FluentSpecification.Abstractions is a abstraction layer for Specification design pattern. Contains also interfaces and structures for validation and Linq scenarios.
Specification
ISpecification<T> is absolutely base, for all Specifications and extensions, across all FluentSpecification packages.
But there is couple of differences with known Specification design pattern - interface contains only IsSatisfiedBy method without And, Or etc.
This methods are moved as extensions to the FluentSpecification.Core.
Thanks that implementation of simple Specification is very easy - you need to implement only IsSatisfiedBy method.
Every Specifications also implements empty ISpecification interface - you can represent any kind of Specification regardless of the type.
Validation
For Validation scenarios, IValidationSpecification<T> is prepared. This interface inherit from ISpecification<T>.
Contains also IsSatisfiedBy method but with outer parameter - SpecificationResult.
In this structure, Specification returns all data related to validation of input candidate. Content of SpecificationResult is described in next section.
Linq
Specifications, that support Linq expressions, should implement ILinqSpecification<T> interface.
GetExpression method returns equivalent of IsSatisfiedBy method, as Linq expression.
ILinqSpecification<T> inherit from ISpecification<T>.
All in one
IComplexSpecification<T> interface, is prepared for Specifications with support of all functionalities, described above. Every built-in Specifications implements this interface.