diff --git a/apps/workflow/api/src/main/java/org/onosproject/workflow/api/JsonDataModelTree.java b/apps/workflow/api/src/main/java/org/onosproject/workflow/api/JsonDataModelTree.java
new file mode 100644
index 0000000..3a74bd2
--- /dev/null
+++ b/apps/workflow/api/src/main/java/org/onosproject/workflow/api/JsonDataModelTree.java
@@ -0,0 +1,319 @@
+/*
+ * Copyright 2018-present Open Networking 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.
+ */
+package org.onosproject.workflow.api;
+
+
+import com.fasterxml.jackson.core.JsonPointer;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.JsonNode;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.JsonNodeFactory;
+import com.fasterxml.jackson.databind.node.JsonNodeType;
+import com.fasterxml.jackson.databind.node.MissingNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.google.common.base.MoreObjects;
+
+import java.util.Objects;
+
+/**
+ * Class for json data model tree.
+ */
+public final class JsonDataModelTree implements DataModelTree {
+
+    /**
+     * Root node of json data model tree.
+     */
+    private JsonNode root;
+
+    /**
+     * Constructor of JsonDataModelTree.
+     */
+    public JsonDataModelTree() {
+        this.root = JsonNodeFactory.instance.objectNode();
+    }
+
+    /**
+     * Constructor of JsonDataModelTree.
+     * @param root root node of json data model tree
+     */
+    public JsonDataModelTree(JsonNode root) {
+        this.root = root;
+    }
+
+    @Override
+    public DataModelTree subtree(String path) {
+        JsonNode node = root.at(path);
+        if (Objects.isNull(node) || node.isMissingNode()) {
+            return null;
+        }
+        return new JsonDataModelTree(node);
+    }
+
+    @Override
+    public void attach(String path, DataModelTree tree) throws WorkflowException {
+        if (root == null || root instanceof MissingNode) {
+            throw new WorkflowException("Invalid root node");
+        }
+
+        JsonPointer ptr = JsonPointer.compile(path);
+        JsonNode node = root.at(ptr);
+        if (!(node instanceof MissingNode)) {
+            throw new WorkflowException("Path(" + path + ") has already subtree(" + node + ")");
+        }
+
+        if (!(tree instanceof JsonDataModelTree)) {
+            throw new WorkflowException("Invalid subTree(" + tree + ")");
+        }
+        JsonNode attachingNode = ((JsonDataModelTree) tree).root();
+
+        alloc(ptr.head(), Nodetype.MAP);
+        JsonNode parentNode = root.at(ptr.head());
+
+        if (!parentNode.isObject()) {
+            throw new WorkflowException("Invalid parentNode type(" + parentNode.getNodeType() + ")");
+        }
+
+        String key = ptr.last().getMatchingProperty();
+        ((ObjectNode) parentNode).put(key, attachingNode);
+    }
+
+    @Override
+    public JsonDataModelTree alloc(String path, Nodetype leaftype) throws WorkflowException {
+        if (root == null || root instanceof MissingNode) {
+            throw new WorkflowException("Invalid root node");
+        }
+
+        JsonPointer ptr = JsonPointer.compile(path);
+        return alloc(ptr, leaftype);
+    }
+
+    /**
+     * Allocates json data model tree on json pointer path with specific leaf type.
+     * @param ptr json pointer to allocate
+     * @param leaftype type of leaf node
+     * @return json data model tree
+     * @throws WorkflowException workflow exception
+     */
+    private JsonDataModelTree alloc(JsonPointer ptr, Nodetype leaftype) throws WorkflowException {
+        if (root == null || root instanceof MissingNode) {
+            throw new WorkflowException("Invalid root node");
+        }
+
+        switch (leaftype) {
+            case MAP:
+                alloc(root, ptr, JsonNodeType.OBJECT);
+                break;
+            case ARRAY:
+                alloc(root, ptr, JsonNodeType.ARRAY);
+                break;
+            default:
+                throw new WorkflowException("Not supported leaftype(" + leaftype + ")");
+        }
+        return this;
+    }
+
+    /**
+     * Gets root json node.
+     * @return root json node
+     * @throws WorkflowException workflow exception
+     */
+    public JsonNode root() throws WorkflowException {
+        return nodeAt("");
+    }
+
+    /**
+     * Gets root json node as ObjectNode (MAP type).
+     * @return root json node as ObjectNode
+     * @throws WorkflowException workflow exception
+     */
+    public ObjectNode rootObject() throws WorkflowException {
+        return objectAt("");
+    }
+
+    /**
+     * Gets root json node as ArrayNode (Array type).
+     * @return root json node as ArrayNode
+     * @throws WorkflowException workflow exception
+     */
+    public ArrayNode rootArray() throws WorkflowException {
+        return arrayAt("");
+    }
+
+    /**
+     * Gets json node on specific path.
+     * @param path path of json node
+     * @return json node on specific path
+     * @throws WorkflowException workflow exception
+     */
+    public JsonNode nodeAt(String path) throws WorkflowException {
+        JsonPointer ptr = JsonPointer.compile(path);
+        return nodeAt(ptr);
+    }
+
+    /**
+     * Gets json node on specific json pointer.
+     * @param ptr json pointer
+     * @return json node on specific json pointer.
+     * @throws WorkflowException workflow exception
+     */
+    public JsonNode nodeAt(JsonPointer ptr) throws WorkflowException {
+        if (root == null || root instanceof MissingNode) {
+            throw new WorkflowException("Invalid root node");
+        }
+        JsonNode node = root.at(ptr);
+        return node;
+    }
+
+    /**
+     * Gets json node on specific path as ObjectNode.
+     * @param path path of json node
+     * @return ObjectNode type json node on specific path
+     * @throws WorkflowException workflow exception
+     */
+    public ObjectNode objectAt(String path) throws WorkflowException {
+        JsonPointer ptr = JsonPointer.compile(path);
+        return objectAt(ptr);
+    }
+
+    /**
+     * Gets json node on specific json pointer as ObjectNode.
+     * @param ptr json pointer
+     * @return ObjectNode type json node on specific json pointer.
+     * @throws WorkflowException workflow exception
+     */
+    public ObjectNode objectAt(JsonPointer ptr) throws WorkflowException {
+        if (root == null || root instanceof MissingNode) {
+            throw new WorkflowException("Invalid root node");
+        }
+        JsonNode node = root.at(ptr);
+        if (!(node instanceof ObjectNode)) {
+            throw new WorkflowException("Invalid node(" + node + ") at " + ptr);
+        }
+        return (ObjectNode) node;
+    }
+
+    /**
+     * Gets json node on specific path as ArrayNode.
+     * @param path path of json node
+     * @return ArrayNode type json node on specific path
+     * @throws WorkflowException workflow exception
+     */
+    public ArrayNode arrayAt(String path) throws WorkflowException {
+        JsonPointer ptr = JsonPointer.compile(path);
+        return arrayAt(ptr);
+    }
+
+    /**
+     * Gets json node on specific json pointer as ArrayNode.
+     * @param ptr json pointer
+     * @return ArrayNode type json node on specific json pointer.
+     * @throws WorkflowException workflow exception
+     */
+    public ArrayNode arrayAt(JsonPointer ptr) throws WorkflowException {
+        if (root == null || root instanceof MissingNode) {
+            throw new WorkflowException("Invalid root node");
+        }
+        JsonNode node = root.at(ptr);
+        if (!(node instanceof ArrayNode)) {
+            throw new WorkflowException("Invalid node(" + node + ") at " + ptr);
+        }
+        return (ArrayNode) node;
+    }
+
+    /**
+     * Allocates json data model tree on json pointer path with specific leaf type.
+     * @param node current json node in the json tree path
+     * @param ptr json pointer
+     * @param leaftype leaf type to be allocated
+     * @return allocated json node
+     * @throws WorkflowException workflow exception
+     */
+    private JsonNode alloc(JsonNode node, JsonPointer ptr, JsonNodeType leaftype) throws WorkflowException {
+
+        if (ptr.matches()) {
+            if (node instanceof MissingNode) {
+                node = createEmpty(leaftype);
+            } else {
+                //TODO: checking existing node type is matched with leaftype
+                if (Objects.equals(node.getNodeType(), leaftype)) {
+                    throw new WorkflowException("Requesting leaftype(" + leaftype + ") is not matched with "
+                            + "existing nodetype(" + node.getNodeType() + ") for " + ptr);
+                }
+            }
+            return node;
+        }
+
+        if (ptr.getMatchingIndex() != -1) {
+            if (node instanceof MissingNode) {
+                node = createEmpty(JsonNodeType.ARRAY);
+            }
+            JsonNode child = alloc(node.get(ptr.getMatchingIndex()), ptr.tail(), leaftype);
+            if (!node.has(ptr.getMatchingIndex())) {
+                ((ArrayNode) node).insert(ptr.getMatchingIndex(), child);
+            }
+        } else if (ptr.getMatchingProperty() != null) {
+            if (node instanceof MissingNode) {
+                node = createEmpty(JsonNodeType.OBJECT);
+            }
+            JsonNode child = alloc(node.get(ptr.getMatchingProperty()), ptr.tail(), leaftype);
+            if (!node.has(ptr.getMatchingProperty())) {
+                ((ObjectNode) node).put(ptr.getMatchingProperty(), child);
+            }
+        }
+        return node;
+    }
+
+    /**
+     * Creating empty json node.
+     * @param type json node type to create
+     * @return created json node
+     * @throws WorkflowException workflow exception
+     */
+    private JsonNode createEmpty(JsonNodeType type) throws WorkflowException {
+        if (type == JsonNodeType.OBJECT) {
+            return JsonNodeFactory.instance.objectNode();
+        } else if (type == JsonNodeType.ARRAY) {
+            return JsonNodeFactory.instance.arrayNode();
+        } else if (type == JsonNodeType.STRING) {
+            return JsonNodeFactory.instance.textNode("");
+        } else {
+            throw new WorkflowException("Not supported JsonNodetype(" + type + ")");
+        }
+    }
+
+    /**
+     * Gets the pretty json formatted string of this json data model tree.
+     * @return pretty json formatted string of this json data model tree
+     */
+    public String formattedRootString() {
+        String str = "";
+        try {
+            str = (new ObjectMapper()).writerWithDefaultPrettyPrinter().writeValueAsString(root);
+        } catch (JsonProcessingException e) {
+            e.printStackTrace();
+        }
+        return str;
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(getClass())
+                .add("json", formattedRootString())
+                .toString();
+    }
+}
+