feat: support DynamicTheme initialization in multi-version add-ons

[javier-godoy]

Close #142

Summary by CodeRabbit

Release Notes

• New Features

  • Dynamic theme initialization support added for Vaadin versions 14-25 and 23-25, enabling users to configure and automatically apply themes to their applications with automatic CSS stylesheet injection.

• Documentation

  • Documentation expanded with comprehensive setup instructions, configuration guidance, and workaround details for implementing dynamic themes on supported versions.

[coderabbitai]

Walkthrough

Extended DynamicTheme feature support to Vaadin versions that cannot use AppShellConfigurator by introducing an alternative initialization path via IndexHtmlResponse and a service initializer that loads theme configuration from a properties file. Updated documentation and service loader registration accordingly.

Changes

Cohort / File(s)	Summary
Documentation README.md	Added guidance for Vaadin 14-25 targets on limitations with AppShellConfigurator approach and documented workaround using META-INF/dynamic-theme.properties configuration file.
Core Initialization src/main/java/com/flowingcode/vaadin/addons/demo/DynamicTheme.java	Added new public method initialize(IndexHtmlResponse response) to enable theme initialization via HTML response injection, complementing the existing AppShellSettings path.
Service Initialization src/main/java/com/flowingcode/vaadin/addons/demo/DynamicThemeInitializer.java	New service initializer class that loads theme configuration from properties resource and registers an IndexHtmlRequestListener to initialize themes for all requests.
Service Registration src/main/resources/META-INF/services/com.vaadin.flow.server.VaadinServiceInitListener	Updated service loader registration to include DynamicThemeInitializer.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related PRs

• feat: add support for dynamic theme switching #140: Main PR that extends DynamicTheme initialization surface with the initialize(IndexHtmlResponse) method and initializer foundation directly implemented in this PR.
• docs(readme): document DynamicTheme #141: Related PR addressing the same DynamicTheme feature; the README documentation in this PR implements guidance for the DynamicTheme usage patterns.

Suggested reviewers

• mlopezFC
• paodb

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 60.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main objective: adding DynamicTheme initialization support for multi-version add-ons, which is the primary purpose of the PR.
Linked Issues check	✅ Passed	The PR implements all requirements from issue #142: enables DynamicTheme initialization across Vaadin 14/23/24-25 without requiring AppShellConfigurator by introducing an IndexHtmlRequestListener-based approach via DynamicThemeInitializer.
Out of Scope Changes check	✅ Passed	All changes are directly related to the stated objective: the new DynamicThemeInitializer class, IndexHtmlResponse initialization method, service loader registration, and README guidance are all necessary for solving the multi-version DynamicTheme initialization problem.

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✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch feat-multi-version-dynamic-theme

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[coderabbitai]

Actionable comments posted: 2

🤖 Fix all issues with AI agents

In `@README.md`:
- Around line 67-71: The fenced code block in README.md showing the
dynamic-theme.properties content lacks a language tag, triggering MD040; update
the block that currently contains "theme=LUMO" to use a properties language tag
(i.e., change the opening fence to ```properties) so the snippet is fenced as a
properties block; locate the block in the README where the instructions mention
creating src/test/resources/META-INF/dynamic-theme.properties and add the
language tag to that fenced code block.

In
`@src/main/java/com/flowingcode/vaadin/addons/demo/DynamicThemeServiceInitListener.java`:
- Around line 1-38: The DynamicThemeServiceInitListener.serviceInit currently
calls DynamicTheme.valueOf(themeName.toUpperCase()) which will throw
IllegalArgumentException for invalid values; update serviceInit to trim the
themeName, convert to upper case using Locale.ROOT (e.g.,
themeName.trim().toUpperCase(Locale.ROOT)), and wrap the DynamicTheme.valueOf
call in a try-catch that catches IllegalArgumentException; when caught, do not
rethrow—log a warning instead and skip registering the IndexHtmlRequestListener
(add a Logger field to the class and use it to record the invalid theme value
and the exception), leaving valid values to call
event.addIndexHtmlRequestListener(theme::initialize).

[sonarqubecloud]

Quality Gate passed

Issues
5 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud