Adding experimental Flow Objective composition

Change-Id: I35e4414845ad5034145157ab83f933e40f75a1d9
diff --git a/core/api/src/main/java/org/onosproject/net/flowobjective/FlowObjectiveService.java b/core/api/src/main/java/org/onosproject/net/flowobjective/FlowObjectiveService.java
index cb9a248..d325415 100644
--- a/core/api/src/main/java/org/onosproject/net/flowobjective/FlowObjectiveService.java
+++ b/core/api/src/main/java/org/onosproject/net/flowobjective/FlowObjectiveService.java
@@ -56,4 +56,10 @@
      */
     int allocateNextId();
 
+    /**
+     * Installs the filtering rules onto the specified device.
+     *
+     * @param policy            policy expression
+     */
+    void initPolicy(String policy);
 }