超时时间轮---优化时间推送，还剩简化Runnable！

src/main/java/com/jd/platform/async/executor/wheel/TimeWheel.java

@@ -2,7 +2,6 @@ package com.jd.platform.async.executor.wheel;
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.concurrent.DelayQueue;
 
 /**
  * 时间轮
@@ -29,11 +28,6 @@ public class TimeWheel {
      */
     private TimerTaskList[] timerTaskLists;
 
-    /**
-     * 当前时间
-     */
-    private long currentTime;
-
     /**
      * 上层时间轮
      */
@@ -44,14 +38,11 @@ public class TimeWheel {
      */
     private List<List<TimerTaskList>> delayList;
 
-    public TimeWheel(long tickMs, int wheelSize, long currentTime, List<List<TimerTaskList>> delayList) {
-        this.currentTime = currentTime;
+    public TimeWheel(long tickMs, int wheelSize, List<List<TimerTaskList>> delayList) {
         this.tickMs = tickMs;
         this.wheelSize = wheelSize;
         this.interval = tickMs * wheelSize;
         this.timerTaskLists = new TimerTaskList[wheelSize];
-        //currentTime为tickMs的整数倍 这里做取整操作
-        this.currentTime = currentTime - (currentTime % tickMs);
         this.delayList = delayList;
         for (int i = 0; i < wheelSize; i++) {
             timerTaskLists[i] = new TimerTaskList();
@@ -65,7 +56,7 @@ public class TimeWheel {
         if (overflowWheel == null) {
             synchronized (this) {
                 if (overflowWheel == null) {
-                    overflowWheel = new TimeWheel(interval, wheelSize, currentTime, delayList);
+                    overflowWheel = new TimeWheel(interval, wheelSize, delayList);
                 }
             }
         }
@@ -77,6 +68,9 @@ public class TimeWheel {
      */
     public boolean addTask(TimerTask timerTask) {
         long expiration = timerTask.getDelayMs();
+        long currentTime = System.currentTimeMillis();
+        currentTime = currentTime - (currentTime % tickMs);
+
         //过期任务直接执行
         if (expiration < currentTime + tickMs) {
             return false;
@@ -102,17 +96,4 @@ public class TimeWheel {
         }
         return true;
     }
-
-    /**
-     * 推进时间
-     */
-    public void advanceClock(long timestamp) {
-        if (timestamp >= currentTime + tickMs) {
-            currentTime = timestamp - (timestamp % tickMs);
-            if (overflowWheel != null) {
-                //推进上层时间轮时间
-                this.getOverflowWheel().advanceClock(timestamp);
-            }
-        }
-    }
 }

src/main/java/com/jd/platform/async/executor/wheel/TimeWheelFlushMession.java

@@ -1,26 +0,0 @@
-package com.jd.platform.async.executor.wheel;
-
-import java.util.List;
-import java.util.concurrent.TimeUnit;
-
-/**
- * @author shenkaiwen5
- * @version 1.0
- * @date 2021-11-15
- */
-public class TimeWheelFlushMession implements Runnable {
-
-    /**
-     * 定时器
-     */
-    private Timer timer;
-
-    public TimeWheelFlushMession(Timer timer) {
-        this.timer = timer;
-    }
-
-    @Override
-    public void run() {
-        timer.advanceClock();
-    }
-}

src/main/java/com/jd/platform/async/executor/wheel/Timer.java

@@ -15,11 +15,6 @@ public class Timer {
      */
     private TimeWheel timeWheel;
 
-    /**
-     * 一个Timer只有一个delayQueue
-     */
-    private DelayQueue<TimerTaskList> delayQueue = new DelayQueue<>();
-
     /**
      * 轮询delayQueue获取过期任务线程
      */
@@ -29,11 +24,6 @@ public class Timer {
      * 总的队列
      */
     private List<List<TimerTaskList>> delayList = new ArrayList<>(20);
-
-    /**
-     * 待执行的任务队列
-     */
-    private List<TimerTask> todoList = new ArrayList<>(16);
     /**
      * 执行到的index
      */
@@ -43,7 +33,7 @@ public class Timer {
      * 构造函数
      */
     public Timer() {
-        timeWheel = new TimeWheel(1, 20, System.currentTimeMillis(), delayList);
+        timeWheel = new TimeWheel(1, 20, delayList);
         //默认就1线程
         bossThreadPool = Executors.newSingleThreadScheduledExecutor();
         //20ms获取一次过期任务
@@ -58,8 +48,8 @@ public class Timer {
     public void addTask(TimerTask timerTask) {
         //尝试添加任务
         if (!timeWheel.addTask(timerTask)) {
-            //添加失败任务直接执行
-            todoList.add(timerTask);
+            //添加失败任务直接执行，反正判断超时的任务很快！
+            timerTask.getTask().run();
         }
     }
 
@@ -70,8 +60,13 @@ public class Timer {
      */
     protected void advanceClock() {
         try {
+            int index = INDEX.get();
+            if (index >= 20) {
+                INDEX.set(index % 20);
+            }
+
             //取20-list对应的时间槽
-            List<TimerTaskList> timerTaskList = delayList.get(INDEX.getAndIncrement());
+            List<TimerTaskList> timerTaskList = delayList.get(index);
             //delayList一个时间槽里所有时间轮的对应槽，先清空再重新添加
             List<TimerTaskList> tmpList = new ArrayList<>(16);
             tmpList.addAll(timerTaskList);
@@ -80,18 +75,12 @@ public class Timer {
             //遍历所有轮的槽，执行
             for (TimerTaskList singleWheelList: tmpList) {
                 if (singleWheelList != null) {
-                    //推进时间
-                    timeWheel.advanceClock(singleWheelList.getExpiration());
                     //执行过期任务（包含降级操作）
-                    //TODO 加到要执行的列表
+                    //TODO 加到要执行的列表，并执行
                     singleWheelList.flush(this::addTask);
-                    //TODO 执行
-                    for (TimerTask task: todoList) {
-                        task.getTask().run();
-                    }
-                    todoList.clear();
                 }
             }
+            INDEX.incrementAndGet();
         } catch (Exception e) {
             e.printStackTrace();
         }