Refactored the code in subscription management.

-This commit addresses an improvement to code redundancy and repetition.

Testing:
- Verified successful installation on multiple environments.

components/application-mgt/io.entgra.device.mgt.core.application.mgt.common/src/main/java/io/entgra/device/mgt/core/application/mgt/common/services/SubscriptionManager.java

@@ -252,7 +252,6 @@ public interface SubscriptionManager {
     SubscriptionResponse getStatusBaseSubscriptions(SubscriptionInfo subscriptionInfo, int limit, int offset)
             throws ApplicationManagementException;
 
-
     /**
      * Get subscription statistics related data describes by the {@link SubscriptionInfo}
      * @param subscriptionInfo {@link SubscriptionInfo}

components/application-mgt/io.entgra.device.mgt.core.application.mgt.core/src/main/java/io/entgra/device/mgt/core/application/mgt/core/impl/SubscriptionManagerImpl.java

@@ -19,13 +19,42 @@
 package io.entgra.device.mgt.core.application.mgt.core.impl;
 
 import com.google.gson.Gson;
-import io.entgra.device.mgt.core.application.mgt.common.*;
+import io.entgra.device.mgt.core.application.mgt.common.ApplicationInstallResponse;
-import io.entgra.device.mgt.core.application.mgt.common.dto.*;
+import io.entgra.device.mgt.core.application.mgt.common.ApplicationSubscriptionInfo;
+import io.entgra.device.mgt.core.application.mgt.common.ApplicationType;
+import io.entgra.device.mgt.core.application.mgt.common.CategorizedSubscriptionResult;
+import io.entgra.device.mgt.core.application.mgt.common.DeviceSubscription;
+import io.entgra.device.mgt.core.application.mgt.common.DeviceSubscriptionData;
+import io.entgra.device.mgt.core.application.mgt.common.DeviceSubscriptionFilterCriteria;
+import io.entgra.device.mgt.core.application.mgt.common.DeviceTypes;
+import io.entgra.device.mgt.core.application.mgt.common.ExecutionStatus;
+import io.entgra.device.mgt.core.application.mgt.common.SubAction;
+import io.entgra.device.mgt.core.application.mgt.common.SubscribingDeviceIdHolder;
+import io.entgra.device.mgt.core.application.mgt.common.SubscriptionEntity;
+import io.entgra.device.mgt.core.application.mgt.common.SubscriptionInfo;
+import io.entgra.device.mgt.core.application.mgt.common.SubscriptionMetadata;
+import io.entgra.device.mgt.core.application.mgt.common.SubscriptionResponse;
+import io.entgra.device.mgt.core.application.mgt.common.SubscriptionStatistics;
+import io.entgra.device.mgt.core.application.mgt.common.SubscriptionType;
+import io.entgra.device.mgt.core.application.mgt.common.dto.ApplicationDTO;
+import io.entgra.device.mgt.core.application.mgt.common.dto.ApplicationPolicyDTO;
+import io.entgra.device.mgt.core.application.mgt.common.dto.ApplicationReleaseDTO;
+import io.entgra.device.mgt.core.application.mgt.common.dto.CategorizedSubscriptionCountsDTO;
+import io.entgra.device.mgt.core.application.mgt.common.dto.DeviceOperationDTO;
+import io.entgra.device.mgt.core.application.mgt.common.dto.DeviceSubscriptionDTO;
+import io.entgra.device.mgt.core.application.mgt.common.dto.ScheduledSubscriptionDTO;
+import io.entgra.device.mgt.core.application.mgt.common.dto.SubscriptionStatisticDTO;
+import io.entgra.device.mgt.core.application.mgt.common.dto.VppAssetDTO;
+import io.entgra.device.mgt.core.application.mgt.common.dto.VppUserDTO;
 import io.entgra.device.mgt.core.application.mgt.common.services.VPPApplicationManager;
 import io.entgra.device.mgt.core.application.mgt.core.dao.ApplicationReleaseDAO;
 import io.entgra.device.mgt.core.application.mgt.core.dao.VppApplicationDAO;
 import io.entgra.device.mgt.core.application.mgt.core.exception.BadRequestException;
 import io.entgra.device.mgt.core.application.mgt.core.util.SubscriptionManagementHelperUtil;
+import io.entgra.device.mgt.core.device.mgt.common.Device;
+import io.entgra.device.mgt.core.device.mgt.common.DeviceIdentifier;
+import io.entgra.device.mgt.core.device.mgt.common.EnrolmentInfo;
+import io.entgra.device.mgt.core.device.mgt.common.MDMAppConstants;
 import io.entgra.device.mgt.core.device.mgt.common.PaginationRequest;
 import io.entgra.device.mgt.core.device.mgt.common.PaginationResult;
 import io.entgra.device.mgt.core.device.mgt.core.DeviceManagementConstants;
@@ -70,7 +99,6 @@ import io.entgra.device.mgt.core.application.mgt.core.util.ConnectionManagerUtil
 import io.entgra.device.mgt.core.application.mgt.core.util.Constants;
 import io.entgra.device.mgt.core.application.mgt.core.util.HelperUtil;
 import io.entgra.device.mgt.core.application.mgt.core.util.OAuthUtils;
-import io.entgra.device.mgt.core.device.mgt.common.*;
 import io.entgra.device.mgt.core.device.mgt.common.app.mgt.App;
 import io.entgra.device.mgt.core.device.mgt.common.app.mgt.MobileAppTypes;
 import io.entgra.device.mgt.core.device.mgt.common.app.mgt.android.CustomApplication;
@@ -103,7 +131,16 @@ import java.net.URL;
 import java.security.KeyManagementException;
 import java.security.KeyStoreException;
 import java.security.NoSuchAlgorithmException;
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Properties;
+import java.util.Set;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.stream.Collectors;
 
@@ -1217,6 +1254,7 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
 
     /**
      * Get the bundle id of the iOS public application.
+     *
      * @param appId Application Id
      * @return {@link String} bundle Id
      * @throws ApplicationManagementException if error occurred while getting the bundle if of the requesting public
@@ -1674,17 +1712,18 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
 
     /**
      * Get subscription data describes by {@link SubscriptionInfo} entity
+     *
      * @param subscriptionInfo {@link SubscriptionInfo}
      * @param limit            Limit value
      * @param offset           Offset value
      * @return {@link SubscriptionResponse}
      * @throws ApplicationManagementException Throws when error encountered while getting subscription data
      */
-
     @Override
     public SubscriptionResponse getSubscriptions(SubscriptionInfo subscriptionInfo, int limit, int offset)
             throws ApplicationManagementException {
-        final boolean isUnsubscribe = Objects.equals(SubscriptionMetadata.SUBSCRIPTION_STATUS_UNSUBSCRIBED, subscriptionInfo.getSubscriptionStatus());
+        final boolean isUnsubscribe = Objects.equals(SubscriptionMetadata.SUBSCRIPTION_STATUS_UNSUBSCRIBED,
+                subscriptionInfo.getSubscriptionStatus());
         final int tenantId = PrivilegedCarbonContext.getThreadLocalCarbonContext().getTenantId();
         try {
             ConnectionManagerUtil.openDBConnection();
@@ -1702,13 +1741,15 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
                 int subscriptionCount = isUnsubscribe ? subscriptionDAO.getGroupUnsubscriptionCount(applicationReleaseDTO.getId(), tenantId) :
                         subscriptionDAO.getGroupSubscriptionCount(applicationReleaseDTO.getId(), tenantId);
                 return new SubscriptionResponse(subscriptionInfo.getApplicationUUID(), subscriptionCount, subscriptionEntities);
-            } if (Objects.equals(subscriptionInfo.getSubscriptionType(), SubscriptionMetadata.SubscriptionTypes.ROLE)){
+            }
+            if (Objects.equals(subscriptionInfo.getSubscriptionType(), SubscriptionMetadata.SubscriptionTypes.ROLE)) {
                 List<SubscriptionEntity> subscriptionEntities = subscriptionDAO.
                         getRoleSubscriptionsByAppReleaseID(applicationReleaseDTO.getId(), isUnsubscribe, tenantId, offset, limit);
                 int subscriptionCount = isUnsubscribe ? subscriptionDAO.getRoleUnsubscriptionCount(applicationReleaseDTO.getId(), tenantId) :
                         subscriptionDAO.getRoleSubscriptionCount(applicationReleaseDTO.getId(), tenantId);
                 return new SubscriptionResponse(subscriptionInfo.getApplicationUUID(), subscriptionCount, subscriptionEntities);
-            } if (Objects.equals(subscriptionInfo.getSubscriptionType(), SubscriptionMetadata.SubscriptionTypes.USER)){
+            }
+            if (Objects.equals(subscriptionInfo.getSubscriptionType(), SubscriptionMetadata.SubscriptionTypes.USER)) {
                 List<SubscriptionEntity> subscriptionEntities = subscriptionDAO.
                         getUserSubscriptionsByAppReleaseID(applicationReleaseDTO.getId(), isUnsubscribe, tenantId, offset, limit);
                 int subscriptionCount = isUnsubscribe ? subscriptionDAO.getUserUnsubscriptionCount(applicationReleaseDTO.getId(), tenantId) :
@@ -1728,17 +1769,18 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
 
     /**
      * Retrieves subscription statistics described by the {@link SubscriptionInfo} entity.
+     *
      * @param subscriptionInfo The {@link SubscriptionInfo} containing details about the subscription type and identifier.
      * @return {@link SubscriptionStatistics} The subscription statistics for the specified subscription type and identifier.
      * @throws ApplicationManagementException Throws when an error is encountered while getting subscription statistics.
      */
-
     public SubscriptionStatistics getSubscriptionStatistics(SubscriptionInfo subscriptionInfo)
             throws ApplicationManagementException {
         if (Objects.equals(subscriptionInfo.getSubscriptionType(), SubscriptionMetadata.SubscriptionTypes.DEVICE)) {
             return null;
         }
-        final boolean isUnsubscribe = Objects.equals(SubscriptionMetadata.SUBSCRIPTION_STATUS_UNSUBSCRIBED, subscriptionInfo.getSubscriptionStatus());
+        final boolean isUnsubscribe = Objects.equals(SubscriptionMetadata.SUBSCRIPTION_STATUS_UNSUBSCRIBED,
+                subscriptionInfo.getSubscriptionStatus());
         int tenantId = PrivilegedCarbonContext.getThreadLocalCarbonContext().getTenantId();
         try {
             ConnectionManagerUtil.openDBConnection();
@@ -1751,25 +1793,27 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
                 throw new NotFoundException(msg);
             }
             if (Objects.equals(subscriptionInfo.getSubscriptionType(), SubscriptionMetadata.SubscriptionTypes.GROUP)) {
-                List<Device> devices = HelperUtil.getGroupManagementProviderService().
+                return SubscriptionManagementHelperUtil.getSubscriptionStatistics(
-                        getAllDevicesOfGroup(subscriptionInfo.getIdentifier(), false);
+                        subscriptionDAO.getSubscriptionStatistic(
-                List<Integer> deviceIdsOwnByGroup = devices.stream().map(Device::getId).collect(Collectors.toList());
+                                HelperUtil.getGroupManagementProviderService()
-                SubscriptionStatisticDTO subscriptionStatisticDTO = subscriptionDAO.
+                                        .getAllDevicesOfGroup(subscriptionInfo.getIdentifier(), false)
-                        getSubscriptionStatistic(deviceIdsOwnByGroup, isUnsubscribe, tenantId, applicationReleaseDTO.getId());
+                                        .stream().map(Device::getId).collect(Collectors.toList()),
-                int allDeviceCount = HelperUtil.getGroupManagementProviderService().getDeviceCount(subscriptionInfo.getIdentifier());
+                                isUnsubscribe, tenantId, applicationReleaseDTO.getId()),
-                return SubscriptionManagementHelperUtil.getSubscriptionStatistics(subscriptionStatisticDTO, allDeviceCount);
+                        HelperUtil.getGroupManagementProviderService().getDeviceCount(subscriptionInfo.getIdentifier())
-            } if (Objects.equals(subscriptionInfo.getSubscriptionType(), SubscriptionMetadata.SubscriptionTypes.ROLE)){
+                );
-                List<Integer> deviceIdsOwnByRole = getDeviceIdsOwnByRole(subscriptionInfo.getIdentifier(), tenantId);
+            }
-                SubscriptionStatisticDTO subscriptionStatisticDTO = subscriptionDAO.
+            if (Objects.equals(subscriptionInfo.getSubscriptionType(), SubscriptionMetadata.SubscriptionTypes.ROLE)) {
-                        getSubscriptionStatistic(deviceIdsOwnByRole, isUnsubscribe, tenantId, applicationReleaseDTO.getId());
+                return SubscriptionManagementHelperUtil.getSubscriptionStatistics(subscriptionDAO.getSubscriptionStatistic(
-                int allDeviceCount = deviceIdsOwnByRole.size();
+                        getDeviceIdsOwnByRole(subscriptionInfo.getIdentifier(), tenantId), isUnsubscribe, tenantId,
-                return SubscriptionManagementHelperUtil.getSubscriptionStatistics(subscriptionStatisticDTO, allDeviceCount);
+                        applicationReleaseDTO.getId()
-            } if (Objects.equals(subscriptionInfo.getSubscriptionType(), SubscriptionMetadata.SubscriptionTypes.USER)){
+                ), getDeviceIdsOwnByRole(subscriptionInfo.getIdentifier(), tenantId).size());
-                List<Integer> deviceIdsOwnByUser = getDeviceIdsOwnByUser(subscriptionInfo.getIdentifier());
+            }
-                SubscriptionStatisticDTO subscriptionStatisticDTO = subscriptionDAO.
+            if (Objects.equals(subscriptionInfo.getSubscriptionType(), SubscriptionMetadata.SubscriptionTypes.USER)) {
-                        getSubscriptionStatistic(deviceIdsOwnByUser, isUnsubscribe, tenantId, applicationReleaseDTO.getId());
+                return SubscriptionManagementHelperUtil.getSubscriptionStatistics(
-                int allDeviceCount = deviceIdsOwnByUser.size();
+                        subscriptionDAO.getSubscriptionStatistic(getDeviceIdsOwnByUser(subscriptionInfo.getIdentifier()),
-                return SubscriptionManagementHelperUtil.getSubscriptionStatistics(subscriptionStatisticDTO, allDeviceCount);
+                                isUnsubscribe, tenantId, applicationReleaseDTO.getId()),
+                        getDeviceIdsOwnByUser(subscriptionInfo.getIdentifier()).size()
+                );
             } else {
                 return null;
             }
@@ -1796,13 +1840,14 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
 
     /**
      * Get status based subscription data describes by {@link SubscriptionInfo} entity
+     *
      * @param subscriptionInfo {@link SubscriptionInfo}
      * @param limit            Limit value
      * @param offset           Offset value
      * @return {@link SubscriptionResponse}
      * @throws ApplicationManagementException Throws when error encountered while getting subscription data
      */
-
+    @Override
     public SubscriptionResponse getStatusBaseSubscriptions(SubscriptionInfo subscriptionInfo, int limit, int offset)
             throws ApplicationManagementException {
         if (Objects.equals(subscriptionInfo.getSubscriptionType(), SubscriptionMetadata.SubscriptionTypes.DEVICE)) {
@@ -1810,14 +1855,14 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
         } else if (Objects.equals(subscriptionInfo.getSubscriptionType(), SubscriptionMetadata.SubscriptionTypes.GROUP)) {
             return getStatusBaseSubscriptionsGroup(subscriptionInfo, limit, offset);
         } else {
-            return getStatusBaseSubscriptionsRoleUser(subscriptionInfo, limit, offset);
+            return getStatusBaseSubscriptionsRoleAndUser(subscriptionInfo, limit, offset);
         }
     }
 
-
+    private SubscriptionResponse getStatusBaseSubscriptionsDevice(SubscriptionInfo subscriptionInfo, int limit, int offset)
-   public SubscriptionResponse getStatusBaseSubscriptionsDevice(SubscriptionInfo subscriptionInfo, int limit, int offset)
             throws ApplicationManagementException {
-        final boolean isUnsubscribe = Objects.equals(SubscriptionMetadata.SUBSCRIPTION_STATUS_UNSUBSCRIBED, subscriptionInfo.getSubscriptionStatus());
+        final boolean isUnsubscribe = Objects.equals(SubscriptionMetadata.SUBSCRIPTION_STATUS_UNSUBSCRIBED,
+                subscriptionInfo.getSubscriptionStatus());
         List<DeviceSubscriptionDTO> deviceSubscriptionDTOS;
         int deviceCount = 0;
         int tenantId = PrivilegedCarbonContext.getThreadLocalCarbonContext().getTenantId();
@@ -1843,7 +1888,8 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
             String deviceSubscriptionStatus = SubscriptionManagementHelperUtil.getDeviceSubscriptionStatus(subscriptionInfo);
             DeviceSubscriptionFilterCriteria deviceSubscriptionFilterCriteria = subscriptionInfo.getDeviceSubscriptionFilterCriteria();
             DeviceManagementProviderService deviceManagementProviderService = HelperUtil.getDeviceManagementProviderService();
-            List<String> dbSubscriptionStatus = SubscriptionManagementHelperUtil.getDBSubscriptionStatus(subscriptionInfo.getDeviceSubscriptionStatus());
+            List<String> dbSubscriptionStatus = SubscriptionManagementHelperUtil.getDBSubscriptionStatus
+                    (subscriptionInfo.getDeviceSubscriptionStatus());
 
             if (Objects.equals(SubscriptionMetadata.DeviceSubscriptionStatus.NEW, deviceSubscriptionStatus)) {
                 deviceSubscriptionDTOS = subscriptionDAO.getAllSubscriptionsDetails(applicationReleaseDTO.
@@ -1862,7 +1908,6 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
                         deviceSubscriptionFilterCriteria.getTriggeredBy(), -1, -1);
             }
 
-
             List<DeviceSubscription> deviceSubscriptions = SubscriptionManagementHelperUtil.getDeviceSubscriptionData(deviceSubscriptionDTOS,
                     subscriptionInfo.getDeviceSubscriptionFilterCriteria(), isUnsubscribe, applicationDTO.getDeviceTypeId(), limit, offset);
             return new SubscriptionResponse(subscriptionInfo.getApplicationUUID(), deviceCount, deviceSubscriptions);
@@ -1879,10 +1924,11 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
         }
     }
 
-    public SubscriptionResponse getStatusBaseSubscriptionsGroup(SubscriptionInfo subscriptionInfo, int limit, int offset)
+    private SubscriptionResponse getStatusBaseSubscriptionsGroup(SubscriptionInfo subscriptionInfo, int limit, int offset)
             throws ApplicationManagementException {
 
-        final boolean isUnsubscribe = Objects.equals(SubscriptionMetadata.SUBSCRIPTION_STATUS_UNSUBSCRIBED, subscriptionInfo.getSubscriptionStatus());
+        final boolean isUnsubscribe = Objects.equals(SubscriptionMetadata.SUBSCRIPTION_STATUS_UNSUBSCRIBED,
+                subscriptionInfo.getSubscriptionStatus());
         List<DeviceSubscriptionDTO> deviceSubscriptionDTOS;
         int deviceCount = 0;
         int tenantId = PrivilegedCarbonContext.getThreadLocalCarbonContext().getTenantId();
@@ -1912,11 +1958,14 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
 
             GroupManagementProviderService groupManagementProviderService = HelperUtil.getGroupManagementProviderService();
             GroupDetailsDTO groupDetailsDTO;
-            List<String> dbSubscriptionStatus = SubscriptionManagementHelperUtil.getDBSubscriptionStatus(subscriptionInfo.getDeviceSubscriptionStatus());
+            List<String> dbSubscriptionStatus = SubscriptionManagementHelperUtil.getDBSubscriptionStatus
+                    (subscriptionInfo.getDeviceSubscriptionStatus());
 
             if (Objects.equals(SubscriptionMetadata.DeviceSubscriptionStatus.NEW, deviceSubscriptionStatus)) {
-                List<Integer> allDeviceIdsOwnByGroup = groupManagementProviderService.getGroupDetailsWithDevices(subscriptionInfo.getIdentifier(),
+                List<Integer> allDeviceIdsOwnByGroup = groupManagementProviderService.getGroupDetailsWithDevices
-                        applicationDTO.getDeviceTypeId(), deviceSubscriptionFilterCriteria.getOwner(), deviceSubscriptionFilterCriteria.getName(),
+                        (subscriptionInfo.getIdentifier(),
+                                applicationDTO.getDeviceTypeId(), deviceSubscriptionFilterCriteria.getOwner(),
+                                deviceSubscriptionFilterCriteria.getName(),
                                 deviceSubscriptionFilterCriteria.getDeviceStatus(), -1, -1).getDeviceIds();
 
                 deviceSubscriptionDTOS = subscriptionDAO.getSubscriptionDetailsByDeviceIds(applicationReleaseDTO.getId(),
@@ -1964,10 +2013,10 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
         }
     }
 
-
+    private SubscriptionResponse getStatusBaseSubscriptionsRoleAndUser(SubscriptionInfo subscriptionInfo, int limit, int offset)
-    public SubscriptionResponse getStatusBaseSubscriptionsRoleUser(SubscriptionInfo subscriptionInfo, int limit, int offset)
             throws ApplicationManagementException {
-        final boolean isUnsubscribe = Objects.equals(SubscriptionMetadata.SUBSCRIPTION_STATUS_UNSUBSCRIBED, subscriptionInfo.getSubscriptionStatus());
+        final boolean isUnsubscribe = Objects.equals(SubscriptionMetadata.SUBSCRIPTION_STATUS_UNSUBSCRIBED,
+                subscriptionInfo.getSubscriptionStatus());
         List<DeviceSubscriptionDTO> deviceSubscriptionDTOS;
         int deviceCount = 0;
         int tenantId = PrivilegedCarbonContext.getThreadLocalCarbonContext().getTenantId();
@@ -1995,7 +2044,8 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
             String deviceSubscriptionStatus = SubscriptionManagementHelperUtil.getDeviceSubscriptionStatus(subscriptionInfo);
             DeviceSubscriptionFilterCriteria deviceSubscriptionFilterCriteria = subscriptionInfo.getDeviceSubscriptionFilterCriteria();
             DeviceManagementProviderService deviceManagementProviderService = HelperUtil.getDeviceManagementProviderService();
-            List<String> dbSubscriptionStatus = SubscriptionManagementHelperUtil.getDBSubscriptionStatus(subscriptionInfo.getDeviceSubscriptionStatus());
+            List<String> dbSubscriptionStatus = SubscriptionManagementHelperUtil.getDBSubscriptionStatus
+                    (subscriptionInfo.getDeviceSubscriptionStatus());
 
             if (Objects.equals(SubscriptionMetadata.DeviceSubscriptionStatus.NEW, deviceSubscriptionStatus)) {
                 deviceSubscriptionDTOS = subscriptionDAO.getSubscriptionDetailsByDeviceIds(applicationReleaseDTO.getId(),
@@ -2021,7 +2071,8 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
 
             List<DeviceSubscription> deviceSubscriptions = SubscriptionManagementHelperUtil.
                     getDeviceSubscriptionData(deviceSubscriptionDTOS,
-                            subscriptionInfo.getDeviceSubscriptionFilterCriteria(), isUnsubscribe, applicationDTO.getDeviceTypeId(), limit, offset);
+                            subscriptionInfo.getDeviceSubscriptionFilterCriteria(), isUnsubscribe,
+                            applicationDTO.getDeviceTypeId(), limit, offset);
             return new SubscriptionResponse(subscriptionInfo.getApplicationUUID(), deviceCount, deviceSubscriptions);
 
         } catch (UserStoreException e) {
@@ -2041,7 +2092,6 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
         }
     }
 
-
     @SuppressWarnings("unchecked")
     private List<Integer> getDeviceIdsOwnByRole(String roleName, int tenantId) throws UserStoreException, DeviceManagementException {
         UserStoreManager userStoreManager = DataHolder.getInstance().getRealmService().
@@ -2076,6 +2126,15 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
         return deviceListOwnByUser.stream().map(Device::getId).collect(Collectors.toList());
     }
 
+    /**
+     * Retrieves a list of device IDs associated with the subscription described by the {@link SubscriptionInfo}.
+     * The device IDs are determined based on the subscription type, which could be either a role or a user.
+     *
+     * @param subscriptionInfo {@link SubscriptionInfo} containing the subscription details.
+     * @return A {@link List} of device IDs corresponding to the subscription type, or {@code null} if the type is not recognized.
+     * @throws DeviceManagementException Thrown when an error occurs while retrieving device IDs.
+     * @throws UserStoreException        Thrown when an error occurs while accessing the user store.
+     */
     private List<Integer> getAllDeviceIds(SubscriptionInfo subscriptionInfo) throws DeviceManagementException, UserStoreException {
         String type = subscriptionInfo.getSubscriptionType();
         int tenantId = PrivilegedCarbonContext.getThreadLocalCarbonContext().getTenantId();
@@ -2084,13 +2143,14 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
         }
         if (Objects.equals(type, SubscriptionMetadata.SubscriptionTypes.USER)) {
             return getDeviceIdsOwnByUser(subscriptionInfo.getIdentifier());
-        }else
+        } else {
             return null;
         }
-
+    }
 
     /**
      * Get subscription statistics related data describes by the {@link SubscriptionInfo}
+     *
      * @param subscriptionInfo {@link SubscriptionInfo}
      * @return {@link SubscriptionStatistics}
      * @throws ApplicationManagementException Throws when error encountered while getting statistics
@@ -2100,7 +2160,6 @@ public class SubscriptionManagerImpl implements SubscriptionManager {
         return getSubscriptionStatistics(subscriptionInfo);
     }
 
-
     @Override
     public List<DeviceOperationDTO> getSubscriptionOperationsByUUIDAndDeviceID(int deviceId, String uuid)
             throws ApplicationManagementException {