inheriting static methods and fields

开发者_C百科Im writing an android application that contains several (4 to be exact) Services.

Each service has a static boolean field labeled 'running'. It is set to true when the service is created, and set to false when it is destroyed.

Each service also has a static method labeled 'isRunning()' that simply returns 'running'

Currently, I have identical code in all 4 services to provide this functionality. Ideally, the code should be located in one place. How can this be achieved? An interface? an abstract class? neither?

(I think the fact that this field and method are static place limitations on the answer)

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If the methods must be static and available on the involved classes, then they must belong to the individual classes; no way around it. But perhaps you could have a static map of Class -> boolean which kept track of the running services in some central location; when a service is started, it sets the appropriate value in that map by calling a (single) static method for that purpose. Then when anything needs to know if ServiceClass is running, they query that map using ServiceClass.class as the key. Sound good?