Device config synchronizer

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

Change-Id: I57c8ab6c3511f12c15e3501aa61498eb18264b27
diff --git a/apps/configsync-netconf/src/main/java/org/onosproject/d/config/sync/impl/netconf/NetconfDeviceConfigSynchronizerComponent.java b/apps/configsync-netconf/src/main/java/org/onosproject/d/config/sync/impl/netconf/NetconfDeviceConfigSynchronizerComponent.java
new file mode 100644
index 0000000..ced2b41
--- /dev/null
+++ b/apps/configsync-netconf/src/main/java/org/onosproject/d/config/sync/impl/netconf/NetconfDeviceConfigSynchronizerComponent.java
@@ -0,0 +1,139 @@
+/*
+ * 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.d.config.sync.impl.netconf;
+
+import org.apache.felix.scr.annotations.Activate;
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Deactivate;
+import org.apache.felix.scr.annotations.Reference;
+import org.apache.felix.scr.annotations.ReferenceCardinality;
+import org.onosproject.d.config.sync.DeviceConfigSynchronizationProviderRegistry;
+import org.onosproject.d.config.sync.DeviceConfigSynchronizationProviderService;
+import org.onosproject.net.device.DeviceService;
+import org.onosproject.net.provider.ProviderId;
+import org.onosproject.netconf.NetconfController;
+import org.onosproject.yang.model.SchemaContextProvider;
+import org.onosproject.yang.runtime.YangRuntimeService;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.common.annotations.Beta;
+
+/**
+ * Main component of Dynamic config synchronizer for NETCONF.
+ * <p>
+ * <ul>
+ * <li> bootstrap Active and Passive synchronization modules
+ * <li> start background anti-entropy mechanism for offline device configuration
+ * </ul>
+ */
+@Component(immediate = true)
+public class NetconfDeviceConfigSynchronizerComponent {
+
+    private final Logger log = LoggerFactory.getLogger(getClass());
+
+    /**
+     * NETCONF dynamic config synchronizer provider ID.
+     */
+    public static final ProviderId PID =
+            new ProviderId("netconf", "org.onosproject.d.config.sync.netconf");
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected DeviceConfigSynchronizationProviderRegistry registry;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected NetconfController netconfController;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected YangRuntimeService yangRuntimeService;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected SchemaContextProvider schemaContextProvider;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected DeviceService deviceService;
+
+    private NetconfDeviceConfigSynchronizerProvider provider;
+
+    private DeviceConfigSynchronizationProviderService providerService;
+
+
+    @Activate
+    protected void activate() {
+        provider = new NetconfDeviceConfigSynchronizerProvider(PID, new InnerNetconfContext());
+        providerService = registry.register(provider);
+
+        // TODO (Phase 2 or later)
+        //      listen to NETCONF events (new Device appeared, etc.)
+        //      for PASSIVE "state" synchronization upward
+
+        // TODO listen to DeviceEvents (Offline pre-configuration scenario)
+
+        // TODO background anti-entropy mechanism
+
+        log.info("Started");
+    }
+
+    @Deactivate
+    protected void deactivate() {
+        registry.unregister(provider);
+        log.info("Stopped");
+    }
+
+    /**
+     * Context object to provide reference to OSGi services, etc.
+     */
+    @Beta
+    public static interface NetconfContext {
+
+        /**
+         * Returns DeviceConfigSynchronizationProviderService interface.
+         *
+         * @return DeviceConfigSynchronizationProviderService
+         */
+        DeviceConfigSynchronizationProviderService providerService();
+
+        SchemaContextProvider schemaContextProvider();
+
+        YangRuntimeService yangRuntime();
+
+        NetconfController netconfController();
+
+    }
+
+    class InnerNetconfContext implements NetconfContext {
+
+        @Override
+        public NetconfController netconfController() {
+            return netconfController;
+        }
+
+        @Override
+        public YangRuntimeService yangRuntime() {
+            return yangRuntimeService;
+        }
+
+        @Override
+        public SchemaContextProvider schemaContextProvider() {
+            return schemaContextProvider;
+        }
+
+        @Override
+        public DeviceConfigSynchronizationProviderService providerService() {
+            return providerService;
+        }
+    }
+}