jaegonkim | 6a7b524 | 2018-09-12 23:09:42 +0900 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2018-present Open Networking Foundation |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | package org.onosproject.workflow.api; |
| 17 | |
| 18 | import java.util.Date; |
| 19 | import java.util.PriorityQueue; |
| 20 | import java.util.Timer; |
| 21 | import java.util.TimerTask; |
| 22 | |
| 23 | /** |
| 24 | * Class for time chain timer. |
| 25 | */ |
| 26 | public class TimerChain { |
| 27 | |
| 28 | private PriorityQueue<TimerChainTask> taskQueue = new PriorityQueue<>(); |
| 29 | |
| 30 | private Timer impendingTimer; |
| 31 | private TimerChainTask impendingTask; |
| 32 | |
| 33 | /** |
| 34 | * Schedules timer event. |
| 35 | * @param afterMs millisecond which time event happens. |
| 36 | * @param runnable runnable to be executed after 'afterMs' |
| 37 | */ |
| 38 | public void schedule(long afterMs, Runnable runnable) { |
| 39 | schedule(new Date((new Date()).getTime() + afterMs), runnable); |
| 40 | } |
| 41 | |
| 42 | /** |
| 43 | * Schedules timer event. |
| 44 | * @param date date which timer event happens. |
| 45 | * @param runnable runnable to be executed on 'date' |
| 46 | */ |
| 47 | public void schedule(Date date, Runnable runnable) { |
| 48 | schedule(new TimerChainTask(this, date, runnable)); |
| 49 | } |
| 50 | |
| 51 | /** |
| 52 | * Schedule timer chain task. |
| 53 | * @param task task to be scheduled. |
| 54 | */ |
| 55 | private void schedule(TimerChainTask task) { |
| 56 | synchronized (this) { |
| 57 | if (taskQueue.size() == 0) { |
| 58 | scheduleImpending(task); |
| 59 | return; |
| 60 | } |
| 61 | |
| 62 | if (task.date().getTime() < head().date().getTime()) { |
| 63 | impendingTimer.cancel(); |
| 64 | impendingTask.cancel(); |
| 65 | TimerChainTask prevImpendingTask = pop().copy(); |
| 66 | taskQueue.offer(prevImpendingTask); |
| 67 | |
| 68 | scheduleImpending(task); |
| 69 | } else { |
| 70 | taskQueue.offer(task); |
| 71 | } |
| 72 | } |
| 73 | } |
| 74 | |
| 75 | /** |
| 76 | * Schedule impending timer task. |
| 77 | * @param task impending timer chain task |
| 78 | * @return timer chain task |
| 79 | */ |
| 80 | private TimerChainTask scheduleImpending(TimerChainTask task) { |
| 81 | taskQueue.offer(task); |
| 82 | Timer timer = new Timer(); |
| 83 | this.setImpendingTask(task); |
| 84 | this.setImpendingTimer(timer); |
| 85 | timer.schedule(task, task.date()); |
| 86 | return task; |
| 87 | } |
| 88 | |
| 89 | /** |
| 90 | * Gets impending timer. |
| 91 | * @return impending timer |
| 92 | */ |
| 93 | public Timer implendingTimer() { |
| 94 | return impendingTimer; |
| 95 | } |
| 96 | |
| 97 | /** |
| 98 | * Sets impending timer. |
| 99 | * @param impendingTimer impending timer |
| 100 | */ |
| 101 | public void setImpendingTimer(Timer impendingTimer) { |
| 102 | this.impendingTimer = impendingTimer; |
| 103 | } |
| 104 | |
| 105 | /** |
| 106 | * Gets impending timer task. |
| 107 | * @return impending timer task |
| 108 | */ |
| 109 | public TimerTask impendingTask() { |
| 110 | return impendingTask; |
| 111 | } |
| 112 | |
| 113 | /** |
| 114 | * Sets impending timer task. |
| 115 | * @param impendingTask impending timer task |
| 116 | */ |
| 117 | public void setImpendingTask(TimerChainTask impendingTask) { |
| 118 | this.impendingTask = impendingTask; |
| 119 | } |
| 120 | |
| 121 | /** |
| 122 | * Gets head of timer chain task queue. |
| 123 | * @return timer chain task |
| 124 | */ |
| 125 | public TimerChainTask head() { |
| 126 | if (taskQueue.size() > 0) { |
| 127 | return taskQueue.peek(); |
| 128 | } else { |
| 129 | return null; |
| 130 | } |
| 131 | } |
| 132 | |
| 133 | /** |
| 134 | * Pops head of timer chain task queue. |
| 135 | * @return timer chain task |
| 136 | */ |
| 137 | public TimerChainTask pop() { |
| 138 | if (taskQueue.size() > 0) { |
| 139 | return taskQueue.poll(); |
| 140 | } else { |
| 141 | return null; |
| 142 | } |
| 143 | } |
| 144 | |
| 145 | /** |
| 146 | * Class for timer chain task. |
| 147 | */ |
| 148 | public static class TimerChainTask extends TimerTask implements Comparable<TimerChainTask> { |
| 149 | |
| 150 | private final TimerChain timerchain; |
| 151 | private final Date date; |
| 152 | private final Runnable runnable; |
| 153 | |
| 154 | /** |
| 155 | * Constructor of timer chain task. |
| 156 | * @param timerchain timer chain |
| 157 | * @param date date to be scheduled |
| 158 | * @param runnable runnable to be executed by timer |
| 159 | */ |
| 160 | public TimerChainTask(TimerChain timerchain, Date date, Runnable runnable) { |
| 161 | this.timerchain = timerchain; |
| 162 | this.date = date; |
| 163 | this.runnable = runnable; |
| 164 | } |
| 165 | |
| 166 | /** |
| 167 | * Gets date. |
| 168 | * @return date of timer chain task |
| 169 | */ |
| 170 | public Date date() { |
| 171 | return this.date; |
| 172 | } |
| 173 | |
| 174 | /** |
| 175 | * Gets runnable. |
| 176 | * @return runnable of timer chain task |
| 177 | */ |
| 178 | public Runnable runnable() { |
| 179 | return this.runnable; |
| 180 | } |
| 181 | |
| 182 | @Override |
| 183 | public void run() { |
| 184 | |
| 185 | TimerChainTask nextTask; |
| 186 | synchronized (timerchain) { |
| 187 | if (timerchain.impendingTask() != this) { |
| 188 | System.out.println("Invalid impendingTask"); |
| 189 | runnable().run(); |
| 190 | return; |
| 191 | } |
| 192 | |
| 193 | timerchain.implendingTimer().cancel(); |
| 194 | timerchain.pop(); |
| 195 | |
| 196 | nextTask = timerchain.head(); |
| 197 | |
| 198 | if (nextTask != null) { |
| 199 | Timer nextTimer = new Timer(); |
| 200 | this.timerchain.setImpendingTask(nextTask); |
| 201 | this.timerchain.setImpendingTimer(nextTimer); |
| 202 | nextTimer.schedule(nextTask, nextTask.date()); |
| 203 | } |
| 204 | } |
| 205 | |
| 206 | runnable().run(); |
| 207 | |
| 208 | } |
| 209 | |
| 210 | @Override |
| 211 | public int compareTo(TimerChainTask target) { |
| 212 | return date().compareTo(target.date()); |
| 213 | } |
| 214 | |
| 215 | /** |
| 216 | * Copies timer chain task. |
| 217 | * @return timer chain task |
| 218 | */ |
| 219 | public TimerChainTask copy() { |
| 220 | return new TimerChainTask(timerchain, date, runnable); |
| 221 | } |
| 222 | } |
| 223 | } |