Compare commits

..

7 Commits

30 changed files with 51 additions and 1469 deletions

View File

@ -1296,51 +1296,6 @@
"contributions": [
"doc"
]
},
{
"login": "omk13",
"name": "Omar Karazoun",
"avatar_url": "https://avatars0.githubusercontent.com/u/59054172?v=4",
"profile": "https://github.com/omk13",
"contributions": [
"code"
]
},
{
"login": "jeff303",
"name": "Jeff Evans",
"avatar_url": "https://avatars0.githubusercontent.com/u/3521562?v=4",
"profile": "https://github.com/jeff303",
"contributions": [
"code"
]
},
{
"login": "viveksb007",
"name": "Vivek Singh",
"avatar_url": "https://avatars1.githubusercontent.com/u/12713808?v=4",
"profile": "https://viveksb007.github.io",
"contributions": [
"code"
]
},
{
"login": "siavashsoleymani",
"name": "siavash",
"avatar_url": "https://avatars2.githubusercontent.com/u/18074419?v=4",
"profile": "https://github.com/siavashsoleymani",
"contributions": [
"code"
]
},
{
"login": "ruchpeanuts",
"name": "ruchpeanuts",
"avatar_url": "https://avatars0.githubusercontent.com/u/29301900?v=4",
"profile": "https://github.com/ruchpeanuts",
"contributions": [
"doc"
]
}
],
"contributorsPerLine": 4,

View File

@ -10,7 +10,7 @@
[![Coverage](https://sonarcloud.io/api/project_badges/measure?project=iluwatar_java-design-patterns&metric=coverage)](https://sonarcloud.io/dashboard?id=iluwatar_java-design-patterns)
[![Join the chat at https://gitter.im/iluwatar/java-design-patterns](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/iluwatar/java-design-patterns?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
<!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
[![All Contributors](https://img.shields.io/badge/all_contributors-147-orange.svg?style=flat-square)](#contributors-)
[![All Contributors](https://img.shields.io/badge/all_contributors-142-orange.svg?style=flat-square)](#contributors-)
<!-- ALL-CONTRIBUTORS-BADGE:END -->
# Introduction
@ -282,13 +282,6 @@ This project is licensed under the terms of the MIT license.
<tr>
<td align="center"><a href="https://ibrahimalii.github.io/"><img src="https://avatars2.githubusercontent.com/u/21141301?v=4" width="100px;" alt=""/><br /><sub><b>Ibrahim ali abdelghany</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3AibrahimAlii" title="Reviewed Pull Requests">👀</a></td>
<td align="center"><a href="https://github.com/gkulkarni2020"><img src="https://avatars3.githubusercontent.com/u/5161548?v=4" width="100px;" alt=""/><br /><sub><b>Girish Kulkarni</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=gkulkarni2020" title="Documentation">📖</a></td>
<td align="center"><a href="https://github.com/omk13"><img src="https://avatars0.githubusercontent.com/u/59054172?v=4" width="100px;" alt=""/><br /><sub><b>Omar Karazoun</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=omk13" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/jeff303"><img src="https://avatars0.githubusercontent.com/u/3521562?v=4" width="100px;" alt=""/><br /><sub><b>Jeff Evans</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=jeff303" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://viveksb007.github.io"><img src="https://avatars1.githubusercontent.com/u/12713808?v=4" width="100px;" alt=""/><br /><sub><b>Vivek Singh</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=viveksb007" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/siavashsoleymani"><img src="https://avatars2.githubusercontent.com/u/18074419?v=4" width="100px;" alt=""/><br /><sub><b>siavash</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=siavashsoleymani" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/ruchpeanuts"><img src="https://avatars0.githubusercontent.com/u/29301900?v=4" width="100px;" alt=""/><br /><sub><b>ruchpeanuts</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ruchpeanuts" title="Documentation">📖</a></td>
</tr>
</table>

View File

@ -1,54 +0,0 @@
---
layout: pattern
title: Data Transfer Object
folder: data-transfer-object
permalink: /patterns/data-transfer-object/
categories: Architectural
tags:
- Performance
---
## Intent
Pass data with multiple attributes in one shot from client to server, to avoid multiple calls to
remote server.
## Explanation
Real world example
> We need to fetch information about customers from remote database. Instead of querying the
> attributes one at a time, we use DTOs to transfer all the relevant attributes in a single shot.
In plain words
> Using DTO relevant information can be fetched with a single backend query.
Wikipedia says
> In the field of programming a data transfer object (DTO) is an object that carries data between
> processes. The motivation for its use is that communication between processes is usually done
> resorting to remote interfaces (e.g. web services), where each call is an expensive operation.
> Because the majority of the cost of each call is related to the round-trip time between the client
> and the server, one way of reducing the number of calls is to use an object (the DTO) that
> aggregates the data that would have been transferred by the several calls, but that is served by
> one call only.
## Class diagram
![alt text](./etc/dto-enum-uml.png "data-transfer-object")
## Applicability
Use the Data Transfer Object pattern when:
* The client is asking for multiple information. And the information is related.
* When you want to boost the performance to get resources.
* You want reduced number of remote calls.
## Credits
* [Design Pattern - Transfer Object Pattern](https://www.tutorialspoint.com/design_pattern/transfer_object_pattern.htm)
* [Data Transfer Object](https://msdn.microsoft.com/en-us/library/ff649585.aspx)
* [J2EE Design Patterns](https://www.amazon.com/gp/product/0596004273/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596004273&linkCode=as2&tag=javadesignpat-20&linkId=f27d2644fbe5026ea448791a8ad09c94)
* [Patterns of Enterprise Application Architecture](https://www.amazon.com/gp/product/0321127420/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0321127420&linkCode=as2&tag=javadesignpat-20&linkId=014237a67c9d46f384b35e10151956bd)

View File

@ -1,129 +0,0 @@
@startuml
package com.iluwatar.datatransferenum {
class App {
- LOGGER : Logger {static}
+ App()
+ main(args : String[]) {static}
}
class Product {
- cost : Double
- id : Long
- name : String
- price : Double
- supplier : String
+ Product()
+ getCost() : Double
+ getId() : Long
+ getName() : String
+ getPrice() : Double
+ getSupplier() : String
+ setCost(cost : Double) : Product
+ setId(id : Long) : Product
+ setName(name : String) : Product
+ setPrice(price : Double) : Product
+ setSupplier(supplier : String) : Product
+ toString() : String
}
enum ProductDTO {
+ valueOf(name : String) : ProductDTO {static}
+ values() : ProductDTO[] {static}
}
-interface Cost {
+ getCost() : Double {abstract}
}
-interface Id {
+ getId() : Long {abstract}
}
-interface Name {
+ getName() : String {abstract}
}
-interface Price {
+ getPrice() : Double {abstract}
}
enum Request {
+ valueOf(name : String) : Request {static}
+ values() : Request[] {static}
}
class Create {
- cost : Double
- name : String
- price : Double
- supplier : String
+ Create()
+ getCost() : Double
+ getName() : String
+ getPrice() : Double
+ getSupplier() : String
+ setCost(cost : Double) : Create
+ setName(name : String) : Create
+ setPrice(price : Double) : Create
+ setSupplier(supplier : String) : Create
}
enum Response {
+ valueOf(name : String) : Response {static}
+ values() : Response[] {static}
}
class Private {
- cost : Double
- id : Long
- name : String
- price : Double
+ Private()
+ getCost() : Double
+ getId() : Long
+ getName() : String
+ getPrice() : Double
+ setCost(cost : Double) : Private
+ setId(id : Long) : Private
+ setName(name : String) : Private
+ setPrice(price : Double) : Private
+ toString() : String
}
class Public {
- id : Long
- name : String
- price : Double
+ Public()
+ getId() : Long
+ getName() : String
+ getPrice() : Double
+ setId(id : Long) : Public
+ setName(name : String) : Public
+ setPrice(price : Double) : Public
+ toString() : String
}
-interface Supplier {
+ getSupplier() : String {abstract}
}
class ProductResource {
- products : List<Product>
+ ProductResource(products : List<Product>)
+ getAllProductsForAdmin() : List<Private>
+ getAllProductsForCustomer() : List<Public>
+ getProducts() : List<Product>
+ save(createProductDTO : Create)
}
}
Create ..+ Request
Request ..+ ProductDTO
Private ..+ Response
Supplier ..+ ProductDTO
Name ..+ ProductDTO
ProductResource --> "-products" Product
Public ..+ Response
Id ..+ ProductDTO
Price ..+ ProductDTO
Response ..+ ProductDTO
Cost ..+ ProductDTO
Create ..|> Name
Create ..|> Price
Create ..|> Cost
Create ..|> Supplier
Private ..|> Id
Private ..|> Name
Private ..|> Price
Private ..|> Cost
Public ..|> Id
Public ..|> Name
Public ..|> Price
@enduml

Binary file not shown.

Before

Width:  |  Height:  |  Size: 120 KiB

View File

@ -1,61 +0,0 @@
<?xml version="1.0" encoding="UTF-8"?>
<!--
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.
-->
<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.24.0-SNAPSHOT</version>
</parent>
<artifactId>data-transfer-object-enum-impl</artifactId>
<dependencies>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-engine</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<configuration>
<archive>
<manifest>
<mainClass>com.iluwatar.datatransferenum.App</mainClass>
</manifest>
</archive>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>

View File

@ -1,59 +0,0 @@
package com.iluwatar.datatransferenum;
import java.util.ArrayList;
import java.util.Arrays;
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 product details consumer i.e. client to
* request for product details to server.
*
* <p>productResource ({@link ProductResource}) act as server to serve product information. And
* The productDto ({@link ProductDto} is data transfer object to share product 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) {
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()));
}
}

View File

@ -1,91 +0,0 @@
package com.iluwatar.datatransferenum;
/**
* {@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 + '\''
+ '}';
}
}

View File

@ -1,264 +0,0 @@
package com.iluwatar.datatransferenum;
/**
* {@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();
}
}

View File

@ -1,71 +0,0 @@
package com.iluwatar.datatransferenum;
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;
}
}

View File

@ -1,44 +0,0 @@
/*
* 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.datatransferenum;
import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
import org.junit.jupiter.api.Test;
class AppTest {
/**
* Issue: Add at least one assertion to this test case.
* <p>
* Solution: Inserted assertion to check whether the execution of the main method in {@link App#main(String[])}
* throws an exception.
*/
@Test
void shouldExecuteApplicationWithoutException() {
assertDoesNotThrow(() -> App.main(new String[] {}));
}
}

View File

@ -98,7 +98,7 @@ Now on the client code we can create different types of cars using the factory c
var car1 = CarsFactory.getCar(CarType.FORD);
var car2 = CarsFactory.getCar(CarType.FERRARI);
LOGGER.info(car1.getDescription());
LOGGER.info(car2.getDescription());
LOGGER.info(car2.getDescription());;
```
Program output:
@ -126,16 +126,6 @@ Cons
* The code becomes more complicated than it should be.
## Real world examples
* [java.util.Calendar#getInstance()](https://docs.oracle.com/javase/8/docs/api/java/util/Calendar.html#getInstance--)
* [java.util.ResourceBundle#getBundle()](https://docs.oracle.com/javase/8/docs/api/java/util/ResourceBundle.html#getBundle-java.lang.String-)
* [java.text.NumberFormat#getInstance()](https://docs.oracle.com/javase/8/docs/api/java/text/NumberFormat.html#getInstance--)
* [java.nio.charset.Charset#forName()](https://docs.oracle.com/javase/8/docs/api/java/nio/charset/Charset.html#forName-java.lang.String-)
* [java.net.URLStreamHandlerFactory#createURLStreamHandler(String)](https://docs.oracle.com/javase/8/docs/api/java/net/URLStreamHandlerFactory.html) (Returns different singleton objects, depending on a protocol)
* [java.util.EnumSet#of()](https://docs.oracle.com/javase/8/docs/api/java/util/EnumSet.html#of(E))
* [javax.xml.bind.JAXBContext#createMarshaller()](https://docs.oracle.com/javase/8/docs/api/javax/xml/bind/JAXBContext.html#createMarshaller--) and other similar methods.
## Related patterns
* [Factory Method](https://java-design-patterns.com/patterns/factory-method/)

View File

@ -23,7 +23,7 @@
package com.iluwatar.gameloop;
import org.junit.jupiter.api.Test;
import org.junit.Test;
import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;

View File

@ -23,11 +23,10 @@
package com.iluwatar.gameloop;
import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
/**
* FixedStepGameLoop unit test class.
@ -36,12 +35,12 @@ public class FixedStepGameLoopTest {
private FixedStepGameLoop gameLoop;
@BeforeEach
@Before
public void setup() {
gameLoop = new FixedStepGameLoop();
}
@AfterEach
@After
public void tearDown() {
gameLoop = null;
}
@ -49,7 +48,7 @@ public class FixedStepGameLoopTest {
@Test
public void testUpdate() {
gameLoop.update();
assertEquals(0.01f, gameLoop.controller.getBulletPosition(), 0);
Assert.assertEquals(0.01f, gameLoop.controller.getBulletPosition(), 0);
}
}

View File

@ -23,10 +23,10 @@
package com.iluwatar.gameloop;
import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
/**
* FrameBasedGameLoop unit test class.
@ -35,19 +35,19 @@ public class FrameBasedGameLoopTest {
private FrameBasedGameLoop gameLoop;
@BeforeEach
@Before
public void setup() {
gameLoop = new FrameBasedGameLoop();
}
@AfterEach
@After
public void tearDown() {
gameLoop = null;
}
@org.junit.jupiter.api.Test
@Test
public void testUpdate() {
gameLoop.update();
assertEquals(0.5f, gameLoop.controller.getBulletPosition(), 0);
Assert.assertEquals(0.5f, gameLoop.controller.getBulletPosition(), 0);
}
}

View File

@ -23,33 +23,34 @@
package com.iluwatar.gameloop;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
public class GameControllerTest {
private GameController controller;
@BeforeEach
@Before
public void setup() {
controller = new GameController();
}
@AfterEach
@After
public void tearDown() {
controller = null;
}
@org.junit.jupiter.api.Test
@Test
public void testMoveBullet() {
controller.moveBullet(1.5f);
Assertions.assertEquals(1.5f, controller.bullet.getPosition(), 0);
Assert.assertEquals(1.5f, controller.bullet.getPosition(), 0);
}
@org.junit.jupiter.api.Test
@Test
public void testGetBulletPosition() {
Assertions.assertEquals(controller.bullet.getPosition(), controller.getBulletPosition(), 0);
Assert.assertEquals(controller.bullet.getPosition(), controller.getBulletPosition(), 0);
}
}

View File

@ -23,9 +23,10 @@
package com.iluwatar.gameloop;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.BeforeEach;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
/**
* GameLoop unit test class.
@ -37,7 +38,7 @@ public class GameLoopTest {
/**
* Create mock implementation of GameLoop.
*/
@BeforeEach
@Before
public void setup() {
gameLoop = new GameLoop() {
@Override
@ -45,26 +46,26 @@ public class GameLoopTest {
};
}
@AfterEach
@After
public void tearDown() {
gameLoop = null;
}
@org.junit.jupiter.api.Test
@Test
public void testRun() {
gameLoop.run();
Assertions.assertEquals(GameStatus.RUNNING, gameLoop.status);
Assert.assertEquals(GameStatus.RUNNING, gameLoop.status);
}
@org.junit.jupiter.api.Test
@Test
public void testStop() {
gameLoop.stop();
Assertions.assertEquals(GameStatus.STOPPED, gameLoop.status);
Assert.assertEquals(GameStatus.STOPPED, gameLoop.status);
}
@org.junit.jupiter.api.Test
@Test
public void testIsGameRunning() {
Assertions.assertFalse(gameLoop.isGameRunning());
Assert.assertFalse(gameLoop.isGameRunning());
}
}

View File

@ -23,9 +23,11 @@
package com.iluwatar.gameloop;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
import java.lang.reflect.InvocationTargetException;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
/**
* VariableStepGameLoop unit test class.
@ -34,19 +36,19 @@ public class VariableStepGameLoopTest {
private VariableStepGameLoop gameLoop;
@BeforeEach
@Before
public void setup() {
gameLoop = new VariableStepGameLoop();
}
@AfterEach
@After
public void tearDown() {
gameLoop = null;
}
@org.junit.jupiter.api.Test
@Test
public void testUpdate() {
gameLoop.update(20L);
Assertions.assertEquals(0.01f, gameLoop.controller.getBulletPosition(), 0);
Assert.assertEquals(0.01f, gameLoop.controller.getBulletPosition(), 0);
}
}

View File

@ -195,11 +195,9 @@
<module>strangler</module>
<module>arrange-act-assert</module>
<module>transaction-script</module>
<module>registry</module>
<module>filterer</module>
<module>factory</module>
<module>separated-interface</module>
<module>data-transfer-object-enum-impl</module>
</modules>
<repositories>

View File

@ -1,86 +0,0 @@
---
layout: pattern
title: Registry
folder: registry
permalink: /patterns/registry/
categories: Creational
tags:
- Instantiation
---
## Intent
Stores the objects of a single class and provide a global point of access to them.
Similar to Multiton pattern, only difference is that in a registry there is no restriction on the number of objects.
## Explanation
In Plain Words
> Registry is a well-known object that other objects can use to find common objects and services.
**Programmatic Example**
Below is a `Customer` Class
```java
public class Customer {
private final String id;
private final String name;
public Customer(String id, String name) {
this.id = id;
this.name = name;
}
public String getId() {
return id;
}
public String getName() {
return name;
}
}
```
This registry of the `Customer` objects is `CustomerRegistry`
```java
public final class CustomerRegistry {
private static final CustomerRegistry instance = new CustomerRegistry();
public static CustomerRegistry getInstance() {
return instance;
}
private final Map<String, Customer> customerMap;
private CustomerRegistry() {
customerMap = new ConcurrentHashMap<>();
}
public Customer addCustomer(Customer customer) {
return customerMap.put(customer.getId(), customer);
}
public Customer getCustomer(String id) {
return customerMap.get(id);
}
}
```
## Class diagram
![Registry](./etc/registry.png)
## Applicability
Use Registry pattern when
* client wants reference of some object, so client can lookup for that object in the object's registry.
## Consequences
Large number of bulky objects added to registry would result in a lot of memory consumption as objects in the registry are not garbage collected.
## Credits
* https://www.martinfowler.com/eaaCatalog/registry.html
* https://wiki.c2.com/?RegistryPattern

Binary file not shown.

Before

Width:  |  Height:  |  Size: 16 KiB

View File

@ -1,21 +0,0 @@
@startuml
package com.iluwatar.registry {
class App {
- LOGGER : Logger {static}
+ App()
+ main(args : String[]) {static}
}
class Customer {
- id : String
- name : String
+ getId() : String
+ getName() : String
+ toString() : String
}
class CustomerRegistry {
+ addCustomer(customer : Customer)
+ getCustomer(id : String)
}
}
Customer --> "-addCustomer" CustomerRegistry
@enduml

View File

@ -1,46 +0,0 @@
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.24.0-SNAPSHOT</version>
</parent>
<artifactId>registry</artifactId>
<dependencies>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-engine</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<configuration>
<archive>
<manifest>
<mainClass>com.iluwatar.registry.App</mainClass>
</manifest>
</archive>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>

View File

@ -1,27 +0,0 @@
package com.iluwatar.registry;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class App {
private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
/**
* Program entry point.
*
* @param args command line args
*/
public static void main(String[] args) {
CustomerRegistry customerRegistry = CustomerRegistry.getInstance();
var john = new Customer("1", "John");
customerRegistry.addCustomer(john);
var julia = new Customer("2", "Julia");
customerRegistry.addCustomer(julia);
LOGGER.info("John {}", customerRegistry.getCustomer("1"));
LOGGER.info("Julia {}", customerRegistry.getCustomer("2"));
}
}

View File

@ -1,28 +0,0 @@
package com.iluwatar.registry;
public class Customer {
private final String id;
private final String name;
public Customer(String id, String name) {
this.id = id;
this.name = name;
}
public String getId() {
return id;
}
public String getName() {
return name;
}
@Override
public String toString() {
return "Customer{"
+ "id='" + id + '\''
+ ", name='" + name + '\''
+ '}';
}
}

View File

@ -1,28 +0,0 @@
package com.iluwatar.registry;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
public final class CustomerRegistry {
private static final CustomerRegistry instance = new CustomerRegistry();
public static CustomerRegistry getInstance() {
return instance;
}
private final Map<String, Customer> customerMap;
private CustomerRegistry() {
customerMap = new ConcurrentHashMap<>();
}
public Customer addCustomer(Customer customer) {
return customerMap.put(customer.getId(), customer);
}
public Customer getCustomer(String id) {
return customerMap.get(id);
}
}

View File

@ -1,44 +0,0 @@
package com.iluwatar.registry;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertNull;
public class CustomerRegistryTest {
private static CustomerRegistry customerRegistry;
@BeforeAll
public static void setUp() {
customerRegistry = CustomerRegistry.getInstance();
}
@Test
public void shouldBeAbleToAddAndQueryCustomerObjectFromRegistry() {
Customer john = new Customer("1", "john");
Customer julia = new Customer("2", "julia");
customerRegistry.addCustomer(john);
customerRegistry.addCustomer(julia);
Customer customerWithId1 = customerRegistry.getCustomer("1");
assertNotNull(customerWithId1);
assertEquals("1", customerWithId1.getId());
assertEquals("john", customerWithId1.getName());
Customer customerWithId2 = customerRegistry.getCustomer("2");
assertNotNull(customerWithId2);
assertEquals("2", customerWithId2.getId());
assertEquals("julia", customerWithId2.getName());
}
@Test
public void shouldReturnNullWhenQueriedCustomerIsNotInRegistry() {
Customer customerWithId5 = customerRegistry.getCustomer("5");
assertNull(customerWithId5);
}
}

View File

@ -1,205 +0,0 @@
---
layout: pattern
title: Bridge
folder: bridge
permalink: /patterns/bridge/
categories: Structural
tags:
- Gang of Four
---
## 又被称为
手柄/身体模式
## 目的
将抽象与其实现分离,以便二者可以独立变化。
## 解释
真实世界例子
> 考虑一下你拥有一种具有不同附魔的武器,并且应该允许将具有不同附魔的不同武器混合使用。 你会怎么做? 为每个附魔创建每种武器的多个副本,还是只是创建单独的附魔并根据需要为武器设置它? 桥接模式使您可以进行第二次操作。
通俗的说
> 桥接模式是一个更推荐组合而不是继承的模式。将实现细节从一个层次结构推送到具有单独层次结构的另一个对象。
维基百科说
> 桥接模式是软件工程中使用的一种设计模式,旨在“将抽象与其实现分离,从而使两者可以独立变化”
**程序示例**
翻译一下上面的武器示例。下面我们有武器的类层级:
```java
public interface Weapon {
void wield();
void swing();
void unwield();
Enchantment getEnchantment();
}
public class Sword implements Weapon {
private final Enchantment enchantment;
public Sword(Enchantment enchantment) {
this.enchantment = enchantment;
}
@Override
public void wield() {
LOGGER.info("The sword is wielded.");
enchantment.onActivate();
}
@Override
public void swing() {
LOGGER.info("The sword is swinged.");
enchantment.apply();
}
@Override
public void unwield() {
LOGGER.info("The sword is unwielded.");
enchantment.onDeactivate();
}
@Override
public Enchantment getEnchantment() {
return enchantment;
}
}
public class Hammer implements Weapon {
private final Enchantment enchantment;
public Hammer(Enchantment enchantment) {
this.enchantment = enchantment;
}
@Override
public void wield() {
LOGGER.info("The hammer is wielded.");
enchantment.onActivate();
}
@Override
public void swing() {
LOGGER.info("The hammer is swinged.");
enchantment.apply();
}
@Override
public void unwield() {
LOGGER.info("The hammer is unwielded.");
enchantment.onDeactivate();
}
@Override
public Enchantment getEnchantment() {
return enchantment;
}
}
```
这里是单独的附魔类结构:
```java
public interface Enchantment {
void onActivate();
void apply();
void onDeactivate();
}
public class FlyingEnchantment implements Enchantment {
@Override
public void onActivate() {
LOGGER.info("The item begins to glow faintly.");
}
@Override
public void apply() {
LOGGER.info("The item flies and strikes the enemies finally returning to owner's hand.");
}
@Override
public void onDeactivate() {
LOGGER.info("The item's glow fades.");
}
}
public class SoulEatingEnchantment implements Enchantment {
@Override
public void onActivate() {
LOGGER.info("The item spreads bloodlust.");
}
@Override
public void apply() {
LOGGER.info("The item eats the soul of enemies.");
}
@Override
public void onDeactivate() {
LOGGER.info("Bloodlust slowly disappears.");
}
}
```
这里是两种层次结构的实践:
```java
var enchantedSword = new Sword(new SoulEatingEnchantment());
enchantedSword.wield();
enchantedSword.swing();
enchantedSword.unwield();
// The sword is wielded.
// The item spreads bloodlust.
// The sword is swinged.
// The item eats the soul of enemies.
// The sword is unwielded.
// Bloodlust slowly disappears.
var hammer = new Hammer(new FlyingEnchantment());
hammer.wield();
hammer.swing();
hammer.unwield();
// The hammer is wielded.
// The item begins to glow faintly.
// The hammer is swinged.
// The item flies and strikes the enemies finally returning to owner's hand.
// The hammer is unwielded.
// The item's glow fades.
```
## 类图
![alt text](../../bridge/etc/bridge.urm.png "Bridge class diagram")
## 适用性
使用桥接模式当
* 你想永久性的避免抽象和他的实现之间的绑定。有可能是这种情况,当实现需要被选择或者在运行时切换。
* 抽象和他们的实现应该能通过写子类来扩展。这种情况下,桥接模式让你可以组合不同的抽象和实现并独立的扩展他们。
* 对抽象的实现的改动应当不会对客户产生影响;也就是说,他们的代码不必重新编译。
* 你有种类繁多的类。这样的类层次结构表明需要将一个对象分为两部分。Rumbaugh 使用术语“嵌套归纳”来指代这种类层次结构。
* 你想在多个对象间分享一种实现可能使用引用计数这个事实应该对客户隐藏。一个简单的示例是Coplien的String类其中多个对象可以共享同一字符串表示形式
## 教程
* [Bridge Pattern Tutorial](https://www.journaldev.com/1491/bridge-design-pattern-java)
## 鸣谢
* [Design Patterns: Elements of Reusable Object-Oriented Software](https://www.amazon.com/gp/product/0201633612/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0201633612&linkCode=as2&tag=javadesignpat-20&linkId=675d49790ce11db99d90bde47f1aeb59)
* [Head First Design Patterns: A Brain-Friendly Guide](https://www.amazon.com/gp/product/0596007124/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596007124&linkCode=as2&tag=javadesignpat-20&linkId=6b8b6eea86021af6c8e3cd3fc382cb5b)

View File

@ -33,6 +33,8 @@ tags:
以巨魔的为例。首先我有有一个简单的巨魔,实现了巨魔接口。
程序mple. First of all we have a simple troll implementing the troll interface
```java
public interface Troll {
void attack();

View File

@ -1,101 +0,0 @@
---
layout: pattern
title: Dependency Injection
folder: dependency-injection
permalink: /patterns/dependency-injection/
categories: Creational
tags:
- Decoupling
---
## 目的
依赖注入是一种软件设计模式,其中一个或多个依赖项(或服务)被注入或通过引用传递到一个依赖对象(或客户端)中,并成为客户端状态的一部分。该模式将客户的依赖关系的创建与其自身的行为分开,这使程序设计可以松散耦合,并遵循控制反转和单一职责原则。
## 解释
真实世界例子
> 老巫师喜欢不时地装满烟斗抽烟。 但是,他不想只依赖一个烟草品牌,而是希望能够互换使用它们。
通俗的说
> 依赖注入将客户端依赖的创建与其自身行为分开。
维基百科说
> 在软件工程中,依赖注入是一种对象接收其依赖的其他对象的技术。 这些其他对象称为依赖项。
**程序示例**
先介绍一下烟草接口和具体的品牌。
```java
public abstract class Tobacco {
private static final Logger LOGGER = LoggerFactory.getLogger(Tobacco.class);
public void smoke(Wizard wizard) {
LOGGER.info("{} smoking {}", wizard.getClass().getSimpleName(),
this.getClass().getSimpleName());
}
}
public class SecondBreakfastTobacco extends Tobacco {
}
public class RivendellTobacco extends Tobacco {
}
public class OldTobyTobacco extends Tobacco {
}
```
下面是老巫师的类的层次结构。
```java
public interface Wizard {
void smoke();
}
public class AdvancedWizard implements Wizard {
private final Tobacco tobacco;
public AdvancedWizard(Tobacco tobacco) {
this.tobacco = tobacco;
}
@Override
public void smoke() {
tobacco.smoke(this);
}
}
```
最后我们可以看到给老巫师任意品牌的烟草是多么的简单。
```java
var advancedWizard = new AdvancedWizard(new SecondBreakfastTobacco());
advancedWizard.smoke();
```
## 类图
![alt text](../../dependency-injection/etc/dependency-injection.png "Dependency Injection")
## 适用性
使用依赖注入当:
- 当你需要从对象中移除掉具体的实现内容时
* 使用模拟对象或存根隔离地启用类的单元测试
## 鸣谢
* [Dependency Injection Principles, Practices, and Patterns](https://www.amazon.com/gp/product/161729473X/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=javadesignpat-20&creative=9325&linkCode=as2&creativeASIN=161729473X&linkId=57079257a5c7d33755493802f3b884bd)
* [Clean Code: A Handbook of Agile Software Craftsmanship](https://www.amazon.com/gp/product/0132350882/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0132350882&linkCode=as2&tag=javadesignpat-20&linkId=2c390d89cc9e61c01b9e7005c7842871)
* [Java 9 Dependency Injection: Write loosely coupled code with Spring 5 and Guice](https://www.amazon.com/gp/product/1788296257/ref=as_li_tl?ie=UTF8&tag=javadesignpat-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=1788296257&linkId=4e9137a3bf722a8b5b156cce1eec0fc1)
* [Google Guice Tutorial: Open source Java based dependency injection framework](https://www.amazon.com/gp/product/B083P7DZ8M/ref=as_li_tl?ie=UTF8&tag=javadesignpat-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=B083P7DZ8M&linkId=04f0f902c877921e45215b624a124bfe)