SDK DMF Support - from declarative to imperative - to support host per tenant (#1709)

Signed-off-by: Marinov Avgustin <Avgustin.Marinov@bosch.com>

hawkbit-sdk/hawkbit-sdk-device/src/main/java/org/eclipse/hawkbit/sdk/device/DdiTenant.java

@@ -0,0 +1,56 @@
+/**
+ * Copyright (c) 2024 Contributors to the Eclipse Foundation
+ *
+ * This program and the accompanying materials are made
+ * available under the terms of the Eclipse Public License 2.0
+ * which is available at https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package org.eclipse.hawkbit.sdk.device;
+
+import lombok.Getter;
+import org.eclipse.hawkbit.sdk.Controller;
+import org.eclipse.hawkbit.sdk.HawkbitClient;
+import org.eclipse.hawkbit.sdk.Tenant;
+
+import java.util.Map;
+import java.util.Optional;
+import java.util.concurrent.ConcurrentHashMap;
+
+/**
+ * An in-memory simulated DMF Tenant to hold the controller twins in
+ * memory and be able to retrieve them again.
+ */
+public class DdiTenant {
+
+    @Getter
+    private final Tenant tenant;
+
+    private final Map<String, DdiController> controllers = new ConcurrentHashMap<>();
+    private final HawkbitClient hawkbitClient;
+
+    public DdiTenant(final Tenant tenant, final HawkbitClient hawkbitClient) {
+        this.tenant = tenant;
+        this.hawkbitClient = hawkbitClient;
+    }
+
+    public void destroy() {
+        controllers.values().forEach(DdiController::stop);
+        controllers.clear();
+    }
+
+    public DdiController create(final Controller controller, final UpdateHandler updateHandler) {
+        final DdiController ddiController = new DdiController(tenant, controller, updateHandler, hawkbitClient);
+        controllers.put(controller.getControllerId(), ddiController);
+        return ddiController;
+    }
+
+    public void remove(final String controllerId) {
+        Optional.ofNullable(controllers.remove(controllerId)).ifPresent(DdiController::stop);
+    }
+
+    public Optional<DdiController> getController(final String controllerId) {
+        return Optional.ofNullable(controllers.get(controllerId));
+    }
+}