ONOS-5863, ONOS-5804 DynamicConfig store and service implementation(create and read supported)

Change-Id: I299a27afe46b87f98d4af79643732e2f1bdc2010
diff --git a/apps/config/src/main/java/org/onosproject/config/model/InnerNode.java b/apps/config/src/main/java/org/onosproject/config/model/InnerNode.java
new file mode 100644
index 0000000..2a0dfee
--- /dev/null
+++ b/apps/config/src/main/java/org/onosproject/config/model/InnerNode.java
@@ -0,0 +1,190 @@
+/*
+ * Copyright 2016-present Open Networking Laboratory
+ *
+ * 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.
+ */
+package org.onosproject.config.model;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import static org.onosproject.config.model.ModelConstants.LEAF_IS_TERMINAL;
+
+/**
+ * Abstraction of an entity which represents an inner node in data store.
+ */
+public final class InnerNode extends DataNode {
+
+    /**
+     * Map containing info of all child data nodes with respect to their node
+     * keys.
+     */
+    private Map<NodeKey, DataNode> childNodes = new LinkedHashMap<>();
+
+    /**
+     * Returns the children nodes to the current node.
+     * Children nodes are identified based on the node key.
+     *
+     * @return read only linked map of children nodes
+     */
+    public Map<NodeKey, DataNode> childNodes() {
+        return childNodes;
+    }
+
+    /**
+     * Creates an instance of inner node.
+     *
+     * @param builder inner node builder
+     */
+    public InnerNode(Builder builder) {
+        super(builder);
+        childNodes = builder.childNodes;
+    }
+
+    /**
+     * Returns inner node builder instance.
+     *
+     * @param name      name of node
+     * @param nameSpace namespace of node
+     * @return inner node builder instance
+     */
+    public static Builder builder(String name, String nameSpace) {
+        return new Builder(name, nameSpace);
+    }
+
+    /**
+     * Returns inner node copy builder.
+     *
+     * @return inner node copy builder
+     */
+    @Override
+    public Builder copyBuilder() {
+        return new Builder(this);
+    }
+
+    /**
+     * Builder with get and set functions to build inner node,
+     * builder will be used both to create inner node from scratch or from a
+     * given inner node.
+     */
+    public static class Builder extends DataNode.Builder<Builder> {
+
+        /**
+         * Map containing info of all child data nodes with respect to their
+         * node keys.
+         */
+        private Map<NodeKey, DataNode> childNodes = new LinkedHashMap<>();
+
+        public Builder() {
+        }
+        /**
+         * Creates an instance of data node builder.
+         *
+         * @param name      name of node
+         * @param namespace namespace of node
+         */
+        public Builder(String name, String namespace) {
+            keyBuilder = NodeKey.builder().schemaId(name, namespace);
+        }
+
+        /**
+         * Creates an instance of inner node builder.
+         *
+         * @param node old inner node
+         */
+        public Builder(InnerNode node) {
+            super(node);
+            childNodes = node.childNodes;
+        }
+
+        /**
+         * Adds node to the builder.
+         *
+         * @param node node to be added
+         * @return inner node builder
+         */
+        public Builder addNode(DataNode node) {
+            childNodes.put(node.key(), node);
+            return this;
+        }
+
+        /**
+         * Builds a inner node object.
+         *
+         * @return inner node
+         */
+        @Override
+        public InnerNode build() {
+            if (type == null) {
+                throw new IllegalStateException("node should have a type.");
+            }
+            if (key == null) {
+                key = keyBuilder.build();
+            }
+            return new InnerNode(this);
+        }
+
+        @Override
+        public InnerNode.Builder createChildBuilder(String name, String nameSpace) {
+            return InnerNode.builder(name, nameSpace)
+                    .parent(this);
+        }
+
+        @Override
+        public LeafNode.Builder createChildBuilder(String name, String nameSpace,
+                                                   Object value) {
+            return LeafNode.builder(name, nameSpace)
+                    .parent(this)
+                    .value(value);
+        }
+
+        @Override
+        public InnerNode.Builder deleteChild(NodeKey key) {
+            childNodes.remove(key);
+            return this;
+        }
+
+        @Override
+        public Builder getChildBuilder(NodeKey nodeKey) {
+            DataNode node = childNodes.get(nodeKey);
+            if (node == null) {
+                throw new IllegalArgumentException(
+                        "Invalid key: no child nodes found for given key: " +
+                                nodeKey);
+            }
+            return (Builder) node.copyBuilder().parent(this);
+        }
+
+        @Override
+        public Builder addKeyLeaf(String name, String nameSpace, Object val) {
+            ListKey.ListKeyBuilder listKeyBuilder;
+            if (!(keyBuilder instanceof ListKey.ListKeyBuilder)) {
+                if (keyBuilder instanceof LeafListKey.LeafListKeyBuilder) {
+                    throw new ModelException(LEAF_IS_TERMINAL);
+                }
+
+                listKeyBuilder = new ListKey.ListKeyBuilder(keyBuilder);
+            } else {
+                listKeyBuilder = (ListKey.ListKeyBuilder) keyBuilder;
+            }
+
+            listKeyBuilder.addKeyLeaf(name, nameSpace, val);
+            keyBuilder = listKeyBuilder;
+            return this;
+        }
+
+        @Override
+        public LeafNode.Builder addLeafListValue(Object val) {
+            throw new IllegalStateException("node is not of leaf list type.");
+        }
+    }
+}