| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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.onlab.util; |
| |
| import org.jboss.netty.util.HashedWheelTimer; |
| |
| /** |
| * Hashed-wheel timer singleton. Care must be taken to shutdown the timer |
| * only when the VM is ready to exit. |
| */ |
| public final class Timer { |
| |
| private static volatile HashedWheelTimer timer; |
| |
| // Ban public construction |
| private Timer() { |
| } |
| |
| /** |
| * Returns the singleton hashed-wheel timer. |
| * |
| * @return hashed-wheel timer |
| */ |
| public static HashedWheelTimer getTimer() { |
| if (Timer.timer == null) { |
| initTimer(); |
| } |
| return Timer.timer; |
| } |
| |
| private static synchronized void initTimer() { |
| if (Timer.timer == null) { |
| HashedWheelTimer hwTimer = new HashedWheelTimer(); |
| hwTimer.start(); |
| Timer.timer = hwTimer; |
| } |
| } |
| |
| } |