1 files changed, 108 insertions, 0 deletions
diff --git a/cps-service/src/main/java/org/onap/cps/api/impl/CpsDeltaServiceImpl.java b/cps-service/src/main/java/org/onap/cps/api/impl/CpsDeltaServiceImpl.java
new file mode 100644
index 000000000..683ddce3d
--- /dev/null
+++ b/cps-service/src/main/java/org/onap/cps/api/impl/CpsDeltaServiceImpl.java
@@ -0,0 +1,108 @@
+/*
+ *  ============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.api.impl;
+
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import lombok.NoArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.onap.cps.api.CpsDeltaService;
+import org.onap.cps.spi.model.DataNode;
+import org.onap.cps.spi.model.DeltaReport;
+import org.onap.cps.spi.model.DeltaReportBuilder;
+import org.springframework.stereotype.Service;
+
+@Slf4j
+@Service
+@NoArgsConstructor
+public class CpsDeltaServiceImpl implements CpsDeltaService {
+
+    @Override
+    public List<DeltaReport> getDeltaReports(final Collection<DataNode> sourceDataNodes,
+                                             final Collection<DataNode> targetDataNodes) {
+
+        final List<DeltaReport> deltaReport = new ArrayList<>();
+
+        final Map<String, DataNode> xpathToSourceDataNodes = convertToXPathToDataNodesMap(sourceDataNodes);
+        final Map<String, DataNode> xpathToTargetDataNodes = convertToXPathToDataNodesMap(targetDataNodes);
+
+        deltaReport.addAll(getRemovedDeltaReports(xpathToSourceDataNodes, xpathToTargetDataNodes));
+
+        deltaReport.addAll(getAddedDeltaReports(xpathToSourceDataNodes, xpathToTargetDataNodes));
+
+        return Collections.unmodifiableList(deltaReport);
+    }
+
+    private static Map<String, DataNode> convertToXPathToDataNodesMap(
+                                                                    final Collection<DataNode> dataNodes) {
+        final Map<String, DataNode> xpathToDataNode = new LinkedHashMap<>();
+        for (final DataNode dataNode : dataNodes) {
+            xpathToDataNode.put(dataNode.getXpath(), dataNode);
+            final Collection<DataNode> childDataNodes = dataNode.getChildDataNodes();
+            if (!childDataNodes.isEmpty()) {
+                xpathToDataNode.putAll(convertToXPathToDataNodesMap(childDataNodes));
+            }
+        }
+        return xpathToDataNode;
+    }
+
+    private static List<DeltaReport> getRemovedDeltaReports(
+                                                            final Map<String, DataNode> xpathToSourceDataNodes,
+                                                            final Map<String, DataNode> xpathToTargetDataNodes) {
+
+        final List<DeltaReport> removedDeltaReportEntries = new ArrayList<>();
+        for (final Map.Entry<String, DataNode> entry: xpathToSourceDataNodes.entrySet()) {
+            final String xpath = entry.getKey();
+            final DataNode sourceDataNode = entry.getValue();
+            final DataNode targetDataNode = xpathToTargetDataNodes.get(xpath);
+
+            if (targetDataNode == null) {
+                final Map<String, Serializable> sourceDataNodeLeaves = sourceDataNode.getLeaves();
+                final DeltaReport removedData = new DeltaReportBuilder().actionRemove().withXpath(xpath)
+                        .withSourceData(sourceDataNodeLeaves).build();
+                removedDeltaReportEntries.add(removedData);
+            }
+        }
+        return removedDeltaReportEntries;
+    }
+
+    private static List<DeltaReport> getAddedDeltaReports(final Map<String, DataNode> xpathToSourceDataNodes,
+                                                          final Map<String, DataNode> xpathToTargetDataNodes) {
+
+        final List<DeltaReport> addedDeltaReportEntries = new ArrayList<>();
+        final Map<String, DataNode> xpathToAddedNodes = new LinkedHashMap<>(xpathToTargetDataNodes);
+        xpathToAddedNodes.keySet().removeAll(xpathToSourceDataNodes.keySet());
+        for (final Map.Entry<String, DataNode> entry: xpathToAddedNodes.entrySet()) {
+            final String xpath = entry.getKey();
+            final DataNode dataNode = entry.getValue();
+            final DeltaReport addedDataForDeltaReport = new DeltaReportBuilder().actionAdd().withXpath(xpath)
+                                .withTargetData(dataNode.getLeaves()).build();
+            addedDeltaReportEntries.add(addedDataForDeltaReport);
+        }
+        return addedDeltaReportEntries;
+    }
+}