Add MCP `regenerate_form_code(path)` to regenerate modified swing-based forms in Netbeans by Rizky92 · Pull Request #192 · nbplugins/NetbeansPluginClaudeCodeGui

Rizky92 · 2026-10-13T03:21:21Z

This PR added MCP regenerate_form_code(path). The purpose is to allow Claude Code reload the swing-based module after modifying the design form. Support for adding generated event block is not available, as it's separate concerns and maybe for the future.

Tested on Netbeans-31, windows 10 22H2. Some local unit tests was skipped because my environment is not supported.

… forms in netbeans. Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

oleg68

Thanks for the PR! The feature fits the plugin well (an IDE-only capability exposed over MCP) and the tests are thorough. Main concerns: this is the first tool that drives a non-API NetBeans module through reflection, and the tool is auto-allowed although it overwrites two project files. Items 1, 3 and 8 are required for merge; the rest are suggestions.

1. `ClaudeProcess.java` — `OUR_ALLOWED_TOOLS` (required)

The tool overwrites .java and re-serializes .form, bypassing the plugin's diff/permission UI. Unlike show_markdown* it is not read-only. Please don't auto-allow it; let Claude Code's normal permission prompt apply:

            "mcp__netbeans__show_markdown",
            "mcp__netbeans__show_markdown_file"

If auto-allow is wanted, make it an opt-in setting (default off) and document it.

2. `RegenerateFormCode` — verify the reflective API up front

The sequence can fail midway (form loaded, fireFormChanged sent, then a method is missing). Resolve all required methods (isOpened, loadForm, reloadFormEditor, getFormEditor, getDocument, saveDocument, ...) before touching the form, so an unsupported NetBeans version fails with "Unsupported NetBeans form editor version" before any state changes. Please also document the NetBeans versions this was verified on (31 per the description).

3. `regenerateInFormEditor(...)` — always close the form (required)

When the designer was closed, closeForm is skipped if fireFormChanged, regenerateCodeIfNeeded or saveDocument throws, leaking the loaded form. Suggestion: wrap the tail in try/finally and drop the early closeForm branches:

try {
    call(formModel, "fireFormChanged", boolean.class, true);
    call(formEditor, "regenerateCodeIfNeeded");
    String after = documentText(document);
    call(editorSupport, "saveDocument");
    return new Outcome(open, !before.equals(after), after);
} finally {
    if (!open) {
        call(formEditor, "closeForm");
    }
}

4. `call(...)` — non-public runtime class

getClass().getMethod(...) + invoke throws IllegalAccessException if the runtime class is not public. Map it to the same "Unsupported NetBeans form editor version" error:

} catch (IllegalAccessException e) {
    throw new IllegalStateException("Unsupported NetBeans form editor version: "
            + target.getClass().getName() + "." + methodName + "() is not accessible", e);
}

5. EDT work

saveDocument (disk I/O + formatting) runs inside invokeAndWait. If unavoidable per the form API's threading rules, please say so in the Javadoc.

6. `waitForDocumentInSync` / `documentMatchesDisk`

The whitespace-insensitive comparison treats whitespace-only external edits as "in sync". Fine, but please note it in the Javadoc, and that the method must never be called on the EDT (Thread.sleep).

7. `checkAccess`

The path comes straight from the model. Please confirm NbUtils.isPathWithinOpenProjects normalizes .. and symlinks; if not, use FileUtil.normalizeFile / toRealPath() first.

8. Manual test plan (required)

The fake-object tests prove the call sequence, not that real NetBeans behaves that way. Please add a manual test plan to the PR: closed designer, open designer, malformed .form, .java with unsaved changes, NetBeans without the form module. Also mention which tests were skipped and why.

9. `pom.xml`

1.3.53 -> 1.3.55; the project rule is +1 patch:

<version>1.3.54-SNAPSHOT</version>

10. `CHANGELOG.md` wording

Entries should describe the change from the user's perspective, without implementation details:

- Added the `regenerate_form_code` tool: after Claude edits a Swing form (`.form`), it can regenerate the form's code in the IDE instead of editing the generated code by hand

11. Commit message / PR title

Per CLAUDE.md a past-tense verb is expected, e.g. "Added MCP regenerate_form_code tool to regenerate Swing form code". Also, the parameter is filePath, not path.

12. `docs/user-manual.md`

Please add a short limitation note: the tool relies on NetBeans form-module internals and may stop working after an IDE update; it requires the Swing GUI Builder to be enabled.

oleg68

Thanks for the PR! The feature fits the plugin well (an IDE-only capability exposed over MCP) and the tests are thorough. Main concerns: this is the first tool that drives a non-API NetBeans module through reflection, and it is auto-allowed although it overwrites two project files. Inline comments marked (required) should be addressed before merge; the rest are suggestions.

Also required:

Manual test plan. The fake-object tests prove the call sequence, not that real NetBeans behaves that way. Please add a manual test plan to the PR description: closed designer, open designer, malformed .form, .java with unsaved changes, NetBeans without the form module. Mention which tests were skipped and why.

Minor:

Commit message / PR title: CLAUDE.md requires a past-tense verb, e.g. "Added MCP regenerate_form_code tool to regenerate Swing form code". The parameter is filePath, not path.

oleg68 · 2026-10-16T20:09:43Z

+            "mcp__netbeans__show_markdown_file",
+            "mcp__netbeans__regenerate_form_code"


(required) This tool overwrites .java and re-serializes .form, bypassing the plugin's diff/permission UI. Unlike show_markdown* it is not read-only. Please don't auto-allow it; let Claude Code's normal permission prompt apply. If auto-allow is wanted, make it an opt-in setting (default off) and document it.

Suggested change

"mcp__netbeans__show_markdown_file",

"mcp__netbeans__regenerate_form_code"

"mcp__netbeans__show_markdown_file"

Removed from allowlist 3ff268e.

oleg68 · 2026-10-16T20:09:43Z

+    }
+
+    /** Returns the form module's {@code EditorSupport}, or {@code null} for a non-form data object. */
+    private static Object formEditorSupport(DataObject dataObject) throws Exception {


Resolve all reflectively used methods (isOpened, loadForm, reloadFormEditor, getFormEditor, getDocument, saveDocument, ...) up front, here, before touching the form. Now the sequence can fail midway (form loaded, fireFormChanged sent, then a method is missing). An unsupported NetBeans version should fail with "Unsupported NetBeans form editor version" before any state changes. Please also document the NetBeans versions this was verified on (31 per the description).

oleg68 · 2026-10-16T20:09:43Z

+     *
+     * @param file file to check
+     */
+    protected void checkAccess(File file) {


The path comes straight from the model. Please confirm NbUtils.isPathWithinOpenProjects normalizes .. and symlinks; if not, normalize (FileUtil.normalizeFile / toRealPath()) before the check.

oleg68 · 2026-10-16T20:09:43Z

+        }
+        Document document = (Document) call(editorSupport, "getDocument");
+        String before = documentText(document);
+        call(formModel, "fireFormChanged", boolean.class, true);


(required) When the designer was closed, closeForm is skipped if fireFormChanged, regenerateCodeIfNeeded or saveDocument throws, leaking the loaded form. Wrap this tail in try/finally:

Suggested change

call(formModel, "fireFormChanged", boolean.class, true);

try {

call(formModel, "fireFormChanged", boolean.class, true);

call(formEditor, "regenerateCodeIfNeeded");

String after = documentText(document);

call(editorSupport, "saveDocument");

return new Outcome(open, !before.equals(after), after);

} finally {

if (!open) {

call(formEditor, "closeForm");

}

}

Resolved here dc77aa3.

oleg68 · 2026-10-16T20:09:43Z

+     * asynchronously. Waits until it shows the content on disk so the regenerated
+     * code is not merged into, and saved over, a stale document.
+     */
+    private static void waitForDocumentInSync(EditorCookie editorCookie, FileObject javaFo, String javaName)


Two notes for the Javadoc: the whitespace-insensitive comparison treats whitespace-only external edits as "in sync" (acceptable, but worth stating), and this method uses Thread.sleep so it must never be called on the EDT.

oleg68 · 2026-10-16T20:09:43Z

+        }
+        try {
+            return paramType == null ? method.invoke(target) : method.invoke(target, arg);
+        } catch (InvocationTargetException e) {


getMethod + invoke throws IllegalAccessException if the runtime class is not public. Map it to the same "Unsupported NetBeans form editor version" error:

Suggested change

} catch (InvocationTargetException e) {

} catch (IllegalAccessException e) {

throw new IllegalStateException("Unsupported NetBeans form editor version: "

+ target.getClass().getName() + "." + methodName + "() is not accessible", e);

} catch (InvocationTargetException e) {

oleg68 · 2026-10-16T20:09:43Z

+        }
+        AtomicReference<T> result = new AtomicReference<>();
+        AtomicReference<Exception> error = new AtomicReference<>();
+        EventQueue.invokeAndWait(() -> {


saveDocument (disk I/O + formatting) runs inside this invokeAndWait, so a slow disk blocks the IDE. If unavoidable per the form API's threading rules, please say so in the Javadoc and keep validation/waiting outside the EDT (as is already done).

oleg68 · 2026-10-16T20:09:43Z

    <groupId>io.github.nbplugins</groupId>
    <artifactId>netbeans-plugin-claude-code-gui</artifactId>
-    <version>1.3.53-SNAPSHOT</version>
+    <version>1.3.55-SNAPSHOT</version>


The project rule is a +1 patch bump (main is at 1.3.53).

Suggested change

<version>1.3.55-SNAPSHOT</version>

<version>1.3.54-SNAPSHOT</version>

I'll keep this +1 of target branch instead.

oleg68 · 2026-10-16T20:09:43Z

@@ -1,3 +1,4 @@
+- Added the `regenerate_form_code` MCP tool: after Claude edits a Swing GUI Builder `.form` file, it regenerates the form's `initComponents()` and variable declarations in the `.java` file exactly as the NetBeans GUI Builder does and saves the form, instead of Claude hand-editing the generated code; an open GUI Builder designer is reloaded from the edited `.form`, and Claude is told when the generated code was already up to date


Per CLAUDE.md, entries describe the change from the user's perspective, without implementation details:

Suggested change

- Added the `regenerate_form_code` MCP tool: after Claude edits a Swing GUI Builder `.form` file, it regenerates the form's `initComponents()` and variable declarations in the `.java` file exactly as the NetBeans GUI Builder does and saves the form, instead of Claude hand-editing the generated code; an open GUI Builder designer is reloaded from the edited `.form`, and Claude is told when the generated code was already up to date

- Added the `regenerate_form_code` MCP tool: after Claude edits a Swing form (`.form`), it can regenerate the form's code in the IDE instead of editing the generated code by hand

oleg68 · 2026-10-16T20:09:43Z

 | `permission_prompt` | Shows proposed file changes in the diff panel and waits for your approval |
 | `show_markdown` | Renders markdown text directly in a Markdown Preview tab; accepts the markdown content plus optional title and file path |
 | `show_markdown_file` | Opens a live-updating Markdown Preview tab for an existing `.md` file on disk; the tab automatically refreshes when the file changes |
+| `regenerate_form_code` | Regenerates the GUI Builder code (`initComponents()` and the variables declaration) of a Swing form's `.java` file from its edited `.form` file, exactly as the NetBeans GUI Builder does, and saves the form (NetBeans re-saves the `.form` in its own formatting). Claude calls it after changing a `.form` file. An open designer is reloaded from it. Refused if the form has unsaved changes in the IDE |


Please add a short limitation note: the tool relies on NetBeans form-module internals and may stop working after an IDE update; it requires the Swing GUI Builder to be enabled.

Would it be applicable to introduce integration test towards generated code?

Yes, it would be nice.

Integration setup here 414faf5 and implementation details here 3c7c260.

Rizky92 · 2026-10-20T00:23:31Z

Drafting while I resolve.

Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

Add MCP regenerate_form_code(path) to regenerate modified swing-based…

ae76ba3

… forms in netbeans. Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

oleg68 reviewed Oct 16, 2026

View reviewed changes

oleg68 requested changes Oct 16, 2026

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Rizky92 marked this pull request as draft October 20, 2026 00:22

Rizky92 added 7 commits October 23, 2026 16:13

Merge branch 'main' into feature/regenerate-form-code

cc59e9a

Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

Remove duplicate NbBundle resource

42fed1f

Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

Remove mcp__netbeans__regenerate_form_code from allow list

3ff268e

Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

Clarify limitation

f8a75ec

Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

Shorten changelog description

d52351f

Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

wip

dc77aa3

Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

Keeping this +1 of target branch

3aa4ee1

Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

Rizky92 commented Oct 26, 2026

View reviewed changes

Comment thread src/main/java/io/github/nbplugins/claudecodegui/actions/OpenWithClaudeAction.java Resolved

Rizky92 added 5 commits October 26, 2026 15:25

Integration test setup

414faf5

Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

Added auto-generated event handler

3bdf5f4

Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

Added integration tests, covers many common cases

3c7c260

Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

Added back NbBundle.Messages annotation. This was needed duh

0009280

Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

Ensure formEditorSupport exists on supported netbeans version

7655353

Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

Rizky92 force-pushed the feature/regenerate-form-code branch from d6679c4 to 7655353 Compare October 28, 2026 14:12

Rizky92 added 2 commits November 11, 2026 10:32

wip

f34cd53

Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

Merge branch 'main' into feature/regenerate-form-code

25f2d22

Signed-off-by: Muhammad Rizky Rizaldi <myquinn489@gmail.com>

		"mcp__netbeans__show_markdown_file",
		"mcp__netbeans__regenerate_form_code"

	"mcp__netbeans__show_markdown_file",
	"mcp__netbeans__regenerate_form_code"
	"mcp__netbeans__show_markdown_file"

	<version>1.3.55-SNAPSHOT</version>
	<version>1.3.54-SNAPSHOT</version>

		@@ -1,3 +1,4 @@
		- Added the `regenerate_form_code` MCP tool: after Claude edits a Swing GUI Builder `.form` file, it regenerates the form's `initComponents()` and variable declarations in the `.java` file exactly as the NetBeans GUI Builder does and saves the form, instead of Claude hand-editing the generated code; an open GUI Builder designer is reloaded from the edited `.form`, and Claude is told when the generated code was already up to date

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Rizky92 commented Oct 13, 2026

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1. ClaudeProcess.java — OUR_ALLOWED_TOOLS (required)

2. RegenerateFormCode — verify the reflective API up front

3. regenerateInFormEditor(...) — always close the form (required)

4. call(...) — non-public runtime class

5. EDT work

6. waitForDocumentInSync / documentMatchesDisk

7. checkAccess

8. Manual test plan (required)

9. pom.xml

10. CHANGELOG.md wording

11. Commit message / PR title

12. docs/user-manual.md

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Rizky92 commented Oct 20, 2026

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1. `ClaudeProcess.java` — `OUR_ALLOWED_TOOLS` (required)

2. `RegenerateFormCode` — verify the reflective API up front

3. `regenerateInFormEditor(...)` — always close the form (required)

4. `call(...)` — non-public runtime class

6. `waitForDocumentInSync` / `documentMatchesDisk`

7. `checkAccess`

9. `pom.xml`

10. `CHANGELOG.md` wording

12. `docs/user-manual.md`