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Merge branch 'master' of https://github.com/besok/java-design-patterns

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Ilkka Seppälä 2019-11-14 08:02:05 +02:00
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2
pom.xml
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@ -183,6 +183,8 @@
<module>data-locality</module> <module>data-locality</module>
<module>subclass-sandbox</module> <module>subclass-sandbox</module>
<module>circuit-breaker</module> <module>circuit-breaker</module>
<module>role-object</module>
<module>saga</module>
<module>double-buffer</module> <module>double-buffer</module>
<module>sharding</module> <module>sharding</module>
</modules> </modules>

2
role-object/src/main/java/com/iluwatar/roleobject/InvestorRole.java
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@ -43,6 +43,6 @@ public class InvestorRole extends CustomerRole {
} }
public String invest() { public String invest() {
return String.format("Investor %s has invested %d dollars", name, amountToInvest); return String.format("Investor %s has invested %d dollars", name, amountToInvest);
} }
} }

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saga/README.md Normal file
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---
layout: pattern
title: Saga
folder: saga
permalink: /patterns/saga/
categories: Behavioral
tags:
- Java
- Difficulty-Expert
- Idiom
- Distributed communication
---
## Also known as
This pattern has a similar goal with two-phase commit (XA transaction)
## Intent
This pattern is used in distributed services to perform a group of operations atomically.
This is an analog of transaction in a database but in terms of microservices architecture this is executed
in a distributed environment
## Explanation
A saga is a sequence of local transactions in a certain context. If one transaction fails for some reason,
the saga executes compensating transactions(rollbacks) to undo the impact of the preceding transactions.
There are two types of Saga:
- Choreography-Based Saga.
In this approach, there is no central orchestrator.
Each service participating in the Saga performs their transaction and publish events.
The other services act upon those events and perform their transactions.
Also, they may or not publish other events based on the situation.
- Orchestration-Based Saga
In this approach, there is a Saga orchestrator that manages all the transactions and directs
the participant services to execute local transactions based on events.
This orchestrator can also be though of as a Saga Manager.
## Applicability
Use the Saga pattern, if:
- you need to perform a group of operations related to different microservices atomically
- you need to rollback changes in different places in case of failure one of the operation
- you need to take care of data consistency in different places including different databases
- you can not use 2PC(two phase commit)
## Credits
- [Pattern: Saga](https://microservices.io/patterns/data/saga.html)

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saga/pom.xml Normal file
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<?xml version="1.0"?>
<!--
The MIT License
Copyright © 2014-2019 Ilkka Seppälä
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
-->
<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.22.0-SNAPSHOT</version>
</parent>
<artifactId>saga</artifactId>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
</project>

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saga/src/main/java/com/iluwatar/saga/choreography/ChoreographyChapter.java Normal file
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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.choreography;
/**
* ChoreographyChapter is an interface representing a contract for an external service.
* In that case, a service needs to make a decision what to do further
* hence the server needs to get all context representing {@link Saga}
*/
public interface ChoreographyChapter {
/**
* In that case, every method is responsible to make a decision on what to do then.
*
* @param saga incoming saga
* @return saga result
*/
Saga execute(Saga saga);
/**
* get name method.
* @return service name.
*/
String getName();
/**
* The operation executed in general case.
*
* @param saga incoming saga
* @return result {@link Saga}
*/
Saga process(Saga saga);
/**
* The operation executed in rollback case.
*
* @param saga incoming saga
* @return result {@link Saga}
*/
Saga rollback(Saga saga);
}

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saga/src/main/java/com/iluwatar/saga/choreography/FlyBookingService.java Normal file
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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.choreography;
/**
* Class representing a service to book a fly.
*/
public class FlyBookingService extends Service {
public FlyBookingService(ServiceDiscoveryService service) {
super(service);
}
@Override
public String getName() {
return "booking a Fly";
}
}

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saga/src/main/java/com/iluwatar/saga/choreography/HotelBookingService.java Normal file
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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.choreography;
/**
* Class representing a service to book a hotel.
*/
public class HotelBookingService extends Service {
public HotelBookingService(ServiceDiscoveryService service) {
super(service);
}
@Override
public String getName() {
return "booking a Hotel";
}
}

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saga/src/main/java/com/iluwatar/saga/choreography/OrderService.java Normal file
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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.choreography;
/**
* Class representing a service to init a new order.
*/
public class OrderService extends Service {
public OrderService(ServiceDiscoveryService service) {
super(service);
}
@Override
public String getName() {
return "init an order";
}
}

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saga/src/main/java/com/iluwatar/saga/choreography/Saga.java Normal file
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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.choreography;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
/**
* Saga representation.
* Saga consists of chapters.
* Every ChoreographyChapter is executed a certain service.
*/
public class Saga {
private List<Chapter> chapters;
private int pos;
private boolean forward;
private boolean finished;
public static Saga create() {
return new Saga();
}
/**
* get resuzlt of saga.
*
* @return result of saga @see {@link SagaResult}
*/
public SagaResult getResult() {
if (finished) {
return forward
? SagaResult.FINISHED
: SagaResult.ROLLBACKED;
}
return SagaResult.PROGRESS;
}
/**
* add chapter to saga.
* @param name chapter name
* @return this
*/
public Saga chapter(String name) {
this.chapters.add(new Chapter(name));
return this;
}
/**
* set value to last chapter.
* @param value invalue
* @return this
*/
public Saga setInValue(Object value) {
if (chapters.isEmpty()) {
return this;
}
chapters.get(chapters.size() - 1).setInValue(value);
return this;
}
/**
* get value from current chapter.
* @return value
*/
public Object getCurrentValue() {
return chapters.get(pos).getInValue();
}
/**
* set value to current chapter.
* @param value to set
*/
public void setCurrentValue(Object value) {
chapters.get(pos).setInValue(value);
}
/**
* set status for current chapter.
* @param result to set
*/
public void setCurrentStatus(ChapterResult result) {
chapters.get(pos).setResult(result);
}
void setFinished(boolean finished) {
this.finished = finished;
}
boolean isForward() {
return forward;
}
int forward() {
return ++pos;
}
int back() {
this.forward = false;
return --pos;
}
private Saga() {
this.chapters = new ArrayList<>();
this.pos = 0;
this.forward = true;
this.finished = false;
}
Chapter getCurrent() {
return chapters.get(pos);
}
boolean isPresent() {
return pos >= 0 && pos < chapters.size();
}
boolean isCurrentSuccess() {
return chapters.get(pos).isSuccess();
}
/**
* Class presents a chapter status and incoming
* parameters(incoming parameter transforms to outcoming parameter).
*/
public static class Chapter {
private String name;
private ChapterResult result;
private Object inValue;
public Chapter(String name) {
this.name = name;
this.result = ChapterResult.INIT;
}
public Object getInValue() {
return inValue;
}
public void setInValue(Object object) {
this.inValue = object;
}
public String getName() {
return name;
}
/**
* set result.
* @param result {@link ChapterResult}
*/
public void setResult(ChapterResult result) {
this.result = result;
}
/**
* the result for chapter is good.
* @return true if is good otherwise bad
*/
public boolean isSuccess() {
return result == ChapterResult.SUCCESS;
}
}
/**
* result for chapter.
*/
public enum ChapterResult {
INIT, SUCCESS, ROLLBACK
}
/**
* result for saga.
*/
public enum SagaResult {
PROGRESS, FINISHED, ROLLBACKED
}
@Override
public String toString() {
return "Saga{"
+ "chapters="
+ Arrays.toString(chapters.toArray())
+ ", pos="
+ pos
+ ", forward="
+ forward
+ '}';
}
}

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saga/src/main/java/com/iluwatar/saga/choreography/SagaApplication.java Normal file
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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.choreography;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* This pattern is used in distributed services to perform a group of operations atomically.
* This is an analog of transaction in a database but in terms
* of microservices architecture this is executed
* in a distributed environment
*
* <p>A saga is a sequence of local transactions in a certain context.
* If one transaction fails for some reason,
* the saga executes compensating transactions(rollbacks)
* to undo the impact of the preceding transactions.
*
* <p>In this approach, there are no mediators or orchestrators services.
* All chapters are handled and moved by services manually.
*
* <p>The major difference with choreography saga is an ability to handle crashed services
* (otherwise in choreography services very hard to prevent a saga
* if one of them has been crashed)
*
* @see com.iluwatar.saga.choreography.Saga
* @see Service
*/
public class SagaApplication {
private static final Logger LOGGER = LoggerFactory.getLogger(SagaApplication.class);
/**
* main method.
*/
public static void main(String[] args) {
ServiceDiscoveryService sd = serviceDiscovery();
ChoreographyChapter service = sd.findAny();
Saga goodOrderSaga = service.execute(newSaga("good_order"));
Saga badOrderSaga = service.execute(newSaga("bad_order"));
LOGGER.info("orders: goodOrder is {}, badOrder is {}",
goodOrderSaga.getResult(), badOrderSaga.getResult());
}
private static Saga newSaga(Object value) {
return Saga
.create()
.chapter("init an order").setInValue(value)
.chapter("booking a Fly")
.chapter("booking a Hotel")
.chapter("withdrawing Money");
}
private static ServiceDiscoveryService serviceDiscovery() {
ServiceDiscoveryService sd = new ServiceDiscoveryService();
return sd
.discover(new OrderService(sd))
.discover(new FlyBookingService(sd))
.discover(new HotelBookingService(sd))
.discover(new WithdrawMoneyService(sd));
}
}

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saga/src/main/java/com/iluwatar/saga/choreography/Service.java Normal file
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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.choreography;
import java.util.function.Supplier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Common abstraction class representing services.
* implementing a general contract @see {@link ChoreographyChapter}
*/
public abstract class Service implements ChoreographyChapter {
protected static final Logger LOGGER = LoggerFactory.getLogger(Service.class);
private final ServiceDiscoveryService sd;
public Service(ServiceDiscoveryService service) {
this.sd = service;
}
@Override
public Saga execute(Saga saga) {
Saga nextSaga = saga;
Object nextVal;
String chapterName = saga.getCurrent().getName();
if (chapterName.equals(getName())) {
if (saga.isForward()) {
nextSaga = process(saga);
nextVal = nextSaga.getCurrentValue();
if (nextSaga.isCurrentSuccess()) {
nextSaga.forward();
} else {
nextSaga.back();
}
} else {
nextSaga = rollback(saga);
nextVal = nextSaga.getCurrentValue();
nextSaga.back();
}
if (isSagaFinished(nextSaga)) {
return nextSaga;
}
nextSaga.setCurrentValue(nextVal);
}
Saga finalNextSaga = nextSaga;
return sd.find(chapterName).map(ch -> ch.execute(finalNextSaga))
.orElseThrow(serviceNotFoundException(chapterName));
}
private Supplier<RuntimeException> serviceNotFoundException(String chServiceName) {
return () -> new RuntimeException(
String.format("the service %s has not been found", chServiceName));
}
@Override
public Saga process(Saga saga) {
Object inValue = saga.getCurrentValue();
LOGGER.info("The chapter '{}' has been started. "
+ "The data {} has been stored or calculated successfully",
getName(), inValue);
saga.setCurrentStatus(Saga.ChapterResult.SUCCESS);
saga.setCurrentValue(inValue);
return saga;
}
@Override
public Saga rollback(Saga saga) {
Object inValue = saga.getCurrentValue();
LOGGER.info("The Rollback for a chapter '{}' has been started. "
+ "The data {} has been rollbacked successfully",
getName(), inValue);
saga.setCurrentStatus(Saga.ChapterResult.ROLLBACK);
saga.setCurrentValue(inValue);
return saga;
}
private boolean isSagaFinished(Saga saga) {
if (!saga.isPresent()) {
saga.setFinished(true);
LOGGER.info(" the saga has been finished with {} status", saga.getResult());
return true;
}
return false;
}
}

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saga/src/main/java/com/iluwatar/saga/choreography/ServiceDiscoveryService.java Normal file
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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.choreography;
import java.util.HashMap;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Optional;
/**
* The class representing a service discovery pattern.
*/
public class ServiceDiscoveryService {
private Map<String, ChoreographyChapter> services;
/**
* find any service.
*
* @return any service
* @throws NoSuchElementException if no elements further
*/
public ChoreographyChapter findAny() {
return services.values().iterator().next();
}
public Optional<ChoreographyChapter> find(String service) {
return Optional.ofNullable(services.getOrDefault(service, null));
}
public ServiceDiscoveryService discover(ChoreographyChapter chapterService) {
services.put(chapterService.getName(), chapterService);
return this;
}
public ServiceDiscoveryService() {
this.services = new HashMap<>();
}
}

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saga/src/main/java/com/iluwatar/saga/choreography/WithdrawMoneyService.java Normal file
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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.choreography;
/**
* Class representing a service to withdraw a money.
*/
public class WithdrawMoneyService extends Service {
public WithdrawMoneyService(ServiceDiscoveryService service) {
super(service);
}
@Override
public String getName() {
return "withdrawing Money";
}
@Override
public Saga process(Saga saga) {
Object inValue = saga.getCurrentValue();
if (inValue.equals("bad_order")) {
LOGGER.info("The chapter '{}' has been started. But the exception has been raised."
+ "The rollback is about to start",
getName(), inValue);
saga.setCurrentStatus(Saga.ChapterResult.ROLLBACK);
return saga;
}
return super.process(saga);
}
}

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saga/src/main/java/com/iluwatar/saga/orchestration/ChapterResult.java Normal file
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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.orchestration;
/**
* Executing result for chapter.
*
* @param <K> incoming value
*/
public class ChapterResult<K> {
private K value;
private State state;
public K getValue() {
return value;
}
ChapterResult(K value, State state) {
this.value = value;
this.state = state;
}
public boolean isSuccess() {
return state == State.SUCCESS;
}
public static <K> ChapterResult<K> success(K val) {
return new ChapterResult<>(val, State.SUCCESS);
}
public static <K> ChapterResult<K> failure(K val) {
return new ChapterResult<>(val, State.FAILURE);
}
/**
* state for chapter.
*/
public enum State {
SUCCESS, FAILURE
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.orchestration;
/**
* Class representing a service to book a fly.
*/
public class FlyBookingService extends Service<String> {
@Override
public String getName() {
return "booking a Fly";
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.orchestration;
/**
* Class representing a service to book a hotel.
*/
public class HotelBookingService extends Service<String> {
@Override
public String getName() {
return "booking a Hotel";
}
@Override
public ChapterResult<String> rollback(String value) {
if (value.equals("crashed_order")) {
LOGGER.info("The Rollback for a chapter '{}' has been started. "
+ "The data {} has been failed.The saga has been crashed.",
getName(), value);
return ChapterResult.failure(value);
}
LOGGER.info("The Rollback for a chapter '{}' has been started. "
+ "The data {} has been rollbacked successfully",
getName(), value);
return super.rollback(value);
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.orchestration;
/**
* ChoreographyChapter is an interface representing a contract for an external service.
*
* @param <K> is type for passing params
*/
public interface OrchestrationChapter<K> {
/**
* method get name.
* @return service name.
*/
String getName();
/**
* The operation executed in general case.
*
* @param value incoming value
* @return result {@link ChapterResult}
*/
ChapterResult<K> process(K value);
/**
* The operation executed in rollback case.
*
* @param value incoming value
* @return result {@link ChapterResult}
*/
ChapterResult<K> rollback(K value);
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.orchestration;
/**
* Class representing a service to init a new order.
*/
public class OrderService extends Service<String> {
@Override
public String getName() {
return "init an order";
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.orchestration;
import java.util.ArrayList;
import java.util.List;
/**
* Saga representation.
* Saga consists of chapters.
* Every ChoreographyChapter is executed by a certain service.
*/
public class Saga {
private List<Chapter> chapters;
private Saga() {
this.chapters = new ArrayList<>();
}
public Saga chapter(String name) {
this.chapters.add(new Chapter(name));
return this;
}
public Chapter get(int idx) {
return chapters.get(idx);
}
public boolean isPresent(int idx) {
return idx >= 0 && idx < chapters.size();
}
public static Saga create() {
return new Saga();
}
/**
* result for saga.
*/
public enum Result {
FINISHED, ROLLBACK, CRASHED
}
/**
* class represents chapter name.
*/
public static class Chapter {
String name;
public Chapter(String name) {
this.name = name;
}
public String getName() {
return name;
}
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.orchestration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* This pattern is used in distributed services to perform
* a group of operations atomically.
* This is an analog of transaction in a database but in terms
* of microservices architecture this is executed
* in a distributed environment
*
* <p>A saga is a sequence of local transactions in a certain context.
* If one transaction fails for some reason,
* the saga executes compensating transactions(rollbacks)
* to undo the impact of the preceding transactions.
*
* <p>In this approach, there is an orchestrator @see {@link SagaOrchestrator}
* that manages all the transactions and directs
* the participant services to execute local transactions based on events.
* The major difference with choreography saga is an ability to handle crashed services
* (otherwise in choreography services very hard to prevent a saga
* if one of them has been crashed)
*
* @see Saga
* @see SagaOrchestrator
* @see Service
*/
public class SagaApplication {
private static final Logger LOGGER = LoggerFactory.getLogger(SagaApplication.class);
/**
* method to show common saga logic.
*/
public static void main(String[] args) {
SagaOrchestrator sagaOrchestrator = new SagaOrchestrator(newSaga(), serviceDiscovery());
Saga.Result goodOrder = sagaOrchestrator.execute("good_order");
Saga.Result badOrder = sagaOrchestrator.execute("bad_order");
Saga.Result crashedOrder = sagaOrchestrator.execute("crashed_order");
LOGGER.info("orders: goodOrder is {}, badOrder is {},crashedOrder is {}",
goodOrder, badOrder, crashedOrder);
}
private static Saga newSaga() {
return Saga
.create()
.chapter("init an order")
.chapter("booking a Fly")
.chapter("booking a Hotel")
.chapter("withdrawing Money");
}
private static ServiceDiscoveryService serviceDiscovery() {
return
new ServiceDiscoveryService()
.discover(new OrderService())
.discover(new FlyBookingService())
.discover(new HotelBookingService())
.discover(new WithdrawMoneyService());
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.orchestration;
import static com.iluwatar.saga.orchestration.Saga.Result.CRASHED;
import static com.iluwatar.saga.orchestration.Saga.Result.FINISHED;
import static com.iluwatar.saga.orchestration.Saga.Result.ROLLBACK;
import java.util.Optional;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* The orchestrator that manages all the transactions and directs
* the participant services to execute local transactions based on events.
*/
public class SagaOrchestrator {
private static final Logger LOGGER = LoggerFactory.getLogger(SagaOrchestrator.class);
private final Saga saga;
private final ServiceDiscoveryService sd;
private final CurrentState state;
/**
* Create a new service to orchetrate sagas.
* @param saga saga to process
* @param sd service discovery @see {@link ServiceDiscoveryService}
*/
public SagaOrchestrator(Saga saga, ServiceDiscoveryService sd) {
this.saga = saga;
this.sd = sd;
this.state = new CurrentState();
}
/**
* pipeline to execute saga process/story.
*
* @param value incoming value
* @param <K> type for incoming value
* @return result @see {@link Saga.Result}
*/
@SuppressWarnings("unchecked")
public <K> Saga.Result execute(K value) {
state.cleanUp();
LOGGER.info(" The new saga is about to start");
Saga.Result result = FINISHED;
K tempVal = value;
while (true) {
int next = state.current();
Saga.Chapter ch = saga.get(next);
Optional<OrchestrationChapter> srvOpt = sd.find(ch.name);
if (!srvOpt.isPresent()) {
state.directionToBack();
state.back();
continue;
}
OrchestrationChapter srv = srvOpt.get();
if (state.isForward()) {
ChapterResult processRes = srv.process(tempVal);
if (processRes.isSuccess()) {
next = state.forward();
tempVal = (K) processRes.getValue();
} else {
state.directionToBack();
}
} else {
ChapterResult rlRes = srv.rollback(tempVal);
if (rlRes.isSuccess()) {
next = state.back();
tempVal = (K) rlRes.getValue();
} else {
result = CRASHED;
next = state.back();
}
}
if (!saga.isPresent(next)) {
return state.isForward() ? FINISHED : result == CRASHED ? CRASHED : ROLLBACK;
}
}
}
private static class CurrentState {
int currentNumber;
boolean isForward;
void cleanUp() {
currentNumber = 0;
isForward = true;
}
CurrentState() {
this.currentNumber = 0;
this.isForward = true;
}
boolean isForward() {
return isForward;
}
void directionToBack() {
isForward = false;
}
int forward() {
return ++currentNumber;
}
int back() {
return --currentNumber;
}
int current() {
return currentNumber;
}
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.orchestration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Common abstraction class representing services.
* implementing a general contract @see {@link OrchestrationChapter}
*
* @param <K> type of incoming param
*/
public abstract class Service<K> implements OrchestrationChapter<K> {
protected static final Logger LOGGER = LoggerFactory.getLogger(Service.class);
@Override
public abstract String getName();
@Override
public ChapterResult<K> process(K value) {
LOGGER.info("The chapter '{}' has been started. "
+ "The data {} has been stored or calculated successfully",
getName(), value);
return ChapterResult.success(value);
}
@Override
public ChapterResult<K> rollback(K value) {
LOGGER.info("The Rollback for a chapter '{}' has been started. "
+ "The data {} has been rollbacked successfully",
getName(), value);
return ChapterResult.success(value);
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.orchestration;
import java.util.HashMap;
import java.util.Map;
import java.util.Optional;
/**
* The class representing a service discovery pattern.
*/
public class ServiceDiscoveryService {
private Map<String, OrchestrationChapter<?>> services;
public Optional<OrchestrationChapter> find(String service) {
return Optional.ofNullable(services.getOrDefault(service, null));
}
public ServiceDiscoveryService discover(OrchestrationChapter<?> orchestrationChapterService) {
services.put(orchestrationChapterService.getName(), orchestrationChapterService);
return this;
}
public ServiceDiscoveryService() {
this.services = new HashMap<>();
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.orchestration;
/**
* Class representing a service to withdraw a money.
*/
public class WithdrawMoneyService extends Service<String> {
@Override
public String getName() {
return "withdrawing Money";
}
@Override
public ChapterResult<String> process(String value) {
if (value.equals("bad_order") || value.equals("crashed_order")) {
LOGGER.info("The chapter '{}' has been started. But the exception has been raised."
+ "The rollback is about to start",
getName(), value);
return ChapterResult.failure(value);
}
return super.process(value);
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.choreography;
import com.iluwatar.saga.orchestration.SagaApplication;
import org.junit.Test;
/***
* empty test
*/
public class SagaApplicationTest {
@Test
public void mainTest() {
SagaApplication.main(new String[]{});
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.choreography;
import org.junit.Assert;
import org.junit.Test;
/**
* test to check choreography saga
*/
public class SagaChoreographyTest {
@Test
public void executeTest() {
ServiceDiscoveryService sd = serviceDiscovery();
ChoreographyChapter service = sd.findAny();
Saga badOrderSaga = service.execute(newSaga("bad_order"));
Saga goodOrderSaga = service.execute(newSaga("good_order"));
Assert.assertEquals(badOrderSaga.getResult(), Saga.SagaResult.ROLLBACKED);
Assert.assertEquals(goodOrderSaga.getResult(), Saga.SagaResult.FINISHED);
}
private static Saga newSaga(Object value) {
return Saga
.create()
.chapter("init an order").setInValue(value)
.chapter("booking a Fly")
.chapter("booking a Hotel")
.chapter("withdrawing Money");
}
private static ServiceDiscoveryService serviceDiscovery() {
ServiceDiscoveryService sd = new ServiceDiscoveryService();
return sd
.discover(new OrderService(sd))
.discover(new FlyBookingService(sd))
.discover(new HotelBookingService(sd))
.discover(new WithdrawMoneyService(sd));
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.orchestration;
import org.junit.Test;
import static org.junit.Assert.*;
/**
* empty test
*/
public class SagaApplicationTest {
@Test
public void mainTest() {
SagaApplication.main(new String[]{});
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.orchestration;
import org.junit.Assert;
import org.junit.Test;
import java.util.ArrayList;
import java.util.List;
/**
* test to test orchestration logic
*/
public class SagaOrchestratorInternallyTest {
private List<String> records = new ArrayList<>();
@Test
public void executeTest() {
SagaOrchestrator sagaOrchestrator = new SagaOrchestrator(newSaga(), serviceDiscovery());
Saga.Result result = sagaOrchestrator.execute(1);
Assert.assertEquals(result, Saga.Result.ROLLBACK);
Assert.assertArrayEquals(
records.toArray(new String[]{}),
new String[]{"+1", "+2", "+3", "+4", "-4", "-3", "-2", "-1"});
}
private static Saga newSaga() {
return Saga
.create()
.chapter("1")
.chapter("2")
.chapter("3")
.chapter("4");
}
private ServiceDiscoveryService serviceDiscovery() {
return
new ServiceDiscoveryService()
.discover(new Service1())
.discover(new Service2())
.discover(new Service3())
.discover(new Service4());
}
class Service1 extends Service<Integer> {
@Override
public String getName() {
return "1";
}
@Override
public ChapterResult<Integer> process(Integer value) {
records.add("+1");
return ChapterResult.success(value);
}
@Override
public ChapterResult<Integer> rollback(Integer value) {
records.add("-1");
return ChapterResult.success(value);
}
}
class Service2 extends Service<Integer> {
@Override
public String getName() {
return "2";
}
@Override
public ChapterResult<Integer> process(Integer value) {
records.add("+2");
return ChapterResult.success(value);
}
@Override
public ChapterResult<Integer> rollback(Integer value) {
records.add("-2");
return ChapterResult.success(value);
}
}
class Service3 extends Service<Integer> {
@Override
public String getName() {
return "3";
}
@Override
public ChapterResult<Integer> process(Integer value) {
records.add("+3");
return ChapterResult.success(value);
}
@Override
public ChapterResult<Integer> rollback(Integer value) {
records.add("-3");
return ChapterResult.success(value);
}
}
class Service4 extends Service<Integer> {
@Override
public String getName() {
return "4";
}
@Override
public ChapterResult<Integer> process(Integer value) {
records.add("+4");
return ChapterResult.failure(value);
}
@Override
public ChapterResult<Integer> rollback(Integer value) {
records.add("-4");
return ChapterResult.success(value);
}
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.saga.orchestration;
import org.junit.Assert;
import org.junit.Test;
/**
* test to check general logic
*/
public class SagaOrchestratorTest {
@Test
public void execute() {
SagaOrchestrator sagaOrchestrator = new SagaOrchestrator(newSaga(), serviceDiscovery());
Saga.Result badOrder = sagaOrchestrator.execute("bad_order");
Saga.Result crashedOrder = sagaOrchestrator.execute("crashed_order");
Assert.assertEquals(badOrder, Saga.Result.ROLLBACK);
Assert.assertEquals(crashedOrder, Saga.Result.CRASHED);
}
private static Saga newSaga() {
return Saga
.create()
.chapter("init an order")
.chapter("booking a Fly")
.chapter("booking a Hotel")
.chapter("withdrawing Money");
}
private static ServiceDiscoveryService serviceDiscovery() {
return
new ServiceDiscoveryService()
.discover(new OrderService())
.discover(new FlyBookingService())
.discover(new HotelBookingService())
.discover(new WithdrawMoneyService());
}
}