TE Topoplogy subsystem I2RS API changes

This submission contains the following:

1. Major changes in apps/tetopology. The changes are mainly introduced
   to support new searching keys in TE Topology.

2. Add RESTCONF notification support in the TE Provider. i.e., for
   south-bound RESTCONF communication with the domain controller.

Change-Id: I6786959deb66c98626edc65ff52694dcf08981a3
diff --git a/apps/tetopology/api/src/main/java/org/onosproject/tetopology/management/api/node/NetworkNode.java b/apps/tetopology/api/src/main/java/org/onosproject/tetopology/management/api/node/NetworkNode.java
new file mode 100644
index 0000000..1f3c76b
--- /dev/null
+++ b/apps/tetopology/api/src/main/java/org/onosproject/tetopology/management/api/node/NetworkNode.java
@@ -0,0 +1,64 @@
+/*
+ * Copyright 2016 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.tetopology.management.api.node;
+
+import java.util.List;
+import java.util.Map;
+
+import org.onosproject.tetopology.management.api.KeyId;
+
+/**
+ * Abstraction of a network node.
+ */
+public interface NetworkNode {
+
+    /**
+     * Returns the node identifier.
+     *
+     * @return node identifier
+     */
+    KeyId nodeId();
+
+    /**
+     * Returns the supporting node identifiers.
+     *
+     * @return list of the ids of the supporting nodes
+     */
+    List<NetworkNodeKey> supportingNodeIds();
+
+    /**
+     * Returns the node TE extension attributes.
+     *
+     * @return node TE extension attributes
+     */
+    TeNode teNode();
+
+    /**
+     * Returns a collection of currently known termination points.
+     *
+     * @return a collection of termination points associated with this node
+     */
+    Map<KeyId, TerminationPoint> terminationPoints();
+
+    /**
+     * Returns the termination point.
+     *
+     * @param tpId termination point id
+     * @return value of termination point
+     */
+    TerminationPoint terminationPoint(KeyId tpId);
+
+}