jolshan commented on code in PR #15685: URL: https://github.com/apache/kafka/pull/15685#discussion_r1610251718
########## server-common/src/main/java/org/apache/kafka/server/common/Features.java: ########## @@ -16,72 +16,135 @@ */ package org.apache.kafka.server.common; -import java.util.Collections; -import java.util.HashMap; +import java.util.Arrays; +import java.util.Iterator; +import java.util.List; import java.util.Map; -import java.util.Objects; +import java.util.stream.Collectors; -import static org.apache.kafka.server.common.MetadataVersion.FEATURE_NAME; +/** + * This is enum for the various features implemented for Kafka clusters. + * KIP-584: Versioning Scheme for Features introduced the idea of various features, but only added one feature -- MetadataVersion. + * KIP-1022: Formatting and Updating Features allowed for more features to be added. In order to set and update features, + * they need to be specified via the StorageTool or FeatureCommand tools. + * <br> + * Having a unified enum for the features that will use a shared type in the API used to set and update them + * makes it easier to process these features. + */ +public enum Features { + + /** + * Features defined. If a feature is included in this list, and marked to be used in production they will also be specified when + * formatting a cluster via the StorageTool. MetadataVersion is handled separately, so it is not included here. + * + * See {@link TestFeatureVersion} as an example. See {@link FeatureVersion} when implementing a new feature. + */ + TEST_VERSION("test.feature.version", TestFeatureVersion.values(), TestFeatureVersion::fromFeatureLevel, false); -public final class Features { - private final MetadataVersion version; - private final Map<String, Short> finalizedFeatures; - private final long finalizedFeaturesEpoch; + public static final Features[] FEATURES; + public static final List<Features> PRODUCTION_FEATURES; + private final String name; + private final FeatureVersion[] features; + private final CreateMethod createFeatureVersionMethod; + private final boolean usedInProduction; - public static Features fromKRaftVersion(MetadataVersion version) { - return new Features(version, Collections.emptyMap(), -1, true); + Features(String name, + FeatureVersion[] features, + CreateMethod createMethod, + boolean usedInProduction) { + this.name = name; + this.features = features; + this.createFeatureVersionMethod = createMethod; + this.usedInProduction = usedInProduction; } - public Features( - MetadataVersion version, - Map<String, Short> finalizedFeatures, - long finalizedFeaturesEpoch, - boolean kraftMode - ) { - this.version = version; - this.finalizedFeatures = new HashMap<>(finalizedFeatures); - this.finalizedFeaturesEpoch = finalizedFeaturesEpoch; - // In KRaft mode, we always include the metadata version in the features map. - // In ZK mode, we never include it. - if (kraftMode) { - this.finalizedFeatures.put(FEATURE_NAME, version.featureLevel()); - } else { - this.finalizedFeatures.remove(FEATURE_NAME); - } + static { + Features[] enumValues = Features.values(); + FEATURES = Arrays.copyOf(enumValues, enumValues.length); + + PRODUCTION_FEATURES = Arrays.stream(FEATURES).filter(feature -> + feature.usedInProduction).collect(Collectors.toList()); } - public MetadataVersion metadataVersion() { - return version; + public String featureName() { + return name; } - public Map<String, Short> finalizedFeatures() { - return finalizedFeatures; + public FeatureVersion[] features() { + return features; } - public long finalizedFeaturesEpoch() { - return finalizedFeaturesEpoch; + /** + * Creates a FeatureVersion from a given name and level with the correct feature object underneath. + * + * @param level the level of the feature + * @returns the FeatureVersionUtils.FeatureVersion for the feature the enum is based on. + * @throws IllegalArgumentException if the feature name is not valid (not implemented for this method) + */ + public FeatureVersion fromFeatureLevel(short level) { + return createFeatureVersionMethod.fromFeatureLevel(level); Review Comment: Iterate through all the features and all the levels of each feature? We could I suppose, but this could get slow if we have a lot of different features and levels. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: jira-unsubscr...@kafka.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org