Package hudson

Annotation Interface Extension

@Retention(RUNTIME) @Target({TYPE,FIELD,METHOD}) @Documented public @interface Extension
Marks a field, a method, or a class for automatic discovery, so that Hudson can locate implementations of ExtensionPoints automatically.

(In contrast, in earlier Hudson, the registration was manual.)

In a simplest case, put this on your class, and Hudson will create an instance of it and register it to the appropriate ExtensionList.

If you'd like Hudson to call a factory method instead of a constructor, put this annotation on your static factory method. Hudson will invoke it and if the method returns a non-null instance, it'll be registered. The return type of the method is used to determine which ExtensionList will get the instance. Finally, you can put this annotation on a static field if the field contains a reference to an instance that you'd like to register.

This is the default way of having your implementations auto-registered to Hudson, but Hudson also supports arbitrary DI containers for hosting your implementations. See ExtensionFinder for more details.

Since:
1.286
Author:
Kohsuke Kawaguchi
See Also:

  • Optional Element Summary

    Optional Elements
    Modifier and Type
    Optional Element
    Description
    YesNoMaybe
    dynamicLoadable
    Marks whether this extension works with dynamic loading of a plugin.
    boolean
    optional
    If an extension is optional, don't log any class loading errors when reading it.
    double
    ordinal
    Used for sorting extensions.

  • Element Details

    • ordinal

      double ordinal
      Used for sorting extensions. Extensions will be sorted in the descending order of the ordinal. In other words, the extensions with the highest numbers will be chosen first. This is a rather poor approach to the problem, so its use is generally discouraged.
      Since:
      1.306
      Default:
      0.0

    • optional

      boolean optional
      If an extension is optional, don't log any class loading errors when reading it.
      Since:
      1.358
      Default:
      false

    • dynamicLoadable

      YesNoMaybe dynamicLoadable
      Marks whether this extension works with dynamic loading of a plugin.

      "Yes" indicates an explicit sign-off from the developer indicating this component supports that. Similarly, "No" indicates that this extension is known not to support it, which forces Jenkins not to offer dynamic loading as an option.

      The "MayBe" value indicates that there's no such explicit sign-off. So the dynamic loading may or may not work.

      If your plugin contains any extension that has dynamic loadability set to NO, then Jenkins will prompt the user to restart Jenkins to have the plugin take effect. If every component is marked as YES, then Jenkins will simply dynamic load the plugin without asking the user. Otherwise, Jenkins will ask the user if he wants to restart, or go ahead and dynamically deploy.

      Since:
      1.442
      Default:
      MAYBE