feat: create operating block observer artifact

Author: AndreaGiulianelli

src/env/artifact/environment/OperatingBlockObserverArtifact.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2023. Smart Operating Block
+ *
+ * Use of this source code is governed by an MIT-style
+ * license that can be found in the LICENSE file or at
+ * https://opensource.org/licenses/MIT.
+ */
+
+package artifact.environment;
+
+import application.controller.manager.EventManager;
+import cartago.Artifact;
+import cartago.INTERNAL_OPERATION;
+import cartago.OPERATION;
+import infrastructure.events.KafkaClient;
+
+/**
+ * CArtAgO artifact that is responsible to observe the operating block and expose its data.
+ */
+public class OperatingBlockObserverArtifact extends Artifact {
+    private boolean working;
+    private EventManager eventManager;
+    /**
+     * Initialize the operating block observer artifact.
+     */
+    void init() {
+        this.working = false;
+        this.eventManager = KafkaClient.getInstance();
+    }
+
+    /**
+     * Start the Operating Block Observer.
+     */
+    @OPERATION
+    void start() {
+        if (!working) {
+            working = true;
+            execInternalOp("poll");
+        }
+    }
+
+    /**
+     * Internal artifact's operation used to polling for new events with the event manager.
+     */
+    @INTERNAL_OPERATION
+    void poll() {
+        this.eventManager.poll(event -> {
+            signal("event", event.getKey()); // tobe deleted
+        });
+    }
+}