Filter, Criteria

Specification pattern separates the statement of how to match a candidate, from the candidate object that it is matched against. As well as its usefulness in selection, it is also valuable for validation and for building to order

Use the Specification pattern when

• you need to select a subset of objects based on some criteria, and to refresh the selection at various times
• you need to check that only suitable objects are used for a certain role (validation)

• Repository

• Martin Fowler - Specifications