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New Feature Catalog

Current FeatureCatalog explicitly mentions all Helidon features and adds them. This requires us to keep track of features separately from the feature sources, which is hard to refactor (and keep in sync). To remedy this situation, the following approach is now to be used:

  • Each feature module-info.java is to be annotated with @Feature annotation
  • For preview features (production ready, but being worked on), use @Preview
  • For incubating features (not production ready, for preview only), use @Incubating
  • For information related to Native image, use @Aot

An annotation processor is available to process this annotation and generate a runtime property file with module information.

Module info updates

The module info must require the API, as it is used within the file. As the annotations are source only, we can use requires static:

requires static io.helidon.common.features.api;

Module info example:

import io.helidon.common.features.api.Aot;
import io.helidon.common.features.api.Feature;
import io.helidon.common.features.api.HelidonFlavor;
import io.helidon.common.features.api.Preview;

/**
 * GraphQL server integration with Helidon WebServer.
 */
@Preview
@Feature(value = "GraphQL", 
        in = HelidonFlavor.SE, 
        invalidIn = {HelidonFlavor.MP})
@Aot(description = "Incubating support, tested on limited use cases")
module io.helidon.webserver.graphql {
    requires static io.helidon.common.features.api;
    // other module dependencies and configuration
}

Dependency to be added

<dependency>
    <groupId>io.helidon.common.features</groupId>
    <artifactId>helidon-common-features-api</artifactId>
    <scope>provided</scope>
    <optional>true</optional>
</dependency>

Annotation processor setup

This example provides full plugins tag, if exists, update only relevant sections.

<plugins>
    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
            <annotationProcessorPaths>
                <path>
                    <groupId>io.helidon.common.features</groupId>
                    <artifactId>helidon-common-features-processor</artifactId>
                    <version>${helidon.version}</version>
                </path>
            </annotationProcessorPaths>
        </configuration>
    </plugin>
</plugins>