Big Picture

Due to limitation of our underlying data storage model, the metamodel cannot contain inheritance.

Each new application starts with a default ApplicationModel based on this MetaModel.

DataType/Class

DataType (or Class) are similar to classes in OO languages with few enhancements.

A dataType has a name, belongs to a package, and contains:

• fields: properties of the dataType
• operationFields: equivalent to the object methods
• states: set of state associated with this datatype
• uiTypes: type of user interface that could be associated to this dataType
• validatorTypes: type of data validator that could be associated to this dataType
• serviceTypes: executable service that could be accessed via this dataType

States

DataType can have states. A dataType instance can be in a specific state and anyone can apply a transition on the instance to change its state. When a transition is apply, a set of operation can be executed. Those operations can generate exception and cancel transition. Each operations are transactional but the whole transition is not transactional itself for performance reason. If an exception occurs during a transition, the current operation is rolled back but previous one remains. To be sure to have an atomic set of operation executed in transition you can define a specific method (operationField) and execute all operation in a transition inside this method.

Operations

Operations are executed during transitions.

Service operations are integrated in the platform and can be accessed by most of dataType instance.

Field operations code can be written using scripts language and are owed by one dataType.

For example, in the ApplicationModel, the Member dataType has the field operation 'checkRight'. This operation has one input parameter instance (which is itself a Member). The code script is:

@groovy

if( instance.level < _member.level ) throw new ServiceException( 'Current User Level is lower than assigned level' )

Has you can see first line @groovy indicate that we use Groovy script to write this code.

more to come...