'Static data model implementation in Worklet

Change-Id: Ic5eeb26eaea547523befd509f9f48281cb4c2031
diff --git a/apps/workflow/api/src/main/java/org/onosproject/workflow/api/StaticDataModel.java b/apps/workflow/api/src/main/java/org/onosproject/workflow/api/StaticDataModel.java
new file mode 100644
index 0000000..91e8382
--- /dev/null
+++ b/apps/workflow/api/src/main/java/org/onosproject/workflow/api/StaticDataModel.java
@@ -0,0 +1,45 @@
+/*
+ * Copyright 2019-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 java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Target(ElementType.FIELD)
+@Retention(RetentionPolicy.RUNTIME)
+
+/**
+ * Annotation for injecting static data model on work-let execution context.
+ */
+public @interface StaticDataModel {
+
+    /**
+     * Path of data model.
+     *
+     * @return path of data model
+     */
+    String path() default "/";
+
+    /**
+     * Representing whether this data model is optional or not.
+     *
+     * @return optional or not
+     */
+    boolean optional() default false;
+}