Merge "Delete Subscription method"

7 files changed, 187 insertions, 24 deletions

diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/cache/DmiCacheHandler.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/cache/DmiCacheHandler.java
index c5052f1405..b5ab7f6525 100644
--- a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/cache/DmiCacheHandler.java
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/cache/DmiCacheHandler.java
@@ -50,7 +50,7 @@ public class DmiCacheHandler {
     private final InventoryPersistence inventoryPersistence;
 
     /**
-     * Adds new subscription to the subscription cache.
+     * Adds subscription to the subscription cache.
      *
      * @param subscriptionId    subscription id
      * @param predicates        subscription request predicates
@@ -60,6 +60,18 @@ public class DmiCacheHandler {
     }
 
     /**
+     * Adds subscription to the subscription cache.
+     *
+     * @param subscriptionId subscription id
+     * @param dmiCmSubscriptionDetailsPerDmi map of dmi cm notification subscription details per dmi
+     */
+    public void add(final String subscriptionId,
+                    final Map<String, DmiCmSubscriptionDetails>
+                            dmiCmSubscriptionDetailsPerDmi) {
+        cmNotificationSubscriptionCache.put(subscriptionId, dmiCmSubscriptionDetailsPerDmi);
+    }
+
+    /**
      * Get cm notification subscription cache entry via subscription id.
      *
      * @param subscriptionId    subscription id
@@ -122,8 +134,8 @@ public class DmiCacheHandler {
      * @param status            String of status
      *
      */
-    public void updateDmiSubscriptionStatusPerDmi(final String subscriptionId, final String dmiServiceName,
-            final CmSubscriptionStatus status) {
+    public void updateDmiSubscriptionStatus(final String subscriptionId, final String dmiServiceName,
+                                            final CmSubscriptionStatus status) {
         final Map<String, DmiCmSubscriptionDetails> dmiSubscriptionsPerDmi =
                 cmNotificationSubscriptionCache.get(subscriptionId);
         dmiSubscriptionsPerDmi.get(dmiServiceName).setCmSubscriptionStatus(status);
@@ -162,7 +174,7 @@ public class DmiCacheHandler {
      * @param dmiServiceName    String of dmiServiceName
      *
      */
-    public void removeFromDatabasePerDmi(final String subscriptionId, final String dmiServiceName) {
+    public void removeFromDatabase(final String subscriptionId, final String dmiServiceName) {
         final List<DmiCmSubscriptionPredicate> dmiCmSubscriptionPredicates =
                 cmNotificationSubscriptionCache.get(subscriptionId).get(dmiServiceName)
                         .getDmiCmSubscriptionPredicates();
@@ -210,6 +222,6 @@ public class DmiCacheHandler {
 
     private boolean isAcceptedOrRejected(final DmiCmSubscriptionDetails dmiCmSubscription) {
         return dmiCmSubscription.getCmSubscriptionStatus().toString().equals("ACCEPTED")
-                       || dmiCmSubscription.getCmSubscriptionStatus().toString().equals("REJECTED");
+                || dmiCmSubscription.getCmSubscriptionStatus().toString().equals("REJECTED");
     }
 }
diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/dmi/DmiOutEventConsumer.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/dmi/DmiOutEventConsumer.java
index 20ccf528ed..20c7c7b13d 100644
--- a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/dmi/DmiOutEventConsumer.java
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/dmi/DmiOutEventConsumer.java
@@ -80,7 +80,7 @@ public class DmiOutEventConsumer {
                 dmiCacheHandler.persistIntoDatabasePerDmi(subscriptionId, dmiPluginName);
             }
             if (eventType.equals("subscriptionDeleteResponse")) {
-                dmiCacheHandler.removeFromDatabasePerDmi(subscriptionId, dmiPluginName);
+                dmiCacheHandler.removeFromDatabase(subscriptionId, dmiPluginName);
             }
             handleEventsStatusPerDmi(subscriptionId, eventType);
         }
@@ -96,7 +96,7 @@ public class DmiOutEventConsumer {
 
     private void handleCacheStatusPerDmi(final String subscriptionId, final String dmiPluginName,
             final CmSubscriptionStatus cmSubscriptionStatus) {
-        dmiCacheHandler.updateDmiSubscriptionStatusPerDmi(subscriptionId, dmiPluginName,
+        dmiCacheHandler.updateDmiSubscriptionStatus(subscriptionId, dmiPluginName,
                 cmSubscriptionStatus);
     }
 
diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/models/DmiCmSubscriptionTuple.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/models/DmiCmSubscriptionTuple.java
new file mode 100644
index 0000000000..cd4a15af47
--- /dev/null
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/models/DmiCmSubscriptionTuple.java
@@ -0,0 +1,34 @@
+/*
+ *  ============LICENSE_START=======================================================
+ *  Copyright (C) 2024 Nordix Foundation
+ *  ================================================================================
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *  SPDX-License-Identifier: Apache-2.0
+ * ============LICENSE_END=========================================================
+ */
+
+package org.onap.cps.ncmp.impl.cmnotificationsubscription.models;
+
+import java.util.Collection;
+import java.util.Map;
+
+/**
+ * Tuple to be used during for to delete usecase.
+ *
+ * @param lastRemainingSubscriptionsPerDmi   subscriptions that are used by only one subscriber grouped per dmi
+ * @param overlappingSubscriptionsPerDmi     subscriptions that are shared by multiple subscribers grouped per dmi
+ */
+public record DmiCmSubscriptionTuple(Map<String, Collection<DmiCmSubscriptionKey>> lastRemainingSubscriptionsPerDmi,
+                                     Map<String, Collection<DmiCmSubscriptionKey>> overlappingSubscriptionsPerDmi) {
+}
diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/ncmp/CmSubscriptionHandler.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/ncmp/CmSubscriptionHandler.java
index 3a9b2066b2..90c5c575e6 100644
--- a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/ncmp/CmSubscriptionHandler.java
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/ncmp/CmSubscriptionHandler.java
@@ -37,8 +37,7 @@ public interface CmSubscriptionHandler {
      * Process cm notification subscription delete request.
      *
      * @param subscriptionId subscription id
-     * @param predicates subscription predicates
      */
-    void processSubscriptionDeleteRequest(final String subscriptionId, final List<Predicate> predicates);
+    void processSubscriptionDeleteRequest(final String subscriptionId);
 
 }
\ No newline at end of file
diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/ncmp/CmSubscriptionHandlerImpl.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/ncmp/CmSubscriptionHandlerImpl.java
index 9d33d25816..c2c71dbaae 100644
--- a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/ncmp/CmSubscriptionHandlerImpl.java
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/ncmp/CmSubscriptionHandlerImpl.java
@@ -21,34 +21,50 @@
 package org.onap.cps.ncmp.impl.cmnotificationsubscription.ncmp;
 
 import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 import lombok.RequiredArgsConstructor;
 import org.onap.cps.ncmp.impl.cmnotificationsubscription.cache.DmiCacheHandler;
+import org.onap.cps.ncmp.impl.cmnotificationsubscription.dmi.DmiCmSubscriptionDetailsPerDmiMapper;
 import org.onap.cps.ncmp.impl.cmnotificationsubscription.dmi.DmiInEventMapper;
 import org.onap.cps.ncmp.impl.cmnotificationsubscription.dmi.DmiInEventProducer;
 import org.onap.cps.ncmp.impl.cmnotificationsubscription.models.CmSubscriptionStatus;
 import org.onap.cps.ncmp.impl.cmnotificationsubscription.models.DmiCmSubscriptionDetails;
+import org.onap.cps.ncmp.impl.cmnotificationsubscription.models.DmiCmSubscriptionKey;
 import org.onap.cps.ncmp.impl.cmnotificationsubscription.models.DmiCmSubscriptionPredicate;
+import org.onap.cps.ncmp.impl.cmnotificationsubscription.models.DmiCmSubscriptionTuple;
 import org.onap.cps.ncmp.impl.cmnotificationsubscription.utils.CmSubscriptionPersistenceService;
 import org.onap.cps.ncmp.impl.cmnotificationsubscription_1_0_0.client_to_ncmp.Predicate;
 import org.onap.cps.ncmp.impl.cmnotificationsubscription_1_0_0.ncmp_to_client.NcmpOutEvent;
 import org.onap.cps.ncmp.impl.cmnotificationsubscription_1_0_0.ncmp_to_dmi.DmiInEvent;
+import org.onap.cps.ncmp.impl.inventory.InventoryPersistence;
+import org.onap.cps.spi.model.DataNode;
 import org.springframework.stereotype.Service;
 
 @Service
 @RequiredArgsConstructor
 public class CmSubscriptionHandlerImpl implements CmSubscriptionHandler {
 
+    private static final Pattern SUBSCRIPTION_KEY_FROM_XPATH_PATTERN = Pattern.compile(
+            "^/datastores/datastore\\[@name='([^']*)']/cm-handles/cm-handle\\[@id='([^']*)']/"
+                    + "filters/filter\\[@xpath='(.*)']$");
+
     private final CmSubscriptionPersistenceService cmSubscriptionPersistenceService;
     private final CmSubscriptionComparator cmSubscriptionComparator;
     private final NcmpOutEventMapper ncmpOutEventMapper;
     private final DmiInEventMapper dmiInEventMapper;
+    private final DmiCmSubscriptionDetailsPerDmiMapper dmiCmSubscriptionDetailsPerDmiMapper;
     private final NcmpOutEventProducer ncmpOutEventProducer;
     private final DmiInEventProducer dmiInEventProducer;
     private final DmiCacheHandler dmiCacheHandler;
+    private final InventoryPersistence inventoryPersistence;
 
     @Override
     public void processSubscriptionCreateRequest(final String subscriptionId, final List<Predicate> predicates) {
@@ -62,10 +78,45 @@ public class CmSubscriptionHandlerImpl implements CmSubscriptionHandler {
     }
 
     @Override
-    public void processSubscriptionDeleteRequest(final String subscriptionId, final List<Predicate> predicates) {
-        dmiCacheHandler.add(subscriptionId, predicates);
-        sendSubscriptionDeleteRequestToDmi(subscriptionId);
-        scheduleNcmpOutEventResponse(subscriptionId, "subscriptionDeleteResponse");
+    public void processSubscriptionDeleteRequest(final String subscriptionId) {
+        final Collection<DataNode> subscriptionDataNodes =
+                cmSubscriptionPersistenceService.getAllNodesForSubscriptionId(subscriptionId);
+        final DmiCmSubscriptionTuple dmiCmSubscriptionTuple =
+                getLastRemainingAndOverlappingSubscriptionsPerDmi(subscriptionDataNodes);
+        dmiCacheHandler.add(subscriptionId, mergeDmiCmSubscriptionDetailsPerDmiMaps(dmiCmSubscriptionTuple));
+        if (dmiCmSubscriptionTuple.lastRemainingSubscriptionsPerDmi().isEmpty()) {
+            acceptAndPublishDeleteRequest(subscriptionId);
+        } else {
+            sendSubscriptionDeleteRequestToDmi(subscriptionId,
+                    dmiCmSubscriptionDetailsPerDmiMapper.toDmiCmSubscriptionsPerDmi(
+                            dmiCmSubscriptionTuple.lastRemainingSubscriptionsPerDmi()));
+            scheduleNcmpOutEventResponse(subscriptionId, "subscriptionDeleteResponse");
+        }
+    }
+
+    private Map<String, DmiCmSubscriptionDetails> mergeDmiCmSubscriptionDetailsPerDmiMaps(
+            final DmiCmSubscriptionTuple dmiCmSubscriptionTuple) {
+        final Map<String, DmiCmSubscriptionDetails> lastRemainingDmiSubscriptionsPerDmi =
+                dmiCmSubscriptionDetailsPerDmiMapper.toDmiCmSubscriptionsPerDmi(
+                        dmiCmSubscriptionTuple.lastRemainingSubscriptionsPerDmi());
+        final Map<String, DmiCmSubscriptionDetails> overlappingDmiSubscriptionsPerDmi =
+                dmiCmSubscriptionDetailsPerDmiMapper.toDmiCmSubscriptionsPerDmi(
+                        dmiCmSubscriptionTuple.overlappingSubscriptionsPerDmi());
+        final Map<String, DmiCmSubscriptionDetails> mergedDmiSubscriptionsPerDmi =
+                new HashMap<>(lastRemainingDmiSubscriptionsPerDmi);
+        overlappingDmiSubscriptionsPerDmi.forEach((dmiServiceName, dmiCmSubscriptionDetails) ->
+                mergedDmiSubscriptionsPerDmi.merge(dmiServiceName, dmiCmSubscriptionDetails,
+                        this::mergeDmiCmSubscriptionDetails));
+        return mergedDmiSubscriptionsPerDmi;
+    }
+
+    private DmiCmSubscriptionDetails mergeDmiCmSubscriptionDetails(
+            final DmiCmSubscriptionDetails dmiCmSubscriptionDetails,
+            final DmiCmSubscriptionDetails otherDmiCmSubscriptionDetails) {
+        final List<DmiCmSubscriptionPredicate> mergedDmiCmSubscriptionPredicates =
+                new ArrayList<>(dmiCmSubscriptionDetails.getDmiCmSubscriptionPredicates());
+        mergedDmiCmSubscriptionPredicates.addAll(otherDmiCmSubscriptionDetails.getDmiCmSubscriptionPredicates());
+        return new DmiCmSubscriptionDetails(mergedDmiCmSubscriptionPredicates, CmSubscriptionStatus.PENDING);
     }
 
     private void scheduleNcmpOutEventResponse(final String subscriptionId, final String eventType) {
@@ -81,6 +132,19 @@ public class CmSubscriptionHandlerImpl implements CmSubscriptionHandler {
         ncmpOutEventProducer.publishNcmpOutEvent(subscriptionId, "subscriptionCreateResponse", ncmpOutEvent, false);
     }
 
+    private void acceptAndPublishDeleteRequest(final String subscriptionId) {
+        final Set<String> dmiServiceNames = dmiCacheHandler.get(subscriptionId).keySet();
+        for (final String dmiServiceName : dmiServiceNames) {
+            dmiCacheHandler.updateDmiSubscriptionStatus(subscriptionId, dmiServiceName,
+                    CmSubscriptionStatus.ACCEPTED);
+            dmiCacheHandler.removeFromDatabase(subscriptionId, dmiServiceName);
+        }
+        final NcmpOutEvent ncmpOutEvent = ncmpOutEventMapper.toNcmpOutEvent(subscriptionId,
+                dmiCacheHandler.get(subscriptionId));
+        ncmpOutEventProducer.publishNcmpOutEvent(subscriptionId, "subscriptionDeleteResponse", ncmpOutEvent,
+                false);
+    }
+
     private void handleNewCmSubscription(final String subscriptionId) {
         final Map<String, DmiCmSubscriptionDetails> dmiSubscriptionsPerDmi =
                 dmiCacheHandler.get(subscriptionId);
@@ -98,26 +162,68 @@ public class CmSubscriptionHandlerImpl implements CmSubscriptionHandler {
     }
 
     private void publishDmiInEventPerDmi(final String subscriptionId, final String dmiPluginName,
-            final List<DmiCmSubscriptionPredicate> dmiCmSubscriptionPredicates) {
+                                         final List<DmiCmSubscriptionPredicate> dmiCmSubscriptionPredicates) {
         final DmiInEvent dmiInEvent = dmiInEventMapper.toDmiInEvent(dmiCmSubscriptionPredicates);
         dmiInEventProducer.publishDmiInEvent(subscriptionId, dmiPluginName,
                 "subscriptionCreateRequest", dmiInEvent);
     }
 
     private void acceptAndPublishNcmpOutEventPerDmi(final String subscriptionId, final String dmiPluginName) {
-        dmiCacheHandler.updateDmiSubscriptionStatusPerDmi(subscriptionId, dmiPluginName,
+        dmiCacheHandler.updateDmiSubscriptionStatus(subscriptionId, dmiPluginName,
                 CmSubscriptionStatus.ACCEPTED);
         dmiCacheHandler.persistIntoDatabasePerDmi(subscriptionId, dmiPluginName);
     }
 
-    private void sendSubscriptionDeleteRequestToDmi(final String subscriptionId) {
-        final Map<String, DmiCmSubscriptionDetails> dmiSubscriptionsPerDmi =
-                dmiCacheHandler.get(subscriptionId);
-        dmiSubscriptionsPerDmi.forEach((dmiPluginName, dmiSubscriptionDetails) -> {
-            final DmiInEvent dmiInEvent = dmiInEventMapper.toDmiInEvent(
-                    dmiSubscriptionDetails.getDmiCmSubscriptionPredicates());
-            dmiInEventProducer.publishDmiInEvent(subscriptionId, dmiPluginName,
-                    "subscriptionDeleteRequest", dmiInEvent);
+    private void sendSubscriptionDeleteRequestToDmi(final String subscriptionId,
+                                                    final Map<String, DmiCmSubscriptionDetails>
+                                                            dmiCmSubscriptionsPerDmi) {
+        dmiCmSubscriptionsPerDmi.forEach((dmiPluginName, dmiCmSubscriptionDetails) -> {
+            final DmiInEvent dmiInEvent =
+                    dmiInEventMapper.toDmiInEvent(
+                            dmiCmSubscriptionDetails.getDmiCmSubscriptionPredicates());
+            dmiInEventProducer.publishDmiInEvent(subscriptionId,
+                    dmiPluginName, "subscriptionDeleteRequest", dmiInEvent);
         });
     }
+
+
+    private DmiCmSubscriptionTuple getLastRemainingAndOverlappingSubscriptionsPerDmi(
+            final Collection<DataNode> subscriptionNodes) {
+        final Map<String, Collection<DmiCmSubscriptionKey>> lastRemainingSubscriptionsPerDmi = new HashMap<>();
+        final Map<String, Collection<DmiCmSubscriptionKey>> overlappingSubscriptionsPerDmi = new HashMap<>();
+
+        for (final DataNode subscriptionNode : subscriptionNodes) {
+            final DmiCmSubscriptionKey dmiCmSubscriptionKey = extractCmSubscriptionKey(subscriptionNode.getXpath());
+            final String dmiServiceName = inventoryPersistence.getYangModelCmHandle(
+                    dmiCmSubscriptionKey.cmHandleId()).getDmiServiceName();
+            final List<String> subscribers = (List<String>) subscriptionNode.getLeaves().get("subscriptionIds");
+            populateDmiCmSubscriptionTuple(subscribers, overlappingSubscriptionsPerDmi,
+                    lastRemainingSubscriptionsPerDmi, dmiServiceName, dmiCmSubscriptionKey);
+        }
+        return new DmiCmSubscriptionTuple(lastRemainingSubscriptionsPerDmi, overlappingSubscriptionsPerDmi);
+    }
+
+    private static void populateDmiCmSubscriptionTuple(final List<String> subscribers,
+                                                       final Map<String, Collection<DmiCmSubscriptionKey>>
+                                                               overlappingSubscriptionsPerDmi,
+                                                       final Map<String, Collection<DmiCmSubscriptionKey>>
+                                                               lastRemainingSubscriptionsPerDmi,
+                                                       final String dmiServiceName,
+                                                       final DmiCmSubscriptionKey dmiCmSubscriptionKey) {
+        final Map<String, Collection<DmiCmSubscriptionKey>> targetMap =
+                subscribers.size() > 1 ? overlappingSubscriptionsPerDmi : lastRemainingSubscriptionsPerDmi;
+        targetMap.computeIfAbsent(dmiServiceName, dmiName -> new HashSet<>()).add(dmiCmSubscriptionKey);
+    }
+
+    private DmiCmSubscriptionKey extractCmSubscriptionKey(final String xpath) {
+        final Matcher matcher = SUBSCRIPTION_KEY_FROM_XPATH_PATTERN.matcher(xpath);
+        if (matcher.find()) {
+            final String datastoreName = matcher.group(1);
+            final String cmHandleId = matcher.group(2);
+            final String filterXpath = matcher.group(3);
+            return new DmiCmSubscriptionKey(datastoreName, cmHandleId, filterXpath);
+        }
+        throw new IllegalArgumentException("DataNode xpath does not represent a subscription key");
+    }
+
 }
\ No newline at end of file
diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/ncmp/NcmpInEventConsumer.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/ncmp/NcmpInEventConsumer.java
index 1e1359dd0d..cba64e0e94 100644
--- a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/ncmp/NcmpInEventConsumer.java
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/ncmp/NcmpInEventConsumer.java
@@ -63,7 +63,7 @@ public class NcmpInEventConsumer {
         if ("subscriptionDeleteRequest".equals(cloudEvent.getType())) {
             log.info("Subscription delete request for source {} with subscription id {} ...",
                     cloudEvent.getSource(), subscriptionId);
-            cmSubscriptionHandler.processSubscriptionDeleteRequest(subscriptionId, predicates);
+            cmSubscriptionHandler.processSubscriptionDeleteRequest(subscriptionId);
         }
     }
 }
diff --git a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/utils/CmSubscriptionPersistenceService.java b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/utils/CmSubscriptionPersistenceService.java
index c24507a1a7..c71109013a 100644
--- a/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/utils/CmSubscriptionPersistenceService.java
+++ b/cps-ncmp-service/src/main/java/org/onap/cps/ncmp/impl/cmnotificationsubscription/utils/CmSubscriptionPersistenceService.java
@@ -159,6 +159,18 @@ public class CmSubscriptionPersistenceService {
         }
     }
 
+    /**
+     * Retrieve all existing dataNodes for given subscription id.
+     *
+     * @param subscriptionId  subscription id
+     * @return collection of DataNodes
+     */
+    public Collection<DataNode> getAllNodesForSubscriptionId(final String subscriptionId) {
+        return cpsQueryService.queryDataNodes(NCMP_DATASPACE_NAME, SUBSCRIPTION_ANCHOR_NAME,
+                CPS_PATH_QUERY_FOR_CM_SUBSCRIPTION_WITH_ID.formatted(subscriptionId),
+                OMIT_DESCENDANTS);
+    }
+
     private void deleteListOfSubscriptionsFor(final DatastoreType datastoreType, final String cmHandleId,
             final String xpath) {
         cpsDataService.deleteDataNode(NCMP_DATASPACE_NAME, SUBSCRIPTION_ANCHOR_NAME,