add toplevel javadoc to generated classes

Author: gavinking

tooling/metamodel-generator/src/main/java/org/hibernate/processor/ClassWriter.java

@@ -80,6 +80,8 @@ private static StringBuffer generateBody(Metamodel entity, Context context) {
 		final StringWriter sw = new StringWriter();
 		try ( PrintWriter pw = new PrintWriter(sw) ) {
 
+			pw.println( entity.javadoc() );
+
 			if ( context.addDependentAnnotation() && entity.isInjectable() ) {
 				pw.println( writeScopeAnnotation( entity ) );
 			}

tooling/metamodel-generator/src/main/java/org/hibernate/processor/annotation/AnnotationMetaEntity.java

@@ -3107,4 +3107,20 @@ public List<AnnotationMirror> inheritedAnnotations() {
 			return emptyList();
 		}
 	}
+
+	@Override
+	public String javadoc() {
+		if ( jakartaDataRepository ) {
+			return "/**\n * Implements Jakarta Data repository {@link " + qualifiedName + "}\n **/";
+		}
+		else if ( repository ) {
+			return "/**\n * Implements repository {@link " + qualifiedName + "}\n **/";
+		}
+		else if ( jakartaDataStaticModel ) {
+			return "/**\n * Jakarta Data static metamodel for {@link " + qualifiedName + "}\n **/";
+		}
+		else {
+			return "/**\n * Static metamodel for {@link " + qualifiedName + "}\n **/";
+		}
+	}
 }

tooling/metamodel-generator/src/main/java/org/hibernate/processor/annotation/AnnotationMetaPackage.java

@@ -170,4 +170,9 @@ public boolean isJakartaDataStyle() {
 	public List<AnnotationMirror> inheritedAnnotations() {
 		return emptyList();
 	}
+
+	@Override
+	public String javadoc() {
+		return "/**\n * Static metamodel package {@link " + element.getQualifiedName() + "}\n **/";
+	}
 }

tooling/metamodel-generator/src/main/java/org/hibernate/processor/model/Metamodel.java

@@ -58,4 +58,6 @@ public interface Metamodel extends ImportContext {
 	boolean isJakartaDataStyle();
 
 	List<AnnotationMirror> inheritedAnnotations();
+
+	String javadoc();
 }

tooling/metamodel-generator/src/main/java/org/hibernate/processor/xml/XmlMetaEntity.java

@@ -653,4 +653,9 @@ public boolean isJakartaDataStyle() {
 	public List<AnnotationMirror> inheritedAnnotations() {
 		return emptyList();
 	}
+
+	@Override
+	public String javadoc() {
+		return "/**\n * Static metamodel for {@link " + clazzName + "}\n **/";
+	}
 }