io.quarkus.deployment.annotations

Annotation Type BuildStep

@Retention(value=RUNTIME)
 @Target(value=METHOD)
public @interface BuildStep

Indicates that a given method is a build step that is run at deployment time to create the runtime output.

Build steps are run concurrently at augmentation time to augment the application. They use a producer/consumer model, where a step is guaranteed not to be run until all items that it is consuming have been created.

Producing and consuming is done via injection. This can be done via field injection, method parameter injection, or constructor parameter injection.

The following types are eligible for injection into a build step:

• Any concrete subclass of SimpleBuildItem
• List of any concrete subclass of MultiBuildItem
• Consumer of any concrete subclass of BuildItem
• Supplier of any concrete subclass of SimpleBuildItem
• Optional instances whose value type is a subclass of SimpleBuildItem
• Recorder template classes, which are annotated with Template (method parameters only, if the method is annotated Record)
• BytecodeRecorderImpl (method parameters only, if the method is annotated Record)

Injecting a SimpleBuildItem or a List of MultiBuildItem makes this step a consumer of these items, and as such will not be run until all producers of the relevant items has been run.

Injecting a BuildProducer makes this class a producer of this item. Alternatively items can be produced by simply returning them from the method.

If field injection is used then every BuildStep method on the class will be a producer/consumer of these items, while method parameter injection is specific to an individual build step. In general method parameter injection should be the preferred approach as it is more fine grained.

Note that a BuildStep will only be run if there is a consumer for items it produces. If nothing is interested in the produced item then it will not be run. A consequence of this is that it must be capable of producing at least one item (it does not actually have to produce anything, but it must have the ability to). A build step that cannot produce anything will never be run.

BuildItem instances must be immutable, as the producer/consumer model does not allow for mutating artifacts. Injecting a build item and modifying it is a bug waiting to happen, as this operation would not be accounted for in the dependency graph.

See Also:

Record

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
String[]	applicationArchiveMarkers Indicates that the provided file names should be considered to be application index markers.
String[]	providesCapabilities A list of capabilities that are provided by this build step.

Element Detail

providesCapabilities

public abstract String[] providesCapabilities

A list of capabilities that are provided by this build step.

Returns:

The capabilities provided by this build step

Default:

{}

applicationArchiveMarkers

public abstract String[] applicationArchiveMarkers

Indicates that the provided file names should be considered to be application index markers. If these are present in library on the class path then the library will be indexed, and this index will be used when evaluating application components. TODO: this should be a different annotation?

Default:

{}