Draft at proposal where the DataNodeBuilder 'replaces' yang Utils to buidl a DataNode

Most complexity is related to immutable collections and the fact taht we are adding data while recursing
over the orignal data in an uncontrolled order.

I cleaned it up as best I could with no logic in DataNode.
Espcially the handling of LitLeaves requires some specialed handling. Thsi is just a draft solution for that
I still propose we get back to that in dedicated user stories for handling the various types of Yang elements

Hope this helps...

Issue-ID: CPS-137

Signed-off-by: ToineSiebelink <toine.siebelink@est.tech>
Change-Id: Iab7cfcff67412c01bcdab95e707e1350bf60fab1

4 files changed, 206 insertions, 258 deletions

diff --git a/cps-service/src/main/java/org/onap/cps/api/impl/Fragment.java b/cps-service/src/main/java/org/onap/cps/api/impl/Fragment.java
deleted file mode 100644
index 0f785b718f..0000000000
--- a/cps-service/src/main/java/org/onap/cps/api/impl/Fragment.java
+++ /dev/null
@@ -1,162 +0,0 @@
-/*
- * ============LICENSE_START=======================================================
- *  Copyright (C) 2020 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.api.impl;
-
-import com.google.common.collect.ImmutableList;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
-import java.util.Set;
-import lombok.Getter;
-import org.opendaylight.yangtools.yang.common.QName;
-import org.opendaylight.yangtools.yang.model.api.DataSchemaNode;
-import org.opendaylight.yangtools.yang.model.api.Module;
-
-/**
- * Class to store a Yang Fragment (container or list element).
- */
-public class Fragment {
-
-    @Getter
-    private final String xpath;
-
-    @Getter
-    private final Map<String, Object> attributes = new HashMap<>();
-
-    @Getter
-    private final Module module;
-
-    @Getter
-    private final Fragment parentFragment;
-
-    @Getter
-    private final Set<Fragment> childFragments = new HashSet<>(0);
-
-    private final QName[] qnames;
-
-    private Optional<Set<String>> optionalLeafListNames = Optional.empty();
-
-    /**
-     * Create a root Fragment.
-     *
-     * @param module the Yang module that encompasses this fragment
-     * @param qnames the list of qualified names that points the schema node for this fragment
-     * @param xpath  the xpath of root fragment
-     */
-    public static Fragment createRootFragment(final Module module, final QName[] qnames, final String xpath) {
-        return new Fragment(null, module, qnames, xpath);
-    }
-
-    /**
-     * Create a Child Fragment under a given Parent Fragment.
-     *
-     * @param parentFragment the parent (can be null for 'root' objects)
-     * @param module         the Yang module that encompasses this fragment
-     * @param qnames         array of qualified names that points the schema node for this fragment
-     * @param xpath          the xpath for this fragment
-     */
-    private Fragment(final Fragment parentFragment, final Module module, final QName[] qnames, final String xpath) {
-        this.parentFragment = parentFragment;
-        this.module = module;
-        this.qnames = qnames;
-        this.xpath = xpath;
-    }
-
-    /**
-     * Create a Child Fragment where the current Fragment is the parent.
-     *
-     * @param childQname The Qualified name for the child (relative to the parent)
-     * @param childXPath The child xpath (relative to the parrent)
-     * @return the child fragment
-     */
-    public Fragment createChildFragment(final QName childQname, final String childXPath) {
-        final QName[] qnamesForChild = Arrays.copyOf(qnames, qnames.length + 1);
-        qnamesForChild[qnamesForChild.length - 1] = childQname;
-        final Fragment childFragment = new Fragment(this, module, qnamesForChild, getXpath() + childXPath);
-        childFragments.add(childFragment);
-        return childFragment;
-    }
-
-    /**
-     * Define a leaf list by providing its name.
-     * The list is not instantiated until the first value is provided
-     *
-     * @param name the name of the leaf list
-     */
-    public void addLeafListName(final String name) {
-        if (optionalLeafListNames.isEmpty()) {
-            optionalLeafListNames = Optional.of(new HashSet<>());
-        }
-        optionalLeafListNames.get().add(name);
-    }
-
-    /**
-     * Add a leaf or leaf list value.
-     * For Leaf lists it is essential to first define the attribute is a leaf list by using addLeafListName method
-     *
-     * @param name  the name of the leaf (or leaf list)
-     * @param value the value of the leaf (or element of leaf list)
-     */
-    public void addLeafValue(final String name, final Object value) {
-        if (optionalLeafListNames.isPresent() && optionalLeafListNames.get().contains(name)) {
-            addLeafListValue(name, value);
-        } else {
-            attributes.put(name, value);
-        }
-    }
-
-    private void addLeafListValue(final String name, final Object value) {
-        if (attributes.containsKey(name)) {
-            final ImmutableList<Object> oldList = (ImmutableList<Object>) attributes.get(name);
-            final List<Object> newList = new ArrayList<>(oldList);
-            newList.add(value);
-            attributes.put(name, ImmutableList.copyOf(newList));
-        } else {
-            attributes.put(name, ImmutableList.of(value));
-        }
-    }
-
-    /**
-     * Get the SchemaNodeIdentifier for this fragment.
-     *
-     * @return the SchemaNodeIdentifier
-     */
-    public String getSchemaNodeIdentifier() {
-        final StringBuilder stringBuilder = new StringBuilder();
-        for (final QName qname : qnames) {
-            stringBuilder.append(qname.getLocalName());
-            stringBuilder.append('/');
-        }
-        return stringBuilder.toString();
-    }
-
-    /**
-     * Get the Optional SchemaNode (model) for this data fragment.
-     *
-     * @return the Optional SchemaNode
-     */
-    public Optional<DataSchemaNode> getSchemaNode() {
-        return module.findDataTreeChild(qnames);
-    }
-}
diff --git a/cps-service/src/main/java/org/onap/cps/spi/model/DataNode.java b/cps-service/src/main/java/org/onap/cps/spi/model/DataNode.java
index e9c6b56ea5..721a7c0426 100644
--- a/cps-service/src/main/java/org/onap/cps/spi/model/DataNode.java
+++ b/cps-service/src/main/java/org/onap/cps/spi/model/DataNode.java
@@ -1,6 +1,7 @@
 /*-
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2020 Nordix Foundation. All rights reserved.
+ *  Modifications Copyright (C) 2021 Bell Canada. All rights reserved.
  * ================================================================================
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,24 +22,27 @@
 package org.onap.cps.spi.model;
 
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Map;
-import lombok.AllArgsConstructor;
-import lombok.Builder;
-import lombok.Data;
-import lombok.NoArgsConstructor;
+import java.util.Optional;
+import java.util.Set;
+import lombok.AccessLevel;
+import lombok.Getter;
+import lombok.Setter;
 
-@Data
-@Builder
-@NoArgsConstructor
-@AllArgsConstructor
+@Setter(AccessLevel.PROTECTED)
+@Getter
 public class DataNode {
 
+    DataNode() {    }
+
     private String dataspace;
     private String schemaSetName;
     private String anchorName;
     private ModuleReference moduleReference;
     private String xpath;
-    private Map<String, Object> leaves;
+    private Map<String, Object> leaves = Collections.emptyMap();
     private Collection<String> xpathsChildren;
-    private Collection<DataNode> childDataNodes;
+    private Collection<DataNode> childDataNodes = Collections.emptySet();
+    private Optional<Set<String>> optionalLeafListNames = Optional.empty();
 }
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
new file mode 100644
index 0000000000..cd6a3a2201
--- /dev/null
+++ b/cps-service/src/main/java/org/onap/cps/spi/model/DataNodeBuilder.java
@@ -0,0 +1,176 @@
+/*
+ * ============LICENSE_START=======================================================
+ *  Copyright (C) 2021 Bell Canada. All rights reserved.
+ *  ================================================================================
+ *  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.model;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import lombok.extern.slf4j.Slf4j;
+import org.onap.cps.utils.YangUtils;
+import org.opendaylight.yangtools.yang.data.api.schema.DataContainerNode;
+import org.opendaylight.yangtools.yang.data.api.schema.LeafSetNode;
+import org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode;
+import org.opendaylight.yangtools.yang.data.api.schema.MapNode;
+import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
+import org.opendaylight.yangtools.yang.data.api.schema.ValueNode;
+
+@Slf4j
+public class DataNodeBuilder {
+
+    private NormalizedNode normalizedNodeTree;
+    private String xpath;
+    private Collection<DataNode> childDataNodes = Collections.emptySet();
+
+
+    /** To use {@link NormalizedNode} for creating {@link DataNode}.
+     *
+     * @param normalizedNodeTree used for creating the Data Node
+     *
+     * @return this {@link DataNodeBuilder} object
+     */
+    public DataNodeBuilder withNormalizedNodeTree(final NormalizedNode normalizedNodeTree) {
+        this.normalizedNodeTree = normalizedNodeTree;
+        return this;
+    }
+
+    /**
+     * To use xpath for creating {@link DataNode}.
+     * @param xpath for the data node
+     * @return DataNodeBuilder
+     */
+    public DataNodeBuilder withXpath(final String xpath) {
+        this.xpath = xpath;
+        return this;
+    }
+
+    /**
+     * To specify child nodes needs to be used while creating {@link DataNode}.
+     * @param childDataNodes to be added to the dataNode
+     * @return DataNodeBuilder
+     */
+    public DataNodeBuilder withChildDataNodes(final Collection<DataNode> childDataNodes) {
+        // Added as this is being set from test cases .
+        // Open for suggestions
+        this.childDataNodes = childDataNodes;
+        return this;
+    }
+
+    /**
+     * To create the {@link DataNode}.
+     *
+     * @return {@link DataNode}
+     */
+    public DataNode build() {
+        if (normalizedNodeTree != null) {
+            return buildFromNormalizedNodeTree();
+        } else {
+            return buildFromAttributes();
+        }
+    }
+
+    private DataNode buildFromAttributes() {
+        final DataNode dataNode = new DataNode();
+        dataNode.setXpath(xpath);
+        dataNode.setChildDataNodes(childDataNodes);
+        return dataNode;
+    }
+
+    private DataNode buildFromNormalizedNodeTree() {
+        xpath = YangUtils.buildXpath(normalizedNodeTree.getIdentifier());
+        final DataNode dataNode = new DataNodeBuilder().withXpath(xpath).build();
+        addDataNodeFromNormalizedNode(dataNode, normalizedNodeTree);
+        return dataNode;
+    }
+
+    private void addDataNodeFromNormalizedNode(final DataNode currentDataNode,
+        final NormalizedNode normalizedNode) {
+        if (normalizedNode instanceof DataContainerNode) {
+            addYangContainer(currentDataNode, (DataContainerNode) normalizedNode);
+        } else if (normalizedNode instanceof MapNode) {
+            addDataNodeForEachListElement(currentDataNode, (MapNode) normalizedNode);
+        } else if (normalizedNode instanceof ValueNode) {
+            final ValueNode valuesNode = (ValueNode) normalizedNode;
+            addYangLeaf(currentDataNode, valuesNode.getNodeType().getLocalName(), valuesNode.getValue());
+        } else if (normalizedNode instanceof LeafSetNode) {
+            addYangLeafList(currentDataNode, (LeafSetNode) normalizedNode);
+        } else {
+            log.warn("Cannot normalize {}", normalizedNode.getClass());
+        }
+    }
+
+    private void addYangContainer(final DataNode currentDataNode, final DataContainerNode dataContainerNode) {
+        final Collection<NormalizedNode> normalizedChildNodes = dataContainerNode.getValue();
+        for (final NormalizedNode normalizedNode : normalizedChildNodes) {
+            addDataNodeFromNormalizedNode(currentDataNode, normalizedNode);
+        }
+    }
+
+    private void addYangLeaf(final DataNode currentDataNode, final String leafName, final Object leafValue) {
+        final Map leaves = new ImmutableMap.Builder<String, Object>()
+            .putAll(currentDataNode.getLeaves())
+            .put(leafName, leafValue)
+            .build();
+        currentDataNode.setLeaves(leaves);
+    }
+
+    private void addYangLeafList(final DataNode currentDataNode, final LeafSetNode leafSetNode) {
+        final ImmutableSet.Builder builder = new ImmutableSet.Builder<String>();
+        final String leafListName = leafSetNode.getNodeType().getLocalName();
+        final Optional<Set<String>> optionalLeafListNames = currentDataNode.getOptionalLeafListNames();
+        if (optionalLeafListNames.isPresent()) {
+            builder.addAll(optionalLeafListNames.get());
+        }
+        builder.add(leafListName);
+        final ImmutableSet leafListNames = builder.build();
+        currentDataNode.setOptionalLeafListNames(Optional.of(leafListNames));
+        final List leafListValues = new LinkedList();
+        for (final NormalizedNode normalizedNode : (Collection<NormalizedNode>) leafSetNode.getValue()) {
+            leafListValues.add(((ValueNode) normalizedNode).getValue());
+        }
+        addYangLeaf(currentDataNode, leafListName, leafListValues);
+    }
+
+    private void addDataNodeForEachListElement(final DataNode currentDataNode, final MapNode mapNode) {
+        final Collection<MapEntryNode> mapEntryNodes = mapNode.getValue();
+        for (final MapEntryNode mapEntryNode : mapEntryNodes) {
+            final String xpathChild = YangUtils.buildXpath(mapEntryNode.getIdentifier());
+            final DataNode childDataNode = createAndAddChildDataNode(currentDataNode, xpathChild);
+            addDataNodeFromNormalizedNode(childDataNode, mapEntryNode);
+        }
+    }
+
+    private DataNode createAndAddChildDataNode(final DataNode parentDataNode, final String childXpath) {
+        final DataNode newChildDataNode = new DataNodeBuilder().withXpath(xpath + childXpath)
+            .build();
+        final Set<DataNode> allChildDataNodes = new ImmutableSet.Builder<DataNode>()
+            .addAll(parentDataNode.getChildDataNodes())
+            .add(newChildDataNode)
+            .build();
+        parentDataNode.setChildDataNodes(allChildDataNodes);
+        return newChildDataNode;
+    }
+
+}
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 8077ed7d88..1244d54afb 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
@@ -1,6 +1,7 @@
 /*
  * ============LICENSE_START=======================================================
  *  Copyright (C) 2020 Nordix Foundation
+ *  Modifications Copyright (C) 2021 Bell Canada. All rights reserved.
  *  ================================================================================
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -22,35 +23,26 @@ package org.onap.cps.utils;
 import com.google.gson.stream.JsonReader;
 import java.io.IOException;
 import java.io.StringReader;
-import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.stream.Collectors;
 import lombok.extern.slf4j.Slf4j;
-import org.onap.cps.api.impl.Fragment;
-import org.opendaylight.yangtools.yang.common.QName;
 import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier;
-import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier.NodeIdentifierWithPredicates;
-import org.opendaylight.yangtools.yang.data.api.schema.DataContainerNode;
-import org.opendaylight.yangtools.yang.data.api.schema.LeafSetNode;
-import org.opendaylight.yangtools.yang.data.api.schema.MapEntryNode;
-import org.opendaylight.yangtools.yang.data.api.schema.MapNode;
 import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode;
-import org.opendaylight.yangtools.yang.data.api.schema.ValueNode;
 import org.opendaylight.yangtools.yang.data.api.schema.stream.NormalizedNodeStreamWriter;
 import org.opendaylight.yangtools.yang.data.codec.gson.JSONCodecFactory;
 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.Module;
 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
 
 @Slf4j
 public class YangUtils {
 
+
     private YangUtils() {
-        throw new IllegalStateException("Utility class");
+        // Private constructor fo security reasons
     }
 
     /**
@@ -60,7 +52,7 @@ public class YangUtils {
      * @param schemaContext the SchemaContext for the given data
      * @return the NormalizedNode representing the json data
      */
-    public static NormalizedNode<?, ?> parseJsonData(final String jsonData, final SchemaContext schemaContext)
+    public static NormalizedNode parseJsonData(final String jsonData, final SchemaContext schemaContext)
             throws IOException {
         final JSONCodecFactory jsonCodecFactory = JSONCodecFactorySupplier.DRAFT_LHOTKA_NETMOD_YANG_JSON_02
                 .getShared(schemaContext);
@@ -76,85 +68,23 @@ public class YangUtils {
     }
 
     /**
-     * Break a Normalized Node tree into fragments that can be stored by the persistence service.
-     *
-     * @param tree   the normalized node tree
-     * @param module the module applicable for the data in the normalized node
-     * @return the 'root' Fragment for the tree contain all relevant children etc.
+     * Create an xpath form a Yang Tools NodeIdentifier (i.e. PathArgument).
+     * @param nodeIdentifier the NodeIdentifier
+     * @return an xpath
      */
-    public static Fragment fragmentNormalizedNode(
-            final NormalizedNode<? extends YangInstanceIdentifier.PathArgument, ?> tree,
-            final Module module) {
-        final QName[] nodeTypes = {tree.getNodeType()};
-        final String xpath = buildXpathId(tree.getIdentifier());
-        final Fragment rootFragment = Fragment.createRootFragment(module, nodeTypes, xpath);
-        fragmentNormalizedNode(rootFragment, tree);
-        return rootFragment;
-    }
-
-    private static void fragmentNormalizedNode(final Fragment currentFragment,
-                                               final NormalizedNode normalizedNode) {
-        if (normalizedNode instanceof DataContainerNode) {
-            inspectContainer(currentFragment, (DataContainerNode) normalizedNode);
-        } else if (normalizedNode instanceof MapNode) {
-            inspectKeyedList(currentFragment, (MapNode) normalizedNode);
-        } else if (normalizedNode instanceof ValueNode) {
-            inspectLeaf(currentFragment, (ValueNode) normalizedNode);
-        } else if (normalizedNode instanceof LeafSetNode) {
-            inspectLeafList(currentFragment, (LeafSetNode) normalizedNode);
-        } else {
-            log.warn("Cannot normalize {}", normalizedNode.getClass());
-        }
-    }
-
-    private static void inspectLeaf(final Fragment currentFragment,
-                                    final ValueNode valueNode) {
-        final Object value = valueNode.getValue();
-        currentFragment.addLeafValue(valueNode.getNodeType().getLocalName(), value);
-    }
-
-    private static void inspectLeafList(final Fragment currentFragment,
-                                        final LeafSetNode leafSetNode) {
-        currentFragment.addLeafListName(leafSetNode.getNodeType().getLocalName());
-        for (final NormalizedNode value : (Collection<NormalizedNode>) leafSetNode.getValue()) {
-            fragmentNormalizedNode(currentFragment, value);
-        }
-    }
-
-    private static void inspectContainer(final Fragment currentFragment,
-                                         final DataContainerNode dataContainerNode) {
-        final Collection<NormalizedNode> leaves = (Collection) dataContainerNode.getValue();
-        for (final NormalizedNode leaf : leaves) {
-            fragmentNormalizedNode(currentFragment, leaf);
-        }
-    }
-
-    private static void inspectKeyedList(final Fragment currentFragment,
-                                         final MapNode mapNode) {
-        createNodeForEachListElement(currentFragment, mapNode);
-    }
-
-    private static void createNodeForEachListElement(final Fragment currentFragment, final MapNode mapNode) {
-        final Collection<MapEntryNode> mapEntryNodes = mapNode.getValue();
-        for (final MapEntryNode mapEntryNode : mapEntryNodes) {
-            final String xpathId = buildXpathId(mapEntryNode.getIdentifier());
-            final Fragment listElementFragment =
-                currentFragment.createChildFragment(mapNode.getNodeType(), xpathId);
-            fragmentNormalizedNode(listElementFragment, mapEntryNode);
-        }
-    }
-
-    private static String buildXpathId(final YangInstanceIdentifier.PathArgument nodeIdentifier) {
-        final StringBuilder xpathIdBuilder = new StringBuilder();
-        xpathIdBuilder.append("/").append(nodeIdentifier.getNodeType().getLocalName());
+    public static String buildXpath(final YangInstanceIdentifier.PathArgument nodeIdentifier) {
+        final StringBuilder xpathBuilder = new StringBuilder();
+        xpathBuilder.append("/").append(nodeIdentifier.getNodeType().getLocalName());
 
-        if (nodeIdentifier instanceof NodeIdentifierWithPredicates) {
-            xpathIdBuilder.append(getKeyAttributesStatement((NodeIdentifierWithPredicates) nodeIdentifier));
+        if (nodeIdentifier instanceof YangInstanceIdentifier.NodeIdentifierWithPredicates) {
+            xpathBuilder.append(getKeyAttributesStatement(
+                    (YangInstanceIdentifier.NodeIdentifierWithPredicates) nodeIdentifier));
         }
-        return xpathIdBuilder.toString();
+        return xpathBuilder.toString();
     }
 
-    private static String getKeyAttributesStatement(final NodeIdentifierWithPredicates nodeIdentifier) {
+    private static String getKeyAttributesStatement(
+            final YangInstanceIdentifier.NodeIdentifierWithPredicates nodeIdentifier) {
         final List<String> keyAttributes = nodeIdentifier.entrySet().stream().map(
             entry -> {
                 final String name = entry.getKey().getLocalName();