#1936: Improve localization of gui by KarimALotfy · Pull Request #1979 · devonfw/IDEasy

KarimALotfy · 2026-05-27T08:23:43Z

This PR fixes #1936

Implemented changes:

Add interactive i18n support: app can switch locales (English/Deutsch) via combo box
I18nService manages locale state with listener notifications for UI text updates
MainController registers locale change listener to refresh all UI labels and prompts on language switch

Testing instructions

Please add conscise, understandable instructions on how a reviewer can test/verify the functionality of your contribution here:

Run in /ide-gui AppLauncher , interact with the third combo box (Language) -- check if language is correctly switched
Add and remove properties to messages.properties and messages_de.properties--> run I18nServiceTest

Checklist for this PR

Make sure everything is checked before merging this PR. For further info please also see
our DoD.

When running mvn clean test locally all tests pass and build is successful
PR title is of the form #«issue-id»: «brief summary» (e.g. #921: fixed setup.bat). If no issue ID exists, title only.
PR top-level comment summarizes what has been done and contains link to addressed issue(s)
PR and issue(s) have suitable labels
Issue is set to In Progress and assigned to you or there is no issue (might happen for very small PRs)
You followed all coding conventions
You have added the issue implemented by your PR in CHANGELOG.adoc unless issue is labeled
with internal
You have formulated clear instructions on how to test your contribution under "Testing instructions"

- Added testing class for modals

- Added logging to IdeGuiStateManager. - Added functionality, that selecting a different project now switches the IdeContext to the new project.

- Added testing class for modals

- Added logging to IdeGuiStateManager. - Added functionality, that selecting a different project now switches the IdeContext to the new project.

…t-for-gui' into devonfw#1785-implement-modals-in-idecontext

- Added functionality, that selecting a different project now switches the IdeContext to the new project.

…plementation' into devonfw#1802-state-management-implementation

…r other ui feature branches

- added DI for IdeGuiStateManager.switchContext

…reading the list of workspaces/projects instead of reading those from the UI

…nager, when switchContext(Path rootDirectory, ...) is called.

This reverts commit 6f92d93.

…plementation' into devonfw#1802-state-management-implementation

…tateManager is now set when calling getInstance(), allowing us to provide a getInstance() method with a DI parameter

… getInstance()) (see previous commit)

…can be extended by tests

…plementation' into devonfw#1802-state-management-implementation

coveralls · 2026-05-27T08:28:57Z

Coverage Report for CI Build 28107858485

Warning

Build has drifted: This PR's base is out of sync with its target branch, so coverage data may include unrelated changes.
Quick fix: rebase this PR. Learn more →

Coverage decreased (-0.08%) to 71.305%

Details

Coverage decreased (-0.08%) from the base build.
Patch coverage: No coverable lines changed in this PR.
55 coverage regressions across 4 files.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

55 previously-covered lines in 4 files lost coverage.

File	Lines Losing Coverage	Coverage
com/devonfw/ide/gui/MainController.java	27	59.0%
com/devonfw/ide/gui/App.java	26	0.0%
com/devonfw/tools/ide/variable/IdeVariables.java	1	94.34%
com/devonfw/tools/ide/version/VersionSegment.java	1	89.24%

Coverage Stats


Relevant Lines:	16433
Covered Lines:	12225
Line Coverage:	74.39%
Relevant Branches:	7352
Covered Branches:	4735
Branch Coverage:	64.4%
Branches in Coverage %:	Yes
Coverage Strength:	3.15 hits per line

💛 - Coveralls

…-gui"

laim2003

looks good! just left some thoughts😊

laim2003 · 2026-06-16T13:31:33Z

+  public static synchronized I18nService getInstance() {
+
+    if (instance == null) {
+      return getInstance(null);
+    }
+    return instance;
+  }


@hohwille said that we should avoid Singleton patterns where possible and use Dependency Injection. I know i used this pattern a lot in my own state management implementation, but I will also be moving away from Singeltons there. Maybe we can discuss about whether its okay to use them in some instances in the Next daily, probably would also help me clear up some questions. I would probably leave this how it is here for now, but then open a second issue for the future where we update this to DI.

…/1936-improve-localization-of-gui"

hohwille · 2026-06-22T17:51:11Z

@@ -0,0 +1,17 @@
+# IDEasy GUI - English (default) Translation File


In cli we named the folder nls for "Native Language Support".
For homogeneity, it would be nice to have both folder named the same.
If the team better understands localization we can also change nls but it is short and maybe more speaking than l10n what other projects use as shortcut for localization.

So should localization be changed to nls , and accordingly the usage of the service also to nls ?

hohwille · 2026-06-22T17:57:14Z

+  public void testGetInstanceSingleton() {
+
+    LocalizationService service1 = LocalizationService.getInstance(Locale.ENGLISH);
+    LocalizationService service2 = LocalizationService.getInstance();


Better do not rely on default locale in JUnits.
If the user has a different local configured than English, the test will fail.
This will happen sooner or later and cause confusion if some developers have red tests and others have green tests.

hohwille · 2026-06-22T17:58:28Z

+    service.setLocale(Locale.GERMAN);
+
+    assertThat(service.getLocale().getLanguage()).isEqualTo("de");
+    assertThat(service.getResourceBundle()).isNotNull();


I would also expect that we lookup some key for German and assert the expected translation.
If you choose a generic key that will not likely change, the test should also stay stable.

hohwille · 2026-06-22T18:02:59Z

+  @BeforeEach
+  public void setUp() {
+
+    // Reset the singleton instance before each test
+    LocalizationService.resetInstance();
+    // Preload English bundle keys used by bundle-completion tests
+    ResourceBundle englishBundle = ResourceBundle.getBundle("localization.messages", Locale.ENGLISH);
+    this.englishKeys = extractKeys(englishBundle);
+  }


Only needed for testing the German keys match the English keys.
I usually expect that setup method does some generic setup used for all test methods.
Nothing wrong here but you could simply do a single test that checks that English keys and German keys are identical and then move this from setup to that single test method.
Surely nice to have...

hohwille · 2026-06-22T18:09:29Z

+
+    // Initialize language choices
+    selectedLanguage.getItems().clear();
+    selectedLanguage.getItems().addAll("English", "Deutsch");


we should not hardcode the lanugages.
Instead simply add a key like CurrentLanguage so e.g.

CurrentLanguage=English (en)

or

CurrentLanguage=Deutsch (de)

Then we can dynamically lookup the available resource bundles and add new languages without changing the code.

BTW: Adding the ISO-Codes in parenthesis improves UX if you see languages that you cannot read but still want to get an idea of. Example

แบบไทย (th)

hohwille · 2026-06-22T18:12:24Z

+    // Set Labels
+    labelProject.setText(localizationService.get("label.project"));
+    labelWorkspace.setText(localizationService.get("label.workspace"));
+    labelLanguage.setText(localizationService.get("label.language"));
+
+    // Set ComboBox prompts
+    selectedProject.setPromptText(localizationService.get("prompt.chooseProject"));
+    selectedWorkspace.setPromptText(localizationService.get("prompt.chooseWorkspace"));
+    selectedLanguage.setPromptText(localizationService.get("prompt.chooseLanguage"));
+
+    // Set Button texts
+    androidStudioOpen.setText(localizationService.get("button.open"));
+    eclipseOpen.setText(localizationService.get("button.open"));
+    intellijOpen.setText(localizationService.get("button.open"));
+    vsCodeOpen.setText(localizationService.get("button.open"));


This also looks unmaintainable.
We cannot hard-code all labels, buttons, etc. of all dialogues here.

KISS solution: To change the language, the GUI has to be restarted.
Otherwise research how to tell JavaFx to reload the messages (or the entire FXML).

hohwille · 2026-06-22T18:17:06Z

+  public void setLocale(Locale locale) {
+
+    this.locale = locale;
+    loadBundle();
+    LOG.info("Locale set to: {}", locale.getLanguage());
+    for (Runnable listener : this.localeListeners) {
+      try {
+        listener.run();
+      } catch (Exception e) {
+        LOG.warn("Locale change listener threw: {}", e.getMessage());
+      }
+    }
+  }


usually the language is set on operating system level and then Java takes it from there via the default locale. Would be sufficient for KISS. Custom language for IDEasy can IMHO be set via

export IDE_OPTIONS=-Duser.lang=de

in ~/.ide/ide.properties what should already work for the CLI0.
It is nice that you add the option to change in individually in the GUI.
But if you do this, we have to persist the value so that if I close the GUI and reopen it, I do not have to change it every time again.

FYI: If you want to go for KISS, you may keep this out of this first PR and we will add that later. But when we already introduce it, we should IMHO do it properly.

hohwille

@KarimALotfy thanks for your PR.
Very nice that you figured out how to do NLS (i18n and l10n) with JavaFx (using Locale, ResourceBundle and the % syntax in fxml files). Great that you also added a proper JUnit test and some advanced features. 👍
I left quite some comments for rework.
In some cases you may decide to go for more KISS and keep some advanced features out of this first PR and introduce in a later improving PR after this one is merged or you should go for the full solution if you already start it.

- Generalize localization keys in the `.properties` files - Detect available resource bundles automatically instead of hardcoding languages - Persist the selected language in `~/.ide/ide.properties` using `IDE_LOCALE` - Load and apply the persisted locale during GUI initialization - Remove `updateTexts()` from `MainController` - Reload the app after each language selection to apply localization changes - Refactor tests to match the updated localization flow

laim2003 added 30 commits March 27, 2026 17:52

devonfw#1296: implemented basic IdeDialog Class

029f03d

devonfw#1296: Added basic context state manager class

89cfb67

- Added testing class for modals

devonfw#1785: Added basic question/confirmation modal implementation

a53296d

- Added logging to IdeGuiStateManager. - Added functionality, that selecting a different project now switches the IdeContext to the new project.

devonfw#1296: implemented basic IdeDialog Class

37cad74

devonfw#1296: Added basic context state manager class

55a50ce

- Added testing class for modals

devonfw#1785: Added basic question/confirmation modal implementation

3f1569f

- Added logging to IdeGuiStateManager. - Added functionality, that selecting a different project now switches the IdeContext to the new project.

Merge remote-tracking branch 'origin/devonfw#1296-implement-idecontex…

6ce99b3

…t-for-gui' into devonfw#1785-implement-modals-in-idecontext

devonfw#1785: - Added logging to IdeGuiStateManager.

7ef65f3

- Added functionality, that selecting a different project now switches the IdeContext to the new project.

devonfw#1724: implemented basic gui state management

1764b2f

devonfw#1802: implemented basic gui state management

ddd3e5f

Merge remote-tracking branch 'origin/devonfw#1802-state-management-im…

9c5a720

…plementation' into devonfw#1802-state-management-implementation

devonfw#1802: removed a few changes so this branch can be the base fo…

b28e216

…r other ui feature branches

devonfw#1802: disabled javadoc warning

234e98b

devonfw#1802: - fixed AppBaseTest being stuck

1c4e766

- added DI for IdeGuiStateManager.switchContext

Merge branch 'main' into devonfw#1802-state-management-implementation

6fc3884

devonfw#1802: Added ProjectManager class to handle business logic of …

2026757

…reading the list of workspaces/projects instead of reading those from the UI

devonfw#1802: Updated IdeGuiStateManager to also update its projectMa…

c76e185

…nager, when switchContext(Path rootDirectory, ...) is called.

devonfw#1802: javafx updated to java 25

6f92d93

Merge branch 'main' into devonfw#1802-state-management-implementation

9f741a5

Revert "devonfw#1802: javafx updated to java 25"

48fe018

This reverts commit 6f92d93.

devonfw#1803: added DI for IDE_ROOT in GuiStateManager

e0ad015

devonfw#1802: added DI for IDE_ROOT in GuiStateManager

2c9fc55

Merge remote-tracking branch 'origin/devonfw#1802-state-management-im…

2b62c60

…plementation' into devonfw#1802-state-management-implementation

devonfw#1802: Workaround for IDE_ROOT=null issue. The ideRoot in GuiS…

40ff54e

…tateManager is now set when calling getInstance(), allowing us to provide a getInstance() method with a DI parameter

devonfw#1802: removed redundant DI variant of switchContext() (DI via…

0b67210

… getInstance()) (see previous commit)

devonfw#1802: Added tests for GuiStateManager

2e15d60

Merge branch 'main' into devonfw#1802-state-management-implementation

10cf940

devonfw#1802: Extracted mock IDE_ROOT logic into seperate class that …

5f0b40a

…can be extended by tests

Merge remote-tracking branch 'origin/devonfw#1802-state-management-im…

3b567ef

…plementation' into devonfw#1802-state-management-implementation

devonfw#1802: added ProjectManagerTest

e406b65

KarimALotfy moved this from 🆕 New to 🏗 In progress in IDEasy board May 27, 2026

KarimALotfy self-assigned this May 27, 2026

devonfw#1936: Add to CHANGELOG.adoc

5943b23

hohwille moved this from 🏗 In progress to Team Review in IDEasy board May 28, 2026

hohwille moved this from Team Review to 🏗 In progress in IDEasy board May 28, 2026

KarimALotfy added 5 commits May 28, 2026 16:57

Merge "PR-1807" to "feature/1936-improve-localization-of-gui"

01d696b

Merge main into "feature/1936-improve-localization-of-gui"

df6f21b

devonfw#1928: Merge "main" into "feature/1936-improve-localization-of…

519a8bb

…-gui"

devonfw#1928: Remove duplicated Imports

aaa1763

devonfw#1928: Align structure of ide-projects with main

3441ed4

laim2003 self-assigned this Jun 16, 2026

laim2003 self-requested a review June 16, 2026 13:20

KarimALotfy moved this from 🏗 In progress to Team Review in IDEasy board Jun 16, 2026

laim2003 suggested changes Jun 16, 2026

View reviewed changes

devonfw#1936: Refactor I18n wording to Localization

a63acb0

KarimALotfy mentioned this pull request Jun 18, 2026

#1928: Added Upgrade IDEasy and Update functionalities to the GUI with pro active notifications #2027

Open

8 tasks

Merge branch 'main' of https://github.com/devonfw/IDEasy into feature…

d8b8377

…/1936-improve-localization-of-gui"

hohwille moved this from Team Review to 👀 In review in IDEasy board Jun 22, 2026

hohwille added this to the release:2026.07.001 milestone Jun 22, 2026

hohwille reviewed Jun 22, 2026

View reviewed changes

Comment thread gui/src/main/resources/localization/messages.properties Outdated

hohwille reviewed Jun 22, 2026

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hohwille requested changes Jun 22, 2026

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		@@ -0,0 +1,17 @@
		# IDEasy GUI - English (default) Translation File

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This PR fixes #1936

Implemented changes:

Testing instructions

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Coverage Report for CI Build 28107858485

Coverage decreased (-0.08%) to 71.305%

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