Java SDK

GoGreen feature flag and experimentation SDK for Java. Evaluate flags, stream real-time updates, and track events with a simple API. Supports OpenFeature provider.

Requirements

Java 11 or later
Gradle 8.x (or use the included wrapper: ./gradlew)

Installation

Maven


<dependency>
    <groupId>com.gogreen</groupId>
    <artifactId>gogreen-sdk</artifactId>
    <version>1.0.0</version>
</dependency>

Gradle


repositories {
    mavenCentral()
}
dependencies {
    implementation 'com.gogreen:gogreen-sdk:1.0.0'
}

Building from source


cd sdk/java
./gradlew build
./gradlew publishToMavenLocal

Then in your project:


repositories {
    mavenLocal()
}
dependencies {
    implementation 'com.gogreen:gogreen-sdk:1.0.0'
}

Quick start


import com.gogreen.sdk.*;
 
// Build config (builder pattern)
GoGreenConfig config = GoGreenConfig.builder()
    .sdkKey("your-sdk-key")
    .envId("your-environment-id")
    .apiBaseUrl("https://app.gogreenflags.com")
    .defaultContext(EvaluationContext.builder("user-123").build())
    .build();
 
GoGreenClient client = new GoGreenClient(config);
 
// Wait for initial config (e.g. up to 10 seconds)
client.waitForInitialization(10, TimeUnit.SECONDS);
 
// Evaluate flags
boolean showNewUI = client.boolVariation("new-ui", false);
String plan = client.stringVariation("plan", "free");
double discount = client.numberVariation("discount", 0.0);
 
// With context override
EvaluationContext ctx = EvaluationContext.builder("other-user")
    .putCustom("region", "eu")
    .build();
boolean flag = client.boolVariationDetail("feature-x", false, ctx);
 
// Track events for experimentation
client.track("purchase", Map.of("amount", 99.99));
 
client.close();

Configuration

Option	Description	Default
`sdkKey`	SDK key (required)	—
`envId`	Environment ID (required)	—
`apiBaseUrl`	Evaluation API base URL	`http://localhost:8092`
`streamUrl`	SSE stream URL	same as apiBaseUrl
`eventsUrl`	Events ingestion URL	same as apiBaseUrl
`enableStreaming`	Real-time SSE updates	`true`
`offline`	Offline mode (bootstrap only)	`false`
`requestTimeoutMs`	HTTP timeout (ms)	`10000`
`flushIntervalMs`	Event flush interval (ms)	`30000`
`defaultContext`	Default evaluation context (required)	—
`bootstrap`	Bootstrap flags for offline	`null`

OpenFeature provider


import com.gogreen.sdk.*;
import com.gogreen.sdk.provider.*;
import dev.openfeature.sdk.*;
 
GoGreenClient client = new GoGreenClient(config);
GoGreenProvider provider = new GoGreenProvider(client);
 
OpenFeatureAPI api = OpenFeatureAPI.getInstance();
api.setProvider(provider);
 
Client ofClient = api.getClient();
boolean value = ofClient.getBooleanValue("my-flag", false);

Testing

Use GoGreenClient.testClient(Map.of("flag-key", value)) for unit tests with no network:


GoGreenClient client = GoGreenClient.testClient(Map.of(
    "feature-x", true,
    "ui-theme", "dark",
    "rate-limit", 50
));
boolean enabled = client.boolVariation("feature-x", false); // returns true

API reference

Variation methods: boolVariation, stringVariation, numberVariation, jsonVariation — return the flag value or default.
Detail methods: boolVariationDetail, stringVariationDetail, etc. — return EvaluationDetail<T> with value, variationId, reason, ruleIndex, prerequisiteKey.
Context: setContext, identify — set evaluation context (user key and custom attributes).
Events: track(eventKey, properties) — send custom events for experimentation.
Lifecycle: waitForInitialization, initialized, enterOfflineMode, exitOfflineMode, close.