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refactorUn
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updateThro
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| f003844c25 |
@ -1776,15 +1776,6 @@
|
||||
"contributions": [
|
||||
"code"
|
||||
]
|
||||
},
|
||||
{
|
||||
"login": "castleKing1997",
|
||||
"name": "DragonDreamer",
|
||||
"avatar_url": "https://avatars.githubusercontent.com/u/35420129?v=4",
|
||||
"profile": "http://rosaecrucis.cn",
|
||||
"contributions": [
|
||||
"code"
|
||||
]
|
||||
}
|
||||
],
|
||||
"contributorsPerLine": 7,
|
||||
|
||||
@ -10,7 +10,7 @@
|
||||
[](https://sonarcloud.io/dashboard?id=iluwatar_java-design-patterns)
|
||||
[](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 -->
|
||||
[](#contributors-)
|
||||
[](#contributors-)
|
||||
<!-- ALL-CONTRIBUTORS-BADGE:END -->
|
||||
|
||||
<br/>
|
||||
@ -325,7 +325,6 @@ This project is licensed under the terms of the MIT license.
|
||||
<td align="center"><a href="https://github.com/interactwithankush"><img src="https://avatars.githubusercontent.com/u/18613127?v=4?s=100" width="100px;" alt=""/><br /><sub><b>interactwithankush</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=interactwithankush" title="Code">💻</a></td>
|
||||
<td align="center"><a href="https://github.com/yuhangbin"><img src="https://avatars.githubusercontent.com/u/17566866?v=4?s=100" width="100px;" alt=""/><br /><sub><b>CharlieYu</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=yuhangbin" title="Code">💻</a></td>
|
||||
<td align="center"><a href="https://github.com/Leisterbecker"><img src="https://avatars.githubusercontent.com/u/20650323?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Leisterbecker</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Leisterbecker" title="Code">💻</a></td>
|
||||
<td align="center"><a href="http://rosaecrucis.cn"><img src="https://avatars.githubusercontent.com/u/35420129?v=4?s=100" width="100px;" alt=""/><br /><sub><b>DragonDreamer</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=castleKing1997" title="Code">💻</a></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
|
||||
@ -1,182 +0,0 @@
|
||||
---
|
||||
layout: pattern
|
||||
title: Metadata Mapping
|
||||
folder: metadata-mapping
|
||||
permalink: /patterns/metadata-mapping/
|
||||
categories: Architectural
|
||||
language: en
|
||||
tags:
|
||||
- Data access
|
||||
---
|
||||
|
||||
## Intent
|
||||
|
||||
Holds details of object-relational mapping in the metadata.
|
||||
|
||||
## Explanation
|
||||
|
||||
Real world example
|
||||
|
||||
> Hibernate ORM Tool uses Metadata Mapping Pattern to specify the mapping between classes and tables either using XML or annotations in code.
|
||||
|
||||
In plain words
|
||||
|
||||
> Metadata Mapping specifies the mapping between classes and tables so that we could treat a table of any database like a Java class.
|
||||
|
||||
Wikipedia says
|
||||
|
||||
> Create a "virtual [object database](https://en.wikipedia.org/wiki/Object_database)" that can be used from within the programming language.
|
||||
|
||||
**Programmatic Example**
|
||||
|
||||
We give an example about visiting the information of `USER` table in `h2` database. Firstly, we create `USER` table with `h2`:
|
||||
|
||||
```java
|
||||
@Slf4j
|
||||
public class DatabaseUtil {
|
||||
private static final String DB_URL = "jdbc:h2:mem:metamapping";
|
||||
private static final String CREATE_SCHEMA_SQL = "DROP TABLE IF EXISTS `user`;"
|
||||
+ "CREATE TABLE `user` (\n"
|
||||
+ " `id` int(11) NOT NULL AUTO_INCREMENT,\n"
|
||||
+ " `username` varchar(255) NOT NULL,\n"
|
||||
+ " `password` varchar(255) NOT NULL,\n"
|
||||
+ " PRIMARY KEY (`id`)\n"
|
||||
+ ");";
|
||||
|
||||
/**
|
||||
* Create database.
|
||||
*/
|
||||
static {
|
||||
LOGGER.info("create h2 database");
|
||||
var source = new JdbcDataSource();
|
||||
source.setURL(DB_URL);
|
||||
try (var statement = source.getConnection().createStatement()) {
|
||||
statement.execute(CREATE_SCHEMA_SQL);
|
||||
} catch (SQLException e) {
|
||||
LOGGER.error("unable to create h2 data source", e);
|
||||
}
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Correspondingly, here's the basic `User` entity.
|
||||
|
||||
```java
|
||||
@Setter
|
||||
@Getter
|
||||
@ToString
|
||||
public class User {
|
||||
private Integer id;
|
||||
private String username;
|
||||
private String password;
|
||||
|
||||
/**
|
||||
* Get a user.
|
||||
* @param username user name
|
||||
* @param password user password
|
||||
*/
|
||||
public User(String username, String password) {
|
||||
this.username = username;
|
||||
this.password = password;
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Then we write a `xml` file to show the mapping between the table and the object:
|
||||
|
||||
```xml
|
||||
<?xml version="1.0" encoding="utf-8"?>
|
||||
<!DOCTYPE hibernate-mapping PUBLIC
|
||||
"-//Hibernate/Hibernate Mapping DTD//EN"
|
||||
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
|
||||
|
||||
<hibernate-mapping>
|
||||
<class name="com.iluwatar.metamapping.model.User" table="user">
|
||||
<id name="id" type="java.lang.Integer" column="id">
|
||||
<generator class="native"/>
|
||||
</id>
|
||||
<property name="username" column="username" type="java.lang.String"/>
|
||||
<property name="password" column="password" type="java.lang.String"/>
|
||||
</class>
|
||||
</hibernate-mapping>
|
||||
```
|
||||
|
||||
We use `Hibernate` to resolve the mapping and connect to our database, here's its configuration:
|
||||
|
||||
```xml
|
||||
<?xml version="1.0" encoding="utf-8"?>
|
||||
<!DOCTYPE hibernate-configuration PUBLIC
|
||||
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
|
||||
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
|
||||
<hibernate-configuration>
|
||||
<session-factory>
|
||||
<!-- JDBC Database connection settings -->
|
||||
<property name="connection.url">jdbc:h2:mem:metamapping</property>
|
||||
<property name="connection.driver_class">org.h2.Driver</property>
|
||||
<!-- JDBC connection pool settings ... using built-in test pool -->
|
||||
<property name="connection.pool_size">1</property>
|
||||
<!-- Select our SQL dialect -->
|
||||
<property name="dialect">org.hibernate.dialect.H2Dialect</property>
|
||||
<!-- Echo the SQL to stdout -->
|
||||
<property name="show_sql">false</property>
|
||||
<!-- Drop and re-create the database schema on startup -->
|
||||
<property name="hbm2ddl.auto">create-drop</property>
|
||||
<mapping resource="com/iluwatar/metamapping/model/User.hbm.xml" />
|
||||
</session-factory>
|
||||
</hibernate-configuration>
|
||||
```
|
||||
|
||||
Then we can get access to the table just like an object with `Hibernate`, here's some CRUDs:
|
||||
|
||||
```java
|
||||
@Slf4j
|
||||
public class UserService {
|
||||
private static final SessionFactory factory = HibernateUtil.getSessionFactory();
|
||||
|
||||
/**
|
||||
* List all users.
|
||||
* @return list of users
|
||||
*/
|
||||
public List<User> listUser() {
|
||||
LOGGER.info("list all users.");
|
||||
List<User> users = new ArrayList<>();
|
||||
try (var session = factory.openSession()) {
|
||||
var tx = session.beginTransaction();
|
||||
List<User> userIter = session.createQuery("FROM User").list();
|
||||
for (var iterator = userIter.iterator(); iterator.hasNext();) {
|
||||
users.add(iterator.next());
|
||||
}
|
||||
tx.commit();
|
||||
} catch (HibernateException e) {
|
||||
LOGGER.debug("fail to get users", e);
|
||||
}
|
||||
return users;
|
||||
}
|
||||
|
||||
// other CRUDs ->
|
||||
...
|
||||
|
||||
public void close() {
|
||||
HibernateUtil.shutdown();
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
## Class diagram
|
||||
|
||||
|
||||
|
||||
## Applicability
|
||||
|
||||
Use the Metadata Mapping when:
|
||||
|
||||
- you want reduce the amount of work needed to handle database mapping.
|
||||
|
||||
## Known uses
|
||||
|
||||
[Hibernate](https://hibernate.org/), [EclipseLink](https://www.eclipse.org/eclipselink/), [MyBatis](https://blog.mybatis.org/)......
|
||||
|
||||
## Credits
|
||||
|
||||
- [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=48d37c67fb3d845b802fa9b619ad8f31)
|
||||
|
||||
Binary file not shown.
|
Before Width: | Height: | Size: 49 KiB |
@ -1,32 +0,0 @@
|
||||
@startuml
|
||||
interface com.iluwatar.metamapping.service.UserService {
|
||||
+ List<User> listUser()
|
||||
+ int createUser(User)
|
||||
+ void updateUser(Integer,User)
|
||||
+ void deleteUser(Integer)
|
||||
+ User getUser(Integer)
|
||||
+ void close()
|
||||
}
|
||||
class com.iluwatar.metamapping.utils.DatabaseUtil {
|
||||
+ {static} void createDataSource()
|
||||
}
|
||||
class com.iluwatar.metamapping.model.User {
|
||||
- Integer id
|
||||
- String username
|
||||
- String password
|
||||
+ User(String username, String password)
|
||||
}
|
||||
class com.iluwatar.metamapping.utils.HibernateUtil {
|
||||
+ {static} SessionFactory getSessionFactory()
|
||||
+ {static} void shutdown()
|
||||
}
|
||||
class com.iluwatar.metamapping.App {
|
||||
+ {static} void main(String[])
|
||||
+ {static} List<User> generateSampleUsers()
|
||||
}
|
||||
|
||||
com.iluwatar.metamapping.service.UserService <.. com.iluwatar.metamapping.App
|
||||
com.iluwatar.metamapping.model.User <.. com.iluwatar.metamapping.service.UserService
|
||||
com.iluwatar.metamapping.utils.HibernateUtil <.. com.iluwatar.metamapping.service.UserService
|
||||
com.iluwatar.metamapping.utils.DatabaseUtil <-- com.iluwatar.metamapping.utils.HibernateUtil
|
||||
@enduml
|
||||
@ -1,87 +0,0 @@
|
||||
<?xml version="1.0" encoding="UTF-8"?>
|
||||
<!--
|
||||
|
||||
The MIT License
|
||||
Copyright © 2014-2021 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="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">
|
||||
<parent>
|
||||
<artifactId>java-design-patterns</artifactId>
|
||||
<groupId>com.iluwatar</groupId>
|
||||
<version>1.26.0-SNAPSHOT</version>
|
||||
</parent>
|
||||
<modelVersion>4.0.0</modelVersion>
|
||||
|
||||
<artifactId>metadata-mapping</artifactId>
|
||||
<dependencies>
|
||||
<dependency>
|
||||
<groupId>org.junit.jupiter</groupId>
|
||||
<artifactId>junit-jupiter-engine</artifactId>
|
||||
<scope>test</scope>
|
||||
</dependency>
|
||||
<dependency>
|
||||
<groupId>com.h2database</groupId>
|
||||
<artifactId>h2</artifactId>
|
||||
</dependency>
|
||||
<dependency>
|
||||
<groupId>org.hibernate</groupId>
|
||||
<artifactId>hibernate-core</artifactId>
|
||||
</dependency>
|
||||
<dependency>
|
||||
<groupId>com.h2database</groupId>
|
||||
<artifactId>h2</artifactId>
|
||||
</dependency>
|
||||
<dependency>
|
||||
<groupId>javax.xml.bind</groupId>
|
||||
<artifactId>jaxb-api</artifactId>
|
||||
</dependency>
|
||||
<dependency>
|
||||
<groupId>com.sun.xml.bind</groupId>
|
||||
<artifactId>jaxb-impl</artifactId>
|
||||
</dependency>
|
||||
<dependency>
|
||||
<groupId>com.sun.istack</groupId>
|
||||
<artifactId>istack-commons-runtime</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.metamapping.App</mainClass>
|
||||
</manifest>
|
||||
</archive>
|
||||
</configuration>
|
||||
</execution>
|
||||
</executions>
|
||||
</plugin>
|
||||
</plugins>
|
||||
</build>
|
||||
</project>
|
||||
@ -1,72 +0,0 @@
|
||||
package com.iluwatar.metamapping;
|
||||
|
||||
import com.iluwatar.metamapping.model.User;
|
||||
import com.iluwatar.metamapping.service.UserService;
|
||||
import com.iluwatar.metamapping.utils.DatabaseUtil;
|
||||
import java.util.List;
|
||||
import lombok.extern.slf4j.Slf4j;
|
||||
import org.hibernate.service.ServiceRegistry;
|
||||
|
||||
/**
|
||||
* Metadata Mapping specifies the mapping
|
||||
* between classes and tables so that
|
||||
* we could treat a table of any database like a Java class.
|
||||
*
|
||||
* <p>With hibernate, we achieve list/create/update/delete/get operations:
|
||||
* 1)Create the H2 Database in {@link DatabaseUtil}.
|
||||
* 2)Hibernate resolve hibernate.cfg.xml and generate service like save/list/get/delete.
|
||||
* For learning metadata mapping pattern, we go deeper into Hibernate here:
|
||||
* a)read properties from hibernate.cfg.xml and mapping from *.hbm.xml
|
||||
* b)create session factory to generate session interacting with database
|
||||
* c)generate session with factory pattern
|
||||
* d)create query object or use basic api with session,
|
||||
* hibernate will convert all query to database query according to metadata
|
||||
* 3)We encapsulate hibernate service in {@link UserService} for our use.
|
||||
* @see org.hibernate.cfg.Configuration#configure(String)
|
||||
* @see org.hibernate.cfg.Configuration#buildSessionFactory(ServiceRegistry)
|
||||
* @see org.hibernate.internal.SessionFactoryImpl#openSession()
|
||||
*/
|
||||
@Slf4j
|
||||
public class App {
|
||||
/**
|
||||
* Program entry point.
|
||||
*
|
||||
* @param args command line args.
|
||||
* @throws Exception if any error occurs.
|
||||
*/
|
||||
public static void main(String[] args) throws Exception {
|
||||
// get service
|
||||
var userService = new UserService();
|
||||
// use create service to add users
|
||||
for (var user: generateSampleUsers()) {
|
||||
var id = userService.createUser(user);
|
||||
LOGGER.info("Add user" + user + "at" + id + ".");
|
||||
}
|
||||
// use list service to get users
|
||||
var users = userService.listUser();
|
||||
LOGGER.info(String.valueOf(users));
|
||||
// use get service to get a user
|
||||
var user = userService.getUser(1);
|
||||
LOGGER.info(String.valueOf(user));
|
||||
// change password of user 1
|
||||
user.setPassword("new123");
|
||||
// use update service to update user 1
|
||||
userService.updateUser(1, user);
|
||||
// use delete service to delete user 2
|
||||
userService.deleteUser(2);
|
||||
// close service
|
||||
userService.close();
|
||||
}
|
||||
|
||||
/**
|
||||
* Generate users.
|
||||
*
|
||||
* @return list of users.
|
||||
*/
|
||||
public static List<User> generateSampleUsers() {
|
||||
final var user1 = new User("ZhangSan", "zhs123");
|
||||
final var user2 = new User("LiSi", "ls123");
|
||||
final var user3 = new User("WangWu", "ww123");
|
||||
return List.of(user1, user2, user3);
|
||||
}
|
||||
}
|
||||
@ -1,29 +0,0 @@
|
||||
package com.iluwatar.metamapping.model;
|
||||
|
||||
import lombok.Getter;
|
||||
import lombok.Setter;
|
||||
import lombok.ToString;
|
||||
|
||||
/**
|
||||
* User Entity.
|
||||
*/
|
||||
@Setter
|
||||
@Getter
|
||||
@ToString
|
||||
public class User {
|
||||
private Integer id;
|
||||
private String username;
|
||||
private String password;
|
||||
|
||||
public User() {}
|
||||
|
||||
/**
|
||||
* Get a user.
|
||||
* @param username user name
|
||||
* @param password user password
|
||||
*/
|
||||
public User(String username, String password) {
|
||||
this.username = username;
|
||||
this.password = password;
|
||||
}
|
||||
}
|
||||
@ -1,114 +0,0 @@
|
||||
package com.iluwatar.metamapping.service;
|
||||
|
||||
import com.iluwatar.metamapping.model.User;
|
||||
import com.iluwatar.metamapping.utils.HibernateUtil;
|
||||
import java.util.ArrayList;
|
||||
import java.util.List;
|
||||
import lombok.extern.slf4j.Slf4j;
|
||||
import org.hibernate.HibernateException;
|
||||
import org.hibernate.SessionFactory;
|
||||
|
||||
/**
|
||||
* Service layer for user.
|
||||
*/
|
||||
@Slf4j
|
||||
public class UserService {
|
||||
private static final SessionFactory factory = HibernateUtil.getSessionFactory();
|
||||
|
||||
/**
|
||||
* List all users.
|
||||
* @return list of users
|
||||
*/
|
||||
public List<User> listUser() {
|
||||
LOGGER.info("list all users.");
|
||||
List<User> users = new ArrayList<>();
|
||||
try (var session = factory.openSession()) {
|
||||
var tx = session.beginTransaction();
|
||||
List<User> userIter = session.createQuery("FROM User").list();
|
||||
for (var iterator = userIter.iterator(); iterator.hasNext();) {
|
||||
users.add(iterator.next());
|
||||
}
|
||||
tx.commit();
|
||||
} catch (HibernateException e) {
|
||||
LOGGER.debug("fail to get users", e);
|
||||
}
|
||||
return users;
|
||||
}
|
||||
|
||||
/**
|
||||
* Add a user.
|
||||
* @param user user entity
|
||||
* @return user id
|
||||
*/
|
||||
public int createUser(User user) {
|
||||
LOGGER.info("create user: " + user.getUsername());
|
||||
var id = -1;
|
||||
try (var session = factory.openSession()) {
|
||||
var tx = session.beginTransaction();
|
||||
id = (Integer) session.save(user);
|
||||
tx.commit();
|
||||
} catch (HibernateException e) {
|
||||
LOGGER.debug("fail to create user", e);
|
||||
}
|
||||
LOGGER.info("create user " + user.getUsername() + " at " + id);
|
||||
return id;
|
||||
}
|
||||
|
||||
/**
|
||||
* Update user.
|
||||
* @param id user id
|
||||
* @param user new user entity
|
||||
*/
|
||||
public void updateUser(Integer id, User user) {
|
||||
LOGGER.info("update user at " + id);
|
||||
try (var session = factory.openSession()) {
|
||||
var tx = session.beginTransaction();
|
||||
user.setId(id);
|
||||
session.update(user);
|
||||
tx.commit();
|
||||
} catch (HibernateException e) {
|
||||
LOGGER.debug("fail to update user", e);
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Delete user.
|
||||
* @param id user id
|
||||
*/
|
||||
public void deleteUser(Integer id) {
|
||||
LOGGER.info("delete user at: " + id);
|
||||
try (var session = factory.openSession()) {
|
||||
var tx = session.beginTransaction();
|
||||
var user = session.get(User.class, id);
|
||||
session.delete(user);
|
||||
tx.commit();
|
||||
} catch (HibernateException e) {
|
||||
LOGGER.debug("fail to delete user", e);
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Get user.
|
||||
* @param id user id
|
||||
* @return deleted user
|
||||
*/
|
||||
public User getUser(Integer id) {
|
||||
LOGGER.info("get user at: " + id);
|
||||
User user = null;
|
||||
try (var session = factory.openSession()) {
|
||||
var tx = session.beginTransaction();
|
||||
user = session.get(User.class, id);
|
||||
tx.commit();
|
||||
} catch (HibernateException e) {
|
||||
LOGGER.debug("fail to get user", e);
|
||||
}
|
||||
return user;
|
||||
}
|
||||
|
||||
/**
|
||||
* Close hibernate.
|
||||
*/
|
||||
public void close() {
|
||||
HibernateUtil.shutdown();
|
||||
}
|
||||
}
|
||||
@ -1,39 +0,0 @@
|
||||
package com.iluwatar.metamapping.utils;
|
||||
|
||||
import java.sql.SQLException;
|
||||
import lombok.extern.slf4j.Slf4j;
|
||||
import org.h2.jdbcx.JdbcDataSource;
|
||||
|
||||
/**
|
||||
* Create h2 database.
|
||||
*/
|
||||
@Slf4j
|
||||
public class DatabaseUtil {
|
||||
private static final String DB_URL = "jdbc:h2:mem:metamapping";
|
||||
private static final String CREATE_SCHEMA_SQL = "DROP TABLE IF EXISTS `user`;"
|
||||
+ "CREATE TABLE `user` (\n"
|
||||
+ " `id` int(11) NOT NULL AUTO_INCREMENT,\n"
|
||||
+ " `username` varchar(255) NOT NULL,\n"
|
||||
+ " `password` varchar(255) NOT NULL,\n"
|
||||
+ " PRIMARY KEY (`id`)\n"
|
||||
+ ");";
|
||||
|
||||
/**
|
||||
* Hide constructor.
|
||||
*/
|
||||
private DatabaseUtil() {}
|
||||
|
||||
/**
|
||||
* Create database.
|
||||
*/
|
||||
static {
|
||||
LOGGER.info("create h2 database");
|
||||
var source = new JdbcDataSource();
|
||||
source.setURL(DB_URL);
|
||||
try (var statement = source.getConnection().createStatement()) {
|
||||
statement.execute(CREATE_SCHEMA_SQL);
|
||||
} catch (SQLException e) {
|
||||
LOGGER.error("unable to create h2 data source", e);
|
||||
}
|
||||
}
|
||||
}
|
||||
@ -1,45 +0,0 @@
|
||||
package com.iluwatar.metamapping.utils;
|
||||
|
||||
import lombok.extern.slf4j.Slf4j;
|
||||
import org.hibernate.SessionFactory;
|
||||
import org.hibernate.cfg.Configuration;
|
||||
|
||||
/**
|
||||
* Manage hibernate.
|
||||
*/
|
||||
@Slf4j
|
||||
public class HibernateUtil {
|
||||
|
||||
private static final SessionFactory sessionFactory = buildSessionFactory();
|
||||
|
||||
/**
|
||||
* Hide constructor.
|
||||
*/
|
||||
private HibernateUtil() {}
|
||||
|
||||
/**
|
||||
* Build session factory.
|
||||
* @return session factory
|
||||
*/
|
||||
private static SessionFactory buildSessionFactory() {
|
||||
// Create the SessionFactory from hibernate.cfg.xml
|
||||
return new Configuration().configure().buildSessionFactory();
|
||||
}
|
||||
|
||||
/**
|
||||
* Get session factory.
|
||||
* @return session factory
|
||||
*/
|
||||
public static SessionFactory getSessionFactory() {
|
||||
return sessionFactory;
|
||||
}
|
||||
|
||||
/**
|
||||
* Close session factory.
|
||||
*/
|
||||
public static void shutdown() {
|
||||
// Close caches and connection pools
|
||||
getSessionFactory().close();
|
||||
}
|
||||
|
||||
}
|
||||
@ -1,14 +0,0 @@
|
||||
<?xml version="1.0" encoding="utf-8"?>
|
||||
<!DOCTYPE hibernate-mapping PUBLIC
|
||||
"-//Hibernate/Hibernate Mapping DTD//EN"
|
||||
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
|
||||
|
||||
<hibernate-mapping>
|
||||
<class name="com.iluwatar.metamapping.model.User" table="user">
|
||||
<id name="id" type="java.lang.Integer" column="id">
|
||||
<generator class="native"/>
|
||||
</id>
|
||||
<property name="username" column="username" type="java.lang.String"/>
|
||||
<property name="password" column="password" type="java.lang.String"/>
|
||||
</class>
|
||||
</hibernate-mapping>
|
||||
@ -1,20 +0,0 @@
|
||||
<?xml version="1.0" encoding="utf-8"?>
|
||||
<!DOCTYPE hibernate-configuration PUBLIC
|
||||
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
|
||||
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
|
||||
<hibernate-configuration>
|
||||
<session-factory>
|
||||
<!-- JDBC Database connection settings -->
|
||||
<property name="connection.url">jdbc:h2:mem:metamapping</property>
|
||||
<property name="connection.driver_class">org.h2.Driver</property>
|
||||
<!-- JDBC connection pool settings ... using built-in test pool -->
|
||||
<property name="connection.pool_size">1</property>
|
||||
<!-- Select our SQL dialect -->
|
||||
<property name="dialect">org.hibernate.dialect.H2Dialect</property>
|
||||
<!-- Echo the SQL to stdout -->
|
||||
<property name="show_sql">false</property>
|
||||
<!-- Drop and re-create the database schema on startup -->
|
||||
<property name="hbm2ddl.auto">create-drop</property>
|
||||
<mapping resource="com/iluwatar/metamapping/model/User.hbm.xml" />
|
||||
</session-factory>
|
||||
</hibernate-configuration>
|
||||
@ -1,20 +0,0 @@
|
||||
package com.iluwatar.metamapping;
|
||||
|
||||
import org.junit.jupiter.api.Test;
|
||||
import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
|
||||
|
||||
/**
|
||||
* Tests that metadata mapping example runs without errors.
|
||||
*/
|
||||
class AppTest {
|
||||
/**
|
||||
* Issue: Add at least one assertion to this test case.
|
||||
*
|
||||
* Solution: Inserted assertion to check whether the execution of the main method in {@link App#main(String[])}
|
||||
* throws an exception.
|
||||
*/
|
||||
@Test
|
||||
void shouldExecuteMetaMappingWithoutException() {
|
||||
assertDoesNotThrow(() -> App.main(new String[]{}));
|
||||
}
|
||||
}
|
||||
7
pom.xml
7
pom.xml
@ -75,7 +75,6 @@
|
||||
<license-maven-plugin.version>3.0</license-maven-plugin.version>
|
||||
<urm-maven-plugin.version>1.4.8</urm-maven-plugin.version>
|
||||
<commons-io.version>2.7</commons-io.version>
|
||||
<istack-commons-runtime.version>4.0.1</istack-commons-runtime.version>
|
||||
<!-- SonarCloud -->
|
||||
<sonar.host.url>https://sonarcloud.io</sonar.host.url>
|
||||
<sonar.organization>iluwatar</sonar.organization>
|
||||
@ -228,7 +227,6 @@
|
||||
<module>lockable-object</module>
|
||||
<module>fanout-fanin</module>
|
||||
<module>domain-model</module>
|
||||
<module>metadata-mapping</module>
|
||||
</modules>
|
||||
<repositories>
|
||||
<repository>
|
||||
@ -379,11 +377,6 @@
|
||||
<artifactId>commons-io</artifactId>
|
||||
<version>${commons-io.version}</version>
|
||||
</dependency>
|
||||
<dependency>
|
||||
<groupId>com.sun.istack</groupId>
|
||||
<artifactId>istack-commons-runtime</artifactId>
|
||||
<version>${istack-commons-runtime.version}</version>
|
||||
</dependency>
|
||||
</dependencies>
|
||||
</dependencyManagement>
|
||||
<dependencies>
|
||||
|
||||
@ -18,11 +18,11 @@ threads and eliminating the latency of creating new threads.
|
||||
|
||||
## Explanation
|
||||
|
||||
Real world example
|
||||
Real-world example
|
||||
|
||||
> We have a large number of relatively short tasks at hand. We need to peel huge amounts of potatoes
|
||||
> and serve mighty amount of coffee cups. Creating a new thread for each task would be a waste so we
|
||||
> establish a thread pool.
|
||||
> and serve a mighty amount of coffee cups. Creating a new thread for each task would be a waste so
|
||||
> we establish a thread pool.
|
||||
|
||||
In plain words
|
||||
|
||||
@ -99,7 +99,7 @@ public class PotatoPeelingTask extends Task {
|
||||
}
|
||||
```
|
||||
|
||||
Next we present a runnable `Worker` class that the thread pool will utilize to handle all the potato
|
||||
Next, we present a runnable `Worker` class that the thread pool will utilize to handle all the potato
|
||||
peeling and coffee making.
|
||||
|
||||
```java
|
||||
|
||||
@ -16,10 +16,12 @@ Ensure that a given client is not able to access service resources more than the
|
||||
|
||||
## Explanation
|
||||
|
||||
Real world example
|
||||
Real-world example
|
||||
|
||||
> A large multinational corporation offers API to its customers. The API is rate-limited and each
|
||||
> customer can only make certain amount of calls per second.
|
||||
> A young human and an old dwarf walk into a bar. They start ordering beers from the bartender.
|
||||
> The bartender immediately sees that the young human shouldn't consume too many drinks too fast
|
||||
> and refuses to serve if enough time has not passed. For the old dwarf, the serving rate can
|
||||
> be higher.
|
||||
|
||||
In plain words
|
||||
|
||||
@ -33,30 +35,25 @@ In plain words
|
||||
|
||||
**Programmatic Example**
|
||||
|
||||
Tenant class presents the clients of the API. CallsCount tracks the number of API calls per tenant.
|
||||
`BarCustomer` class presents the clients of the `Bartender` API. `CallsCount` tracks the number of
|
||||
calls per `BarCustomer`.
|
||||
|
||||
```java
|
||||
public class Tenant {
|
||||
public class BarCustomer {
|
||||
|
||||
private final String name;
|
||||
private final int allowedCallsPerSecond;
|
||||
@Getter
|
||||
private final String name;
|
||||
@Getter
|
||||
private final int allowedCallsPerSecond;
|
||||
|
||||
public Tenant(String name, int allowedCallsPerSecond, CallsCount callsCount) {
|
||||
if (allowedCallsPerSecond < 0) {
|
||||
throw new InvalidParameterException("Number of calls less than 0 not allowed");
|
||||
public BarCustomer(String name, int allowedCallsPerSecond, CallsCount callsCount) {
|
||||
if (allowedCallsPerSecond < 0) {
|
||||
throw new InvalidParameterException("Number of calls less than 0 not allowed");
|
||||
}
|
||||
this.name = name;
|
||||
this.allowedCallsPerSecond = allowedCallsPerSecond;
|
||||
callsCount.addTenant(name);
|
||||
}
|
||||
this.name = name;
|
||||
this.allowedCallsPerSecond = allowedCallsPerSecond;
|
||||
callsCount.addTenant(name);
|
||||
}
|
||||
|
||||
public String getName() {
|
||||
return name;
|
||||
}
|
||||
|
||||
public int getAllowedCallsPerSecond() {
|
||||
return allowedCallsPerSecond;
|
||||
}
|
||||
}
|
||||
|
||||
@Slf4j
|
||||
@ -76,14 +73,14 @@ public final class CallsCount {
|
||||
}
|
||||
|
||||
public void reset() {
|
||||
LOGGER.debug("Resetting the map.");
|
||||
tenantCallsCount.replaceAll((k, v) -> new AtomicLong(0));
|
||||
LOGGER.info("reset counters");
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Next we introduce the service that the tenants are calling. To track the call count we use the
|
||||
throttler timer.
|
||||
Next, the service that the tenants are calling is introduced. To track the call count, a throttler
|
||||
timer is used.
|
||||
|
||||
```java
|
||||
public interface Throttler {
|
||||
@ -111,71 +108,103 @@ public class ThrottleTimerImpl implements Throttler {
|
||||
}, 0, throttlePeriod);
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
class B2BService {
|
||||
`Bartender` offers the `orderDrink` service to the `BarCustomer`s. The customers probably don't
|
||||
know that the beer serving rate is limited by their appearances.
|
||||
|
||||
private static final Logger LOGGER = LoggerFactory.getLogger(B2BService.class);
|
||||
private final CallsCount callsCount;
|
||||
```java
|
||||
class Bartender {
|
||||
|
||||
public B2BService(Throttler timer, CallsCount callsCount) {
|
||||
this.callsCount = callsCount;
|
||||
timer.start();
|
||||
}
|
||||
private static final Logger LOGGER = LoggerFactory.getLogger(Bartender.class);
|
||||
private final CallsCount callsCount;
|
||||
|
||||
public int dummyCustomerApi(Tenant tenant) {
|
||||
var tenantName = tenant.getName();
|
||||
var count = callsCount.getCount(tenantName);
|
||||
LOGGER.debug("Counter for {} : {} ", tenant.getName(), count);
|
||||
if (count >= tenant.getAllowedCallsPerSecond()) {
|
||||
LOGGER.error("API access per second limit reached for: {}", tenantName);
|
||||
return -1;
|
||||
public Bartender(Throttler timer, CallsCount callsCount) {
|
||||
this.callsCount = callsCount;
|
||||
timer.start();
|
||||
}
|
||||
callsCount.incrementCount(tenantName);
|
||||
return getRandomCustomerId();
|
||||
}
|
||||
|
||||
private int getRandomCustomerId() {
|
||||
return ThreadLocalRandom.current().nextInt(1, 10000);
|
||||
}
|
||||
public int orderDrink(BarCustomer barCustomer) {
|
||||
var tenantName = barCustomer.getName();
|
||||
var count = callsCount.getCount(tenantName);
|
||||
if (count >= barCustomer.getAllowedCallsPerSecond()) {
|
||||
LOGGER.error("I'm sorry {}, you've had enough for today!", tenantName);
|
||||
return -1;
|
||||
}
|
||||
callsCount.incrementCount(tenantName);
|
||||
LOGGER.debug("Serving beer to {} : [{} consumed] ", barCustomer.getName(), count+1);
|
||||
return getRandomCustomerId();
|
||||
}
|
||||
|
||||
private int getRandomCustomerId() {
|
||||
return ThreadLocalRandom.current().nextInt(1, 10000);
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Now we are ready to see the full example in action. Tenant Adidas is rate-limited to 5 calls per
|
||||
second and Nike to 6.
|
||||
Now it is possible to see the full example in action. `BarCustomer` young human is rate-limited to 2
|
||||
calls per second and the old dwarf to 4.
|
||||
|
||||
```java
|
||||
public static void main(String[] args) {
|
||||
public static void main(String[] args) {
|
||||
var callsCount = new CallsCount();
|
||||
var adidas = new Tenant("Adidas", 5, callsCount);
|
||||
var nike = new Tenant("Nike", 6, callsCount);
|
||||
var human = new BarCustomer("young human", 2, callsCount);
|
||||
var dwarf = new BarCustomer("dwarf soldier", 4, callsCount);
|
||||
|
||||
var executorService = Executors.newFixedThreadPool(2);
|
||||
executorService.execute(() -> makeServiceCalls(adidas, callsCount));
|
||||
executorService.execute(() -> makeServiceCalls(nike, callsCount));
|
||||
executorService.shutdown();
|
||||
|
||||
try {
|
||||
executorService.awaitTermination(10, TimeUnit.SECONDS);
|
||||
} catch (InterruptedException e) {
|
||||
LOGGER.error("Executor Service terminated: {}", e.getMessage());
|
||||
}
|
||||
}
|
||||
|
||||
private static void makeServiceCalls(Tenant tenant, CallsCount callsCount) {
|
||||
var timer = new ThrottleTimerImpl(10, callsCount);
|
||||
var service = new B2BService(timer, callsCount);
|
||||
executorService.execute(() -> makeServiceCalls(human, callsCount));
|
||||
executorService.execute(() -> makeServiceCalls(dwarf, callsCount));
|
||||
|
||||
executorService.shutdown();
|
||||
try {
|
||||
executorService.awaitTermination(10, TimeUnit.SECONDS);
|
||||
} catch (InterruptedException e) {
|
||||
LOGGER.error("Executor service terminated: {}", e.getMessage());
|
||||
}
|
||||
}
|
||||
|
||||
private static void makeServiceCalls(BarCustomer barCustomer, CallsCount callsCount) {
|
||||
var timer = new ThrottleTimerImpl(1000, callsCount);
|
||||
var service = new Bartender(timer, callsCount);
|
||||
// Sleep is introduced to keep the output in check and easy to view and analyze the results.
|
||||
IntStream.range(0, 20).forEach(i -> {
|
||||
service.dummyCustomerApi(tenant);
|
||||
try {
|
||||
Thread.sleep(1);
|
||||
} catch (InterruptedException e) {
|
||||
LOGGER.error("Thread interrupted: {}", e.getMessage());
|
||||
}
|
||||
IntStream.range(0, 50).forEach(i -> {
|
||||
service.orderDrink(barCustomer);
|
||||
try {
|
||||
Thread.sleep(100);
|
||||
} catch (InterruptedException e) {
|
||||
LOGGER.error("Thread interrupted: {}", e.getMessage());
|
||||
}
|
||||
});
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
An excerpt from the example's console output:
|
||||
|
||||
```
|
||||
18:46:36.218 [Timer-0] INFO com.iluwatar.throttling.CallsCount - reset counters
|
||||
18:46:36.218 [Timer-1] INFO com.iluwatar.throttling.CallsCount - reset counters
|
||||
18:46:36.242 [pool-1-thread-2] DEBUG com.iluwatar.throttling.Bartender - Serving beer to dwarf soldier : [1 consumed]
|
||||
18:46:36.242 [pool-1-thread-1] DEBUG com.iluwatar.throttling.Bartender - Serving beer to young human : [1 consumed]
|
||||
18:46:36.342 [pool-1-thread-2] DEBUG com.iluwatar.throttling.Bartender - Serving beer to dwarf soldier : [2 consumed]
|
||||
18:46:36.342 [pool-1-thread-1] DEBUG com.iluwatar.throttling.Bartender - Serving beer to young human : [2 consumed]
|
||||
18:46:36.443 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
|
||||
18:46:36.443 [pool-1-thread-2] DEBUG com.iluwatar.throttling.Bartender - Serving beer to dwarf soldier : [3 consumed]
|
||||
18:46:36.544 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
|
||||
18:46:36.544 [pool-1-thread-2] DEBUG com.iluwatar.throttling.Bartender - Serving beer to dwarf soldier : [4 consumed]
|
||||
18:46:36.645 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
|
||||
18:46:36.645 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
|
||||
18:46:36.745 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
|
||||
18:46:36.745 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
|
||||
18:46:36.846 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
|
||||
18:46:36.846 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
|
||||
18:46:36.947 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
|
||||
18:46:36.947 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
|
||||
18:46:37.048 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
|
||||
18:46:37.048 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
|
||||
18:46:37.148 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
|
||||
18:46:37.148 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
|
||||
```
|
||||
|
||||
## Class diagram
|
||||
|
||||
@ -185,7 +214,7 @@ second and Nike to 6.
|
||||
|
||||
The Throttling pattern should be used:
|
||||
|
||||
* When a service access needs to be restricted to not have high impacts on the performance of the service.
|
||||
* When service access needs to be restricted not to have high impact on the performance of the service.
|
||||
* When multiple clients are consuming the same service resources and restriction has to be made according to the usage per client.
|
||||
|
||||
## Credits
|
||||
|
||||
@ -34,11 +34,11 @@ import lombok.extern.slf4j.Slf4j;
|
||||
* complete service by users or a particular tenant. This can allow systems to continue to function
|
||||
* and meet service level agreements, even when an increase in demand places load on resources.
|
||||
* <p>
|
||||
* In this example we have ({@link App}) as the initiating point of the service. This is a time
|
||||
* In this example there is a {@link Bartender} serving beer to {@link BarCustomer}s. This is a time
|
||||
* based throttling, i.e. only a certain number of calls are allowed per second.
|
||||
* </p>
|
||||
* ({@link Tenant}) is the Tenant POJO class with which many tenants can be created ({@link
|
||||
* B2BService}) is the service which is consumed by the tenants and is throttled.
|
||||
* ({@link BarCustomer}) is the service tenant class having a name and the number of calls allowed.
|
||||
* ({@link Bartender}) is the service which is consumed by the tenants and is throttled.
|
||||
*/
|
||||
@Slf4j
|
||||
public class App {
|
||||
@ -50,33 +50,35 @@ public class App {
|
||||
*/
|
||||
public static void main(String[] args) {
|
||||
var callsCount = new CallsCount();
|
||||
var adidas = new Tenant("Adidas", 5, callsCount);
|
||||
var nike = new Tenant("Nike", 6, callsCount);
|
||||
var human = new BarCustomer("young human", 2, callsCount);
|
||||
var dwarf = new BarCustomer("dwarf soldier", 4, callsCount);
|
||||
|
||||
var executorService = Executors.newFixedThreadPool(2);
|
||||
|
||||
executorService.execute(() -> makeServiceCalls(adidas, callsCount));
|
||||
executorService.execute(() -> makeServiceCalls(nike, callsCount));
|
||||
executorService.execute(() -> makeServiceCalls(human, callsCount));
|
||||
executorService.execute(() -> makeServiceCalls(dwarf, callsCount));
|
||||
|
||||
executorService.shutdown();
|
||||
try {
|
||||
executorService.awaitTermination(10, TimeUnit.SECONDS);
|
||||
if (!executorService.awaitTermination(10, TimeUnit.SECONDS)) {
|
||||
executorService.shutdownNow();
|
||||
}
|
||||
} catch (InterruptedException e) {
|
||||
LOGGER.error("Executor Service terminated: {}", e.getMessage());
|
||||
executorService.shutdownNow();
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Make calls to the B2BService dummy API.
|
||||
* Make calls to the bartender.
|
||||
*/
|
||||
private static void makeServiceCalls(Tenant tenant, CallsCount callsCount) {
|
||||
var timer = new ThrottleTimerImpl(10, callsCount);
|
||||
var service = new B2BService(timer, callsCount);
|
||||
private static void makeServiceCalls(BarCustomer barCustomer, CallsCount callsCount) {
|
||||
var timer = new ThrottleTimerImpl(1000, callsCount);
|
||||
var service = new Bartender(timer, callsCount);
|
||||
// Sleep is introduced to keep the output in check and easy to view and analyze the results.
|
||||
IntStream.range(0, 20).forEach(i -> {
|
||||
service.dummyCustomerApi(tenant);
|
||||
IntStream.range(0, 50).forEach(i -> {
|
||||
service.orderDrink(barCustomer);
|
||||
try {
|
||||
Thread.sleep(1);
|
||||
Thread.sleep(100);
|
||||
} catch (InterruptedException e) {
|
||||
LOGGER.error("Thread interrupted: {}", e.getMessage());
|
||||
}
|
||||
|
||||
@ -25,22 +25,26 @@ package com.iluwatar.throttling;
|
||||
|
||||
import java.security.InvalidParameterException;
|
||||
|
||||
/**
|
||||
* A Pojo class to create a basic Tenant with the allowed calls per second.
|
||||
*/
|
||||
public class Tenant {
|
||||
import lombok.Getter;
|
||||
|
||||
/**
|
||||
* BarCustomer is a tenant with a name and a number of allowed calls per second.
|
||||
*/
|
||||
public class BarCustomer {
|
||||
|
||||
@Getter
|
||||
private final String name;
|
||||
@Getter
|
||||
private final int allowedCallsPerSecond;
|
||||
|
||||
/**
|
||||
* Constructor.
|
||||
*
|
||||
* @param name Name of the tenant
|
||||
* @param allowedCallsPerSecond The number of calls allowed for a particular tenant.
|
||||
* @param name Name of the BarCustomer
|
||||
* @param allowedCallsPerSecond The number of calls allowed for this particular tenant.
|
||||
* @throws InvalidParameterException If number of calls is less than 0, throws exception.
|
||||
*/
|
||||
public Tenant(String name, int allowedCallsPerSecond, CallsCount callsCount) {
|
||||
public BarCustomer(String name, int allowedCallsPerSecond, CallsCount callsCount) {
|
||||
if (allowedCallsPerSecond < 0) {
|
||||
throw new InvalidParameterException("Number of calls less than 0 not allowed");
|
||||
}
|
||||
@ -48,12 +52,4 @@ public class Tenant {
|
||||
this.allowedCallsPerSecond = allowedCallsPerSecond;
|
||||
callsCount.addTenant(name);
|
||||
}
|
||||
|
||||
public String getName() {
|
||||
return name;
|
||||
}
|
||||
|
||||
public int getAllowedCallsPerSecond() {
|
||||
return allowedCallsPerSecond;
|
||||
}
|
||||
}
|
||||
@ -29,33 +29,32 @@ import org.slf4j.Logger;
|
||||
import org.slf4j.LoggerFactory;
|
||||
|
||||
/**
|
||||
* A service which accepts a tenant and throttles the resource based on the time given to the
|
||||
* tenant.
|
||||
* Bartender is a service which accepts a BarCustomer (tenant) and throttles
|
||||
* the resource based on the time given to the tenant.
|
||||
*/
|
||||
class B2BService {
|
||||
class Bartender {
|
||||
|
||||
private static final Logger LOGGER = LoggerFactory.getLogger(B2BService.class);
|
||||
private static final Logger LOGGER = LoggerFactory.getLogger(Bartender.class);
|
||||
private final CallsCount callsCount;
|
||||
|
||||
public B2BService(Throttler timer, CallsCount callsCount) {
|
||||
public Bartender(Throttler timer, CallsCount callsCount) {
|
||||
this.callsCount = callsCount;
|
||||
timer.start();
|
||||
}
|
||||
|
||||
/**
|
||||
* Calls dummy customer api.
|
||||
*
|
||||
* Orders a drink from the bartender.
|
||||
* @return customer id which is randomly generated
|
||||
*/
|
||||
public int dummyCustomerApi(Tenant tenant) {
|
||||
var tenantName = tenant.getName();
|
||||
public int orderDrink(BarCustomer barCustomer) {
|
||||
var tenantName = barCustomer.getName();
|
||||
var count = callsCount.getCount(tenantName);
|
||||
LOGGER.debug("Counter for {} : {} ", tenant.getName(), count);
|
||||
if (count >= tenant.getAllowedCallsPerSecond()) {
|
||||
LOGGER.error("API access per second limit reached for: {}", tenantName);
|
||||
if (count >= barCustomer.getAllowedCallsPerSecond()) {
|
||||
LOGGER.error("I'm sorry {}, you've had enough for today!", tenantName);
|
||||
return -1;
|
||||
}
|
||||
callsCount.incrementCount(tenantName);
|
||||
LOGGER.debug("Serving beer to {} : [{} consumed] ", barCustomer.getName(), count + 1);
|
||||
return getRandomCustomerId();
|
||||
}
|
||||
|
||||
@ -69,7 +69,7 @@ public final class CallsCount {
|
||||
* Resets the count of all the tenants in the map.
|
||||
*/
|
||||
public void reset() {
|
||||
LOGGER.debug("Resetting the map.");
|
||||
tenantCallsCount.replaceAll((k, v) -> new AtomicLong(0));
|
||||
LOGGER.info("reset counters");
|
||||
}
|
||||
}
|
||||
|
||||
@ -23,20 +23,21 @@
|
||||
|
||||
package com.iluwatar.throttling;
|
||||
|
||||
import static org.junit.jupiter.api.Assertions.assertThrows;
|
||||
import org.junit.jupiter.api.Test;
|
||||
|
||||
import java.security.InvalidParameterException;
|
||||
import org.junit.jupiter.api.Test;
|
||||
|
||||
import static org.junit.jupiter.api.Assertions.assertThrows;
|
||||
|
||||
/**
|
||||
* TenantTest to test the creation of Tenant with valid parameters.
|
||||
*/
|
||||
public class TenantTest {
|
||||
public class BarCustomerTest {
|
||||
|
||||
@Test
|
||||
void constructorTest() {
|
||||
assertThrows(InvalidParameterException.class, () -> {
|
||||
new Tenant("FailTenant", -1, new CallsCount());
|
||||
new BarCustomer("sirBrave", -1, new CallsCount());
|
||||
});
|
||||
}
|
||||
}
|
||||
@ -32,19 +32,18 @@ import org.junit.jupiter.api.Test;
|
||||
/**
|
||||
* B2BServiceTest class to test the B2BService
|
||||
*/
|
||||
public class B2BServiceTest {
|
||||
public class BartenderTest {
|
||||
|
||||
private final CallsCount callsCount = new CallsCount();
|
||||
|
||||
@Test
|
||||
void dummyCustomerApiTest() {
|
||||
var tenant = new Tenant("testTenant", 2, callsCount);
|
||||
var tenant = new BarCustomer("pirate", 2, callsCount);
|
||||
// In order to assure that throttling limits will not be reset, we use an empty throttling implementation
|
||||
var timer = (Throttler) () -> {
|
||||
};
|
||||
var service = new B2BService(timer, callsCount);
|
||||
var timer = (Throttler) () -> {};
|
||||
var service = new Bartender(timer, callsCount);
|
||||
|
||||
IntStream.range(0, 5).mapToObj(i -> tenant).forEach(service::dummyCustomerApi);
|
||||
IntStream.range(0, 5).mapToObj(i -> tenant).forEach(service::orderDrink);
|
||||
var counter = callsCount.getCount(tenant.getName());
|
||||
assertEquals(2, counter, "Counter limit must be reached");
|
||||
}
|
||||
@ -12,20 +12,20 @@ tags:
|
||||
|
||||
## Intent
|
||||
|
||||
When a business transaction is completed, all the updates are sent as one big unit of work to be
|
||||
When a business transaction is completed, all the the updates are sent as one big unit of work to be
|
||||
persisted in one go to minimize database round-trips.
|
||||
|
||||
## Explanation
|
||||
|
||||
Real-world example
|
||||
Real world example
|
||||
|
||||
> Arms dealer has a database containing weapon information. Merchants all over the town are
|
||||
> constantly updating this information and it causes a high load on the database server. To make the
|
||||
> We have a database containing student information. Administrators all over the country are
|
||||
> constantly updating this information and it causes high load on the database server. To make the
|
||||
> load more manageable we apply to Unit of Work pattern to send many small updates in batches.
|
||||
|
||||
In plain words
|
||||
|
||||
> Unit of Work merges many small database updates in a single batch to optimize the number of
|
||||
> Unit of Work merges many small database updates in single batch to optimize the number of
|
||||
> round-trips.
|
||||
|
||||
[MartinFowler.com](https://martinfowler.com/eaaCatalog/unitOfWork.html) says
|
||||
@ -35,20 +35,37 @@ In plain words
|
||||
|
||||
**Programmatic Example**
|
||||
|
||||
Here's the `Weapon` entity that is being persisted in the database.
|
||||
Here's the `Student` entity that is being persisted to the database.
|
||||
|
||||
```java
|
||||
@Getter
|
||||
@RequiredArgsConstructor
|
||||
public class Weapon {
|
||||
private final Integer id;
|
||||
private final String name;
|
||||
public class Student {
|
||||
private final Integer id;
|
||||
private final String name;
|
||||
private final String address;
|
||||
|
||||
public Student(Integer id, String name, String address) {
|
||||
this.id = id;
|
||||
this.name = name;
|
||||
this.address = address;
|
||||
}
|
||||
|
||||
public String getName() {
|
||||
return name;
|
||||
}
|
||||
|
||||
public Integer getId() {
|
||||
return id;
|
||||
}
|
||||
|
||||
public String getAddress() {
|
||||
return address;
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
The essence of the implementation is the `ArmsDealer` implementing the Unit of Work pattern.
|
||||
The essence of the implementation is the `StudentRepository` implementing the Unit of Work pattern.
|
||||
It maintains a map of database operations (`context`) that need to be done and when `commit` is
|
||||
called it applies them in a single batch.
|
||||
called it applies them in single batch.
|
||||
|
||||
```java
|
||||
public interface IUnitOfWork<T> {
|
||||
@ -67,117 +84,96 @@ public interface IUnitOfWork<T> {
|
||||
}
|
||||
|
||||
@Slf4j
|
||||
@RequiredArgsConstructor
|
||||
public class ArmsDealer implements IUnitOfWork<Weapon> {
|
||||
public class StudentRepository implements IUnitOfWork<Student> {
|
||||
|
||||
private final Map<String, List<Weapon>> context;
|
||||
private final WeaponDatabase weaponDatabase;
|
||||
private final Map<String, List<Student>> context;
|
||||
private final StudentDatabase studentDatabase;
|
||||
|
||||
@Override
|
||||
public void registerNew(Weapon weapon) {
|
||||
LOGGER.info("Registering {} for insert in context.", weapon.getName());
|
||||
register(weapon, UnitActions.INSERT.getActionValue());
|
||||
public StudentRepository(Map<String, List<Student>> context, StudentDatabase studentDatabase) {
|
||||
this.context = context;
|
||||
this.studentDatabase = studentDatabase;
|
||||
}
|
||||
|
||||
@Override
|
||||
public void registerNew(Student student) {
|
||||
LOGGER.info("Registering {} for insert in context.", student.getName());
|
||||
register(student, IUnitOfWork.INSERT);
|
||||
}
|
||||
|
||||
@Override
|
||||
public void registerModified(Student student) {
|
||||
LOGGER.info("Registering {} for modify in context.", student.getName());
|
||||
register(student, IUnitOfWork.MODIFY);
|
||||
|
||||
}
|
||||
|
||||
@Override
|
||||
public void registerDeleted(Student student) {
|
||||
LOGGER.info("Registering {} for delete in context.", student.getName());
|
||||
register(student, IUnitOfWork.DELETE);
|
||||
}
|
||||
|
||||
private void register(Student student, String operation) {
|
||||
var studentsToOperate = context.get(operation);
|
||||
if (studentsToOperate == null) {
|
||||
studentsToOperate = new ArrayList<>();
|
||||
}
|
||||
studentsToOperate.add(student);
|
||||
context.put(operation, studentsToOperate);
|
||||
}
|
||||
|
||||
@Override
|
||||
public void commit() {
|
||||
if (context == null || context.size() == 0) {
|
||||
return;
|
||||
}
|
||||
LOGGER.info("Commit started");
|
||||
if (context.containsKey(IUnitOfWork.INSERT)) {
|
||||
commitInsert();
|
||||
}
|
||||
|
||||
@Override
|
||||
public void registerModified(Weapon weapon) {
|
||||
LOGGER.info("Registering {} for modify in context.", weapon.getName());
|
||||
register(weapon, UnitActions.MODIFY.getActionValue());
|
||||
|
||||
if (context.containsKey(IUnitOfWork.MODIFY)) {
|
||||
commitModify();
|
||||
}
|
||||
|
||||
@Override
|
||||
public void registerDeleted(Weapon weapon) {
|
||||
LOGGER.info("Registering {} for delete in context.", weapon.getName());
|
||||
register(weapon, UnitActions.DELETE.getActionValue());
|
||||
if (context.containsKey(IUnitOfWork.DELETE)) {
|
||||
commitDelete();
|
||||
}
|
||||
LOGGER.info("Commit finished.");
|
||||
}
|
||||
|
||||
private void register(Weapon weapon, String operation) {
|
||||
var weaponsToOperate = context.get(operation);
|
||||
if (weaponsToOperate == null) {
|
||||
weaponsToOperate = new ArrayList<>();
|
||||
}
|
||||
weaponsToOperate.add(weapon);
|
||||
context.put(operation, weaponsToOperate);
|
||||
private void commitInsert() {
|
||||
var studentsToBeInserted = context.get(IUnitOfWork.INSERT);
|
||||
for (var student : studentsToBeInserted) {
|
||||
LOGGER.info("Saving {} to database.", student.getName());
|
||||
studentDatabase.insert(student);
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* All UnitOfWork operations are batched and executed together on commit only.
|
||||
*/
|
||||
@Override
|
||||
public void commit() {
|
||||
if (context == null || context.size() == 0) {
|
||||
return;
|
||||
}
|
||||
LOGGER.info("Commit started");
|
||||
if (context.containsKey(UnitActions.INSERT.getActionValue())) {
|
||||
commitInsert();
|
||||
}
|
||||
|
||||
if (context.containsKey(UnitActions.MODIFY.getActionValue())) {
|
||||
commitModify();
|
||||
}
|
||||
if (context.containsKey(UnitActions.DELETE.getActionValue())) {
|
||||
commitDelete();
|
||||
}
|
||||
LOGGER.info("Commit finished.");
|
||||
private void commitModify() {
|
||||
var modifiedStudents = context.get(IUnitOfWork.MODIFY);
|
||||
for (var student : modifiedStudents) {
|
||||
LOGGER.info("Modifying {} to database.", student.getName());
|
||||
studentDatabase.modify(student);
|
||||
}
|
||||
}
|
||||
|
||||
private void commitInsert() {
|
||||
var weaponsToBeInserted = context.get(UnitActions.INSERT.getActionValue());
|
||||
for (var weapon : weaponsToBeInserted) {
|
||||
LOGGER.info("Inserting a new weapon {} to sales rack.", weapon.getName());
|
||||
weaponDatabase.insert(weapon);
|
||||
}
|
||||
}
|
||||
|
||||
private void commitModify() {
|
||||
var modifiedWeapons = context.get(UnitActions.MODIFY.getActionValue());
|
||||
for (var weapon : modifiedWeapons) {
|
||||
LOGGER.info("Scheduling {} for modification work.", weapon.getName());
|
||||
weaponDatabase.modify(weapon);
|
||||
}
|
||||
}
|
||||
|
||||
private void commitDelete() {
|
||||
var deletedWeapons = context.get(UnitActions.DELETE.getActionValue());
|
||||
for (var weapon : deletedWeapons) {
|
||||
LOGGER.info("Scrapping {}.", weapon.getName());
|
||||
weaponDatabase.delete(weapon);
|
||||
}
|
||||
private void commitDelete() {
|
||||
var deletedStudents = context.get(IUnitOfWork.DELETE);
|
||||
for (var student : deletedStudents) {
|
||||
LOGGER.info("Deleting {} to database.", student.getName());
|
||||
studentDatabase.delete(student);
|
||||
}
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Here is how the whole app is put together.
|
||||
Finally, here's how we use the `StudentRepository` and `commit` the transaction.
|
||||
|
||||
```java
|
||||
// create some weapons
|
||||
var enchantedHammer = new Weapon(1, "enchanted hammer");
|
||||
var brokenGreatSword = new Weapon(2, "broken great sword");
|
||||
var silverTrident = new Weapon(3, "silver trident");
|
||||
|
||||
// create repository
|
||||
var weaponRepository = new ArmsDealer(new HashMap<String, List<Weapon>>(), new WeaponDatabase());
|
||||
|
||||
// perform operations on the weapons
|
||||
weaponRepository.registerNew(enchantedHammer);
|
||||
weaponRepository.registerModified(silverTrident);
|
||||
weaponRepository.registerDeleted(brokenGreatSword);
|
||||
weaponRepository.commit();
|
||||
```
|
||||
|
||||
Here is the console output.
|
||||
|
||||
```
|
||||
21:39:21.984 [main] INFO com.iluwatar.unitofwork.ArmsDealer - Registering enchanted hammer for insert in context.
|
||||
21:39:21.989 [main] INFO com.iluwatar.unitofwork.ArmsDealer - Registering silver trident for modify in context.
|
||||
21:39:21.989 [main] INFO com.iluwatar.unitofwork.ArmsDealer - Registering broken great sword for delete in context.
|
||||
21:39:21.989 [main] INFO com.iluwatar.unitofwork.ArmsDealer - Commit started
|
||||
21:39:21.989 [main] INFO com.iluwatar.unitofwork.ArmsDealer - Inserting a new weapon enchanted hammer to sales rack.
|
||||
21:39:21.989 [main] INFO com.iluwatar.unitofwork.ArmsDealer - Scheduling silver trident for modification work.
|
||||
21:39:21.989 [main] INFO com.iluwatar.unitofwork.ArmsDealer - Scrapping broken great sword.
|
||||
21:39:21.989 [main] INFO com.iluwatar.unitofwork.ArmsDealer - Commit finished.
|
||||
studentRepository.registerNew(ram);
|
||||
studentRepository.registerModified(shyam);
|
||||
studentRepository.registerDeleted(gopi);
|
||||
studentRepository.commit();
|
||||
```
|
||||
|
||||
## Class diagram
|
||||
@ -190,7 +186,7 @@ Use the Unit Of Work pattern when
|
||||
|
||||
* To optimize the time taken for database transactions.
|
||||
* To send changes to database as a unit of work which ensures atomicity of the transaction.
|
||||
* To reduce the number of database calls.
|
||||
* To reduce number of database calls.
|
||||
|
||||
## Tutorials
|
||||
|
||||
|
||||
@ -1,7 +1,7 @@
|
||||
<?xml version="1.0" encoding="UTF-8"?>
|
||||
<class-diagram version="1.2.1" icons="true" always-add-relationships="false" generalizations="true" realizations="true"
|
||||
associations="true" dependencies="false" nesting-relationships="true" router="FAN">
|
||||
<class id="1" language="java" name="com.iluwatar.unitofwork.WeaponDatabase" project="unit-of-work"
|
||||
<class id="1" language="java" name="com.iluwatar.unitofwork.StudentDatabase" project="unit-of-work"
|
||||
file="/unit-of-work/src/main/java/com/iluwatar/unitofwork/StudentDatabase.java" binary="false" corner="BOTTOM_RIGHT">
|
||||
<position height="-1" width="-1" x="170" y="406"/>
|
||||
<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
|
||||
@ -28,7 +28,7 @@
|
||||
<operations public="true" package="true" protected="true" private="true" static="true"/>
|
||||
</display>
|
||||
</class>
|
||||
<class id="4" language="java" name="com.iluwatar.unitofwork.ArmsDealer" project="unit-of-work"
|
||||
<class id="4" language="java" name="com.iluwatar.unitofwork.StudentRepository" project="unit-of-work"
|
||||
file="/unit-of-work/src/main/java/com/iluwatar/unitofwork/StudentRepository.java" binary="false"
|
||||
corner="BOTTOM_RIGHT">
|
||||
<position height="-1" width="-1" x="377" y="166"/>
|
||||
@ -38,7 +38,7 @@
|
||||
<operations public="true" package="true" protected="true" private="true" static="true"/>
|
||||
</display>
|
||||
</class>
|
||||
<class id="5" language="java" name="com.iluwatar.unitofwork.Weapon" project="unit-of-work"
|
||||
<class id="5" language="java" name="com.iluwatar.unitofwork.Student" project="unit-of-work"
|
||||
file="/unit-of-work/src/main/java/com/iluwatar/unitofwork/Student.java" binary="false" corner="BOTTOM_RIGHT">
|
||||
<position height="-1" width="-1" x="696" y="130"/>
|
||||
<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
|
||||
|
||||
@ -27,7 +27,7 @@ import java.util.HashMap;
|
||||
import java.util.List;
|
||||
|
||||
/**
|
||||
* {@link App} Application demonstrating unit of work pattern.
|
||||
* {@link App} Application for managing student data.
|
||||
*/
|
||||
public class App {
|
||||
/**
|
||||
@ -37,19 +37,17 @@ public class App {
|
||||
*/
|
||||
|
||||
public static void main(String[] args) {
|
||||
// create some weapons
|
||||
var enchantedHammer = new Weapon(1, "enchanted hammer");
|
||||
var brokenGreatSword = new Weapon(2, "broken great sword");
|
||||
var silverTrident = new Weapon(3, "silver trident");
|
||||
var ram = new Student(1, "Ram", "Street 9, Cupertino");
|
||||
var shyam = new Student(2, "Shyam", "Z bridge, Pune");
|
||||
var gopi = new Student(3, "Gopi", "Street 10, Mumbai");
|
||||
|
||||
// create repository
|
||||
var weaponRepository = new ArmsDealer(new HashMap<String, List<Weapon>>(),
|
||||
new WeaponDatabase());
|
||||
var context = new HashMap<String, List<Student>>();
|
||||
var studentDatabase = new StudentDatabase();
|
||||
var studentRepository = new StudentRepository(context, studentDatabase);
|
||||
|
||||
// perform operations on the weapons
|
||||
weaponRepository.registerNew(enchantedHammer);
|
||||
weaponRepository.registerModified(silverTrident);
|
||||
weaponRepository.registerDeleted(brokenGreatSword);
|
||||
weaponRepository.commit();
|
||||
studentRepository.registerNew(ram);
|
||||
studentRepository.registerModified(shyam);
|
||||
studentRepository.registerDeleted(gopi);
|
||||
studentRepository.commit();
|
||||
}
|
||||
}
|
||||
|
||||
@ -27,12 +27,14 @@ import lombok.Getter;
|
||||
import lombok.RequiredArgsConstructor;
|
||||
|
||||
/**
|
||||
* {@link Weapon} is an entity.
|
||||
* {@link Student} is an entity.
|
||||
*/
|
||||
@Getter
|
||||
@RequiredArgsConstructor
|
||||
public class Weapon {
|
||||
public class Student {
|
||||
|
||||
private final Integer id;
|
||||
private final String name;
|
||||
private final String address;
|
||||
|
||||
}
|
||||
@ -24,19 +24,19 @@
|
||||
package com.iluwatar.unitofwork;
|
||||
|
||||
/**
|
||||
* Act as database for weapon records.
|
||||
* Act as Database for student records.
|
||||
*/
|
||||
public class WeaponDatabase {
|
||||
public class StudentDatabase {
|
||||
|
||||
public void insert(Weapon weapon) {
|
||||
public void insert(Student student) {
|
||||
//Some insert logic to DB
|
||||
}
|
||||
|
||||
public void modify(Weapon weapon) {
|
||||
public void modify(Student student) {
|
||||
//Some modify logic to DB
|
||||
}
|
||||
|
||||
public void delete(Weapon weapon) {
|
||||
public void delete(Student student) {
|
||||
//Some delete logic to DB
|
||||
}
|
||||
}
|
||||
@ -30,41 +30,41 @@ import lombok.RequiredArgsConstructor;
|
||||
import lombok.extern.slf4j.Slf4j;
|
||||
|
||||
/**
|
||||
* {@link ArmsDealer} Weapon repository that supports unit of work for weapons.
|
||||
* {@link StudentRepository} Student database repository. supports unit of work for student data.
|
||||
*/
|
||||
@Slf4j
|
||||
@RequiredArgsConstructor
|
||||
public class ArmsDealer implements IUnitOfWork<Weapon> {
|
||||
public class StudentRepository implements IUnitOfWork<Student> {
|
||||
|
||||
private final Map<String, List<Weapon>> context;
|
||||
private final WeaponDatabase weaponDatabase;
|
||||
private final Map<String, List<Student>> context;
|
||||
private final StudentDatabase studentDatabase;
|
||||
|
||||
@Override
|
||||
public void registerNew(Weapon weapon) {
|
||||
LOGGER.info("Registering {} for insert in context.", weapon.getName());
|
||||
register(weapon, UnitActions.INSERT.getActionValue());
|
||||
public void registerNew(Student student) {
|
||||
LOGGER.info("Registering {} for insert in context.", student.getName());
|
||||
register(student, UnitActions.INSERT.getActionValue());
|
||||
}
|
||||
|
||||
@Override
|
||||
public void registerModified(Weapon weapon) {
|
||||
LOGGER.info("Registering {} for modify in context.", weapon.getName());
|
||||
register(weapon, UnitActions.MODIFY.getActionValue());
|
||||
public void registerModified(Student student) {
|
||||
LOGGER.info("Registering {} for modify in context.", student.getName());
|
||||
register(student, UnitActions.MODIFY.getActionValue());
|
||||
|
||||
}
|
||||
|
||||
@Override
|
||||
public void registerDeleted(Weapon weapon) {
|
||||
LOGGER.info("Registering {} for delete in context.", weapon.getName());
|
||||
register(weapon, UnitActions.DELETE.getActionValue());
|
||||
public void registerDeleted(Student student) {
|
||||
LOGGER.info("Registering {} for delete in context.", student.getName());
|
||||
register(student, UnitActions.DELETE.getActionValue());
|
||||
}
|
||||
|
||||
private void register(Weapon weapon, String operation) {
|
||||
var weaponsToOperate = context.get(operation);
|
||||
if (weaponsToOperate == null) {
|
||||
weaponsToOperate = new ArrayList<>();
|
||||
private void register(Student student, String operation) {
|
||||
var studentsToOperate = context.get(operation);
|
||||
if (studentsToOperate == null) {
|
||||
studentsToOperate = new ArrayList<>();
|
||||
}
|
||||
weaponsToOperate.add(weapon);
|
||||
context.put(operation, weaponsToOperate);
|
||||
studentsToOperate.add(student);
|
||||
context.put(operation, studentsToOperate);
|
||||
}
|
||||
|
||||
/**
|
||||
@ -90,26 +90,26 @@ public class ArmsDealer implements IUnitOfWork<Weapon> {
|
||||
}
|
||||
|
||||
private void commitInsert() {
|
||||
var weaponsToBeInserted = context.get(UnitActions.INSERT.getActionValue());
|
||||
for (var weapon : weaponsToBeInserted) {
|
||||
LOGGER.info("Inserting a new weapon {} to sales rack.", weapon.getName());
|
||||
weaponDatabase.insert(weapon);
|
||||
var studentsToBeInserted = context.get(UnitActions.INSERT.getActionValue());
|
||||
for (var student : studentsToBeInserted) {
|
||||
LOGGER.info("Saving {} to database.", student.getName());
|
||||
studentDatabase.insert(student);
|
||||
}
|
||||
}
|
||||
|
||||
private void commitModify() {
|
||||
var modifiedWeapons = context.get(UnitActions.MODIFY.getActionValue());
|
||||
for (var weapon : modifiedWeapons) {
|
||||
LOGGER.info("Scheduling {} for modification work.", weapon.getName());
|
||||
weaponDatabase.modify(weapon);
|
||||
var modifiedStudents = context.get(UnitActions.MODIFY.getActionValue());
|
||||
for (var student : modifiedStudents) {
|
||||
LOGGER.info("Modifying {} to database.", student.getName());
|
||||
studentDatabase.modify(student);
|
||||
}
|
||||
}
|
||||
|
||||
private void commitDelete() {
|
||||
var deletedWeapons = context.get(UnitActions.DELETE.getActionValue());
|
||||
for (var weapon : deletedWeapons) {
|
||||
LOGGER.info("Scrapping {}.", weapon.getName());
|
||||
weaponDatabase.delete(weapon);
|
||||
var deletedStudents = context.get(UnitActions.DELETE.getActionValue());
|
||||
for (var student : deletedStudents) {
|
||||
LOGGER.info("Deleting {} to database.", student.getName());
|
||||
studentDatabase.delete(student);
|
||||
}
|
||||
}
|
||||
}
|
||||
@ -36,102 +36,102 @@ import java.util.Map;
|
||||
import org.junit.jupiter.api.Test;
|
||||
|
||||
/**
|
||||
* tests {@link ArmsDealer}
|
||||
* tests {@link StudentRepository}
|
||||
*/
|
||||
|
||||
class ArmsDealerTest {
|
||||
private final Weapon weapon1 = new Weapon(1, "battle ram");
|
||||
private final Weapon weapon2 = new Weapon(1, "wooden lance");
|
||||
class StudentRepositoryTest {
|
||||
private final Student student1 = new Student(1, "Ram", "street 9, cupertino");
|
||||
private final Student student2 = new Student(1, "Sham", "Z bridge, pune");
|
||||
|
||||
private final Map<String, List<Weapon>> context = new HashMap<>();
|
||||
private final WeaponDatabase weaponDatabase = mock(WeaponDatabase.class);
|
||||
private final ArmsDealer armsDealer = new ArmsDealer(context, weaponDatabase);;
|
||||
private final Map<String, List<Student>> context = new HashMap<>();
|
||||
private final StudentDatabase studentDatabase = mock(StudentDatabase.class);
|
||||
private final StudentRepository studentRepository = new StudentRepository(context, studentDatabase);;
|
||||
|
||||
@Test
|
||||
void shouldSaveNewStudentWithoutWritingToDb() {
|
||||
armsDealer.registerNew(weapon1);
|
||||
armsDealer.registerNew(weapon2);
|
||||
studentRepository.registerNew(student1);
|
||||
studentRepository.registerNew(student2);
|
||||
|
||||
assertEquals(2, context.get(UnitActions.INSERT.getActionValue()).size());
|
||||
verifyNoMoreInteractions(weaponDatabase);
|
||||
verifyNoMoreInteractions(studentDatabase);
|
||||
}
|
||||
|
||||
@Test
|
||||
void shouldSaveDeletedStudentWithoutWritingToDb() {
|
||||
armsDealer.registerDeleted(weapon1);
|
||||
armsDealer.registerDeleted(weapon2);
|
||||
studentRepository.registerDeleted(student1);
|
||||
studentRepository.registerDeleted(student2);
|
||||
|
||||
assertEquals(2, context.get(UnitActions.DELETE.getActionValue()).size());
|
||||
verifyNoMoreInteractions(weaponDatabase);
|
||||
verifyNoMoreInteractions(studentDatabase);
|
||||
}
|
||||
|
||||
@Test
|
||||
void shouldSaveModifiedStudentWithoutWritingToDb() {
|
||||
armsDealer.registerModified(weapon1);
|
||||
armsDealer.registerModified(weapon2);
|
||||
studentRepository.registerModified(student1);
|
||||
studentRepository.registerModified(student2);
|
||||
|
||||
assertEquals(2, context.get(UnitActions.MODIFY.getActionValue()).size());
|
||||
verifyNoMoreInteractions(weaponDatabase);
|
||||
verifyNoMoreInteractions(studentDatabase);
|
||||
}
|
||||
|
||||
@Test
|
||||
void shouldSaveAllLocalChangesToDb() {
|
||||
context.put(UnitActions.INSERT.getActionValue(), List.of(weapon1));
|
||||
context.put(UnitActions.MODIFY.getActionValue(), List.of(weapon1));
|
||||
context.put(UnitActions.DELETE.getActionValue(), List.of(weapon1));
|
||||
context.put(UnitActions.INSERT.getActionValue(), List.of(student1));
|
||||
context.put(UnitActions.MODIFY.getActionValue(), List.of(student1));
|
||||
context.put(UnitActions.DELETE.getActionValue(), List.of(student1));
|
||||
|
||||
armsDealer.commit();
|
||||
studentRepository.commit();
|
||||
|
||||
verify(weaponDatabase, times(1)).insert(weapon1);
|
||||
verify(weaponDatabase, times(1)).modify(weapon1);
|
||||
verify(weaponDatabase, times(1)).delete(weapon1);
|
||||
verify(studentDatabase, times(1)).insert(student1);
|
||||
verify(studentDatabase, times(1)).modify(student1);
|
||||
verify(studentDatabase, times(1)).delete(student1);
|
||||
}
|
||||
|
||||
@Test
|
||||
void shouldNotWriteToDbIfContextIsNull() {
|
||||
var weaponRepository = new ArmsDealer(null, weaponDatabase);
|
||||
var studentRepository = new StudentRepository(null, studentDatabase);
|
||||
|
||||
weaponRepository.commit();
|
||||
studentRepository.commit();
|
||||
|
||||
verifyNoMoreInteractions(weaponDatabase);
|
||||
verifyNoMoreInteractions(studentDatabase);
|
||||
}
|
||||
|
||||
@Test
|
||||
void shouldNotWriteToDbIfNothingToCommit() {
|
||||
var weaponRepository = new ArmsDealer(new HashMap<>(), weaponDatabase);
|
||||
var studentRepository = new StudentRepository(new HashMap<>(), studentDatabase);
|
||||
|
||||
weaponRepository.commit();
|
||||
studentRepository.commit();
|
||||
|
||||
verifyNoMoreInteractions(weaponDatabase);
|
||||
verifyNoMoreInteractions(studentDatabase);
|
||||
}
|
||||
|
||||
@Test
|
||||
void shouldNotInsertToDbIfNoRegisteredStudentsToBeCommitted() {
|
||||
context.put(UnitActions.MODIFY.getActionValue(), List.of(weapon1));
|
||||
context.put(UnitActions.DELETE.getActionValue(), List.of(weapon1));
|
||||
context.put(UnitActions.MODIFY.getActionValue(), List.of(student1));
|
||||
context.put(UnitActions.DELETE.getActionValue(), List.of(student1));
|
||||
|
||||
armsDealer.commit();
|
||||
studentRepository.commit();
|
||||
|
||||
verify(weaponDatabase, never()).insert(weapon1);
|
||||
verify(studentDatabase, never()).insert(student1);
|
||||
}
|
||||
|
||||
@Test
|
||||
void shouldNotModifyToDbIfNotRegisteredStudentsToBeCommitted() {
|
||||
context.put(UnitActions.INSERT.getActionValue(), List.of(weapon1));
|
||||
context.put(UnitActions.DELETE.getActionValue(), List.of(weapon1));
|
||||
context.put(UnitActions.INSERT.getActionValue(), List.of(student1));
|
||||
context.put(UnitActions.DELETE.getActionValue(), List.of(student1));
|
||||
|
||||
armsDealer.commit();
|
||||
studentRepository.commit();
|
||||
|
||||
verify(weaponDatabase, never()).modify(weapon1);
|
||||
verify(studentDatabase, never()).modify(student1);
|
||||
}
|
||||
|
||||
@Test
|
||||
void shouldNotDeleteFromDbIfNotRegisteredStudentsToBeCommitted() {
|
||||
context.put(UnitActions.INSERT.getActionValue(), List.of(weapon1));
|
||||
context.put(UnitActions.MODIFY.getActionValue(), List.of(weapon1));
|
||||
context.put(UnitActions.INSERT.getActionValue(), List.of(student1));
|
||||
context.put(UnitActions.MODIFY.getActionValue(), List.of(student1));
|
||||
|
||||
armsDealer.commit();
|
||||
studentRepository.commit();
|
||||
|
||||
verify(weaponDatabase, never()).delete(weapon1);
|
||||
verify(studentDatabase, never()).delete(student1);
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user