PCEP Protocol code restructured to move under PCEP Server code for more readability. Later Client code can be added under client folder.

Change-Id: Ie79599a170d94d8e0a00e0d034b083b3894199ee
diff --git a/protocols/pcep/server/api/src/main/java/org/onosproject/pcep/server/PcepClientListener.java b/protocols/pcep/server/api/src/main/java/org/onosproject/pcep/server/PcepClientListener.java
new file mode 100644
index 0000000..5a0d5bc
--- /dev/null
+++ b/protocols/pcep/server/api/src/main/java/org/onosproject/pcep/server/PcepClientListener.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright 2015-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.pcep.server;
+
+/**
+ * Allows for providers interested in PCC client events to be notified.
+ */
+public interface PcepClientListener {
+
+    /**
+     * Notify that the PCC was connected.
+     *
+     * @param pccId the id of the client that connected
+     */
+    void clientConnected(PccId pccId);
+
+    /**
+     * Notify that the PCC was disconnected.
+     *
+     * @param pccId the id of the client that disconnected.
+     */
+    void clientDisconnected(PccId pccId);
+}