documentation/src/content/spi.adoc

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= Arthur SPI

Arthur SPI enables you to add custom logic to generate `native-image` configuration.

== Dependencies

[source,xml]
----
<dependency>
  <groupId>org.apache.geronimo.arthur</groupId>
  <artifactId>arthur-spi</artifactId>
  <version>${arthur.version}</version>
</dependency>
----

== Usage

You must implement a `org.apache.geronimo.arthur.spi.ArthurExtension` and register it as a SPI (fully qualified name in `META-INF/services/org.apache.geronimo.arthur.spi.ArthurExtension`).
This extension will have to implement `execute(Context)` method to register reflection, resource, ... metadata needed by `native-image` build.

Here is an example:

[source,java]
----
public class MyJaxbExtension implements ArthurExtension {

    @Override
    public void execute(final Context context) {
        context.findAnnotatedClasses(XmlRootElement.class).stream()
                .flatMap(clazz -> createReflectionModel(clazz))
                .forEach(context::register);
    }

    // createReflectionModel() just instantiate a ClassReflectionModel instance
}
----

TIP: you can use `context.finder()` to find classes based on some annotation.

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