Design & Soltion FAQ

What is a entity ?

An entity is something that exists as itself. It does not need to be of material existence. source - wiki
So in our marketing plus bundle we can call Brand, Project, Roles, Budget etc,. as entity.
Every entities has its own set of attributes and behaviours.
So Entities definitions is same as Class definition ?
- May be yes, But the term entitiy so not specific to Programming or Software Development.
- But if we do relate Class-Object and Entity, yes those are same.
There is another terminology like Entity Class to confuse us, this is very specific to software devlopment particularly which comes under ORM. Enitity Class is java POJO class where its attributes represents DB table row structure. Thats what we call Object Relational Mapping (ORM).

In simple terms, we can say a java class as service class when it serves functionalities of a enitity to the consumers.
- What I mean by functionality is business use case operation.
- What I mean by Consumer is those who use that business use case.
In most cases services are dedicatedly created for a single entity. Sometimes for multiple entities when those entities are in strong association relationship.
So Service are same as Util classes in our code base ?
- In our code base we do name all services as utils so yes. (ex: ProjectUtil)
- But the term Util has a complete diffirent meaning compare to service, Where service holds business logic whereas the utils are not that intelligent, Utils just do some low level operations which helps services to do its job. Which help the Busniness Logic to always be completely seperated in Service Layer.
- Other than terminology issue, We can say Our ProjectsUtil.java is a service.

Contract is one of mechanism to achieve loosely coupled communication b/w two services.