Data fragment update by xpath - parsing and validation

Issue-ID: CPS-58
Change-Id: I6363c39d7046afc3b20dcd1224d6399b043c4386
Signed-off-by: Ruslan Kashapov <ruslan.kashapov@pantheon.tech>

2 files changed, 107 insertions, 21 deletions

diff --git a/cps-service/src/main/java/org/onap/cps/spi/model/DataNodeBuilder.java b/cps-service/src/main/java/org/onap/cps/spi/model/DataNodeBuilder.java
index 67e93dd82b..ea0626c2b2 100644
--- a/cps-service/src/main/java/org/onap/cps/spi/model/DataNodeBuilder.java
+++ b/cps-service/src/main/java/org/onap/cps/spi/model/DataNodeBuilder.java
@@ -43,9 +43,21 @@ public class DataNodeBuilder {
 
     private NormalizedNode<?, ?> normalizedNodeTree;
     private String xpath;
+    private String parentNodeXpath = "";
     private Map<String, Object> leaves = Collections.emptyMap();
     private Collection<DataNode> childDataNodes = Collections.emptySet();
 
+    /**
+     * To use parent node xpath for creating {@link DataNode}.
+     *
+     * @param parentNodeXpath xpath of a parent node
+     * @return this {@link DataNodeBuilder} object
+     */
+    public DataNodeBuilder withParentNodeXpath(final String parentNodeXpath) {
+        this.parentNodeXpath = parentNodeXpath;
+        return this;
+    }
+
 
     /**
      * To use {@link NormalizedNode} for creating {@link DataNode}.
@@ -115,9 +127,9 @@ public class DataNodeBuilder {
     }
 
     private DataNode buildFromNormalizedNodeTree() {
-        final DataNode formalRootDataNode = new DataNodeBuilder().withXpath("").build();
-        addDataNodeFromNormalizedNode(formalRootDataNode, normalizedNodeTree);
-        return formalRootDataNode.getChildDataNodes().iterator().next();
+        final DataNode parentDataNode = new DataNodeBuilder().withXpath(parentNodeXpath).build();
+        addDataNodeFromNormalizedNode(parentDataNode, normalizedNodeTree);
+        return parentDataNode.getChildDataNodes().iterator().next();
     }
 
     private static void addDataNodeFromNormalizedNode(final DataNode currentDataNode,
diff --git a/cps-service/src/main/java/org/onap/cps/utils/YangUtils.java b/cps-service/src/main/java/org/onap/cps/utils/YangUtils.java
index 389b8967a9..733378ecba 100755..100644
--- a/cps-service/src/main/java/org/onap/cps/utils/YangUtils.java
+++ b/cps-service/src/main/java/org/onap/cps/utils/YangUtils.java
@@ -2,6 +2,7 @@
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2020 Nordix Foundation
  *  Modifications Copyright (C) 2021 Bell Canada. All rights reserved.
+ *  Modifications Copyright (C) 2021 Pantheon.tech
  *  ================================================================================
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -23,9 +24,14 @@ package org.onap.cps.utils;
 import com.google.gson.stream.JsonReader;
 import java.io.IOException;
 import java.io.StringReader;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.Optional;
 import java.util.stream.Collectors;
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.onap.cps.spi.exceptions.DataValidationException;
 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
@@ -36,36 +42,58 @@ import org.opendaylight.yangtools.yang.data.codec.gson.JSONCodecFactorySupplier;
 import org.opendaylight.yangtools.yang.data.codec.gson.JsonParserStream;
 import org.opendaylight.yangtools.yang.data.impl.schema.ImmutableNormalizedNodeStreamWriter;
 import org.opendaylight.yangtools.yang.data.impl.schema.NormalizedNodeResult;
+import org.opendaylight.yangtools.yang.model.api.DataNodeContainer;
+import org.opendaylight.yangtools.yang.model.api.DataSchemaNode;
 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
 
 @Slf4j
+@NoArgsConstructor(access = AccessLevel.PRIVATE)
 public class YangUtils {
 
+    private static final String XPATH_DELIMITER_REGEX = "\\/";
+    private static final String XPATH_NODE_KEY_ATTRIBUTES_REGEX = "\\[.+";
 
-    private YangUtils() {
-        // Private constructor fo security reasons
+    /**
+     * Parses jsonData into NormalizedNode according to given schema context.
+     *
+     * @param jsonData      json data as string
+     * @param schemaContext schema context describing associated data model
+     * @return the NormalizedNode object
+     */
+    public static NormalizedNode<?, ?> parseJsonData(final String jsonData, final SchemaContext schemaContext) {
+        return parseJsonData(jsonData, schemaContext, Optional.empty());
     }
 
     /**
-     * Parse a string containing json data for a certain model (schemaContext).
+     * Parses jsonData into NormalizedNode according to given schema context.
      *
-     * @param jsonData      a string containing json data for the given model
-     * @param schemaContext the SchemaContext for the given data
-     * @return the NormalizedNode representing the json data
+     * @param jsonData        json data fragment as string
+     * @param schemaContext   schema context describing associated data model
+     * @param parentNodeXpath the xpath referencing the parent node current data fragment belong to
+     * @return the NormalizedNode object
      */
-    public static NormalizedNode<?, ?> parseJsonData(final String jsonData, final SchemaContext schemaContext) {
+    public static NormalizedNode<?, ?> parseJsonData(final String jsonData, final SchemaContext schemaContext,
+        final String parentNodeXpath) {
+        final DataSchemaNode parentSchemaNode = getDataSchemaNodeByXpath(parentNodeXpath, schemaContext);
+        return parseJsonData(jsonData, schemaContext, Optional.of(parentSchemaNode));
+    }
+
+    private static NormalizedNode<?, ?> parseJsonData(final String jsonData, final SchemaContext schemaContext,
+        final Optional<DataSchemaNode> optionalParentSchemaNode) {
         final JSONCodecFactory jsonCodecFactory = JSONCodecFactorySupplier.DRAFT_LHOTKA_NETMOD_YANG_JSON_02
-                .getShared(schemaContext);
+            .getShared(schemaContext);
         final NormalizedNodeResult normalizedNodeResult = new NormalizedNodeResult();
         final NormalizedNodeStreamWriter normalizedNodeStreamWriter = ImmutableNormalizedNodeStreamWriter
-                .from(normalizedNodeResult);
-        try {
-            try (final JsonParserStream jsonParserStream = JsonParserStream
-                    .create(normalizedNodeStreamWriter, jsonCodecFactory)) {
-                final JsonReader jsonReader = new JsonReader(new StringReader(jsonData));
-                jsonParserStream.parse(jsonReader);
-            }
-        } catch (final IOException e) {
+            .from(normalizedNodeResult);
+
+        try (final JsonParserStream jsonParserStream = optionalParentSchemaNode.isPresent()
+            ? JsonParserStream.create(normalizedNodeStreamWriter, jsonCodecFactory, optionalParentSchemaNode.get())
+            : JsonParserStream.create(normalizedNodeStreamWriter, jsonCodecFactory)
+        ) {
+            final JsonReader jsonReader = new JsonReader(new StringReader(jsonData));
+            jsonParserStream.parse(jsonReader);
+
+        } catch (final IOException | IllegalStateException e) {
             throw new DataValidationException("Failed to parse json data.", String
                 .format("Exception occurred on parsing string %s.", jsonData), e);
         }
@@ -74,6 +102,7 @@ public class YangUtils {
 
     /**
      * Create an xpath form a Yang Tools NodeIdentifier (i.e. PathArgument).
+     *
      * @param nodeIdentifier the NodeIdentifier
      * @return an xpath
      */
@@ -83,13 +112,13 @@ public class YangUtils {
 
         if (nodeIdentifier instanceof YangInstanceIdentifier.NodeIdentifierWithPredicates) {
             xpathBuilder.append(getKeyAttributesStatement(
-                    (YangInstanceIdentifier.NodeIdentifierWithPredicates) nodeIdentifier));
+                (YangInstanceIdentifier.NodeIdentifierWithPredicates) nodeIdentifier));
         }
         return xpathBuilder.toString();
     }
 
     private static String getKeyAttributesStatement(
-            final YangInstanceIdentifier.NodeIdentifierWithPredicates nodeIdentifier) {
+        final YangInstanceIdentifier.NodeIdentifierWithPredicates nodeIdentifier) {
         final List<String> keyAttributes = nodeIdentifier.entrySet().stream().map(
             entry -> {
                 final String name = entry.getKey().getLocalName();
@@ -105,4 +134,49 @@ public class YangUtils {
             return "[" + String.join(" and ", keyAttributes) + "]";
         }
     }
+
+    private static DataSchemaNode getDataSchemaNodeByXpath(final String parentNodeXpath,
+        final SchemaContext schemaContext) {
+        final String[] xpathNodeIdSequence = xpathToNodeIdSequence(parentNodeXpath);
+        return findDataSchemaNodeByXpathNodeIdSequence(xpathNodeIdSequence, schemaContext.getChildNodes());
+    }
+
+    private static String[] xpathToNodeIdSequence(final String xpath) {
+        final String[] xpathNodeIdSequence = Arrays.stream(xpath.split(XPATH_DELIMITER_REGEX))
+            .map(identifier -> identifier.replaceFirst(XPATH_NODE_KEY_ATTRIBUTES_REGEX, ""))
+            .filter(identifier -> !identifier.isEmpty())
+            .toArray(String[]::new);
+        if (xpathNodeIdSequence.length < 1) {
+            throw new DataValidationException("Invalid xpath.", "Xpath contains no node identifiers.");
+        }
+        return xpathNodeIdSequence;
+    }
+
+    private static DataSchemaNode findDataSchemaNodeByXpathNodeIdSequence(final String[] xpathNodeIdSequence,
+        final Collection<? extends DataSchemaNode> dataSchemaNodes) {
+        final String currentXpathNodeId = xpathNodeIdSequence[0];
+        final DataSchemaNode currentDataSchemaNode = dataSchemaNodes.stream()
+            .filter(dataSchemaNode -> currentXpathNodeId.equals(dataSchemaNode.getQName().getLocalName()))
+            .findFirst().orElseThrow(() -> schemaNodeNotFoundException(currentXpathNodeId));
+        if (xpathNodeIdSequence.length <= 1) {
+            return currentDataSchemaNode;
+        }
+        if (currentDataSchemaNode instanceof DataNodeContainer) {
+            return findDataSchemaNodeByXpathNodeIdSequence(
+                getNextLevelXpathNodeIdSequence(xpathNodeIdSequence),
+                ((DataNodeContainer) currentDataSchemaNode).getChildNodes());
+        }
+        throw schemaNodeNotFoundException(xpathNodeIdSequence[1]);
+    }
+
+    private static String[] getNextLevelXpathNodeIdSequence(final String[] xpathNodeIdSequence) {
+        final String[] nextXpathNodeIdSequence = new String[xpathNodeIdSequence.length - 1];
+        System.arraycopy(xpathNodeIdSequence, 1, nextXpathNodeIdSequence, 0, nextXpathNodeIdSequence.length);
+        return nextXpathNodeIdSequence;
+    }
+
+    private static DataValidationException schemaNodeNotFoundException(final String schemaNodeIdentifier) {
+        return new DataValidationException("Invalid xpath.",
+            String.format("No schema node was found for xpath identifier '%s'.", schemaNodeIdentifier));
+    }
 }