Support pagination in query across all anchors(ep4)

Add pagination query parameters in query across all anchors API
pagination parameters (pageIndex and pageSize) are optional
default is to query all fragments
each pageSize represents number of records(number of anchors)
TotalRecords is returned in response header to find number of pages.

- If pagination option is provided in request then query number of
  anchors equal to pageSize. pageIndex is used for setting offset.

- return number of records(one anchor per record) as per pagesize
  and pageSize

Issue-ID: CPS-1605
Change-ID: I73f97f986a817d423f93a8d922dcd9647b2504bc
Signed-off-by: rajesh.kumar <rk00747546@techmahindra.com>

6 files changed, 106 insertions, 15 deletions

diff --git a/cps-service/src/main/java/org/onap/cps/api/CpsQueryService.java b/cps-service/src/main/java/org/onap/cps/api/CpsQueryService.java
index af54077fea..edd2d2ad32 100644
--- a/cps-service/src/main/java/org/onap/cps/api/CpsQueryService.java
+++ b/cps-service/src/main/java/org/onap/cps/api/CpsQueryService.java
@@ -23,6 +23,7 @@ package org.onap.cps.api;
 
 import java.util.Collection;
 import org.onap.cps.spi.FetchDescendantsOption;
+import org.onap.cps.spi.PaginationOption;
 import org.onap.cps.spi.model.DataNode;
 
 /*
@@ -50,8 +51,18 @@ public interface CpsQueryService {
      * @param cpsPath CPS path
      * @param fetchDescendantsOption defines whether the descendants of the node(s) found by the query should be
      *                               included in the output
+     * @param paginationOption pagination option
      * @return a collection of data nodes
      */
     Collection<DataNode> queryDataNodesAcrossAnchors(String dataspaceName, String cpsPath,
-                                                     FetchDescendantsOption fetchDescendantsOption);
+                                                     FetchDescendantsOption fetchDescendantsOption,
+                                                     PaginationOption paginationOption);
+
+    /**
+     * Query total number of anchors for given dataspace name and cps path.
+     * @param dataspaceName dataspace name
+     * @param cpsPath cps path
+     * @return total number of anchors for given dataspace name and cps path.
+     */
+    Integer countAnchorsForDataspaceAndCpsPath(String dataspaceName, String cpsPath);
 }
diff --git a/cps-service/src/main/java/org/onap/cps/api/impl/CpsQueryServiceImpl.java b/cps-service/src/main/java/org/onap/cps/api/impl/CpsQueryServiceImpl.java
index ac018c9e8f..1d7a7ceeb0 100644
--- a/cps-service/src/main/java/org/onap/cps/api/impl/CpsQueryServiceImpl.java
+++ b/cps-service/src/main/java/org/onap/cps/api/impl/CpsQueryServiceImpl.java
@@ -27,6 +27,7 @@ import lombok.RequiredArgsConstructor;
 import org.onap.cps.api.CpsQueryService;
 import org.onap.cps.spi.CpsDataPersistenceService;
 import org.onap.cps.spi.FetchDescendantsOption;
+import org.onap.cps.spi.PaginationOption;
 import org.onap.cps.spi.model.DataNode;
 import org.onap.cps.spi.utils.CpsValidator;
 import org.springframework.stereotype.Service;
@@ -49,8 +50,17 @@ public class CpsQueryServiceImpl implements CpsQueryService {
 
     @Override
     public Collection<DataNode> queryDataNodesAcrossAnchors(final String dataspaceName,
-        final String cpsPath, final FetchDescendantsOption fetchDescendantsOption) {
+        final String cpsPath, final FetchDescendantsOption fetchDescendantsOption,
+        final PaginationOption paginationOption) {
+        cpsValidator.validateNameCharacters(dataspaceName);
+        cpsValidator.validatePaginationOption(paginationOption);
+        return cpsDataPersistenceService.queryDataNodesAcrossAnchors(dataspaceName, cpsPath,
+                fetchDescendantsOption, paginationOption);
+    }
+
+    @Override
+    public Integer countAnchorsForDataspaceAndCpsPath(final String dataspaceName, final String cpsPath) {
         cpsValidator.validateNameCharacters(dataspaceName);
-        return cpsDataPersistenceService.queryDataNodesAcrossAnchors(dataspaceName, cpsPath, fetchDescendantsOption);
+        return cpsDataPersistenceService.countAnchorsForDataspaceAndCpsPath(dataspaceName, cpsPath);
     }
 }
diff --git a/cps-service/src/main/java/org/onap/cps/spi/CpsDataPersistenceService.java b/cps-service/src/main/java/org/onap/cps/spi/CpsDataPersistenceService.java
index 9674bbe8c1..1baca4ea7d 100644
--- a/cps-service/src/main/java/org/onap/cps/spi/CpsDataPersistenceService.java
+++ b/cps-service/src/main/java/org/onap/cps/spi/CpsDataPersistenceService.java
@@ -200,11 +200,12 @@ public interface CpsDataPersistenceService {
      * @param cpsPath                cps path
      * @param fetchDescendantsOption defines whether the descendants of the node(s) found by the query should be
      *                               included in the output
+     * @param paginationOption pagination option
      * @return the data nodes found i.e. 0 or more data nodes
      */
     List<DataNode> queryDataNodesAcrossAnchors(String dataspaceName,
-                                  String cpsPath, FetchDescendantsOption fetchDescendantsOption);
-
+                                  String cpsPath, FetchDescendantsOption fetchDescendantsOption,
+                                  PaginationOption paginationOption);
 
     /**
      * Starts a session which allows use of locks and batch interaction with the persistence service.
@@ -230,4 +231,12 @@ public interface CpsDataPersistenceService {
      * @param timeoutInMilliseconds lock attempt timeout in milliseconds
      */
     void lockAnchor(String sessionID, String dataspaceName, String anchorName, Long timeoutInMilliseconds);
+
+    /**
+     * Query total anchors for dataspace name and cps path.
+     * @param dataspaceName datasoace name
+     * @param cpsPath cps path
+     * @return total anchors for dataspace name and cps path
+     */
+    Integer countAnchorsForDataspaceAndCpsPath(String dataspaceName, String cpsPath);
 }
diff --git a/cps-service/src/main/java/org/onap/cps/spi/PaginationOption.java b/cps-service/src/main/java/org/onap/cps/spi/PaginationOption.java
new file mode 100644
index 0000000000..17f025dba6
--- /dev/null
+++ b/cps-service/src/main/java/org/onap/cps/spi/PaginationOption.java
@@ -0,0 +1,38 @@
+/*
+ *  ============LICENSE_START=======================================================
+ *  Copyright (C) 2023 TechMahindra Ltd.
+ *  ================================================================================
+ *  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.spi;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+
+@Data
+@AllArgsConstructor
+public class PaginationOption {
+
+    private int pageIndex;
+
+    private int pageSize;
+
+    public static final PaginationOption NO_PAGINATION = null;
+
+    public boolean isValidPaginationOption() {
+        return this.pageIndex > 0 && this.pageSize > 0;
+    }
+}
diff --git a/cps-service/src/main/java/org/onap/cps/spi/utils/CpsValidator.java b/cps-service/src/main/java/org/onap/cps/spi/utils/CpsValidator.java
index 231094cf16..ceb75c09b2 100644
--- a/cps-service/src/main/java/org/onap/cps/spi/utils/CpsValidator.java
+++ b/cps-service/src/main/java/org/onap/cps/spi/utils/CpsValidator.java
@@ -20,6 +20,8 @@
 
 package org.onap.cps.spi.utils;
 
+import org.onap.cps.spi.PaginationOption;
+
 public interface CpsValidator {
 
     /**
@@ -35,4 +37,11 @@ public interface CpsValidator {
      * @param names names of data to be validated
      */
     void validateNameCharacters(final Iterable<String> names);
+
+    /**
+     * Validate pagination option.
+     *
+     * @param paginationOption pagination option
+     */
+    void validatePaginationOption(final PaginationOption paginationOption);
 }
diff --git a/cps-service/src/main/java/org/onap/cps/utils/DataMapUtils.java b/cps-service/src/main/java/org/onap/cps/utils/DataMapUtils.java
index b4d5a09447..1ac2bddf88 100644
--- a/cps-service/src/main/java/org/onap/cps/utils/DataMapUtils.java
+++ b/cps-service/src/main/java/org/onap/cps/utils/DataMapUtils.java
@@ -28,8 +28,10 @@ import static java.util.stream.Collectors.toUnmodifiableList;
 import static java.util.stream.Collectors.toUnmodifiableMap;
 
 import com.google.common.collect.ImmutableMap;
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.List;
 import java.util.Map;
 import lombok.AccessLevel;
 import lombok.NoArgsConstructor;
@@ -52,17 +54,29 @@ public class DataMapUtils {
     }
 
     /**
-     * Converts DataNode structure into a map including the root node identifier for a JSON response.
-     *
-     * @param dataNode data node object
-     * @return a map representing same data with the root node identifier
+     * Converts list of DataNode structure into a map including the root node identifier for a JSON response.
+     * @param dataNodeList list of data nodes for a given anchor name
+     * @param anchorName anchor name
+     * @param prefix prefix
+     * @return a map representing same list of data for given anchor with the root node identifier
      */
-    public static Map<String, Object> toDataMapWithIdentifierAndAnchor(final DataNode dataNode, final String prefix) {
-        final String nodeIdentifierWithPrefix = getNodeIdentifierWithPrefix(dataNode.getXpath(), prefix);
-        final Map<String, Object> dataMap = ImmutableMap.<String, Object>builder()
-                .put(nodeIdentifierWithPrefix, toDataMap(dataNode)).build();
-        return ImmutableMap.<String, Object>builder().put("anchorName", dataNode.getAnchorName())
-                .put("dataNode", dataMap).build();
+    public static Map<String, Object> toDataMapWithIdentifierAndAnchor(final List<DataNode> dataNodeList,
+                                                                       final String anchorName, final String prefix) {
+        final List<Map<String, Object>> dataMaps = toDataNodesWithIdentifier(dataNodeList, prefix);
+        return ImmutableMap.<String, Object>builder().put("anchorName", anchorName)
+                .put("dataNodes", dataMaps).build();
+    }
+
+    private static List<Map<String, Object>> toDataNodesWithIdentifier(final List<DataNode> dataNodeList,
+                                                                       final String prefix) {
+        final List<Map<String, Object>> dataMaps = new ArrayList<>(dataNodeList.size());
+        for (final DataNode dataNode: dataNodeList) {
+            final String nodeIdentifierWithPrefix = getNodeIdentifierWithPrefix(dataNode.getXpath(), prefix);
+            final Map<String, Object> dataMap = ImmutableMap.<String, Object>builder()
+                    .put(nodeIdentifierWithPrefix, toDataMap(dataNode)).build();
+            dataMaps.add(dataMap);
+        }
+        return dataMaps;
     }
 
     /**