| /* |
| * 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.ui.impl.topo.model; |
| |
| import org.onosproject.ui.impl.topo.UiTopoSession; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * A lazily-initialized Singleton that creates and maintains the UI-model |
| * of the network topology. |
| */ |
| public final class UiSharedTopologyModel { |
| |
| private static final Logger log = |
| LoggerFactory.getLogger(UiSharedTopologyModel.class); |
| |
| |
| private UiSharedTopologyModel() { |
| // TODO: set up core model listeners and build the state of the model |
| } |
| |
| // TODO: Note to Thomas (or others).. |
| // Don't we have a common pattern for adding/removing listeners and |
| // invoking them when things happen? |
| |
| |
| /** |
| * Registers a UI topology session with the topology model. |
| * |
| * @param session the session to register |
| */ |
| public void register(UiTopoSession session) { |
| log.info("Registering topology session {}", session); |
| // TODO: register the session |
| } |
| |
| /** |
| * Unregisters a UI topology session from the topology model. |
| * |
| * @param session the session to unregister |
| */ |
| public void unregister(UiTopoSession session) { |
| log.info("Unregistering topology session {}", session); |
| // TODO: unregister the session |
| } |
| |
| /** |
| * Bill Pugh Singleton pattern. INSTANCE won't be instantiated until the |
| * LazyHolder class is loaded via a call to the instance() method below. |
| */ |
| private static class LazyHolder { |
| private static final UiSharedTopologyModel INSTANCE = |
| new UiSharedTopologyModel(); |
| } |
| |
| /** |
| * Returns a reference to the Singleton UI network topology model. |
| * |
| * @return the singleton topology model |
| */ |
| public static UiSharedTopologyModel instance() { |
| return LazyHolder.INSTANCE; |
| } |
| } |