[melcloud] Improve null handling (#17295)

* Add null annotations

Signed-off-by: Leo Siepel <leosiepel@gmail.com>

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/MelCloudBindingConstants.java

@@ -17,6 +17,7 @@ import java.util.Set;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.openhab.core.thing.ThingTypeUID;
 
 /**
@@ -26,6 +27,7 @@ import org.openhab.core.thing.ThingTypeUID;
  * @author Luca Calcaterra - Initial contribution
  * @author Wietse van Buitenen - Added heatpump device
  */
+@NonNullByDefault
 public class MelCloudBindingConstants {
 
     private static final String BINDING_ID = "melcloud";

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/MelCloudHandlerFactory.java

@@ -14,6 +14,7 @@ package org.openhab.binding.melcloud.internal;
 
 import static org.openhab.binding.melcloud.internal.MelCloudBindingConstants.*;
 
+import org.eclipse.jdt.annotation.NonNullByDefault;
 import org.eclipse.jdt.annotation.Nullable;
 import org.openhab.binding.melcloud.internal.handler.MelCloudAccountHandler;
 import org.openhab.binding.melcloud.internal.handler.MelCloudDeviceHandler;
@@ -33,6 +34,7 @@ import org.osgi.service.component.annotations.Component;
  * @author Luca Calcaterra - Initial contribution
  * @author Wietse van Buitenen - Added heatpump device
  */
+@NonNullByDefault
 @Component(configurationPid = "binding.melcloud", service = ThingHandlerFactory.class)
 public class MelCloudHandlerFactory extends BaseThingHandlerFactory {
 

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/api/MelCloudConnection.java

@@ -19,13 +19,15 @@ import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Objects;
 import java.util.Properties;
 
-import org.openhab.binding.melcloud.internal.api.json.Device;
+import org.eclipse.jdt.annotation.NonNullByDefault;
-import org.openhab.binding.melcloud.internal.api.json.DeviceStatus;
+import org.openhab.binding.melcloud.internal.api.dto.Device;
-import org.openhab.binding.melcloud.internal.api.json.HeatpumpDeviceStatus;
+import org.openhab.binding.melcloud.internal.api.dto.DeviceStatus;
-import org.openhab.binding.melcloud.internal.api.json.ListDevicesResponse;
+import org.openhab.binding.melcloud.internal.api.dto.HeatpumpDeviceStatus;
-import org.openhab.binding.melcloud.internal.api.json.LoginClientResponse;
+import org.openhab.binding.melcloud.internal.api.dto.ListDevicesResponse;
+import org.openhab.binding.melcloud.internal.api.dto.LoginClientResponse;
 import org.openhab.binding.melcloud.internal.exceptions.MelCloudCommException;
 import org.openhab.binding.melcloud.internal.exceptions.MelCloudLoginException;
 import org.openhab.core.io.net.http.HttpUtil;
@@ -45,6 +47,7 @@ import com.google.gson.JsonSyntaxException;
  * @author Pauli Anttila - Refactoring
  * @author Wietse van Buitenen - Return all devices, added heatpump device
  */
+@NonNullByDefault
 public class MelCloudConnection {
 
     private static final String LOGIN_URL = "https://app.melcloud.com/Mitsubishi.Wifi.Client/Login/ClientLogin";
@@ -54,18 +57,18 @@ public class MelCloudConnection {
     private static final int TIMEOUT_MILLISECONDS = 10000;
 
     // Gson objects are safe to share across threads and are somewhat expensive to construct. Use a single instance.
-    private static final Gson gson = new GsonBuilder().excludeFieldsWithoutExposeAnnotation()
+    private static final Gson GSON = new GsonBuilder().excludeFieldsWithoutExposeAnnotation()
             .setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE).create();
 
     private final Logger logger = LoggerFactory.getLogger(MelCloudConnection.class);
 
     private boolean isConnected = false;
-    private String sessionKey;
+    private String sessionKey = "";
 
     public void login(String username, String password, int languageId)
             throws MelCloudCommException, MelCloudLoginException {
         setConnected(false);
-        sessionKey = null;
+        sessionKey = "";
         JsonObject jsonReq = new JsonObject();
         jsonReq.addProperty("Email", username);
         jsonReq.addProperty("Password", password);
@@ -79,7 +82,7 @@ public class MelCloudConnection {
             String loginResponse = HttpUtil.executeUrl("POST", LOGIN_URL, null, data, "application/json",
                     TIMEOUT_MILLISECONDS);
             logger.debug("Login response: {}", loginResponse);
-            LoginClientResponse resp = gson.fromJson(loginResponse, LoginClientResponse.class);
+            LoginClientResponse resp = Objects.requireNonNull(GSON.fromJson(loginResponse, LoginClientResponse.class));
             if (resp.getErrorId() != null) {
                 String errorMsg = String.format("Login failed, error code: %s", resp.getErrorId());
                 if (resp.getErrorMessage() != null) {
@@ -101,7 +104,7 @@ public class MelCloudConnection {
                     TIMEOUT_MILLISECONDS);
             logger.debug("Device list response: {}", response);
             List<Device> devices = new ArrayList<>();
-            ListDevicesResponse[] buildings = gson.fromJson(response, ListDevicesResponse[].class);
+            ListDevicesResponse[] buildings = GSON.fromJson(response, ListDevicesResponse[].class);
             Arrays.asList(buildings).forEach(building -> {
                 if (building.getStructure().getDevices() != null) {
                     devices.addAll(building.getStructure().getDevices());
@@ -137,7 +140,7 @@ public class MelCloudConnection {
         try {
             String response = HttpUtil.executeUrl("GET", url, getHeaderProperties(), null, null, TIMEOUT_MILLISECONDS);
             logger.debug("Device status response: {}", response);
-            return gson.fromJson(response, DeviceStatus.class);
+            return Objects.requireNonNull(GSON.fromJson(response, DeviceStatus.class));
         } catch (IOException | JsonSyntaxException e) {
             setConnected(false);
             throw new MelCloudCommException("Error occurred during device status fetch", e);
@@ -146,14 +149,14 @@ public class MelCloudConnection {
 
     public DeviceStatus sendDeviceStatus(DeviceStatus deviceStatus) throws MelCloudCommException {
         assertConnected();
-        String content = gson.toJson(deviceStatus, DeviceStatus.class);
+        String content = GSON.toJson(deviceStatus, DeviceStatus.class);
         logger.debug("Sending device status: {}", content);
         InputStream data = new ByteArrayInputStream(content.getBytes(StandardCharsets.UTF_8));
         try {
             String response = HttpUtil.executeUrl("POST", DEVICE_URL + "/SetAta", getHeaderProperties(), data,
                     "application/json", TIMEOUT_MILLISECONDS);
             logger.debug("Device status sending response: {}", response);
-            return gson.fromJson(response, DeviceStatus.class);
+            return Objects.requireNonNull(GSON.fromJson(response, DeviceStatus.class));
         } catch (IOException | JsonSyntaxException e) {
             setConnected(false);
             throw new MelCloudCommException("Error occurred during device command sending", e);
@@ -166,7 +169,7 @@ public class MelCloudConnection {
         try {
             String response = HttpUtil.executeUrl("GET", url, getHeaderProperties(), null, null, TIMEOUT_MILLISECONDS);
             logger.debug("Device heatpump status response: {}", response);
-            return gson.fromJson(response, HeatpumpDeviceStatus.class);
+            return Objects.requireNonNull(GSON.fromJson(response, HeatpumpDeviceStatus.class));
         } catch (IOException | JsonSyntaxException e) {
             setConnected(false);
             throw new MelCloudCommException("Error occurred during heatpump device status fetch", e);
@@ -176,14 +179,14 @@ public class MelCloudConnection {
     public HeatpumpDeviceStatus sendHeatpumpDeviceStatus(HeatpumpDeviceStatus heatpumpDeviceStatus)
             throws MelCloudCommException {
         assertConnected();
-        String content = gson.toJson(heatpumpDeviceStatus, HeatpumpDeviceStatus.class);
+        String content = GSON.toJson(heatpumpDeviceStatus, HeatpumpDeviceStatus.class);
         logger.debug("Sending heatpump device status: {}", content);
         InputStream data = new ByteArrayInputStream(content.getBytes(StandardCharsets.UTF_8));
         try {
             String response = HttpUtil.executeUrl("POST", DEVICE_URL + "/SetAtw", getHeaderProperties(), data,
                     "application/json", TIMEOUT_MILLISECONDS);
             logger.debug("Device heatpump status sending response: {}", response);
-            return gson.fromJson(response, HeatpumpDeviceStatus.class);
+            return Objects.requireNonNull(GSON.fromJson(response, HeatpumpDeviceStatus.class));
         } catch (IOException | JsonSyntaxException e) {
             setConnected(false);
             throw new MelCloudCommException("Error occurred during heatpump device command sending", e);

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/api/dto/Area.java

@@ -10,7 +10,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0
  */
-package org.openhab.binding.melcloud.internal.api.json;
+package org.openhab.binding.melcloud.internal.api.dto;
 
 import java.util.List;
 

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/api/dto/Device.java

@@ -10,7 +10,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0
  */
-package org.openhab.binding.melcloud.internal.api.json;
+package org.openhab.binding.melcloud.internal.api.dto;
 
 import java.security.Permissions;
 import java.util.List;

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/api/dto/DeviceProps.java

@@ -10,7 +10,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0
  */
-package org.openhab.binding.melcloud.internal.api.json;
+package org.openhab.binding.melcloud.internal.api.dto;
 
 import java.util.List;
 

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/api/dto/DeviceStatus.java

@@ -10,7 +10,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0
  */
-package org.openhab.binding.melcloud.internal.api.json;
+package org.openhab.binding.melcloud.internal.api.dto;
 
 import java.util.List;
 

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/api/dto/Floor.java

@@ -10,7 +10,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0
  */
-package org.openhab.binding.melcloud.internal.api.json;
+package org.openhab.binding.melcloud.internal.api.dto;
 
 import java.util.List;
 

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/api/dto/HeatpumpDeviceStatus.java

@@ -10,7 +10,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0
  */
-package org.openhab.binding.melcloud.internal.api.json;
+package org.openhab.binding.melcloud.internal.api.dto;
 
 import java.util.List;
 

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/api/dto/ListDevicesResponse.java

@@ -10,7 +10,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0
  */
-package org.openhab.binding.melcloud.internal.api.json;
+package org.openhab.binding.melcloud.internal.api.dto;
 
 import com.google.gson.annotations.Expose;
 import com.google.gson.annotations.SerializedName;

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/api/dto/LoginClientResponse.java

@@ -10,7 +10,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0
  */
-package org.openhab.binding.melcloud.internal.api.json;
+package org.openhab.binding.melcloud.internal.api.dto;
 
 import java.util.List;
 

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/api/dto/LoginData.java

@@ -10,7 +10,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0
  */
-package org.openhab.binding.melcloud.internal.api.json;
+package org.openhab.binding.melcloud.internal.api.dto;
 
 import com.google.gson.annotations.Expose;
 

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/api/dto/Preset.java

@@ -10,7 +10,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0
  */
-package org.openhab.binding.melcloud.internal.api.json;
+package org.openhab.binding.melcloud.internal.api.dto;
 
 import com.google.gson.annotations.Expose;
 

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/api/dto/QuantizedCoordinates.java

@@ -10,7 +10,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0
  */
-package org.openhab.binding.melcloud.internal.api.json;
+package org.openhab.binding.melcloud.internal.api.dto;
 
 import com.google.gson.annotations.Expose;
 

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/api/dto/Structure.java

@@ -10,7 +10,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0
  */
-package org.openhab.binding.melcloud.internal.api.json;
+package org.openhab.binding.melcloud.internal.api.dto;
 
 import java.util.List;
 

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/api/dto/WeatherObservation.java

@@ -10,7 +10,7 @@
  *
  * SPDX-License-Identifier: EPL-2.0
  */
-package org.openhab.binding.melcloud.internal.api.json;
+package org.openhab.binding.melcloud.internal.api.dto;
 
 import com.google.gson.annotations.Expose;
 

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/config/AcDeviceConfig.java

@@ -12,17 +12,21 @@
  */
 package org.openhab.binding.melcloud.internal.config;
 
+import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
+
 /**
  * Config class for an A.C. device.
  *
  * @author Pauli Anttila - Initial Contribution
  *
  */
+@NonNullByDefault
 public class AcDeviceConfig {
 
-    public Integer deviceID;
+    public Integer deviceID = 0;
-    public Integer buildingID;
+    public @Nullable Integer buildingID;
-    public Integer pollingInterval;
+    public Integer pollingInterval = 360;
 
     @Override
     public String toString() {

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/config/AccountConfig.java

@@ -12,17 +12,20 @@
  */
 package org.openhab.binding.melcloud.internal.config;
 
+import org.eclipse.jdt.annotation.NonNullByDefault;
+
 /**
  * Config class for MELCloud account parameters.
  *
  * @author Pauli Anttila - Initial Contribution
  *
  */
+@NonNullByDefault
 public class AccountConfig {
 
-    public String username;
+    public String username = "";
-    public String password;
+    public String password = "";
-    public int language;
+    public int language = 0;
 
     @Override
     public String toString() {
@@ -30,9 +33,6 @@ public class AccountConfig {
     }
 
     private String getPasswordForPrinting() {
-        if (password != null) {
+        return password.isEmpty() ? "<empty>" : "*********";
-            return password.isEmpty() ? "<empty>" : "*********";
-        }
-        return "<null>";
     }
 }

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/config/HeatpumpDeviceConfig.java

@@ -12,16 +12,20 @@
  */
 package org.openhab.binding.melcloud.internal.config;
 
+import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
+
 /**
  * Config class for a Heatpump device.
  *
  * @author Wietse van Buitenen - Initial Contribution
  *
  */
+@NonNullByDefault
 public class HeatpumpDeviceConfig {
-    public Integer deviceID;
+    public Integer deviceID = 0;
-    public Integer buildingID;
+    public @Nullable Integer buildingID;
-    public Integer pollingInterval;
+    public Integer pollingInterval = 360;
 
     @Override
     public String toString() {

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/discovery/MelCloudDiscoveryService.java

@@ -20,9 +20,10 @@ import java.util.Map;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 
-import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
 import org.openhab.binding.melcloud.internal.MelCloudBindingConstants;
-import org.openhab.binding.melcloud.internal.api.json.Device;
+import org.openhab.binding.melcloud.internal.api.dto.Device;
 import org.openhab.binding.melcloud.internal.exceptions.MelCloudCommException;
 import org.openhab.binding.melcloud.internal.exceptions.MelCloudLoginException;
 import org.openhab.binding.melcloud.internal.handler.MelCloudAccountHandler;
@@ -43,14 +44,15 @@ import org.slf4j.LoggerFactory;
  * @author Pauli Anttila - Refactoring
  * @author Wietse van Buitenen - Check device type, added heatpump device
  */
+@NonNullByDefault
 @Component(scope = ServiceScope.PROTOTYPE, service = MelCloudDiscoveryService.class)
-public class MelCloudDiscoveryService extends AbstractThingHandlerDiscoveryService<@NonNull MelCloudAccountHandler> {
+public class MelCloudDiscoveryService extends AbstractThingHandlerDiscoveryService<MelCloudAccountHandler> {
     private final Logger logger = LoggerFactory.getLogger(MelCloudDiscoveryService.class);
 
     private static final String PROPERTY_DEVICE_ID = "deviceID";
     private static final int DISCOVER_TIMEOUT_SECONDS = 10;
 
-    private ScheduledFuture<?> scanTask;
+    private @Nullable ScheduledFuture<?> scanTask;
 
     /**
      * Creates a MelCloudDiscoveryService with enabled autostart.
@@ -67,7 +69,8 @@ public class MelCloudDiscoveryService extends AbstractThingHandlerDiscoveryServi
 
     @Override
     protected void startScan() {
-        if (this.scanTask != null) {
+        ScheduledFuture<?> scanTask = this.scanTask;
+        if (scanTask != null) {
             scanTask.cancel(true);
         }
         this.scanTask = scheduler.schedule(() -> discoverDevices(), 0, TimeUnit.SECONDS);
@@ -77,8 +80,9 @@ public class MelCloudDiscoveryService extends AbstractThingHandlerDiscoveryServi
     protected void stopScan() {
         super.stopScan();
 
-        if (this.scanTask != null) {
+        ScheduledFuture<?> scanTask = this.scanTask;
-            this.scanTask.cancel(true);
+        if (scanTask != null) {
+            scanTask.cancel(true);
             this.scanTask = null;
         }
     }
@@ -88,7 +92,7 @@ public class MelCloudDiscoveryService extends AbstractThingHandlerDiscoveryServi
         try {
             List<Device> deviceList = thingHandler.getDeviceList();
 
-            if (deviceList == null) {
+            if (deviceList.isEmpty()) {
                 logger.debug("No devices found");
             } else {
                 ThingUID bridgeUID = thingHandler.getThing().getUID();

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/exceptions/MelCloudCommException.java

@@ -12,11 +12,14 @@
  */
 package org.openhab.binding.melcloud.internal.exceptions;
 
+import org.eclipse.jdt.annotation.NonNullByDefault;
+
 /**
  * Exception to encapsulate any issues communicating with MELCloud.
  *
  * @author Pauli Anttila - Initial Contribution
  */
+@NonNullByDefault
 public class MelCloudCommException extends Exception {
     private static final long serialVersionUID = 1L;
 

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/exceptions/MelCloudLoginException.java

@@ -12,11 +12,14 @@
  */
 package org.openhab.binding.melcloud.internal.exceptions;
 
+import org.eclipse.jdt.annotation.NonNullByDefault;
+
 /**
  * Exception to encapsulate any login issues with MELCloud.
  *
  * @author Pauli Anttila - Initial Contribution
  */
+@NonNullByDefault
 public class MelCloudLoginException extends Exception {
     private static final long serialVersionUID = 1L;
 

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/handler/MelCloudAccountHandler.java

@@ -15,15 +15,16 @@ package org.openhab.binding.melcloud.internal.handler;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
-import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 
+import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
 import org.openhab.binding.melcloud.internal.api.MelCloudConnection;
-import org.openhab.binding.melcloud.internal.api.json.Device;
+import org.openhab.binding.melcloud.internal.api.dto.Device;
-import org.openhab.binding.melcloud.internal.api.json.DeviceStatus;
+import org.openhab.binding.melcloud.internal.api.dto.DeviceStatus;
-import org.openhab.binding.melcloud.internal.api.json.HeatpumpDeviceStatus;
+import org.openhab.binding.melcloud.internal.api.dto.HeatpumpDeviceStatus;
 import org.openhab.binding.melcloud.internal.config.AccountConfig;
 import org.openhab.binding.melcloud.internal.discovery.MelCloudDiscoveryService;
 import org.openhab.binding.melcloud.internal.exceptions.MelCloudCommException;
@@ -47,14 +48,15 @@ import org.slf4j.LoggerFactory;
  * @author Pauli Anttila - Refactoring
  * @author Wietse van Buitenen - Return all devices, added heatpump device
  */
+@NonNullByDefault
 public class MelCloudAccountHandler extends BaseBridgeHandler {
     private final Logger logger = LoggerFactory.getLogger(MelCloudAccountHandler.class);
 
-    private MelCloudConnection connection;
+    private MelCloudConnection connection = new MelCloudConnection();
-    private List<Device> devices;
+    private List<Device> devices = Collections.emptyList();
-    private ScheduledFuture<?> connectionCheckTask;
+    private @Nullable ScheduledFuture<?> connectionCheckTask;
-    private AccountConfig config;
+    private AccountConfig config = new AccountConfig();
-    private boolean loginCredentialError;
+    private boolean loginCredentialError = false;
 
     public MelCloudAccountHandler(Bridge bridge) {
         super(bridge);
@@ -69,8 +71,6 @@ public class MelCloudAccountHandler extends BaseBridgeHandler {
     public void initialize() {
         logger.debug("Initializing MELCloud account handler.");
         config = getConfigAs(AccountConfig.class);
-        connection = new MelCloudConnection();
-        devices = Collections.emptyList();
         loginCredentialError = false;
         startConnectionCheck();
     }
@@ -79,9 +79,7 @@ public class MelCloudAccountHandler extends BaseBridgeHandler {
     public void dispose() {
         logger.debug("Running dispose()");
         stopConnectionCheck();
-        connection = null;
         devices = Collections.emptyList();
-        config = null;
     }
 
     @Override
@@ -102,6 +100,7 @@ public class MelCloudAccountHandler extends BaseBridgeHandler {
             throw new MelCloudLoginException("Connection to MELCloud can't be opened because of wrong credentials");
         }
         logger.debug("Initializing connection to MELCloud");
+
         updateStatus(ThingStatus.OFFLINE);
         try {
             connection.login(config.username, config.password, config.language);
@@ -139,10 +138,10 @@ public class MelCloudAccountHandler extends BaseBridgeHandler {
         }
     }
 
-    public DeviceStatus fetchDeviceStatus(int deviceId, Optional<Integer> buildingId)
+    public DeviceStatus fetchDeviceStatus(int deviceId, @Nullable Integer buildingId)
             throws MelCloudCommException, MelCloudLoginException {
         connectIfNotConnected();
-        int bid = buildingId.orElse(findBuildingId(deviceId));
+        int bid = buildingId != null ? buildingId : findBuildingId(deviceId);
 
         try {
             return connection.fetchDeviceStatus(deviceId, bid);
@@ -165,10 +164,10 @@ public class MelCloudAccountHandler extends BaseBridgeHandler {
         }
     }
 
-    public HeatpumpDeviceStatus fetchHeatpumpDeviceStatus(int deviceId, Optional<Integer> buildingId)
+    public HeatpumpDeviceStatus fetchHeatpumpDeviceStatus(int deviceId, @Nullable Integer buildingId)
             throws MelCloudCommException, MelCloudLoginException {
         connectIfNotConnected();
-        int bid = buildingId.orElse(findBuildingId(deviceId));
+        int bid = buildingId != null ? buildingId : findBuildingId(deviceId);
 
         try {
             return connection.fetchHeatpumpDeviceStatus(deviceId, bid);
@@ -180,15 +179,13 @@ public class MelCloudAccountHandler extends BaseBridgeHandler {
     }
 
     private int findBuildingId(int deviceId) throws MelCloudCommException {
-        if (devices != null) {
+        return devices.stream().filter(d -> d.getDeviceID() == deviceId).findFirst().orElseThrow(
-            return devices.stream().filter(d -> d.getDeviceID() == deviceId).findFirst().orElseThrow(
+                () -> new MelCloudCommException(String.format("Can't find building id for device id %s", deviceId)))
-                    () -> new MelCloudCommException(String.format("Can't find building id for device id %s", deviceId)))
+                .getBuildingID();
-                    .getBuildingID();
-        }
-        throw new MelCloudCommException(String.format("Can't find building id for device id %s", deviceId));
     }
 
     private void startConnectionCheck() {
+        ScheduledFuture<?> connectionCheckTask = this.connectionCheckTask;
         if (connectionCheckTask == null || connectionCheckTask.isCancelled()) {
             logger.debug("Start periodic connection check");
             Runnable runnable = () -> {
@@ -207,17 +204,18 @@ public class MelCloudAccountHandler extends BaseBridgeHandler {
                     }
                 }
             };
-            connectionCheckTask = scheduler.scheduleWithFixedDelay(runnable, 0, 300, TimeUnit.SECONDS);
+            this.connectionCheckTask = scheduler.scheduleWithFixedDelay(runnable, 0, 300, TimeUnit.SECONDS);
         } else {
             logger.debug("Connection check task already running");
         }
     }
 
     private void stopConnectionCheck() {
+        ScheduledFuture<?> connectionCheckTask = this.connectionCheckTask;
         if (connectionCheckTask != null) {
             logger.debug("Stop periodic connection check");
             connectionCheckTask.cancel(true);
-            connectionCheckTask = null;
+            this.connectionCheckTask = null;
         }
     }
 }

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/handler/MelCloudDeviceHandler.java

@@ -22,13 +22,14 @@ import java.time.ZoneId;
 import java.time.ZoneOffset;
 import java.time.ZonedDateTime;
 import java.time.format.DateTimeFormatter;
-import java.util.Optional;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 
 import javax.measure.quantity.Temperature;
 
-import org.openhab.binding.melcloud.internal.api.json.DeviceStatus;
+import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
+import org.openhab.binding.melcloud.internal.api.dto.DeviceStatus;
 import org.openhab.binding.melcloud.internal.config.AcDeviceConfig;
 import org.openhab.binding.melcloud.internal.exceptions.MelCloudCommException;
 import org.openhab.binding.melcloud.internal.exceptions.MelCloudLoginException;
@@ -46,6 +47,7 @@ import org.openhab.core.thing.ThingStatus;
 import org.openhab.core.thing.ThingStatusDetail;
 import org.openhab.core.thing.ThingStatusInfo;
 import org.openhab.core.thing.binding.BaseThingHandler;
+import org.openhab.core.thing.binding.BridgeHandler;
 import org.openhab.core.thing.binding.ThingHandler;
 import org.openhab.core.types.Command;
 import org.openhab.core.types.RefreshType;
@@ -59,7 +61,7 @@ import org.slf4j.LoggerFactory;
  * @author Luca Calcaterra - Initial contribution
  * @author Pauli Anttila - Refactoring
  */
-
+@NonNullByDefault
 public class MelCloudDeviceHandler extends BaseThingHandler {
 
     private static final int EFFECTIVE_FLAG_POWER = 0x01;
@@ -70,10 +72,10 @@ public class MelCloudDeviceHandler extends BaseThingHandler {
     private static final int EFFECTIVE_FLAG_VANE_HORIZONTAL = 0x100;
 
     private final Logger logger = LoggerFactory.getLogger(MelCloudDeviceHandler.class);
-    private AcDeviceConfig config;
+    private AcDeviceConfig config = new AcDeviceConfig();
-    private MelCloudAccountHandler melCloudHandler;
+    private @Nullable MelCloudAccountHandler melCloudHandler;
-    private DeviceStatus deviceStatus;
+    private @Nullable DeviceStatus deviceStatus;
-    private ScheduledFuture<?> refreshTask;
+    private @Nullable ScheduledFuture<?> refreshTask;
 
     public MelCloudDeviceHandler(Thing thing) {
         super(thing);
@@ -84,7 +86,7 @@ public class MelCloudDeviceHandler extends BaseThingHandler {
         logger.debug("Initializing {} handler.", getThing().getThingTypeUID());
 
         Bridge bridge = getBridge();
-        if (bridge == null) {
+        if (bridge == null || !(bridge.getHandler() instanceof BridgeHandler bridgeHandler)) {
             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.CONFIGURATION_ERROR, "Bridge Not set");
             return;
         }
@@ -92,15 +94,16 @@ public class MelCloudDeviceHandler extends BaseThingHandler {
         config = getConfigAs(AcDeviceConfig.class);
         logger.debug("A.C. device config: {}", config);
 
-        initializeBridge(bridge.getHandler(), bridge.getStatus());
+        initializeBridge(bridgeHandler, bridge.getStatus());
     }
 
     @Override
     public void dispose() {
         logger.debug("Running dispose()");
+        ScheduledFuture<?> refreshTask = this.refreshTask;
         if (refreshTask != null) {
             refreshTask.cancel(true);
-            refreshTask = null;
+            this.refreshTask = null;
         }
         melCloudHandler = null;
     }
@@ -109,25 +112,21 @@ public class MelCloudDeviceHandler extends BaseThingHandler {
     public void bridgeStatusChanged(ThingStatusInfo bridgeStatusInfo) {
         logger.debug("bridgeStatusChanged {} for thing {}", bridgeStatusInfo, getThing().getUID());
         Bridge bridge = getBridge();
-        if (bridge != null) {
+        if (bridge != null && bridge.getHandler() instanceof BridgeHandler bridgeHandler) {
-            initializeBridge(bridge.getHandler(), bridgeStatusInfo.getStatus());
+            initializeBridge(bridgeHandler, bridgeStatusInfo.getStatus());
         }
     }
 
     private void initializeBridge(ThingHandler thingHandler, ThingStatus bridgeStatus) {
         logger.debug("initializeBridge {} for thing {}", bridgeStatus, getThing().getUID());
 
-        if (thingHandler != null && bridgeStatus != null) {
+        melCloudHandler = (MelCloudAccountHandler) thingHandler;
-            melCloudHandler = (MelCloudAccountHandler) thingHandler;
 
-            if (bridgeStatus == ThingStatus.ONLINE) {
+        if (bridgeStatus == ThingStatus.ONLINE) {
-                updateStatus(ThingStatus.ONLINE);
+            updateStatus(ThingStatus.ONLINE);
-                startAutomaticRefresh();
+            startAutomaticRefresh();
-            } else {
-                updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.BRIDGE_OFFLINE);
-            }
         } else {
-            updateStatus(ThingStatus.OFFLINE);
+            updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.BRIDGE_OFFLINE);
         }
     }
 
@@ -139,12 +138,12 @@ public class MelCloudDeviceHandler extends BaseThingHandler {
             logger.debug("Refresh command not supported");
             return;
         }
-
+        MelCloudAccountHandler melCloudHandler = this.melCloudHandler;
         if (melCloudHandler == null) {
             logger.warn("No connection to MELCloud available, ignoring command");
             return;
         }
-
+        DeviceStatus deviceStatus = this.deviceStatus;
         if (deviceStatus == null) {
             logger.info("No initial data available, bridge is probably offline. Ignoring command");
             return;
@@ -229,18 +228,19 @@ public class MelCloudDeviceHandler extends BaseThingHandler {
     }
 
     private void startAutomaticRefresh() {
+        ScheduledFuture<?> refreshTask = this.refreshTask;
         if (refreshTask == null || refreshTask.isCancelled()) {
-            refreshTask = scheduler.scheduleWithFixedDelay(this::getDeviceDataAndUpdateChannels, 1,
+            this.refreshTask = scheduler.scheduleWithFixedDelay(this::getDeviceDataAndUpdateChannels, 1,
                     config.pollingInterval, TimeUnit.SECONDS);
         }
     }
 
     private void getDeviceDataAndUpdateChannels() {
-        if (melCloudHandler.isConnected()) {
+        MelCloudAccountHandler melCloudHandler = this.melCloudHandler;
+        if (melCloudHandler != null && melCloudHandler.isConnected()) {
             logger.debug("Update device '{}' channels", getThing().getThingTypeUID());
             try {
-                DeviceStatus newDeviceStatus = melCloudHandler.fetchDeviceStatus(config.deviceID,
+                DeviceStatus newDeviceStatus = melCloudHandler.fetchDeviceStatus(config.deviceID, config.buildingID);
-                        Optional.ofNullable(config.buildingID));
                 updateChannels(newDeviceStatus);
             } catch (MelCloudLoginException e) {
                 logger.debug("Login error occurred during device '{}' polling, reason {}. ",
@@ -255,7 +255,7 @@ public class MelCloudDeviceHandler extends BaseThingHandler {
     }
 
     private synchronized void updateChannels(DeviceStatus newDeviceStatus) {
-        deviceStatus = newDeviceStatus;
+        DeviceStatus deviceStatus = this.deviceStatus = newDeviceStatus;
         for (Channel channel : getThing().getChannels()) {
             updateChannels(channel.getUID().getId(), deviceStatus);
         }

bundles/org.openhab.binding.melcloud/src/main/java/org/openhab/binding/melcloud/internal/handler/MelCloudHeatpumpDeviceHandler.java

@@ -22,13 +22,14 @@ import java.time.ZoneId;
 import java.time.ZoneOffset;
 import java.time.ZonedDateTime;
 import java.time.format.DateTimeFormatter;
-import java.util.Optional;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 
 import javax.measure.quantity.Temperature;
 
-import org.openhab.binding.melcloud.internal.api.json.HeatpumpDeviceStatus;
+import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
+import org.openhab.binding.melcloud.internal.api.dto.HeatpumpDeviceStatus;
 import org.openhab.binding.melcloud.internal.config.HeatpumpDeviceConfig;
 import org.openhab.binding.melcloud.internal.exceptions.MelCloudCommException;
 import org.openhab.binding.melcloud.internal.exceptions.MelCloudLoginException;
@@ -45,6 +46,7 @@ import org.openhab.core.thing.ThingStatus;
 import org.openhab.core.thing.ThingStatusDetail;
 import org.openhab.core.thing.ThingStatusInfo;
 import org.openhab.core.thing.binding.BaseThingHandler;
+import org.openhab.core.thing.binding.BridgeHandler;
 import org.openhab.core.thing.binding.ThingHandler;
 import org.openhab.core.types.Command;
 import org.openhab.core.types.RefreshType;
@@ -57,16 +59,17 @@ import org.slf4j.LoggerFactory;
  *
  * @author Wietse van Buitenen - Initial contribution
  */
+@NonNullByDefault
 public class MelCloudHeatpumpDeviceHandler extends BaseThingHandler {
     private static final long EFFECTIVE_FLAG_POWER = 1L;
     private static final long EFFECTIVE_FLAG_TEMPERATURE_ZONE1 = 8589934720L;
     private static final long EFFECTIVE_FLAG_HOTWATER = 65536L;
 
     private final Logger logger = LoggerFactory.getLogger(MelCloudHeatpumpDeviceHandler.class);
-    private HeatpumpDeviceConfig config;
+    private HeatpumpDeviceConfig config = new HeatpumpDeviceConfig();
-    private MelCloudAccountHandler melCloudHandler;
+    private @Nullable MelCloudAccountHandler melCloudHandler;
-    private HeatpumpDeviceStatus heatpumpDeviceStatus;
+    private @Nullable HeatpumpDeviceStatus heatpumpDeviceStatus;
-    private ScheduledFuture<?> refreshTask;
+    private @Nullable ScheduledFuture<?> refreshTask;
 
     public MelCloudHeatpumpDeviceHandler(Thing thing) {
         super(thing);
@@ -77,7 +80,7 @@ public class MelCloudHeatpumpDeviceHandler extends BaseThingHandler {
         logger.debug("Initializing {} handler.", getThing().getThingTypeUID());
 
         Bridge bridge = getBridge();
-        if (bridge == null) {
+        if (bridge == null || !(bridge.getHandler() instanceof BridgeHandler bridgeHandler)) {
             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.CONFIGURATION_ERROR, "Bridge Not set");
             return;
         }
@@ -85,15 +88,16 @@ public class MelCloudHeatpumpDeviceHandler extends BaseThingHandler {
         config = getConfigAs(HeatpumpDeviceConfig.class);
         logger.debug("Heatpump device config: {}", config);
 
-        initializeBridge(bridge.getHandler(), bridge.getStatus());
+        initializeBridge(bridgeHandler, bridge.getStatus());
     }
 
     @Override
     public void dispose() {
         logger.debug("Running dispose()");
+        ScheduledFuture<?> refreshTask = this.refreshTask;
         if (refreshTask != null) {
             refreshTask.cancel(true);
-            refreshTask = null;
+            this.refreshTask = null;
         }
         melCloudHandler = null;
     }
@@ -102,25 +106,21 @@ public class MelCloudHeatpumpDeviceHandler extends BaseThingHandler {
     public void bridgeStatusChanged(ThingStatusInfo bridgeStatusInfo) {
         logger.debug("bridgeStatusChanged {} for thing {}", bridgeStatusInfo, getThing().getUID());
         Bridge bridge = getBridge();
-        if (bridge != null) {
+        if (bridge != null && bridge.getHandler() instanceof BridgeHandler bridgeHandler) {
-            initializeBridge(bridge.getHandler(), bridgeStatusInfo.getStatus());
+            initializeBridge(bridgeHandler, bridgeStatusInfo.getStatus());
         }
     }
 
     private void initializeBridge(ThingHandler thingHandler, ThingStatus bridgeStatus) {
         logger.debug("initializeBridge {} for thing {}", bridgeStatus, getThing().getUID());
 
-        if (thingHandler != null && bridgeStatus != null) {
+        melCloudHandler = (MelCloudAccountHandler) thingHandler;
-            melCloudHandler = (MelCloudAccountHandler) thingHandler;
 
-            if (bridgeStatus == ThingStatus.ONLINE) {
+        if (bridgeStatus == ThingStatus.ONLINE) {
-                updateStatus(ThingStatus.ONLINE);
+            updateStatus(ThingStatus.ONLINE);
-                startAutomaticRefresh();
+            startAutomaticRefresh();
-            } else {
-                updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.BRIDGE_OFFLINE);
-            }
         } else {
-            updateStatus(ThingStatus.OFFLINE);
+            updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.BRIDGE_OFFLINE);
         }
     }
 
@@ -133,11 +133,12 @@ public class MelCloudHeatpumpDeviceHandler extends BaseThingHandler {
             return;
         }
 
+        MelCloudAccountHandler melCloudHandler = this.melCloudHandler;
         if (melCloudHandler == null) {
             logger.warn("No connection to MELCloud available, ignoring command");
             return;
         }
-
+        HeatpumpDeviceStatus heatpumpDeviceStatus = this.heatpumpDeviceStatus;
         if (heatpumpDeviceStatus == null) {
             logger.info("No initial data available, bridge is probably offline. Ignoring command");
             return;
@@ -207,18 +208,20 @@ public class MelCloudHeatpumpDeviceHandler extends BaseThingHandler {
     }
 
     private void startAutomaticRefresh() {
+        ScheduledFuture<?> refreshTask = this.refreshTask;
         if (refreshTask == null || refreshTask.isCancelled()) {
-            refreshTask = scheduler.scheduleWithFixedDelay(this::getDeviceDataAndUpdateChannels, 1,
+            this.refreshTask = scheduler.scheduleWithFixedDelay(this::getDeviceDataAndUpdateChannels, 1,
                     config.pollingInterval, TimeUnit.SECONDS);
         }
     }
 
     private void getDeviceDataAndUpdateChannels() {
-        if (melCloudHandler.isConnected()) {
+        MelCloudAccountHandler melCloudHandler = this.melCloudHandler;
+        if (melCloudHandler != null && melCloudHandler.isConnected()) {
             logger.debug("Update device '{}' channels", getThing().getThingTypeUID());
             try {
                 HeatpumpDeviceStatus newHeatpumpDeviceStatus = melCloudHandler
-                        .fetchHeatpumpDeviceStatus(config.deviceID, Optional.ofNullable(config.buildingID));
+                        .fetchHeatpumpDeviceStatus(config.deviceID, config.buildingID);
                 updateChannels(newHeatpumpDeviceStatus);
             } catch (MelCloudLoginException e) {
                 logger.debug("Login error occurred during device '{}' polling, reason {}. ",
@@ -233,7 +236,7 @@ public class MelCloudHeatpumpDeviceHandler extends BaseThingHandler {
     }
 
     private synchronized void updateChannels(HeatpumpDeviceStatus newHeatpumpDeviceStatus) {
-        heatpumpDeviceStatus = newHeatpumpDeviceStatus;
+        HeatpumpDeviceStatus heatpumpDeviceStatus = this.heatpumpDeviceStatus = newHeatpumpDeviceStatus;
         for (Channel channel : getThing().getChannels()) {
             updateChannels(channel.getUID().getId(), heatpumpDeviceStatus);
         }