Generic ExtensionTransformerRegistration implementation for subsystem…

…s using SubsystemModel enumerations.

controller/src/main/java/org/jboss/as/controller/transform/SubsystemModelTransformerRegistration.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright The WildFly Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.jboss.as.controller.transform;
+
+import java.util.EnumSet;
+import java.util.function.BiConsumer;
+
+import org.jboss.as.controller.ModelVersion;
+import org.jboss.as.controller.SubsystemModel;
+import org.jboss.as.controller.transform.description.ResourceTransformationDescriptionBuilder;
+import org.jboss.as.controller.transform.description.TransformationDescription;
+
+/**
+ * A transformer registration of a single subsystem.
+ */
+public class SubsystemModelTransformerRegistration<E extends Enum<E> & SubsystemModel> implements ExtensionTransformerRegistration {
+
+    private final String subsystemName;
+    private final E currentSubsystemModel;
+    private final BiConsumer<ResourceTransformationDescriptionBuilder, ModelVersion> transformation;
+
+    /**
+     * Creates a transformer registration for a subsystem.
+     * @param subsystemName the subsystem name
+     * @param currentSubsystemModel the current subsystem model
+     * @param transformation a consumer that builds a transformer description for a given target model version
+     */
+    public SubsystemModelTransformerRegistration(String subsystemName, E currentSubsystemModel, BiConsumer<ResourceTransformationDescriptionBuilder, ModelVersion> transformation) {
+        this.subsystemName = subsystemName;
+        this.currentSubsystemModel = currentSubsystemModel;
+        this.transformation = transformation;
+    }
+
+    @Override
+    public String getSubsystemName() {
+        return this.subsystemName;
+    }
+
+    @Override
+    public void registerTransformers(SubsystemTransformerRegistration registration) {
+        // Build and register transformation descriptions for all but the current subsystem model version
+        for (E model : EnumSet.complementOf(EnumSet.of(this.currentSubsystemModel))) {
+            ModelVersion version = model.getVersion();
+            ResourceTransformationDescriptionBuilder builder = registration.createResourceTransformationDescriptionBuilder();
+            this.transformation.accept(builder, version);
+            TransformationDescription.Tools.register(builder.build(), registration, version);
+        }
+    }
+}