Reduce anchor lookups related to PrefixResolver (CPS-2417 #1)

Instead of looking up same Anchor many times inside a for-loop,
do it once outside the loop.

This greatly improves performance in some cases, such as v2 GET API:
- /cps/api/v2/dataspaces/{dataspace}/anchors/{anchor}/node
Testing shows 3x faster response time.

Issue-ID: CPS-2417
Signed-off-by: danielhanrahan <daniel.hanrahan@est.tech>
Change-Id: I80d97d8cc24372eed70626ed840cad985cbe0a4b

2 files changed, 21 insertions, 11 deletions

diff --git a/cps-rest/src/main/java/org/onap/cps/rest/controller/DataRestController.java b/cps-rest/src/main/java/org/onap/cps/rest/controller/DataRestController.java
index 6015e0e3ae..f86073fb06 100755
--- a/cps-rest/src/main/java/org/onap/cps/rest/controller/DataRestController.java
+++ b/cps-rest/src/main/java/org/onap/cps/rest/controller/DataRestController.java
@@ -2,7 +2,7 @@
  *  ============LICENSE_START=======================================================
  *  Copyright (C) 2020-2022 Bell Canada.
  *  Modifications Copyright (C) 2021 Pantheon.tech
- *  Modifications Copyright (C) 2021-2023 Nordix Foundation
+ *  Modifications Copyright (C) 2021-2024 Nordix Foundation
  *  Modifications Copyright (C) 2022-2024 TechMahindra Ltd.
  *  Modifications Copyright (C) 2022 Deutsche Telekom AG
  *  ================================================================================
@@ -37,9 +37,11 @@ import java.util.List;
 import java.util.Map;
 import lombok.RequiredArgsConstructor;
 import org.apache.commons.lang3.StringUtils;
+import org.onap.cps.api.CpsAnchorService;
 import org.onap.cps.api.CpsDataService;
 import org.onap.cps.rest.api.CpsDataApi;
 import org.onap.cps.spi.FetchDescendantsOption;
+import org.onap.cps.spi.model.Anchor;
 import org.onap.cps.spi.model.DataNode;
 import org.onap.cps.spi.model.DeltaReport;
 import org.onap.cps.utils.ContentType;
@@ -63,6 +65,7 @@ public class DataRestController implements CpsDataApi {
     private static final DateTimeFormatter ISO_TIMESTAMP_FORMATTER = DateTimeFormatter.ofPattern(ISO_TIMESTAMP_FORMAT);
 
     private final CpsDataService cpsDataService;
+    private final CpsAnchorService cpsAnchorService;
     private final JsonObjectMapper jsonObjectMapper;
     private final PrefixResolver prefixResolver;
 
@@ -112,7 +115,8 @@ public class DataRestController implements CpsDataApi {
             ? FetchDescendantsOption.INCLUDE_ALL_DESCENDANTS : FetchDescendantsOption.OMIT_DESCENDANTS;
         final DataNode dataNode = cpsDataService.getDataNodes(dataspaceName, anchorName, xpath,
             fetchDescendantsOption).iterator().next();
-        final String prefix = prefixResolver.getPrefix(dataspaceName, anchorName, dataNode.getXpath());
+        final Anchor anchor = cpsAnchorService.getAnchor(dataspaceName, anchorName);
+        final String prefix = prefixResolver.getPrefix(anchor, dataNode.getXpath());
         return new ResponseEntity<>(DataMapUtils.toDataMapWithIdentifier(dataNode, prefix), HttpStatus.OK);
     }
 
@@ -127,8 +131,9 @@ public class DataRestController implements CpsDataApi {
         final Collection<DataNode> dataNodes = cpsDataService.getDataNodes(dataspaceName, anchorName, xpath,
                 fetchDescendantsOption);
         final List<Map<String, Object>> dataMaps = new ArrayList<>(dataNodes.size());
+        final Anchor anchor = cpsAnchorService.getAnchor(dataspaceName, anchorName);
         for (final DataNode dataNode: dataNodes) {
-            final String prefix = prefixResolver.getPrefix(dataspaceName, anchorName, dataNode.getXpath());
+            final String prefix = prefixResolver.getPrefix(anchor, dataNode.getXpath());
             final Map<String, Object> dataMap = DataMapUtils.toDataMapWithIdentifier(dataNode, prefix);
             dataMaps.add(dataMap);
         }
diff --git a/cps-rest/src/main/java/org/onap/cps/rest/controller/QueryRestController.java b/cps-rest/src/main/java/org/onap/cps/rest/controller/QueryRestController.java
index 5334b48143..547be669ae 100644
--- a/cps-rest/src/main/java/org/onap/cps/rest/controller/QueryRestController.java
+++ b/cps-rest/src/main/java/org/onap/cps/rest/controller/QueryRestController.java
@@ -1,6 +1,6 @@
 /*
  *  ============LICENSE_START=======================================================
- *  Copyright (C) 2021-2022 Nordix Foundation
+ *  Copyright (C) 2021-2024 Nordix Foundation
  *  Modifications Copyright (C) 2022 Bell Canada.
  *  Modifications Copyright (C) 2022-2023 TechMahindra Ltd.
  *  ================================================================================
@@ -29,10 +29,12 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import lombok.RequiredArgsConstructor;
+import org.onap.cps.api.CpsAnchorService;
 import org.onap.cps.api.CpsQueryService;
 import org.onap.cps.rest.api.CpsQueryApi;
 import org.onap.cps.spi.FetchDescendantsOption;
 import org.onap.cps.spi.PaginationOption;
+import org.onap.cps.spi.model.Anchor;
 import org.onap.cps.spi.model.DataNode;
 import org.onap.cps.utils.DataMapUtils;
 import org.onap.cps.utils.JsonObjectMapper;
@@ -48,6 +50,7 @@ import org.springframework.web.bind.annotation.RestController;
 public class QueryRestController implements CpsQueryApi {
 
     private final CpsQueryService cpsQueryService;
+    private final CpsAnchorService cpsAnchorService;
     private final JsonObjectMapper jsonObjectMapper;
     private final PrefixResolver prefixResolver;
 
@@ -87,14 +90,15 @@ public class QueryRestController implements CpsQueryApi {
                 cpsPath, fetchDescendantsOption, paginationOption);
         final List<Map<String, Object>> dataNodesAsListOfMaps = new ArrayList<>(dataNodes.size());
         String prefix = null;
-        final Map<String, List<DataNode>> anchorDataNodeListMap = prepareDataNodesForAnchor(dataNodes);
-        for (final Map.Entry<String, List<DataNode>> anchorDataNodesMapEntry : anchorDataNodeListMap.entrySet()) {
+        final Map<String, List<DataNode>> dataNodesPerAnchor = groupDataNodesPerAnchor(dataNodes);
+        for (final Map.Entry<String, List<DataNode>> dataNodesPerAnchorEntry : dataNodesPerAnchor.entrySet()) {
+            final String anchorName = dataNodesPerAnchorEntry.getKey();
             if (prefix == null) {
-                prefix = prefixResolver.getPrefix(dataspaceName, anchorDataNodesMapEntry.getKey(),
-                        anchorDataNodesMapEntry.getValue().get(0).getXpath());
+                final Anchor anchor = cpsAnchorService.getAnchor(dataspaceName, anchorName);
+                prefix = prefixResolver.getPrefix(anchor, dataNodesPerAnchorEntry.getValue().get(0).getXpath());
             }
             final Map<String, Object> dataMap = DataMapUtils.toDataMapWithIdentifierAndAnchor(
-                    anchorDataNodesMapEntry.getValue(), anchorDataNodesMapEntry.getKey(), prefix);
+                    dataNodesPerAnchorEntry.getValue(), anchorName, prefix);
             dataNodesAsListOfMaps.add(dataMap);
         }
         final Integer totalPages = getTotalPages(dataspaceName, cpsPath, paginationOption);
@@ -112,7 +116,7 @@ public class QueryRestController implements CpsQueryApi {
                 : (int) Math.ceil((double) totalAnchors / paginationOption.getPageSize());
     }
 
-    private Map<String, List<DataNode>> prepareDataNodesForAnchor(final Collection<DataNode> dataNodes) {
+    private Map<String, List<DataNode>> groupDataNodesPerAnchor(final Collection<DataNode> dataNodes) {
         final Map<String, List<DataNode>> dataNodesMapForAnchor = new HashMap<>();
         for (final DataNode dataNode : dataNodes) {
             List<DataNode> dataNodesInAnchor = dataNodesMapForAnchor.get(dataNode.getAnchorName());
@@ -130,10 +134,11 @@ public class QueryRestController implements CpsQueryApi {
         final Collection<DataNode> dataNodes =
             cpsQueryService.queryDataNodes(dataspaceName, anchorName, cpsPath, fetchDescendantsOption);
         final List<Map<String, Object>> dataNodesAsListOfMaps = new ArrayList<>(dataNodes.size());
+        final Anchor anchor = cpsAnchorService.getAnchor(dataspaceName, anchorName);
         String prefix = null;
         for (final DataNode dataNode : dataNodes) {
             if (prefix == null) {
-                prefix = prefixResolver.getPrefix(dataspaceName, anchorName, dataNode.getXpath());
+                prefix = prefixResolver.getPrefix(anchor, dataNode.getXpath());
             }
             final Map<String, Object> dataMap = DataMapUtils.toDataMapWithIdentifier(dataNode, prefix);
             dataNodesAsListOfMaps.add(dataMap);