Device config synchronizer

- initial sketch of Device Config Synchronizer outline (ONOS-6745)

Change-Id: I57c8ab6c3511f12c15e3501aa61498eb18264b27
diff --git a/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfSessionAdapter.java b/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfSessionAdapter.java
new file mode 100644
index 0000000..a399d92
--- /dev/null
+++ b/protocols/netconf/api/src/main/java/org/onosproject/netconf/NetconfSessionAdapter.java
@@ -0,0 +1,105 @@
+/*
+ * Copyright 2017-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.netconf;
+
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+
+import org.onlab.util.Tools;
+
+/**
+ * Adapter mainly intended for usage in tests.
+ */
+public class NetconfSessionAdapter implements NetconfSession {
+
+    @Override
+    public void startSubscription(String filterSchema) throws NetconfException {
+    }
+
+    @Override
+    public void startSubscription() throws NetconfException {
+    }
+
+    @Override
+    public void setDeviceCapabilities(List<String> capabilities) {
+    }
+
+    @Override
+    public String requestSync(String request) throws NetconfException {
+        return null;
+    }
+
+    @Override
+    public CompletableFuture<String> request(String request)
+            throws NetconfException {
+        return Tools.exceptionalFuture(new UnsupportedOperationException());
+    }
+
+    @Override
+    public void removeDeviceOutputListener(NetconfDeviceOutputEventListener listener) {
+    }
+
+    @Override
+    public String getSessionId() {
+        return null;
+    }
+
+    @Override
+    public String getServerCapabilities() {
+        return null;
+    }
+
+    @Override
+    public String get(String filterSchema, String withDefaultsMode)
+            throws NetconfException {
+        return null;
+    }
+
+    @Override
+    public String get(String request) throws NetconfException {
+        return null;
+    }
+
+    @Override
+    public void endSubscription() throws NetconfException {
+    }
+
+    @Override
+    public boolean editConfig(String newConfiguration) throws NetconfException {
+        return true;
+    }
+
+    @Override
+    public String doWrappedRpc(String request) throws NetconfException {
+        return null;
+    }
+
+    @Override
+    public boolean copyConfig(String netconfTargetConfig,
+                              String newConfiguration)
+            throws NetconfException {
+        return true;
+    }
+
+    @Override
+    public boolean close() throws NetconfException {
+        return true;
+    }
+
+    @Override
+    public void addDeviceOutputListener(NetconfDeviceOutputEventListener listener) {
+    }
+}
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