@
* THE SOFTWARE.
*/
package com.iluwatar.datatransfer;
package com.iluwatar.datatransfer.customer;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertTrue;
import java.util.ArrayList;
import java.util.List;
import com.iluwatar.datatransfer.customer.CustomerDto;
import com.iluwatar.datatransfer.customer.CustomerResource;
import org.junit.jupiter.api.Test;
/**