[joaodinissf]

Summary

Migrates the three remaining legacy Xtend sources of com.avaloq.tools.ddk.xtext.expression to Java 21:

• generator/GenModelUtilX — GenModel/EMF-registry lookups, the literalIdentifier and instanceClassName dispatch families, the per-thread resource context
• generator/GeneratorUtilX — contributor-comment and grammar helpers
• generator/Naming — qualified-name helpers

The module keeps jvmmodel/ExpressionJvmModelInferrer.xtend, so the Xtend build infrastructure (xtend-gen, .classpath, build.properties) is untouched. For the Tycho baseline gate, the bundle is micro-bumped to 17.3.3 and the runtime feature that includes it to 19.1.1 (content changed, API identical).

Public API is unchanged. These classes are consumed only by the Xtend inferrers in xtext.export and xtext.scope, which bind by dispatcher name (literalIdentifier(ENamedElement), instanceClassName(EClassifier)), by extension syntax (javaContributorComment, location, canContain, toJavaPackage) and by the property write genModelUtil.resource = … → setResource(Resource). All of them compile unchanged against the Java.

Faithfulness notes

• Dispatchers keep the compiler's shape: protected _name(Type) cases including the Void overload as the null case, and a public dispatcher with the compiler's branch order (EClass → EStructuralFeature/EDataType → supertype → null). As in the compiler output there is no terminal IllegalArgumentException: the Void case makes both dispatchers total.
• ThreadLocal<Resource> context and setResource/getContext are unchanged.
• xbase.lib replacements preserve exact semantics rather than the idiomatic short form: firstInterface() reproduces IterableExtensions.head returning null on an empty interface array (so the failure mode on an interface-less EPackage subclass is unchanged), and toFirstUpper() reproduces StringExtensions.toFirstUpper including its null/empty/already-upper pass-throughs. Xtend ==/!= on objects → Objects.equals; identity !== stays !=. The lazy filter feeding the Xcore candidate loop became a guard inside the loop (same elements, same order).
• Dropped: the vestigial /*cached*/ markers on fifteen defs (remnants of former create methods, no behaviour, already absent from the compiler output). Every other comment and Javadoc is preserved verbatim; the only new Javadoc documents the two private helpers.
• Repeated literals extracted to constants (DOES_NOT_EXIST, DOT) for Checkstyle; values unchanged. Parameters named it renamed per the migration skill.

Known deltas

• The Xtend compiler stamped @XbaseGenerated on the generated dispatchers; the migrated Java does not. The annotation is runtime-retained on public methods in an exported package, so it is a reflectively observable delta — but nothing in the target platform reads it (only JvmModelGenerator emits it), and re-applying a "machine-generated" marker to hand-written code would be false.
• Runtime coverage boundary: with a standalone ResourceSet the .genmodel index is empty, so genPackage() always returns null and the registry/heuristic fallbacks are taken. The isLiteralsInterface() branches of _literalIdentifier and qualifiedSwitchClassName, and genClass/genDataType/genModel, are therefore exercised only in a workspace build, not by the differential above.

Verification

• Ground truth: fresh xtend-gen from a clean build of the Xtend sources as they stood at the point the branch was cut. The branch has since been rebased onto a Checkstyle version bump, which cannot affect the Xtend compiler's output, so the reference still holds; the gates below were re-run after the rebase.
• Two independent translations were produced and reconciled against the compiler output; they differed only in style (parameter names, if-chain vs pattern switch, constant extraction, one Guava-vs-local-helper choice). No fidelity-relevant discrepancy.
• Bytecode comparison of the final classes against the compiler's: public/protected API identical; ordered string constants per method identical; dispatcher branch order identical. Only private members differ (the two helpers replacing xbase.lib calls, the extracted constants, the removed lambda).
• Gates: -amd compile (rebuilds the export/scope Xtend callers) ✅; pmd:check checkstyle:check spotbugs:check ✅; full reactor clean verify with the CI static-analysis goals ✅ (354 tests, 0 failures, 2 skipped).

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