refactor: migrate all Xtend files to Java 21 by joaodinissf · Pull Request #1274 · dsldevkit/dsl-devkit

joaodinissf · 2026-03-01T08:34:53Z

Summary

Migrate all 88 Xtend (.xtend) source files to Java 21, leveraging modern language features (text blocks, enhanced switch, pattern matching, records). This eliminates the Xtend compilation step, significantly improving build times.

What's included

Xtend-to-Java migration of all .xtend files across check, checkcfg, export, expression, format, scope, and generator modules (Batches 1–9)
Xtend build infrastructure removal (maven-xtend-plugin, xtend-maven-plugin configs)
Code quality fixes: resolve all PMD, Checkstyle, and SpotBugs violations in migrated code
Modern Java idioms: replace StringBuilder patterns with String.format() and text blocks, convert string concatenation to text blocks in test DSL sources
Eclipse formatter applied to all migrated files
@SuppressWarnings("nls") added to suppress non-externalized string literal warnings

Build impact

Clean Eclipse build ~2.8x faster: from 14.44s down to 5.13s (measured on MacBook).

Test plan

CI maven-verify passes
CI PMD and Checkstyle checks pass
Manual verification in Eclipse IDE

🤖 Generated with Claude Code

rubenporras · 2026-03-02T09:39:16Z

+   * @return the model stub string
+   */
+  public String modelWithGrammar() {
+    StringBuilder builder = new StringBuilder(512);


@joaodinissf it is not using multi line strings...

Good catch, I'll try to get it to clean this up later today.

rubenporras · 2026-04-16T12:46:35Z

-       *
-       * Also see {@link org.eclipse.xtext.xtext.XtextFormatter} as an example
-       */
-      public class «grammar.formatterStub.simpleName» extends «FormatGeneratorUtil::getFormatterName(grammar, "Abstract")» {


I think that for this kind of files were use use Xtend string interpolation, it actually makes sense to keep Xtend.

Add a structured project skill encoding the Xtend → Java conversion rules and methodology that previously lived only in the stale PR dsldevkit#1274 (`docs/xtend-to-java-conversion-prompt.md` and `docs/xtend-migration.md`). The skill is split into a 1-line entry point, 10 rule files, 4 workflow docs, 2 examples, and 1 reference table — Claude (or any LLM) can load only the parts it needs. Cross-tool generic location at `.agents/skills/` is the source of truth. A POSIX shell script `.agents/sync.sh` mirrors it into `.claude/skills/` (gitignored) for Claude Code's auto-discovery: symlink on macOS/Linux, recursive copy on Windows where Git symlinks need Developer Mode. After cloning, run `./.agents/sync.sh` once. Re-run after pulling changes that touch `.agents/skills/`. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

rubenporras · 2026-06-11T07:14:39Z

Hi @joaodinissf ,

would you mind splitting out some parts of the PR so that we can look one by one?

I think for example, you could split already com.avaloq.tools.ddk.sample.helloworld.* and and com.avaloq.tools.ddk.checkcfg.* and com.avaloq.tools.ddk.xtext.ui.

I am working now on a big refactor of the scope, export and expression language to get rid of Xpand, so I am not sure it is worth to touch them, it would only give me headaches with merging.

rubenporras · 2026-06-11T07:15:10Z

-    b.append(getElementTypeName());
-    b.append("\")"); //$NON-NLS-1$
-    return b.toString();
+    return this.getClass().getSimpleName() + "(\"" + getElementTypeName() + "\")"; //$NON-NLS-1$ //$NON-NLS-2$


this is very unrelated. I would undo it.

rubenporras · 2026-06-11T07:15:20Z

-          StringBuilder stringBuilder = new StringBuilder(valueString.substring(0, MAX_FEATURE_VALUE_LENGTH - CONTINUED.length()));
-          stringBuilder.append(CONTINUED);
-          valueString = stringBuilder.toString();
+          valueString = valueString.substring(0, MAX_FEATURE_VALUE_LENGTH - CONTINUED.length()) + CONTINUED;


this is very unrelated. I would undo it.

rubenporras · 2026-06-11T07:15:41Z

-    result.append('@');
-    result.append(Integer.toHexString(hashCode()));
-
+    String result = String.format("%s@%s", eObject.getClass().getName(), Integer.toHexString(hashCode())); //$NON-NLS-1$


this is very unrelated. I would undo it. Same for all the java files modifies in this plugin in this PR

Consolidate the learnings from the per-module migration campaign into the skill so future runs rely on the skill itself, not prompt-embedded notes: - overview.md / one-file-conversion.md / SKILL.md: a fresh -T 3C build off the integration branch is the authoritative xtend-gen ground truth; the dsldevkit#1274 reference is a (possibly stale) four-eyes cross-check, never a substitute. - known-pitfalls.md: add constant-fields->static-final (FinalFieldCouldBeStatic), public @RegisterExtension, active-annotations-are-not-leaf-conversions, dsldevkit#1274-is-a-parity-not-compliance-oracle, method-count parity, empty-body-needs- comment, text-block-vs-inline-''' fidelity; correct the import-order entry; enrich IllegalCatch/IllegalThrows. - validation-checklist.md: add gates 31-34. - multi-file-batch.md: drop the commit-trailer rule. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Consolidate the learnings from the per-module migration campaign into the skill so future runs rely on the skill itself, not prompt-embedded notes: - overview.md / one-file-conversion.md / SKILL.md: a fresh -T 3C build off the integration branch is the authoritative xtend-gen ground truth; dsldevkit#1274 is a (possibly stale) four-eyes cross-check, never a substitute. - known-pitfalls.md: constant-fields->static-final (FinalFieldCouldBeStatic), public @RegisterExtension, active-annotations-are-not-leaf-conversions, dsldevkit#1274-is-a-parity-not-compliance-oracle, method-count parity, empty-body-needs- comment, text-block-vs-inline-''' fidelity, and don't-carry-xbase.lib-Pair-into- migrated-Java (use a record; Map.entry rejects null); correct import-order; enrich IllegalCatch/IllegalThrows. - infrastructure-cleanup.md: MANIFEST removal of xbase.lib/xtend.lib now requires grepping BOTH src and src-gen (remove iff zero refs; transitive availability is irrelevant at zero refs; Require-Bundle isn't re-exported). - validation-checklist.md: add gates 31-34. - multi-file-batch.md: drop the commit-trailer rule. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Consolidate the learnings from the per-module migration campaign into the skill so future runs rely on the skill itself, not prompt-embedded notes: - overview.md / one-file-conversion.md / SKILL.md: a fresh -T 3C build off the integration branch is the authoritative xtend-gen ground truth; #1274 is a (possibly stale) four-eyes cross-check, never a substitute. - known-pitfalls.md: constant-fields->static-final (FinalFieldCouldBeStatic), public @RegisterExtension, active-annotations-are-not-leaf-conversions, #1274-is-a-parity-not-compliance-oracle, method-count parity, empty-body-needs- comment, text-block-vs-inline-''' fidelity, and don't-carry-xbase.lib-Pair-into- migrated-Java (use a record; Map.entry rejects null); correct import-order; enrich IllegalCatch/IllegalThrows. - infrastructure-cleanup.md: MANIFEST removal of xbase.lib/xtend.lib now requires grepping BOTH src and src-gen (remove iff zero refs; transitive availability is irrelevant at zero refs; Require-Bundle isn't re-exported). - validation-checklist.md: add gates 31-34. - multi-file-batch.md: drop the commit-trailer rule. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

…arlier) Rebased the umbrella migration onto current upstream/master (40034eb). The 7 campaign-merged modules (dsldevkit#1416-dsldevkit#1422) and earlier-merged bundles (format.ide/ui, xtext.ui, generator.test, etc.) are reset to master so they drop from the diff. The umbrella now shows only the remaining-to-migrate modules: xtext.generator, check.core.test, xtext.export, check.core, xtext.format, xtext.expression, xtext.scope, xtext.check.generator, xtext.test.core (+ dsldevkit#1274's repo-wide Xtend-infra cleanup and migration docs). Note: export/generator carry dsldevkit#1274's migration of files master tweaked post-base (ExportGeneratorX dsldevkit#1425, CompareFragment2) — those modules are deferred/in-flight and will be re-migrated against current master. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

rubenporras · 2026-08-24T14:34:15Z

@joaodinissf , also, now that export and scope are migrated, you are welcome as well to finish the migration from xtend to java, it should not conflict with any other ongoing work.

…ed work This PR is the migration tracker: as per-module migrations land on master through dedicated PRs, their counterparts here are dropped, shrinking this PR until it is empty and can be closed. Dropped in this rebase (master wins): - com.avaloq.tools.ddk.check.core/**: migration fully landed on master (fd18e86..30ff3e0 polish series; no .xtend remains there) - com.avaloq.tools.ddk.xtext.{export,expression,scope}/**: superseded by the dsldevkit#1405 Xbase rework (2973c5b); the conversions here predated it - ddk-parent/pom.xml: global xtend-maven-plugin removal was premature (master still carries .xtend sources) Kept (not yet landed via dedicated PRs): xtext.test.core Tag conversion (pending dsldevkit#1423), .ide/.ui/generator Xtend build-infra cleanups, migration docs and configuration. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

check.ide, check.ui, xtext.export.ide, xtext.expression.ide, xtext.scope.ide, xtext.valid.ide and xtext.generator no longer contain any Xtend sources, but still carried the xtend-gen source-folder entry in .classpath, the xtend-gen reference in build.properties and the tracked xtend-gen/.gitignore placeholder. Remove all three per module. Extracted from the migration tracker PR #1274 (which sheds this part on its next rebase). The tracker's accompanying .project linkedResources deletions are deliberately not carried over. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

joaodinissf changed the title ~~[CLAUDE] Xtend to Java migration~~ [WIP] Xtend to Java migration Mar 1, 2026

rubenporras reviewed Mar 2, 2026

View reviewed changes

joaodinissf marked this pull request as ready for review March 3, 2026 08:24

joaodinissf changed the title ~~[WIP] Xtend to Java migration~~ refactor: migrate all Xtend files to Java 21 Mar 3, 2026

joaodinissf force-pushed the feature/xtend-to-java-migration branch 3 times, most recently from 84de93f to 76087e2 Compare March 3, 2026 18:38

joaodinissf marked this pull request as draft March 5, 2026 08:41

joaodinissf force-pushed the feature/xtend-to-java-migration branch 2 times, most recently from dee50e3 to 4163b68 Compare April 4, 2026 11:55

rubenporras reviewed Apr 16, 2026

View reviewed changes

joaodinissf force-pushed the feature/xtend-to-java-migration branch 2 times, most recently from fddb296 to 5710dd2 Compare April 20, 2026 08:22

joaodinissf mentioned this pull request May 19, 2026

build: add Xtend → Java migration skill at .agents/skills/ #1351

Merged

4 tasks

joaodinissf force-pushed the feature/xtend-to-java-migration branch 6 times, most recently from 6d28382 to aef6caa Compare June 2, 2026 19:07

joaodinissf force-pushed the feature/xtend-to-java-migration branch 2 times, most recently from db22e58 to 85b6e59 Compare June 10, 2026 22:03

rubenporras reviewed Jun 11, 2026

View reviewed changes

joaodinissf force-pushed the feature/xtend-to-java-migration branch from 85b6e59 to 6c8b8cf Compare June 12, 2026 15:38

This was referenced Jun 12, 2026

style: collapse verbose string building in pre-existing classes #1412

Merged

refactor: migrate Xtend to Java - com.avaloq.tools.ddk.xtext.test.core (Tag) #1423

Merged

joaodinissf mentioned this pull request Jun 15, 2026

docs: harden the xtend-to-java skill with migration learnings #1415

Merged

joaodinissf force-pushed the feature/xtend-to-java-migration branch from 6c8b8cf to df84b85 Compare June 17, 2026 06:30

joaodinissf force-pushed the feature/xtend-to-java-migration branch 2 times, most recently from b37889f to 917d931 Compare June 25, 2026 09:22

joaodinissf force-pushed the feature/xtend-to-java-migration branch from 917d931 to 6753b0f Compare July 19, 2026 05:37

joaodinissf force-pushed the feature/xtend-to-java-migration branch from 6753b0f to 91ae694 Compare August 25, 2026 11:26

joaodinissf mentioned this pull request Aug 25, 2026

build: drop leftover Xtend build infrastructure from migrated modules #1499

Merged

Navigation Menu

Uh oh!

refactor: migrate all Xtend files to Java 21 - #1274

refactor: migrate all Xtend files to Java 21#1274
joaodinissf wants to merge 1 commit into
dsldevkit:masterfrom
joaodinissf:feature/xtend-to-java-migration

joaodinissf commented Mar 1, 2026 •

edited

Loading

Uh oh!

rubenporras Mar 2, 2026

Uh oh!

joaodinissf Mar 2, 2026 •

edited

Loading

Uh oh!

rubenporras Apr 16, 2026

Uh oh!

rubenporras commented Jun 11, 2026

Uh oh!

rubenporras Jun 11, 2026

Uh oh!

rubenporras Jun 11, 2026

Uh oh!

rubenporras Jun 11, 2026

Uh oh!

rubenporras commented Aug 24, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

Uh oh!

Conversation

joaodinissf commented Mar 1, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Summary

What's included

Build impact

Test plan

Uh oh!

rubenporras Mar 2, 2026

Choose a reason for hiding this comment

Uh oh!

joaodinissf Mar 2, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

rubenporras Apr 16, 2026

Choose a reason for hiding this comment

Uh oh!

rubenporras commented Jun 11, 2026

Uh oh!

rubenporras Jun 11, 2026

Choose a reason for hiding this comment

Uh oh!

rubenporras Jun 11, 2026

Choose a reason for hiding this comment

Uh oh!

rubenporras Jun 11, 2026

Choose a reason for hiding this comment

Uh oh!

rubenporras commented Aug 24, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

2 participants

joaodinissf commented Mar 1, 2026 •

edited

Loading

joaodinissf Mar 2, 2026 •

edited

Loading