publicvoidexample(){// flags defined in memoryMap<String, Flag<?>> myFlags = newHashMap<>(); myFlags.put("v2_enabled", Flag.builder() .variant("on", true) .variant("off", false) .defaultVariant("on") .build()); // configure a providerOpenFeatureAPIapi = OpenFeatureAPI.getInstance(); api.setProviderAndWait(newInMemoryProvider(myFlags)); // create a clientClientclient = api.getClient(); // get a bool flag valuebooleanflagValue = client.getBooleanValue("v2_enabled", false)}

OpenFeatureAPIapi = OpenFeatureAPI.getInstance(); api.setProviderAndWait(newMyProvider());

OpenFeatureAPI.getInstance().setProvider(newMyProvider());

// set a value to the global contextOpenFeatureAPIapi = OpenFeatureAPI.getInstance(); Map<String, Value> apiAttrs = newHashMap<>(); apiAttrs.put("region", newValue(System.getEnv("us-east-1"))); EvaluationContextapiCtx = newImmutableContext(apiAttrs); api.setEvaluationContext(apiCtx); // set a value to the client contextMap<String, Value> clientAttrs = newHashMap<>(); clientAttrs.put("region", newValue(System.getEnv("us-east-1"))); EvaluationContextclientCtx = newImmutableContext(clientAttrs); Clientclient = api.getInstance().getClient(); client.setEvaluationContext(clientCtx); // set a value to the invocation contextMap<String, Value> requestAttrs = newHashMap<>(); requestAttrs.put("email", newValue(session.getAttribute("email"))); requestAttrs.put("product", newValue("productId")); StringtargetingKey = session.getId(); EvaluationContextreqCtx = newImmutableContext(targetingKey, requestAttrs); booleanflagValue = client.getBooleanValue("some-flag", false, reqCtx);

// add a hook globally, to run on all evaluationsOpenFeatureAPIapi = OpenFeatureAPI.getInstance(); api.addHooks(newExampleHook()); // add a hook on this client, to run on all evaluations made by this clientClientclient = api.getClient(); client.addHooks(newExampleHook()); // add a hook for this evaluation onlyBooleanretval = client.getBooleanValue(flagKey, false, null, FlagEvaluationOptions.builder().hook(newExampleHook()).build());

FeatureProviderscopedProvider = newMyProvider(); // registering the default providerOpenFeatureAPI.getInstance().setProvider(LocalProvider()); // registering a provider to a domainOpenFeatureAPI.getInstance().setProvider("my-domain", newCachedProvider()); // A client bound to the default providerClientclientDefault = OpenFeatureAPI.getInstance().getClient(); // A client bound to the CachedProvider providerClientdomainScopedClient = OpenFeatureAPI.getInstance().getClient("my-domain");

// add an event handler to a clientClientclient = OpenFeatureAPI.getInstance().getClient(); client.onProviderConfigurationChanged((EventDetailseventDetails) ->{// do something when the provider's flag settings change }); // add an event handler to the global APIOpenFeatureAPI.getInstance().onProviderStale((EventDetailseventDetails) ->{// do something when the provider's cache goes stale });

// shut down all providersOpenFeatureAPI.getInstance().shutdown();

// registering the ThreadLocalTransactionContextPropagatorOpenFeatureAPI.getInstance().setTransactionContextPropagator(newThreadLocalTransactionContextPropagator());

// adding userId to transaction contextOpenFeatureAPIapi = OpenFeatureAPI.getInstance(); Map<String, Value> transactionAttrs = newHashMap<>(); transactionAttrs.put("userId", newValue("userId")); EvaluationContexttransactionCtx = newImmutableContext(transactionAttrs); api.setTransactionContext(transactionCtx);

publicclassMyProviderimplementsFeatureProvider{@OverridepublicMetadatagetMetadata(){return () -> "My Provider"} @Overridepublicvoidinitialize(EvaluationContextevaluationContext) throwsException{// start up your provider } @Overridepublicvoidshutdown(){// shut down your provider } @OverridepublicProviderEvaluation<Boolean> getBooleanEvaluation(Stringkey, BooleandefaultValue, EvaluationContextctx){// resolve a boolean flag value } @OverridepublicProviderEvaluation<String> getStringEvaluation(Stringkey, StringdefaultValue, EvaluationContextctx){// resolve a string flag value } @OverridepublicProviderEvaluation<Integer> getIntegerEvaluation(Stringkey, IntegerdefaultValue, EvaluationContextctx){// resolve an int flag value } @OverridepublicProviderEvaluation<Double> getDoubleEvaluation(Stringkey, DoubledefaultValue, EvaluationContextctx){// resolve a double flag value } @OverridepublicProviderEvaluation<Value> getObjectEvaluation(Stringkey, ValuedefaultValue, EvaluationContextctx){// resolve an object flag value } }

classMyEventProviderextendsEventProvider{@OverridepublicMetadatagetMetadata(){return () -> "My Event Provider"} @Overridepublicvoidinitialize(EvaluationContextevaluationContext) throwsException{// emit events when flags are changed in a hypothetical REST APIthis.restApiClient.onFlagsChanged(() ->{ProviderEventDetailsdetails = ProviderEventDetails.builder().message("flags changed in API!").build(); this.emitProviderConfigurationChanged(details)})} @Overridepublicvoidshutdown(){// shut down your provider } // remaining provider methods... }

OpenFeatureAPI.getInstance().getClient().getProviderState();

classMyHookimplementsHook{@OverridepublicOptionalbefore(HookContextctx, Maphints){// code that runs before the flag evaluation } @Overridepublicvoidafter(HookContextctx, FlagEvaluationDetailsdetails, Maphints){// code that runs after the flag evaluation succeeds } @Overridepublicvoiderror(HookContextctx, Exceptionerror, Maphints){// code that runs when there's an error during a flag evaluation } @OverridepublicvoidfinallyAfter(HookContextctx, Maphints){// code that runs regardless of success or error } };