[fix] ensure executor is active before starting EventSource (#145)

Author: L-Joli

android-client-sdk/src/main/java/com/devcycle/sdk/android/api/DVCClient.kt

@@ -19,6 +19,8 @@ import org.json.JSONObject
 import java.lang.ref.WeakReference
 import java.net.URI
 import java.util.concurrent.ConcurrentLinkedQueue
+import java.util.concurrent.ExecutorService
+import java.util.concurrent.Executors
 import java.util.concurrent.atomic.AtomicBoolean
 import kotlin.coroutines.CoroutineContext
 
@@ -42,6 +44,7 @@ class DVCClient private constructor(
 ) {
     private var config: BucketedUserConfig? = null
     private var eventSource: EventSource? = null
+    private var executorService: ExecutorService? = null
     private val defaultIntervalInMs: Long = 10000
     private val flushInMs: Long = options?.flushEventsIntervalMs ?: defaultIntervalInMs
     private val dvcSharedPrefs: DVCSharedPrefs = DVCSharedPrefs(context)
@@ -151,10 +154,17 @@ class DVCClient private constructor(
             if (type == "refetchConfig" || type == "") { // Refetch the config if theres no type
                 refetchConfig(true, lastModified, etag)
             }
-        }), URI(config?.sse?.url)).build()
+        }), URI(config?.sse?.url)).executor(this.getValidExecutorService()).build()
         eventSource?.start()
     }
 
+    private fun getValidExecutorService(): ExecutorService? {
+        if (executorService == null || executorService?.isTerminated == true) {
+            executorService = Executors.newSingleThreadExecutor()
+        }
+        return executorService
+    }
+
     fun onInitialized(callback: DVCCallback<String>) {
         if (isInitialized.get()) {
             callback.onSuccess("Config loaded")

android-client-sdk/src/main/java/com/devcycle/sdk/android/eventsource/EventSource.java

@@ -570,6 +570,7 @@ public static final class Builder {
     private int maxEventTasksInFlight = 0;
     private boolean streamEventData;
     private Set<String> expectFields = null;
+    private ExecutorService streamExecutor;
 
     /**
      * Creates a new builder.
@@ -1012,6 +1013,11 @@ public Builder expectFields(String... fieldNames) {
       return this;
     }
 
+    public Builder executor(ExecutorService streamExecutor) {
+      this.streamExecutor = streamExecutor;
+      return this;
+    }
+
     /**
      * Constructs an {@link EventSource} using the builder's current properties.
      * @return the new EventSource instance