aQute.bnd.annotation.headers.About Maven / Gradle / Ivy
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package aQute.bnd.annotation.headers;
/**
* This package contains a number of annotations that create or append headers
* in the manifest. These annotations simplify maintaining these headers:
*
* - The annotations can be applied on the types that are generating their
* need instead of maintaining them in the manifest
*
- Less errors because of the use of annotations
*
- Use of IDE features to track them or navigate
*
* The annotations provide the following features:
*
* - Macros - use the bnd macro preprocessor for DNRY
*
- Coloring - define custom annotations that encapsulate some headers
*
- No runtime dependencies since all annotations are build time.
*
- No duplicates
*
* Macros
Any strings in the annotations are run through the bnd
* preprocessor and can therefore use any of the myriad of bnd macros (except
* system commands, for obvious reason they are excluded). As a convenience, a
* number of local macros are set from the context:
*
* ${@package} – The package name
* ${@class} – The class name to which this macro is
* applied to
* ${@class-short} – The short class name to which this
* macro is applied to
* ${@version} – The package version if set
* ${@frange;version[;isProvider]} – A macro to create a
* filter expression on a version based on the semantic versioning rules.
* Default is consumer, specify true for the isProvider to get provider
* semantics.
*
* Coloring
Annotations can only be applied once, making it impossible
* to add for example two Provide-Capability headers on the same type. It also
* would become unreadable quickly. The advised way to use most of these
* annotation headers is therefore through 'annotation coloring'. These header
* annotations should be applied to custom annotations that represents the
* 'thing'. This is clearly represented in the BundleLicense custom annotations
* like for example the {@link aQute.bnd.annotation.licenses.ASL_2_0 ASL_2_0}
* annotation. This annotation can be applied to any type and will automatically
* then create the appropriate clauses.
*
* For example:
*
*
* public class Webserver {
* @RequireCapability(ns="osgi.extender", name="webserver", version="${@version}")
* @interface Require {}
* @ProvideCapability(ns="osgi.extender", filter="(&(osgi.extender=webserver)${@frange;${@version}}))")
* @interface Provide {}
* ...
* }
*
*
* This resource can now be stored in a library to be used by others. If a
* component now wants to depend this resource, it can declare its component as
* follows:
*
*
* @Webserver.Require
* public class MyResource {
* ...
* }
*
*/
public class About {
}