[ONOS-4691] Refactoring OpticalPortOperator (2/3)

- Define ConfigOperator for a Port
- Refactor OpticalPortOperator as PortConfigOperator
- Add plug-in mechanism for PortConfigOperator on DeviceManager
- Move OpticalPortConfig, OpticalPortOperator to optical-model bundle

Change-Id: I5d416305b0c1b0e31e0ad64baa92d126303548bc
diff --git a/core/api/src/main/java/org/onosproject/net/config/PortConfigOperatorRegistry.java b/core/api/src/main/java/org/onosproject/net/config/PortConfigOperatorRegistry.java
new file mode 100644
index 0000000..dce315c
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/config/PortConfigOperatorRegistry.java
@@ -0,0 +1,44 @@
+/*
+ * 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.net.config;
+
+import org.onosproject.net.ConnectPoint;
+
+import com.google.common.annotations.Beta;
+
+/**
+ * Abstraction of a port operator registry.
+ */
+@Beta
+public interface PortConfigOperatorRegistry {
+
+    /**
+     * Registers {@link PortConfigOperator} instance.
+     *
+     * @param portOp {@link PortConfigOperator} instance.
+     * @param configs {@link Config} class for a Port referred by {@code portOp}
+     */
+    void registerPortConfigOperator(PortConfigOperator portOp,
+                                    Class<? extends Config<ConnectPoint>>... configs);
+
+    /**
+     * Unregisters {@link PortConfigOperator} instance.
+     *
+     * @param portOp {@link PortConfigOperator} instance.
+     */
+    void unregisterPortConfigOperator(PortConfigOperator portOp);
+
+}