36 lines
870 B
Markdown
36 lines
870 B
Markdown
---
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layout: pattern
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title: Specification
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folder: specification
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permalink: /patterns/specification/
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categories: Behavioral
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tags:
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- Java
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- Difficulty-Beginner
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---
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## Also known as
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Filter, Criteria
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## Intent
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Specification pattern separates the statement of how to match a
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candidate, from the candidate object that it is matched against. As well as its
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usefulness in selection, it is also valuable for validation and for building to
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order
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## Applicability
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Use the Specification pattern when
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* you need to select a subset of objects based on some criteria, and to refresh the selection at various times
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* you need to check that only suitable objects are used for a certain role (validation)
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## Related patterns
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* Repository
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## Credits
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* [Martin Fowler - Specifications](http://martinfowler.com/apsupp/spec.pdf)
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