Marker interface pattern: Difference between revisions

Revision as of 20:24, 20 April 2009

Revision as of 01:30, 7 July 2009

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A better solution is for the language to support [[metadata]] directly:

* Both the [[.NET Framework|.NET framework]] and [[Java (software platform)|Java]] (as of Java 5 (1.5)) provide support for such metadata. In .NET, they are called ''"custom attributes"'', in Java they are called ''"annotations"''. Despite the different name, they are conceptually the same thing. They can be defined on classes, member variables, methods, and method parameters and may be accessed using [[Reflection_(computer_science)|reflection]].

* The [[.NET Framework|.NET framework]] supports attributes that can be used to associate any type of data with a class or with its members. Attributes can be inherited or not, thus solving the problem mentioned above.

* In [[Python (programming language)|Python]], the use and term "marker interface" is common in [[Zope 3]] and [[Plone (software)|Plone]]. Interfaces are declared as metadata and subclasses can use <code>implementsOnly</code> to declare they do not implement everything from their super classes.

* [[Java_(software_platform)|Java]], as of Java 5 (1.5), also provides [[Annotation|annotations]] [[Java_annotation|support]] on classes, member variables, methods, and method parameters that may be accessed from an instance using [[Reflection_(computer_science)|reflection]].

* In [[Python (programming language)|Python]], the use and term "marker interface" is common in [[Zope 3]] and [[Plone (software)|Plone]]. Interfaces are declared as metadata and subclasses can use <code>implementsOnly</code> to declare they do not implement everything from their super classes.

== See also ==