2017-05-03 19:48:29 +02:00
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---
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layout: pattern
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title: Marker Interface
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folder: marker
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permalink: /patterns/marker/
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categories: Design
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tags:
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- Java
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- Difficulty-Beginner
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---
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## Intent
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Using empy interfaces as markers to distinguish special treated objects.
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2017-05-03 19:49:25 +02:00
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2017-05-03 19:48:29 +02:00
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## Applicability
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Use the Marker Interface pattern when
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* you want to identify the special objects from normal objects
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* define a type that is implemented by instances of the marked class, marker annotations can not do that
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## Real world examples
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* [javase.7.docs.api.java.io.Serializable](https://docs.oracle.com/javase/7/docs/api/java/io/Serializable.html)
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* [javase.7.docs.api.java.lang.Cloneable](https://docs.oracle.com/javase/7/docs/api/java/lang/Cloneable.html)
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## Credits
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* [Effective Java 2nd Edition by Joshua Bloch](https://www.amazon.com/Effective-Java-2nd-Joshua-Bloch/dp/0321356683)
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