Testing JDL Studio for JHipster application

The newest version of JHipster gives us an opportunity to generate backbone model in 3 different ways. Today we will test the fastest one 🙂 JHipster since version 4.x provided great tool which creates the World a better place. This tool is JDL Studio available here. You can prototype there whole models at once and generate it everytime you would like to.

Available data types

You can prototype your classes with defined below types of fields. Relational and non-relational databases sometimes have different types, just remember about it.

entity <entity name> {
<field name> <type> [<validation>*]
}

Relationships

Available are all relationships: 1:1, 1:n, n:1, m:n. You can always choose if any of those relations is bidirectional or unidirectional.

relationship <type> {
<from entity>[{<relationship name>}]
to
<to entity>[{<relationship name>}]
}

• <type> is the type of your relationship (OneToMany | ManyToOne| OneToOne | ManyToMany)
• <from entity> is the name of the entity owner of the relationship,
• <to entity> is the name of the entity where the relationship goes to,
• <relationship name> is the name of the relationship in the entity.

Enumerations and blobs

They are also available, what can I say more 😉 You can also define some constant values (like PI) and use it in entity model.

enum <enum name> {
<enum values>
}

Option declaration

In JHipster  you can specify options for entities such as generating pagination, service or DTO. Example from docs:

• paginate enable pagination for the entity with pager | pagination | infinite-scroll
• service enable service layer for the entity with serviceClass | serviceImpl
• dto enable DTO for the entity with Mapstruct
• skipClient skip client side code for entity
• skipServer skip server side code for entity
• angularSuffix add a suffix to angular route names
• microservice specify the app name of entity from another microservice
• search specify search option for entity from another microservice

entity A {
name String required
}

entity B {}

entity C {}

dto A, B with mapstruct

paginate A, C with infinite-scroll
paginate B with pager

service A with serviceClass
service C with serviceImpl

Error handling

Web interface returns errors on the top of the schema and shows red stripe on the left. If you use wrong syntax, it will try to show what is expected, how should looks like and – for me the most important – which line has failed. Remember, that you shouldn’t leave commas a the end of enumeration of class parameters 😉

Example JDL Studio

entity City {
	name String
}

enum Fee {
    FREE, PAID	
  }
  
entity Series {
	name String,
	description String,
	organizer String
}

entity Topic {
	name String
}

entity Event {
	name String,
    description String,
    startDate LocalDate,
    endDate LocalDate,
    language String,
    fee Fee,
    place String,
    address String,
    registerationLink String,
    eventWww String
}

relationship OneToMany {
	City{city} to Event{event},
    Series{series} to Event{event},
    Event{event} to Topic{topic}
}

paginate City, Series, Event, Topic with pagination

dto Event with mapstruct
dto Topic with mapstruct

service Event with serviceClass
service Topic with serviceClass

How the generated schema model looks like?

Next time we will be generating these data into EventSearch application. We will use magic command:

yo jhipster:import-jdl .jhipster\input.jh