What's here

This is our Programming Project as part of the INF2 Teaching Unit supervised by Nicolas Herbaut in Paris I Panthéon-Sorbonne University.
It contains configured CDI through Weld and Jersey's integration with HK2. It contains persistence with JPA, implemented with Eclipse Link on top of a H2 database. It has a REST API using JAXRS implemented by Jersey. All the JAXB Classes are generated by an XSD with the appropriate xjc bindings to make sure that we can handle Data smoothly.

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Project structure

The goal of the project is to model an application in order to respond to the problem of the Infocentre / Infogares within the SNCF train company, we implemented business logic corresponding to given specifications, and made the components communicate as required. This section details our conception choices.
project-jee8 is the parent project.

The Model : project-jee8-model

This project contains JAXB generated DTO to be used for communication in the REST, JMS and Business Layer. a.k.a. between the Trains and the Infocentre, and between the Infocentre and the Infogares.

DTOs :

• LiveInfo : Is used by the train to transmit live information to the Infocenter.
  Containing :

  • lastGareIndex: Sequential index of the last station traveled by the train.
  • nextGareIndex: Sequential index of the station where the train is going.
  • percentage: Percentage of distance traveled between stations lastGareIndex and nextGareIndex.
  • timestamp : Time and date the LiveInfo is sent.

• InfoDTO : Is used by the Infocenter to transmit train informations to Infogares according to their JMS topic subscriptions. Containing :

  • infoType : Type of the information sent by the Infocenter (see InfoTypeEnum).
  • trainId : ID of the train concerned by the DTO.
  • trainName : Name of the train concerned by the DTO.
  • trainType : Type of the train concerned by the DTO.
  • timestamp : Time the train arrives at this station.
  • In case of disruption, the field disruptionType is also filled (see EnumConditions).

Enums :

• InfoTypeEnum : Contains different types of InfoDTO (Departure, Arrival, Transit, Disruption), used to determine the type of information received by the Infogare. The All field is used to tell the Infogare to display all types of information.

• EnumConditions : Contains different types of train delay reasons, used in a scenario where a train is delayed because of certain circumstances.

The Infocenter : project-jee8-webapp

This project contains a REST API (JAXRS), the persistence layer (JPA), the service layer and makes use of Messaging Topics (JMS) to send information

REST layer

REST API made with Jersey (reference implementation of JAX-RS), contains two REST controllers :

• TrainEndpoint : This is the main endpoint of the application, the train must make a POST request to /{id}/live to send its LiveInfo (in request body) or to /{id}/live to send info with a delay cause.

• DatabaseEndpoint : Has no value in business logic, only used in this project to populate the database with test data by calling /db/populate and to send first information to infogares by calling /db/init.

Service layer

Contains classes that handle business logic by performing the necessary calculations and dealing with the persistence layer. See JavaDoc for information about their methods.

• TrainService : First service called when receiving LiveInfo. Contains a method that calculates the delay based on the received information. Calls the other services according to the delay.

• StopService : Contains the implementation of :

  Un train desservira exceptionnellement une gare si elle est sur son trajet et que le train précédent a un retard de plus de 2h.

• TERService : Contains the implementation of :

  Un TER pourra attendre un TGV, mais pas l’inverse.

• RuptureService : Contains the implementation of :

  On ne retardera le train que si le nombre de passagers ayant réservés en rupture de correspondance est > 50.

  Note : If trains A, B and C are delayed and cause more than 50 connection breaks (Ruptures) on a train D in a station G, the train D will be delayed to the arrival time of the latest train which arrives at G.

• InfogareSenderService : Is responsible of sending the InfoDTO to the Infogares, uses the right JMS Publisher according to the gareId field. JMSPublishers are classes which handle the JAXB Marshalling of the DTO and send it to the topic injected in them.

  See JavaDoc and code comments for more details about services.

Persistence layer

Use of JPA with an H2 in-memory database, and the DAO pattern as an interface to isolate the business and the persistence layers.
Contains tables :

• Trajet : Describes a ride, with a name, type, lists of passengers and stations.
  • parcoursId : If two train have the same parcoursId, they have exactly the same route but not necessarily the same service.
• Passager : Describes a passenger, used to determine any train connection breaks.
• Correspondance : Describes the reservation of a passenger for another train.
  Notable fields :
  • rupture : Boolean used to mark a connection as broken. Helps in business rule 3.
• DesserteTheorique : Describes the scheduled service of the train. Used in business logic to compare with the current one.
• DesserteReelle : Describes the actual service of the train, after the delays and the decisions of the Infocenter.
  Notable fields :
  • seq : The sequential number of the station, used in the LiveInfo DTO.
  • desservi : A boolean, tells if the station is served by the train.
• Gare : Describes a station.
  Notable fields :
  • code : Used in JMS messaging to determine the topic associated to the station.

JMS Messaging

Use of the Publish-Subscribe mechanism with one topic per station, and injection with CDI, the suppliers provide the necessary instances to be injected.

The Terminal (Infogare) : project-jee8-jms-subscriber

This project consumes InfoDTO produced by the Infocenter. Has a TrainSubscriber which is responsible of Unmarshalling the DTO, filtering and printing it as a formatted output.
The JMSProducer provides the topic instance to be injected into the subscriber.
The data is kept in a HashMap (Map<Integer, InfoDTO>) of key trainId, which ensures us that we have only one information about a given train at a time.
Preview : (looks much better in IntelliJ <3)

The Train : project-jee8-rest-client

This project is supposed to call Infogare REST API using Jersey Client for JAXRS. But we gave the teacher a Postman collection for him to test our project.

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Modeled scenario :

BDX = "Bordeaux Saint-Jean"; PAR = "Paris Montparnasse"; AMS = "Gare d'Amiens"; LIL = "Lille Flandres"; LYN = "Lyon Perrache".

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How to launch

Steps

• mvn clean install in root
• Run Main.main() in project-jee8-webapp
• Run InfoGareApp.main() in project-jee8-jms-subscriber five times, each time by uncommenting one topic injection in jms/TrainSubscriber (starting from line 27), you can also choose which information to display by changing the value of infoGareType in TrainSubscriber.
• Import files/postman.json in Postman
• Run requests in this order :
  • 1 - PopulateDB to populate database with the modeled scenario data.
  • 2 - Init to send first data to the Infogares, you can now check train states in the jms-subscriber consoles.
  • 3 - LiveInfo to send live info, you can now check the changes in the Infogare screens.

Additional information

We used Project Lombok in this project to help us reduce boilerplate code like getters, setters etc.
Make sure you enable Annotation Processing, and that you have it in your compile classpath on Eclipse or have installed the Lombok IntelliJ Plugin.
Baeldung : Setting up Lombok with Eclipse and IntelliJ

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Useful SQL

These are a few SQL statements to paste in the H2 database to have a better visibility on what happens.

• View the current route of a train (replace TRAJET_ID value)

SELECT DESSERTEREELLE.*, NOM AS NOM_GARE, TYPE
FROM DESSERTEREELLE, GARE, TRAJET 
WHERE TRAJET_ID=1 
  AND DESSERTEREELLE.GARE_ID=GARE.ID
  AND DESSERTEREELLE.TRAJET_ID=TRAJET.ID
ORDER BY SEQ

• View Correspondance states

SELECT GARE.NOM AS NOM_GARE, PASSAGER_ID, PASSAGER.TRAJET_ID, RUPTURE, NEWDATE
FROM CORRESPONDANCE, TRAJET, PASSAGER, GARE
WHERE CORRESPONDANCE.TRAJET_ID=TRAJET.ID
  AND PASSAGER.CORRESPONDANCE_ID=CORRESPONDANCE.ID
  AND CORRESPONDANCE.GARE_ID=GARE.ID

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Code quality

Business logic code (Service Layer) is 80% covered by unit tests.


CI with Bitbucket pipelines

Contribution

• Massil TAGUEMOUT
• Nelly UNG
• Nicolas LEWIN
• Sarah MEZIANE
• William DAI

M1 MIAGE APP
Université Paris I Panthéon Sorbonne

Repository link : https://bitbucket.org/maxtag/sncf-infogare