Extend ControlPlaneRedirect (vRouter) to allow multiple redirects

CORD-787

Change-Id: I9e5a6f74b7239eb0dcb42b52e562698ce415debc
diff --git a/apps/routing-api/src/main/java/org/onosproject/routing/config/RouterConfigHelper.java b/apps/routing-api/src/main/java/org/onosproject/routing/config/RouterConfigHelper.java
new file mode 100644
index 0000000..ddfd1db
--- /dev/null
+++ b/apps/routing-api/src/main/java/org/onosproject/routing/config/RouterConfigHelper.java
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2017-present 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.routing.config;
+
+import com.google.common.collect.Sets;
+import org.onosproject.core.ApplicationId;
+import org.onosproject.net.config.NetworkConfigService;
+import org.onosproject.routing.RoutingService;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Collections;
+import java.util.Set;
+
+/**
+ * Helper class to manage retrieving config from multiple Config sections.
+ * Should be unnecessary once old config is removed.
+ */
+public final class RouterConfigHelper {
+
+    private static final String WARNING =
+            "Config apps/org.onosproject.routing/router is deprecated "
+                    + "and will be removed in a future release.";
+    private static final String WARNING2 =
+            "Use apps/org.onosproject.routing/routers instead";
+
+    private static final Logger log = LoggerFactory.getLogger(RouterConfigHelper.class);
+
+    private RouterConfigHelper() {
+        // make checkstyle happy
+    }
+
+    /**
+     * Retrieves the router configurations.
+     *
+     * @param configService network config service
+     * @param routingAppId routing app ID
+     * @return set of router configurations
+     */
+    public static Set<RoutersConfig.Router> getRouterConfigurations(
+            NetworkConfigService configService, ApplicationId routingAppId) {
+
+        RouterConfig config = configService.getConfig(
+                routingAppId, RoutingService.ROUTER_CONFIG_CLASS);
+        RoutersConfig multiConfig = configService.getConfig(routingAppId, RoutersConfig.class);
+
+        if (config != null) {
+            log.warn(WARNING);
+            log.warn(WARNING2);
+
+            return Collections.singleton(
+                    new RoutersConfig.Router(config.getControlPlaneConnectPoint(),
+                            config.getOspfEnabled(),
+                            Sets.newHashSet(config.getInterfaces())));
+        } else if (multiConfig != null) {
+            return multiConfig.getRouters();
+        } else {
+            return Collections.emptySet();
+        }
+    }
+}