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/ProviderClientId.java b/apps/tetopology/api/src/main/java/org/onosproject/tetopology/management/api/ProviderClientId.java
new file mode 100644
index 0000000..04edd14
--- /dev/null
+++ b/apps/tetopology/api/src/main/java/org/onosproject/tetopology/management/api/ProviderClientId.java
@@ -0,0 +1,91 @@
+/*
+ * 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;
+
+import com.google.common.base.MoreObjects;
+import com.google.common.base.MoreObjects.ToStringHelper;
+import com.google.common.base.Objects;
+
+/**
+ * TE topology provider and client identifiers.
+ */
+public abstract class ProviderClientId {
+    private final long providerId;
+    private final long clientId;
+
+    /**
+     * Creates an instance of TE topology provider client identifier.
+     *
+     * @param providerId provider identifier
+     * @param clientId   client identifier
+     */
+    public ProviderClientId(long providerId, long clientId) {
+        this.providerId = providerId;
+        this.clientId = clientId;
+    }
+
+    /**
+     * Returns the provider identifier.
+     *
+     * @return provider identifier
+     */
+    public long providerId() {
+        return providerId;
+    }
+
+    /**
+     * Returns the client identifier.
+     *
+     * @return client identifier
+     */
+    public long clientId() {
+        return clientId;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(providerId, clientId);
+    }
+
+    @Override
+    public boolean equals(Object object) {
+        if (this == object) {
+            return true;
+        }
+        if (object instanceof ProviderClientId) {
+            ProviderClientId that = (ProviderClientId) object;
+            return Objects.equal(providerId, that.providerId) &&
+                    Objects.equal(clientId, that.clientId);
+        }
+        return false;
+    }
+
+    /**
+     * Returns ToStringHelper with providerId and clientId.
+     *
+     * @return toStringHelper
+     */
+    protected ToStringHelper toStringHelper() {
+        return MoreObjects.toStringHelper(this)
+                .add("providerId", providerId)
+                .add("clientId", clientId);
+    }
+
+    @Override
+    public String toString() {
+        return toStringHelper().toString();
+    }
+}