Entity Fetch Strategy

[jhou-pro]

The fetch strategies for the entities are crucial for almost all parts of user interface and domain-driven processes of TG application. Entity Fetch Strategy defines the fullness of objects to be operated with and to be represented in different UI components.

It is very important to understand that only small set of entity tree branches are required to make it operational.

1. entity master -- requires a fetch strategy only to show a set of properties in entity master UI components (reuse in Entity web resource #119);
2. entity validation -- requires a fetch strategy to make validation possible based on inter-property dependencies (reuse in Entity validation web resource #106);
3. entity autocompleters -- requires fetch strategies for entity-typed properties to show the results of autocompletion (reuse in Autocompleter Web Resource #115);
4. entity queries -- requires a fetch strategy to construct synthesized entity etc.
5. entity grid inspector -- requires a fetch strategy to show table view of entities.

As it was disscussed it will be very convenient for end-application developer to provide some sort of default aggregated fetch strategy that will be suited in most cases and will provide single point of reference. But it also will be nice if the fetch strategy for different cases could be easily extended from the aggregated one using convenient API.

[jhou-pro]

As part of implementation details:

1. New entity creation process (including via Entity Producer) should also take into account the fetch strategy for the entity. It will provide the consistency across Entity Resource and Entity Validation Resource results. In particular, it will provide the developer with more safety for Strict Proxy errors and will reduce the amount for the JSON data to be exchanged between the server and the client [potentially minor].
2. The place for the Entity Fetch Strategy declaration should be as convenient as possible and, as discussed, can be the part of companion object (even without special Guice bindings) and with some minimalistic default implementation.
3. Entity Fetch Strategy should be able to generate automatically its correspondent fetch<T> model.
4. The EFS building API should be developer-friendly and should follow dot-notated syntax of fetch<T> class.
5. To be continued...

[jhou-pro]

This issue is considered to be implemented as part of Issue-106 branch. All additional improvements and API extensions should be captured as a separate issues.