Implementing Spring-like package scanning in Android

Question

I\'m attempting to implement a package-scanning feature, similar to Spring\'s component-scan, for the Android framework I\'m developing. Basically, I would like

Answer 1

I share the opinion of Joop Eggen and find his approach a good one. In Android I try to avoid the usual web app features which lead to a long lasting application start. I do not use reflection or package scanning.

But if you want to .... if I understand it correctly you want to have an annotation for a class. Instead of using annotations you could also use marker interfaces (to just have more possibilites).

1) Look at

• Annotation: Java custom annotation and dynamic loading
  Has an implementation in the question which just answers your question.
• Annotation: Scanning Java annotations at runtime
• Interface: Find Java classes implementing an interface
• Interface: Is something similar to ServiceLoader in Java 1.5?
• Interface: How can I get a list of all the implementations of an interface programmatically in Java?
• Interface: Since the approach is expensive, maybe the ServiceLoader is a compromise between execution time and comfort, since it loads only the classes given in the services file. On the other hand if only classes with a certain interface are in your package then the ServiceLoader isn't that faster.

2) AndroidAnnotations

I would prefer the way AndroidAnnotations work (maybe an integration in AndroidAnnotations is the preferable way): It automatically adds an extra compilation step that generates source code, using the standard Java Annotation Processing Tool. So instead of runtime scanning you execute code based on the annotations generated during compile time.

I think the Bean/EBean annotation could work for you (only single class): https://github.com/excilys/androidannotations/wiki/Enhance%20custom%20classes

A scan-feature is not available, see this thread

3) Writing your own annotation processor

• See APT (Annotation Processing Tool). The idea would be to generate a static function which returns a list of classes which are annotated, so that no class scanning is needed.
• A very good ressource is http://javadude.com/articles/annotations/index.html