Editing Balking pattern (section)

{{Short description|Software design pattern}}
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The '''balking pattern''' is a [[design pattern (computer science)|software design pattern]] that only executes an action on an [[object (computer science)|object]] when the object is in a particular state. For example, if an object reads [[ZIP file format|ZIP]] files and a calling method invokes a get method on the object when the ZIP file is not open, the object would "balk" at the request.  In the [[Java (programming language)|Java]] programming language, for example, an <code>IllegalStateException</code> might be thrown under these circumstances. In [[C Sharp (programming language)|C#]] it would be <code>InvalidOperationException</code>.
 
There are some specialists{{who|date=November 2010}} in this field who consider balking more of an [[anti-pattern]] than a design pattern.  If an object cannot support its [[API]], it should either limit the API so that the offending call is not available, or so that the call can be made without limitation. It should:
* Be created in a "sane state";{{elucidate|date=April 2015}}
* not make itself available until it is in a sane state;
* become a [[Facade pattern|facade]] and answer back an object that is in a sane state.