Module specification 

Specification Pattern - Business Rules as Objects

The Specification pattern encapsulates business rules that can be combined and reused. This is a core DDD tactical pattern.

Example

use backbone_core::specification::{Specification, AndSpecification};

// Define a specification
struct UserIsActive;

impl Specification<User> for UserIsActive {
    type Error = String;

    fn is_satisfied_by(&self, user: &User) -> Result<bool, Self::Error> {
        Ok(user.status == UserStatus::Active)
    }
}

// Combine specifications
let spec = UserIsActive.and(UserHasVerifiedEmail);
let is_valid = spec.is_satisfied_by(&user)?;

Structs

AlwaysFalse

Always returns false

AlwaysTrue

Always returns true

AndSpecification

AND specification - both left and right must be satisfied

NotSpecification

NOT specification - negates the inner specification

OrSpecification

OR specification - either left or right must be satisfied

PredicateSpecification

Specification using a closure

SpecificationEvaluator

Evaluates multiple specifications and collects results

SpecificationResult

Result of evaluating a specification with detailed information

Traits

Specification

Core Specification trait

Functions

predicate

Helper function to create a predicate specification