[ONOS-3120] Service Function Forwarder interface.

Change-Id: I8c81a5869e6fdef10e1933fa0327b994b0bd5c7b

+/*
+ * Copyright 2015 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.sfc.forwarder;
+
+import org.onosproject.core.ApplicationId;
+import org.onosproject.net.flowobjective.Objective;
+import org.onosproject.vtnrsc.PortChain;
+
+/**
+ * Abstraction of an entity which provides Service function forwarder.
+ */
+public interface ServiceFunctionForwarder {
+
+    /**
+     * Install Service function chain.
+     *
+     * @param portChain Port chain
+     */
+    void install(PortChain portChain);
+
+    /**
+     * Programs forwarding object for Service Function.
+     *
+     * @param portChain port chain
+     * @param appid application id
+     * @param type forwarding objective operation type
+     */
+    void programServiceFunctionForwarder(PortChain portChain, ApplicationId appid,
+            Objective.Operation type);
+}