ONOS-3758 restructuring driver module with sub-modules for different drivers

Change-Id: I3c65d19be87066448655610abf9d8b89385a4141
diff --git a/core/api/src/main/java/org/onosproject/net/driver/AbstractDriverLoader.java b/core/api/src/main/java/org/onosproject/net/driver/AbstractDriverLoader.java
new file mode 100644
index 0000000..4065c13
--- /dev/null
+++ b/core/api/src/main/java/org/onosproject/net/driver/AbstractDriverLoader.java
@@ -0,0 +1,65 @@
+/*
+ * Copyright 2015 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.net.driver;
+
+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.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.InputStream;
+
+/**
+ * Bootstrap for built in drivers.
+ */
+@Component
+public abstract class AbstractDriverLoader {
+
+    private final Logger log = LoggerFactory.getLogger(getClass());
+
+    //private static final String DRIVERS_XML = "/onos-drivers.xml";
+
+    private DriverProvider provider;
+
+    @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
+    protected DriverAdminService driverAdminService;
+
+    @Activate
+    protected void activate() {
+        try {
+            provider = new XmlDriverLoader(getClassLoaderInstance())
+                    .loadDrivers(loadXMLDriversStream(), driverAdminService);
+            driverAdminService.registerProvider(provider);
+        } catch (Exception e) {
+            log.error("Unable to load default drivers", e);
+        }
+        log.info("Started");
+    }
+
+    @Deactivate
+    protected void deactivate() {
+        driverAdminService.unregisterProvider(provider);
+        log.info("Stopped");
+    }
+
+    protected abstract InputStream loadXMLDriversStream();
+
+    protected abstract ClassLoader getClassLoaderInstance();
+
+}