Modules Reference¶

Complete index of all FlagZen modules with Maven coordinates and descriptions.

Core¶

`flagzen-core`¶

The foundation module. Contains annotations, annotation processor, proxy generation, FeatureDispatcher, and FlagProvider SPI.

Attribute	Value
Group ID	`com.flagzen`
Artifact ID	`flagzen-core`
Version	`1.1.0`
Dependencies	None (zero external dependencies)
Java Version	17+

What it provides:

@Feature annotation
@Variant annotation with @Repeatable support
@DefaultVariant annotation
@WhenTrue / @WhenFalse convenience annotations
@CloseTo annotation for approximate double matching
FeatureType enum (STRING, INT, LONG, BOOLEAN, DOUBLE)
FallbackStrategy enum (EXCEPTION, NOOP)
FeatureDispatcher interface (with default factory method)
FlagProvider SPI interface
EvaluationContext for targeted flag resolution
ContextAccessor SPI for ambient context sources
Annotation processor for code generation
InMemoryFlagProvider for dev/test
Generated proxy classes ({Feature}_FlagZenProxy)

When to use: Always. This is the base dependency.

Gradle:

dependencies {
    implementation("com.flagzen:flagzen-core:1.1.0")
    annotationProcessor("com.flagzen:flagzen-core:1.1.0")
}

Testing¶

`flagzen-test`¶

JUnit 5 extension with @PinFlag, @FlagSource, and TestFlagContext for testing.

Attribute	Value
Group ID	`com.flagzen`
Artifact ID	`flagzen-test`
Version	`1.1.0`
Depends On	`flagzen-core`, `junit-jupiter-api`
Java Version	17+

What it provides:

FlagZenExtension (JUnit 5 extension)
@PinFlag annotation for declarative flag pinning
@FlagSource annotation for loading flags from properties files
TestFlagContext for programmatic flag setup

When to use: In test suites (testImplementation). Not needed in production.

Gradle:

dependencies {
    testImplementation("com.flagzen:flagzen-test:1.1.0")
}

Key Mapping¶

`flagzen-key-mapping`¶

Reusable parser/formatter infrastructure for converting source names (env vars, config properties) to flag keys.

Attribute	Value
Group ID	`com.flagzen`
Artifact ID	`flagzen-key-mapping`
Version	`1.1.0`
Dependencies	None (zero external dependencies)
Java Version	17+

What it provides:

FlagKeyParser interface
FlagKeyParsers factory (screamingSnakeCase, camelCase)
FlagKeyFormat interface
FlagKeyFormats factory (kebabCase, snakeCase, camelCase, pascalCase, dotCase, colonCase)
ConflictStrategy enum (WARN, ERROR)

When to use: When implementing custom FlagProviders that parse source names (env vars, config files, etc.). Used transitively by flagzen-env.

Gradle:

dependencies {
    implementation("com.flagzen:flagzen-key-mapping:1.1.0")
}

Providers¶

`flagzen-env`¶

Environment variable FlagProvider with configurable key mapping.

Attribute	Value
Group ID	`com.flagzen`
Artifact ID	`flagzen-env`
Version	`1.1.0`
Depends On	`flagzen-core`, `flagzen-key-mapping`
Java Version	17+

What it provides:

EnvironmentVariableFlagProvider — reads flags from System.getenv()
Configurable parsers/formatters for mapping env var names to flag keys
Eager loading of all env vars at construction time
Conflict detection and strategy handling

When to use: When you want FlagZen flags to be driven by environment variables (common in cloud deployments).

Gradle:

dependencies {
    implementation("com.flagzen:flagzen-env:1.1.0")
}

Example:

FlagProvider provider = new EnvironmentVariableFlagProvider.builder()
    .parser(FlagKeyParsers.screamingSnakeCase("FLAGZEN_"))
    .format(FlagKeyFormats.kebabCase())
    .build();

// With env var: FLAGZEN_CHECKOUT_FLOW=PREMIUM
// provider.getString("checkout-flow") returns Optional.of("PREMIUM")

`flagzen-launchdarkly`¶

LaunchDarkly SDK adapter.

Attribute	Value
Group ID	`com.flagzen`
Artifact ID	`flagzen-launchdarkly`
Version	`1.1.0`
Depends On	`flagzen-core`, `launchdarkly-java-server-sdk`
Java Version	17+

What it provides:

LaunchDarklyFlagProvider — adapter to LaunchDarkly SDK
Context mapping from EvaluationContext to LaunchDarkly users/attributes

When to use: When you manage flags via LaunchDarkly's control plane.

Gradle:

dependencies {
    implementation("com.flagzen:flagzen-launchdarkly:1.1.0")
}

`flagzen-togglz`¶

Togglz SDK adapter.

Attribute	Value
Group ID	`com.flagzen`
Artifact ID	`flagzen-togglz`
Version	`1.1.0`
Depends On	`flagzen-core`, `togglz-core`
Java Version	17+

What it provides:

TogglzFlagProvider — adapter to Togglz feature toggle framework

When to use: When you manage flags via Togglz.

Gradle:

dependencies {
    implementation("com.flagzen:flagzen-togglz:1.1.0")
}

`flagzen-openfeature`¶

OpenFeature SDK adapter.

Attribute	Value
Group ID	`com.flagzen`
Artifact ID	`flagzen-openfeature`
Version	`1.1.0`
Depends On	`flagzen-core`, `openfeature-sdk`
Java Version	17+

What it provides:

OpenFeatureFlagProvider — adapter to OpenFeature SDK
Reason-based detection for absent flags

When to use: When you use OpenFeature-compliant flag providers (vendor-neutral approach).

Gradle:

dependencies {
    implementation("com.flagzen:flagzen-openfeature:1.1.0")
}

Framework Integration¶

`flagzen-spring`¶

Spring Boot auto-configuration for feature proxy injection.

Attribute	Value
Group ID	`com.flagzen`
Artifact ID	`flagzen-spring`
Version	`1.1.0`
Depends On	`flagzen-core`, `spring-boot-autoconfigure`
Java Version	17+
Spring Boot Version	2.7+

What it provides:

FlagZenAutoConfiguration — Spring Boot auto-configuration
FeatureDispatcher bean registration
Feature proxy beans for @Autowired injection
FeatureProxyRegistrar for dynamic bean discovery

When to use: When building Spring Boot applications (recommended for all Spring Boot projects using FlagZen).

Gradle:

dependencies {
    implementation("com.flagzen:flagzen-spring:1.1.0")
}

`flagzen-reactor`¶

Reactor ContextAccessor for reactive context propagation.

Attribute	Value
Group ID	`com.flagzen`
Artifact ID	`flagzen-reactor`
Version	`1.1.0`
Depends On	`flagzen-core`, `reactor-core`
Java Version	17+

What it provides:

ReactorContextAccessor — provides EvaluationContext from Reactor's Context
Integration with reactive streams

When to use: When using Project Reactor for reactive processing and want flags to be context-aware in reactive pipelines.

Gradle:

dependencies {
    implementation("com.flagzen:flagzen-reactor:1.1.0")
}

`flagzen-mutiny`¶

Mutiny ContextAccessor for reactive context propagation.

Attribute	Value
Group ID	`com.flagzen`
Artifact ID	`flagzen-mutiny`
Version	`1.1.0`
Depends On	`flagzen-core`, `smallrye-mutiny`
Java Version	17+

What it provides:

MutinyContextAccessor — provides EvaluationContext from Mutiny's context
Integration with Mutiny reactive streams

When to use: When using Mutiny for reactive processing and want flags to be context-aware.

Gradle:

dependencies {
    implementation("com.flagzen:flagzen-mutiny:1.1.0")
}

Examples¶

`flagzen-examples`¶

Runnable example applications demonstrating FlagZen usage patterns.

Attribute	Value
Group ID	`com.flagzen`
Artifact ID	`flagzen-examples`
Version	`1.1.0`
Status	Not published to Maven Central
Build	Available in source repository only

What it contains:

Spring Boot example with environment variable provider
Standalone example with custom provider
Testing examples with @PinFlag and @FlagSource
Integration with LaunchDarkly
Reactive example with Reactor

When to use: Reference these when learning FlagZen or creating your own integration.

Dependency Graph¶

flagzen-core (no external deps)
  ↑
  ├── flagzen-test (adds: junit-jupiter-api)
  ├── flagzen-key-mapping (no external deps)
  ├── flagzen-env (depends on flagzen-key-mapping)
  ├── flagzen-spring (adds: spring-boot-autoconfigure)
  ├── flagzen-reactor (adds: reactor-core)
  ├── flagzen-mutiny (adds: smallrye-mutiny)
  ├── flagzen-launchdarkly (adds: launchdarkly-java-server-sdk)
  ├── flagzen-togglz (adds: togglz-core)
  └── flagzen-openfeature (adds: openfeature-sdk)

All extension modules depend on flagzen-core only. No cross-dependencies between extensions.

Version Management¶

All modules are released together with the same version number. Using com.flagzen:*:1.1.0 ensures compatibility across modules.

Gradle BOM (Bill of Materials)

Currently, no official BOM is published. Specify versions explicitly:

dependencies {
    implementation("com.flagzen:flagzen-core:1.1.0")
    implementation("com.flagzen:flagzen-spring:1.1.0")
    implementation("com.flagzen:flagzen-env:1.1.0")
    testImplementation("com.flagzen:flagzen-test:1.1.0")
}

Support Matrix¶

Module	Java	Spring Boot	Notes	Javadoc
flagzen-core	17+	N/A	Zero external dependencies	API docs
flagzen-test	17+	N/A	JUnit 5 only	API docs
flagzen-key-mapping	17+	N/A	Zero external dependencies	API docs
flagzen-env	17+	N/A	Pure Java, no Spring required	API docs
flagzen-spring	17+	2.7+	Tested with 2.7 LTS and 3.x	API docs
flagzen-reactor	17+	N/A	Works standalone or in Spring	API docs
flagzen-mutiny	17+	N/A	Works standalone or in Quarkus	API docs
flagzen-launchdarkly	17+	N/A	LaunchDarkly SDK 7.0+	API docs
flagzen-togglz	17+	N/A	Togglz 2.x	API docs
flagzen-openfeature	17+	N/A	OpenFeature SDK 1.0+	API docs

Minimal Setup¶

For a Spring Boot application with environment variables:

dependencies {
    implementation("com.flagzen:flagzen-core:1.1.0")
    implementation("com.flagzen:flagzen-spring:1.1.0")
    implementation("com.flagzen:flagzen-env:1.1.0")
    annotationProcessor("com.flagzen:flagzen-core:1.1.0")

    testImplementation("com.flagzen:flagzen-test:1.1.0")
}

Architecture Overview — module dependency graph and roles
Design Decisions — rationale behind module split

Modules Reference¶

Core¶

flagzen-core¶

Testing¶

flagzen-test¶

Key Mapping¶

flagzen-key-mapping¶

Providers¶

flagzen-env¶

flagzen-launchdarkly¶

flagzen-togglz¶

flagzen-openfeature¶

Framework Integration¶

flagzen-spring¶

flagzen-reactor¶

flagzen-mutiny¶

Examples¶

flagzen-examples¶

Dependency Graph¶

Version Management¶

Support Matrix¶

Minimal Setup¶

Related¶

`flagzen-core`¶

`flagzen-test`¶

`flagzen-key-mapping`¶

`flagzen-env`¶

`flagzen-launchdarkly`¶

`flagzen-togglz`¶

`flagzen-openfeature`¶

`flagzen-spring`¶

`flagzen-reactor`¶

`flagzen-mutiny`¶

`flagzen-examples`¶