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Modelus Specification

		Modelus Specification is an implementation of the Specification Pattern in .NET. The pattern has been originally described by Eric Evans and Martin Fowler and is referenced in Eric's book "Domain Driven Design".

Intention

Express a domain model using deep and powerful ubiquitous domain language.
Make hidden domain complexities explicit. Increase understandability and flexibility of design.
Support declarative style of design, intention-revealing interfaces, and side-effect-free implementations.

Design Objectives

Allow domain rules to be extracted out of conditional logic and made explicit in a domain model.
Allow complex rules to be build out of simple elements using logical operations of Boolean algebra.

Applicability

Use Specification when you need:

To validate object eligibility for a certain benefit or responsibility.
To select an object from a collection based on a given selection criteria.
To create a new object to fit a particular need or purpose.

Consequences

Introducing specifications into a domain model deepens team's understanding of the domain and uncovers hidden opportunities to increase business value.

Be mindful of the fact that creating irrelevant or weak concepts only clutters the system's core responsibilities. Thus, Specification is not a replacement for every conditional statement we may have in our code.

Alternatives

Simple conditional statements - hide functionality behind code and will miss opportunities to deepen our understanding of the domain.
Rule engines - have potential for a more powerful and flexible solution but are more expensive to develop.

License

The Modelus Specification source code, binaries, and documentation are distributed under the Apache License 2.0.

Downloads

Modelus Specification 2.0

Modelus Specification 2.0 - Source

Previous Versions

Modelus Specification 1.0

Modelus Specification 1.0 - Source

Questions

Have a question about the implementation? Need help? Please direct your questions and comments to Aleh Matus at info@modelus.com.

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