[CAUSEWAY-369] For GSOC: Kemble: A domain-specific language aligned with the Apache Isis programming conventions.

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Won't Fix
• Fix Version/s: 1.10.0
• Component/s: ZZZ: GSOC
• Labels: ddd domain-driven-design dsl framework gsoc gsoc2014 nakedobjects
• Assignee: Unassigned
• Reporter: Daniel Keir Haywood
• Created: 20/Mar/13 21:32
• Updated: 26/Oct/15 12:06
• Resolved: 26/Oct/15 12:06

Description

The obvious technology to use is Eclipse's XText http://www.eclipse.org/Xtext/. The grammar can be based on Xbase, which provides full Java type compatibility and extended language constructs (in common with in XTend, http://www.eclipse.org/xtend/).

NB: xtext now has an FX-based UML integration; see: http://vimeo.com/104115680

~~~

grammar org.apache.isis.kemble.Kemble
with org.eclipse.xtext.xbase.annotations.XbaseWithAnnotations

Below is a sketch of what that DSL might look like.

For entities:

@... // Isis and selected JDO annotations here
entity Customer {
...

inject ProductRepository products;
inject OrderRepository orders;
}

where:

• the products, orders imply an instance variable and a setter to allow services to be injected into
• DomainObjectContainer container is provided automatically as a field

For entity properties:

entity Customer {

@ ... // annotations here
[derived] property String firstName

{ modify; clear; default; choices; hide; disable; validate; }

}

where

• property is a keyword
• String firstName
• implies the instance variable and the getter
• annotations can be specified, apply to the getter
• derived is an optional keyword
• if present, then only the hide keyword may be used
• if present, then the getter is in the business logic interface, not structural.
• modify;
• is optional
• if present, implies the modifyXxx(String value) method
• clear;
• is optional
• if present, implies the void clearXxx() method
• default;
• is optional
• if present, implies the String defaultXxx() method
• choices;
• is optional
• if present, implies the Collection<String> choicesXxx() method
• hide;
• is optional
• if present, implies the boolean hideXxx() method
• disable;
• is optional
• if present, implies the String disableXxx() method
• validate;
• is optional
• if present, implies the String validateXxx(String value) method

similarly for entity collections:

entity Customer {

@ ... // annotations here
[derived] collection List<Order> orders

{ addTo; removeFrom; hide; disable; validateAddTo; validateRemoveFrom; }

}

where

• collection is a keyword
• derived is an optional keyword
• if present, then only the hide keyword may be used
• if present, then the getter is in the business logic interface, not structural.
• addTo;
• is optional
• if present ,implies void addTo(Order o) { }
• removeFrom;
• is optional
• if present ,implies void removeFrom(Order o) { }
• hide;
• as properties
• disable;
• as properties
• validateAddTo;
• is optional
• if present ,implies String validateAddToXxx(Order o) { ... }
  - validateRemoveFrom;
  - is optional
  - if present ,implies String validateRemoveFromXxx(Order o) { ... }

and similarly for entity actions:

entity Customer {

@... // annotations here
action Order placeOrder {
param Product product

{ default; choices; autoComplete; validate; },
param int quantity { default; choices; autoComplete; validate; }

,
param String description

{ default; choices; autoComplete; validate; }

}
hide;
disable;
validate;
}
}

where

• the name of the parameter would imply @Named(...)
• param's default:
• is optional
• corresponds to: Product default0PlaceOrder() { ... }
  or: int default1PlaceOrder() { ... }

  or: String default2PlaceOrder()

  { ... }
  - param's choices
  - is optional
  - corresponds to: Collection<Product> default0PlaceOrder() { ... }

  
  or: Collection<Integer> choices1PlaceOrder(Product p)

  { ... }
  or: Collection<String> choices2PlaceOrder(Product p, int quantity) { ... }
• note how the Nth method has N-1 params
• ALSO: cannot have both choices and autoComplete
• param's autoComplete
• is optional
• corresponds to Collection<Product> autoComplete0PlaceOrder(String search) { ... }
  or: Collection<Integer> autoComplete1PlaceOrder(Product p, String search) { ... }

  or: Collection<String> autoComplete2PlaceOrder(Product p, int quantity, String search)

  { ... }
  - note how the Nth method has N-1 params + search arg
  - ALSO: cannot have both choices and autoComplete
  validate for the parameters apply to that parameter
  - is optional
  - corresponds to String validate0PlaceOrder(Product p) { ... }

  or: String validate1PlaceOrder(int quantity)

  { ... }
  or: String validate2PlaceOrder(String search) { ... }

• hide
• is optional
• corresponds to boolean hidePlaceOrder() { ... }
  - disable
  - is optional
  - corresponds to String disablePlaceOrder() { ... }
• validate (at action level)
• corresponds to validateXxx(...)
• to validate the set of arguments rather than an individual parameter

~~~~~~~~~~~~
THIS STUFF OUT OF SCOPE/NOT NECESSARY

For values:

value FractionalNumber {
int numerator;
int denominator;
}

is basically the same as Lombok @Data
requires information in @ValueSemanticsProvider to be specified (somehow, not sure exactly how)

~~~~~~~~~~~~
THIS STUFF OUT OF SCOPE/NOT NECESSARY

For services/repositories:

service ProductRepository {

}

where:

• any services are injected into as for entities
• DomainObjectContainer container is provided for free, again as for entities
• actions as for entities
• properties and collections are disallowed