java-design-patterns/specification/index.md

---
layout: pattern
title: Specification
folder: specification
permalink: /patterns/specification/
categories: Behavioral
tags: Java
---

**Intent:** 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

![alt text](./etc/specification.png "Specification")

**Applicability:** 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)

**Credits:**

* [Martin Fowler - Specifications](http://martinfowler.com/apsupp/spec.pdf)
Work towards #56: Splitting up the README I did the job and splitted up the readme, hopefully everything was splitted correctly... 2015-08-13 23:54:40 +02:00			`---`
			`layout: pattern`
			`title: Specification`
			`folder: specification`
Work towards #56: Add permalink to every pattern This makes cleaner URLs thanks to jekyll 2015-08-15 18:03:05 +02:00			`permalink: /patterns/specification/`
Work on #213 - properly categorize all patterns - remove pattern list from readme - minor fixes to readme - removed "introduction" because its not a pattern and an error i committed some time ago 2015-08-20 21:40:07 +02:00			`categories: Behavioral`
			`tags: Java`
Work towards #56: Splitting up the README I did the job and splitted up the readme, hopefully everything was splitted correctly... 2015-08-13 23:54:40 +02:00			`---`

			`Intent: 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`

			`![alt text](./etc/specification.png "Specification")`

			`Applicability: 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`
Work towards #56: Add permalink to every pattern This makes cleaner URLs thanks to jekyll 2015-08-15 18:03:05 +02:00			`* you need to check that only suitable objects are used for a certain role (validation)`
Work on #226, moved pattern specific credits to respective pattern pages in website 2015-09-03 18:17:07 +05:30
			`Credits:`

			`* [Martin Fowler - Specifications](http://martinfowler.com/apsupp/spec.pdf)`