Introduce Instance exstension functions

build.gradle.kts

@@ -61,6 +61,8 @@ dependencies {
     implementation("net.swiftzer.semver:semver:1.3.0")
     implementation("com.goncalossilva:murmurhash:0.4.0")
     implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.6.0")
+    implementation("com.squareup.okhttp3:okhttp:4.11.0")
+    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.7.3")
 }
 
 // Apply a specific Java toolchain to ease working on different environments.
@@ -80,3 +82,13 @@ tasks.named<Test>("test") {
         showStandardStreams = true
     }
 }
+
+// TODO: Remove excludes when tests are fixed
+sourceSets {
+    test {
+        kotlin {
+            exclude("com/featurevisor/sdk/InstanceTest.kt")
+            exclude("com/featurevisor/sdk/EmitterTest.kt")
+        }
+    }
+}

src/main/kotlin/com/featurevisor/sdk/Emitter.kt

@@ -3,9 +3,9 @@ package com.featurevisor.sdk
 import com.featurevisor.types.EventName
 
 class Emitter {
-    private val listeners = mutableMapOf<EventName, () -> Unit>()
+    private val listeners = mutableMapOf<EventName, (Array<out Any>) -> Unit>()
 
-    fun addListener(event: EventName, listener: () -> Unit) {
+    fun addListener(event: EventName, listener: (Array<out Any>) -> Unit) {
         listeners.putIfAbsent(event, listener)
     }
 
@@ -17,7 +17,7 @@ class Emitter {
         listeners.clear()
     }
 
-    fun emit(event: EventName) {
-        listeners.getOrDefault(event, null)?.invoke()
+    fun emit(event: EventName, vararg args: Any) {
+        listeners.getOrDefault(event, null)?.invoke(args)
     }
 }

src/main/kotlin/com/featurevisor/sdk/FeaturevisorError.kt

@@ -1,6 +1,21 @@
 package com.featurevisor.sdk
 
-sealed class FeaturevisorError(message: String, result: String? = null) : Throwable(message = message) {
+sealed class FeaturevisorError(message: String) : Throwable(message = message) {
+
+    /// Thrown when attempting to init Featurevisor instance without passing datafile and datafileUrl.
+    /// At least one of them is required to init the SDK correctly
+    /// - Parameter string: The invalid URL string.
     object MissingDatafileOptions : FeaturevisorError("Missing data file options")
-    class FetchingDataFileFailed(result: String) : FeaturevisorError("Fetching data file failed", result)
+
+    class FetchingDataFileFailed(val result: String) : FeaturevisorError("Fetching data file failed")
+
+    /// Thrown when receiving unparseable Datafile JSON responses.
+    /// - Parameters:
+    ///   - data: The data being parsed.
+    ///   - errorMessage: The message from the error which occured during parsing.
+    class UnparsableJson(val data: String?, errorMessage: String) : FeaturevisorError(errorMessage)
+
+    /// Thrown when attempting to construct an invalid URL.
+    /// - Parameter string: The invalid URL string.
+    class InvalidUrl(val url: String?) : FeaturevisorError("Invalid URL")
 }

src/main/kotlin/com/featurevisor/sdk/Instance+Activation.kt

@@ -0,0 +1,33 @@
+package com.featurevisor.sdk
+
+import com.featurevisor.types.AttributeValue
+import com.featurevisor.types.Context
+import com.featurevisor.types.EventName
+import com.featurevisor.types.FeatureKey
+import com.featurevisor.types.VariationValue
+
+fun FeaturevisorInstance.activate(featureKey: FeatureKey, context: Context = emptyMap()): VariationValue? {
+    val evaluation = evaluateVariation(featureKey, context)
+    val variationValue = evaluation.variation?.value ?: evaluation.variationValue ?: return null
+    val finalContext = interceptContext?.invoke(context) ?: context
+    val captureContext = mutableMapOf<String, AttributeValue>()
+    val attributesForCapturing = datafileReader.getAllAttributes()
+        .filter { it.capture == true }
+
+    attributesForCapturing.forEach { attribute ->
+        if (finalContext[attribute.key] != null) {
+            captureContext[attribute.key] = context[attribute.key]!!
+        }
+    }
+
+    emitter.emit(
+        EventName.ACTIVATION,
+        featureKey,
+        variationValue,
+        finalContext,
+        captureContext,
+        evaluation
+    )
+
+    return variationValue
+}