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未验证 提交 2823166c 编写于 作者: I Ilkka Seppälä
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refactor unit of work

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unit-of-work/README.md
浏览文件 @ 2823166c
......@@ -12,20 +12,20 @@ tags:
## Intent
When a business transaction is completed, all the the updates are sent as one big unit of work to be
When a business transaction is completed, all 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
> 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
> 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
> 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 single batch to optimize the number of
> Unit of Work merges many small database updates in a single batch to optimize the number of
> round-trips.
[MartinFowler.com](https://martinfowler.com/eaaCatalog/unitOfWork.html) says
......@@ -35,37 +35,20 @@ In plain words
**Programmatic Example**
Here's the `Student` entity that is being persisted to the database.
Here's the `Weapon` entity that is being persisted in the database.
```java
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;
}
@Getter
@RequiredArgsConstructor
public class Weapon {
private final Integer id;
private final String name;
}
```
The essence of the implementation is the `StudentRepository` implementing the Unit of Work pattern.
The essence of the implementation is the `ArmsDealer` 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 single batch.
called it applies them in a single batch.
```java
public interface IUnitOfWork<T> {
......@@ -84,96 +67,117 @@ public interface IUnitOfWork<T> {
}
@Slf4j
public class StudentRepository implements IUnitOfWork<Student> {
private final Map<String, List<Student>> context;
private final StudentDatabase studentDatabase;
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<>();
@RequiredArgsConstructor
public class ArmsDealer implements IUnitOfWork<Weapon> {
private final Map<String, List<Weapon>> context;
private final WeaponDatabase weaponDatabase;
@Override
public void registerNew(Weapon weapon) {
LOGGER.info("Registering {} for insert in context.", weapon.getName());
register(weapon, UnitActions.INSERT.getActionValue());
}
studentsToOperate.add(student);
context.put(operation, studentsToOperate);
}
@Override
public void commit() {
if (context == null || context.size() == 0) {
return;
@Override
public void registerModified(Weapon weapon) {
LOGGER.info("Registering {} for modify in context.", weapon.getName());
register(weapon, UnitActions.MODIFY.getActionValue());
}
LOGGER.info("Commit started");
if (context.containsKey(IUnitOfWork.INSERT)) {
commitInsert();
@Override
public void registerDeleted(Weapon weapon) {
LOGGER.info("Registering {} for delete in context.", weapon.getName());
register(weapon, UnitActions.DELETE.getActionValue());
}
if (context.containsKey(IUnitOfWork.MODIFY)) {
commitModify();
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);
}
if (context.containsKey(IUnitOfWork.DELETE)) {
commitDelete();
/**
* 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.");
}
LOGGER.info("Commit finished.");
}
private void commitInsert() {
var studentsToBeInserted = context.get(IUnitOfWork.INSERT);
for (var student : studentsToBeInserted) {
LOGGER.info("Saving {} to database.", student.getName());
studentDatabase.insert(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 modifiedStudents = context.get(IUnitOfWork.MODIFY);
for (var student : modifiedStudents) {
LOGGER.info("Modifying {} to database.", student.getName());
studentDatabase.modify(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);
}
}
}
private void commitDelete() {
var deletedStudents = context.get(IUnitOfWork.DELETE);
for (var student : deletedStudents) {
LOGGER.info("Deleting {} to database.", student.getName());
studentDatabase.delete(student);
private void commitDelete() {
var deletedWeapons = context.get(UnitActions.DELETE.getActionValue());
for (var weapon : deletedWeapons) {
LOGGER.info("Scrapping {}.", weapon.getName());
weaponDatabase.delete(weapon);
}
}
}
}
```
Finally, here's how we use the `StudentRepository` and `commit` the transaction.
Here is how the whole app is put together.
```java
studentRepository.registerNew(ram);
studentRepository.registerModified(shyam);
studentRepository.registerDeleted(gopi);
studentRepository.commit();
// 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.
```
## Class diagram
......@@ -186,7 +190,7 @@ 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 number of database calls.
* To reduce the number of database calls.
## Tutorials
......
unit-of-work/etc/unit-of-work.ucls
浏览文件 @ 2823166c
<?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.StudentDatabase" project="unit-of-work"
<class id="1" language="java" name="com.iluwatar.unitofwork.WeaponDatabase" 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.StudentRepository" project="unit-of-work"
<class id="4" language="java" name="com.iluwatar.unitofwork.ArmsDealer" 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.Student" project="unit-of-work"
<class id="5" language="java" name="com.iluwatar.unitofwork.Weapon" 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"
......
unit-of-work/src/main/java/com/iluwatar/unitofwork/App.java
浏览文件 @ 2823166c
......@@ -27,7 +27,7 @@ import java.util.HashMap;
import java.util.List;
/**
* {@link App} Application for managing student data.
* {@link App} Application demonstrating unit of work pattern.
*/
public class App {
/**
......@@ -37,17 +37,19 @@ public class App {
*/
public static void main(String[] args) {
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 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 context = new HashMap<String, List<Student>>();
var studentDatabase = new StudentDatabase();
var studentRepository = new StudentRepository(context, studentDatabase);
// create repository
var weaponRepository = new ArmsDealer(new HashMap<String, List<Weapon>>(),
new WeaponDatabase());
studentRepository.registerNew(ram);
studentRepository.registerModified(shyam);
studentRepository.registerDeleted(gopi);
studentRepository.commit();
// perform operations on the weapons
weaponRepository.registerNew(enchantedHammer);
weaponRepository.registerModified(silverTrident);
weaponRepository.registerDeleted(brokenGreatSword);
weaponRepository.commit();
}
}
unit-of-work/src/main/java/com/iluwatar/unitofwork/StudentRepository.java → unit-of-work/src/main/java/com/iluwatar/unitofwork/ArmsDealer.java
浏览文件 @ 2823166c
......@@ -30,41 +30,41 @@ import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
/**
* {@link StudentRepository} Student database repository. supports unit of work for student data.
* {@link ArmsDealer} Weapon repository that supports unit of work for weapons.
*/
@Slf4j
@RequiredArgsConstructor
public class StudentRepository implements IUnitOfWork<Student> {
public class ArmsDealer implements IUnitOfWork<Weapon> {
private final Map<String, List<Student>> context;
private final StudentDatabase studentDatabase;
private final Map<String, List<Weapon>> context;
private final WeaponDatabase weaponDatabase;
@Override
public void registerNew(Student student) {
LOGGER.info("Registering {} for insert in context.", student.getName());
register(student, UnitActions.INSERT.getActionValue());
public void registerNew(Weapon weapon) {
LOGGER.info("Registering {} for insert in context.", weapon.getName());
register(weapon, UnitActions.INSERT.getActionValue());
}
@Override
public void registerModified(Student student) {
LOGGER.info("Registering {} for modify in context.", student.getName());
register(student, UnitActions.MODIFY.getActionValue());
public void registerModified(Weapon weapon) {
LOGGER.info("Registering {} for modify in context.", weapon.getName());
register(weapon, UnitActions.MODIFY.getActionValue());
}
@Override
public void registerDeleted(Student student) {
LOGGER.info("Registering {} for delete in context.", student.getName());
register(student, UnitActions.DELETE.getActionValue());
public void registerDeleted(Weapon weapon) {
LOGGER.info("Registering {} for delete in context.", weapon.getName());
register(weapon, UnitActions.DELETE.getActionValue());
}
private void register(Student student, String operation) {
var studentsToOperate = context.get(operation);
if (studentsToOperate == null) {
studentsToOperate = new ArrayList<>();
private void register(Weapon weapon, String operation) {
var weaponsToOperate = context.get(operation);
if (weaponsToOperate == null) {
weaponsToOperate = new ArrayList<>();
}
studentsToOperate.add(student);
context.put(operation, studentsToOperate);
weaponsToOperate.add(weapon);
context.put(operation, weaponsToOperate);
}
/**
......@@ -90,26 +90,26 @@ public class StudentRepository implements IUnitOfWork<Student> {
}
private void commitInsert() {
var studentsToBeInserted = context.get(UnitActions.INSERT.getActionValue());
for (var student : studentsToBeInserted) {
LOGGER.info("Saving {} to database.", student.getName());
studentDatabase.insert(student);
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 modifiedStudents = context.get(UnitActions.MODIFY.getActionValue());
for (var student : modifiedStudents) {
LOGGER.info("Modifying {} to database.", student.getName());
studentDatabase.modify(student);
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 deletedStudents = context.get(UnitActions.DELETE.getActionValue());
for (var student : deletedStudents) {
LOGGER.info("Deleting {} to database.", student.getName());
studentDatabase.delete(student);
var deletedWeapons = context.get(UnitActions.DELETE.getActionValue());
for (var weapon : deletedWeapons) {
LOGGER.info("Scrapping {}.", weapon.getName());
weaponDatabase.delete(weapon);
}
}
}
unit-of-work/src/main/java/com/iluwatar/unitofwork/Student.java → unit-of-work/src/main/java/com/iluwatar/unitofwork/Weapon.java
浏览文件 @ 2823166c
......@@ -27,14 +27,12 @@ import lombok.Getter;
import lombok.RequiredArgsConstructor;
/**
* {@link Student} is an entity.
* {@link Weapon} is an entity.
*/
@Getter
@RequiredArgsConstructor
public class Student {
public class Weapon {
private final Integer id;
private final String name;
private final String address;
}
unit-of-work/src/main/java/com/iluwatar/unitofwork/StudentDatabase.java → unit-of-work/src/main/java/com/iluwatar/unitofwork/WeaponDatabase.java
浏览文件 @ 2823166c
......@@ -24,19 +24,19 @@
package com.iluwatar.unitofwork;
/**
* Act as Database for student records.
* Act as database for weapon records.
*/
public class StudentDatabase {
public class WeaponDatabase {
public void insert(Student student) {
public void insert(Weapon weapon) {
//Some insert logic to DB
}
public void modify(Student student) {
public void modify(Weapon weapon) {
//Some modify logic to DB
}
public void delete(Student student) {
public void delete(Weapon weapon) {
//Some delete logic to DB
}
}
unit-of-work/src/test/java/com/iluwatar/unitofwork/StudentRepositoryTest.java → unit-of-work/src/test/java/com/iluwatar/unitofwork/ArmsDealerTest.java
浏览文件 @ 2823166c
......@@ -36,102 +36,102 @@ import java.util.Map;
import org.junit.jupiter.api.Test;
/**
* tests {@link StudentRepository}
* tests {@link ArmsDealer}
*/
class StudentRepositoryTest {
private final Student student1 = new Student(1, "Ram", "street 9, cupertino");
private final Student student2 = new Student(1, "Sham", "Z bridge, pune");
class ArmsDealerTest {
private final Weapon weapon1 = new Weapon(1, "battle ram");
private final Weapon weapon2 = new Weapon(1, "wooden lance");
private final Map<String, List<Student>> context = new HashMap<>();
private final StudentDatabase studentDatabase = mock(StudentDatabase.class);
private final StudentRepository studentRepository = new StudentRepository(context, studentDatabase);;
private final Map<String, List<Weapon>> context = new HashMap<>();
private final WeaponDatabase weaponDatabase = mock(WeaponDatabase.class);
private final ArmsDealer armsDealer = new ArmsDealer(context, weaponDatabase);;
@Test
void shouldSaveNewStudentWithoutWritingToDb() {
studentRepository.registerNew(student1);
studentRepository.registerNew(student2);
armsDealer.registerNew(weapon1);
armsDealer.registerNew(weapon2);
assertEquals(2, context.get(UnitActions.INSERT.getActionValue()).size());
verifyNoMoreInteractions(studentDatabase);
verifyNoMoreInteractions(weaponDatabase);
}
@Test
void shouldSaveDeletedStudentWithoutWritingToDb() {
studentRepository.registerDeleted(student1);
studentRepository.registerDeleted(student2);
armsDealer.registerDeleted(weapon1);
armsDealer.registerDeleted(weapon2);
assertEquals(2, context.get(UnitActions.DELETE.getActionValue()).size());
verifyNoMoreInteractions(studentDatabase);
verifyNoMoreInteractions(weaponDatabase);
}
@Test
void shouldSaveModifiedStudentWithoutWritingToDb() {
studentRepository.registerModified(student1);
studentRepository.registerModified(student2);
armsDealer.registerModified(weapon1);
armsDealer.registerModified(weapon2);
assertEquals(2, context.get(UnitActions.MODIFY.getActionValue()).size());
verifyNoMoreInteractions(studentDatabase);
verifyNoMoreInteractions(weaponDatabase);
}
@Test
void shouldSaveAllLocalChangesToDb() {
context.put(UnitActions.INSERT.getActionValue(), List.of(student1));
context.put(UnitActions.MODIFY.getActionValue(), List.of(student1));
context.put(UnitActions.DELETE.getActionValue(), List.of(student1));
context.put(UnitActions.INSERT.getActionValue(), List.of(weapon1));
context.put(UnitActions.MODIFY.getActionValue(), List.of(weapon1));
context.put(UnitActions.DELETE.getActionValue(), List.of(weapon1));
studentRepository.commit();
armsDealer.commit();
verify(studentDatabase, times(1)).insert(student1);
verify(studentDatabase, times(1)).modify(student1);
verify(studentDatabase, times(1)).delete(student1);
verify(weaponDatabase, times(1)).insert(weapon1);
verify(weaponDatabase, times(1)).modify(weapon1);
verify(weaponDatabase, times(1)).delete(weapon1);
}
@Test
void shouldNotWriteToDbIfContextIsNull() {
var studentRepository = new StudentRepository(null, studentDatabase);
var weaponRepository = new ArmsDealer(null, weaponDatabase);
studentRepository.commit();
weaponRepository.commit();
verifyNoMoreInteractions(studentDatabase);
verifyNoMoreInteractions(weaponDatabase);
}
@Test
void shouldNotWriteToDbIfNothingToCommit() {
var studentRepository = new StudentRepository(new HashMap<>(), studentDatabase);
var weaponRepository = new ArmsDealer(new HashMap<>(), weaponDatabase);
studentRepository.commit();
weaponRepository.commit();
verifyNoMoreInteractions(studentDatabase);
verifyNoMoreInteractions(weaponDatabase);
}
@Test
void shouldNotInsertToDbIfNoRegisteredStudentsToBeCommitted() {
context.put(UnitActions.MODIFY.getActionValue(), List.of(student1));
context.put(UnitActions.DELETE.getActionValue(), List.of(student1));
context.put(UnitActions.MODIFY.getActionValue(), List.of(weapon1));
context.put(UnitActions.DELETE.getActionValue(), List.of(weapon1));
studentRepository.commit();
armsDealer.commit();
verify(studentDatabase, never()).insert(student1);
verify(weaponDatabase, never()).insert(weapon1);
}
@Test
void shouldNotModifyToDbIfNotRegisteredStudentsToBeCommitted() {
context.put(UnitActions.INSERT.getActionValue(), List.of(student1));
context.put(UnitActions.DELETE.getActionValue(), List.of(student1));
context.put(UnitActions.INSERT.getActionValue(), List.of(weapon1));
context.put(UnitActions.DELETE.getActionValue(), List.of(weapon1));
studentRepository.commit();
armsDealer.commit();
verify(studentDatabase, never()).modify(student1);
verify(weaponDatabase, never()).modify(weapon1);
}
@Test
void shouldNotDeleteFromDbIfNotRegisteredStudentsToBeCommitted() {
context.put(UnitActions.INSERT.getActionValue(), List.of(student1));
context.put(UnitActions.MODIFY.getActionValue(), List.of(student1));
context.put(UnitActions.INSERT.getActionValue(), List.of(weapon1));
context.put(UnitActions.MODIFY.getActionValue(), List.of(weapon1));
studentRepository.commit();
armsDealer.commit();
verify(studentDatabase, never()).delete(student1);
verify(weaponDatabase, never()).delete(weapon1);
}
}
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