| /* |
| * Copyright 2018-present Open Networking Foundation |
| * |
| * 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.workflow.api; |
| |
| import java.util.Date; |
| import java.util.Objects; |
| import java.util.PriorityQueue; |
| import java.util.Timer; |
| import java.util.TimerTask; |
| |
| /** |
| * Class for time chain timer. |
| */ |
| public class TimerChain { |
| |
| private PriorityQueue<TimerChainTask> taskQueue = new PriorityQueue<>(); |
| |
| private Timer impendingTimer; |
| private TimerChainTask impendingTask; |
| |
| /** |
| * Constructor of timer chain. |
| */ |
| public TimerChain() { |
| |
| } |
| |
| /** |
| * Schedules timer event. |
| * @param afterMs millisecond which time event happens. |
| * @param runnable runnable to be executed after 'afterMs' |
| */ |
| public void schedule(long afterMs, Runnable runnable) { |
| schedule(new Date((new Date()).getTime() + afterMs), runnable); |
| } |
| |
| /** |
| * Schedules timer event. |
| * @param date date which timer event happens. |
| * @param runnable runnable to be executed on 'date' |
| */ |
| public void schedule(Date date, Runnable runnable) { |
| schedule(new TimerChainTask(this, date, runnable)); |
| } |
| |
| /** |
| * Schedule timer chain task. |
| * @param task task to be scheduled. |
| */ |
| private void schedule(TimerChainTask task) { |
| synchronized (this) { |
| if (taskQueue.isEmpty()) { |
| scheduleImpending(task); |
| return; |
| } |
| |
| if (task.date().getTime() < head().date().getTime()) { |
| impendingTimer.cancel(); |
| impendingTask.cancel(); |
| TimerChainTask prevImpendingTask = pop().copy(); |
| taskQueue.offer(prevImpendingTask); |
| |
| scheduleImpending(task); |
| } else { |
| taskQueue.offer(task); |
| } |
| } |
| } |
| |
| /** |
| * Schedule impending timer task. |
| * @param task impending timer chain task |
| * @return timer chain task |
| */ |
| private TimerChainTask scheduleImpending(TimerChainTask task) { |
| taskQueue.offer(task); |
| Timer timer = new Timer(); |
| this.setImpendingTask(task); |
| this.setImpendingTimer(timer); |
| timer.schedule(task, task.date()); |
| return task; |
| } |
| |
| /** |
| * Gets impending timer. |
| * @return impending timer |
| */ |
| public Timer implendingTimer() { |
| return impendingTimer; |
| } |
| |
| /** |
| * Sets impending timer. |
| * @param impendingTimer impending timer |
| */ |
| public void setImpendingTimer(Timer impendingTimer) { |
| this.impendingTimer = impendingTimer; |
| } |
| |
| /** |
| * Gets impending timer task. |
| * @return impending timer task |
| */ |
| public TimerTask impendingTask() { |
| return impendingTask; |
| } |
| |
| /** |
| * Sets impending timer task. |
| * @param impendingTask impending timer task |
| */ |
| public void setImpendingTask(TimerChainTask impendingTask) { |
| this.impendingTask = impendingTask; |
| } |
| |
| /** |
| * Gets head of timer chain task queue. |
| * @return timer chain task |
| */ |
| public TimerChainTask head() { |
| if (!taskQueue.isEmpty()) { |
| return taskQueue.peek(); |
| } else { |
| return null; |
| } |
| } |
| |
| /** |
| * Pops head of timer chain task queue. |
| * @return timer chain task |
| */ |
| public TimerChainTask pop() { |
| if (!taskQueue.isEmpty()) { |
| return taskQueue.poll(); |
| } else { |
| return null; |
| } |
| } |
| |
| /** |
| * Class for timer chain task. |
| */ |
| public static class TimerChainTask extends TimerTask implements Comparable<TimerChainTask> { |
| |
| private final TimerChain timerchain; |
| private final Date date; |
| private final Runnable runnable; |
| |
| /** |
| * Constructor of timer chain task. |
| * @param timerchain timer chain |
| * @param date date to be scheduled |
| * @param runnable runnable to be executed by timer |
| */ |
| public TimerChainTask(TimerChain timerchain, Date date, Runnable runnable) { |
| this.timerchain = timerchain; |
| this.date = date; |
| this.runnable = runnable; |
| } |
| |
| /** |
| * Gets date. |
| * @return date of timer chain task |
| */ |
| public Date date() { |
| return this.date; |
| } |
| |
| /** |
| * Gets runnable. |
| * @return runnable of timer chain task |
| */ |
| public Runnable runnable() { |
| return this.runnable; |
| } |
| |
| @Override |
| public void run() { |
| |
| TimerChainTask nextTask; |
| synchronized (timerchain) { |
| if (timerchain.impendingTask() != this) { |
| runnable().run(); |
| return; |
| } |
| |
| timerchain.implendingTimer().cancel(); |
| timerchain.pop(); |
| |
| nextTask = timerchain.head(); |
| |
| if (nextTask != null) { |
| Timer nextTimer = new Timer(); |
| this.timerchain.setImpendingTask(nextTask); |
| this.timerchain.setImpendingTimer(nextTimer); |
| nextTimer.schedule(nextTask, nextTask.date()); |
| } |
| } |
| |
| runnable().run(); |
| |
| } |
| |
| @Override |
| public int compareTo(TimerChainTask target) { |
| return date().compareTo(target.date()); |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (this == o) { |
| return true; |
| } |
| if (!(o instanceof TimerChainTask)) { |
| return false; |
| } |
| TimerChainTask that = (TimerChainTask) o; |
| |
| return this.date().equals(that.date()); |
| } |
| |
| @Override |
| public int hashCode() { |
| return Objects.hash(date); |
| } |
| |
| /** |
| * Copies timer chain task. |
| * @return timer chain task |
| */ |
| public TimerChainTask copy() { |
| return new TimerChainTask(timerchain, date, runnable); |
| } |
| } |
| } |