精进Quartz源码—Quartz调度器的Misfire处理规则（四）

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Quartz调度器的Misfire处理规则

调度器的启动和恢复中使用的misfire机制，还需细化！

一、SimpleTrigger的misfire机制 默认的 Trigger.MISFIREINSTRUCTIONSMART_POLICY !!!

trig.updateAfterMisfire(cal); getMisfireInstruction() —-> misfireInstruction == 0 ——以当前时间为触发频率立即触发执行

SimpleScheduleBuilder ssb = SimpleScheduleBuilder.simpleSchedule(); ssb.withMisfireHandlingInstructionFireNow();//1 ssb.withMisfireHandlingInstructionIgnoreMisfires();//2 ssb.withMisfireHandlingInstructionNextWithExistingCount();//3 ssb.withMisfireHandlingInstructionNextWithRemainingCount();//4 ssb.withMisfireHandlingInstructionNowWithExistingCount();//5 ssb.withMisfireHandlingInstructionNowWithRemainingCount();//6 //1 withMisfireHandlingInstructionFireNow ---> misfireInstruction == 1 ——以当前时间为触发频率立即触发执行 ——执行至FinalTIme的剩余周期次数 ——以调度或恢复调度的时刻为基准的周期频率，FinalTime根据剩余次数和当前时间计算得到 ——调整后的FinalTime会略大于根据starttime计算的到的FinalTime值 //2 withMisfireHandlingInstructionIgnoreMisfires ---> misfireInstruction == -1 —以错过的第一个频率时间立刻开始执行 ——重做错过的所有频率周期 ——当下一次触发频率发生时间大于当前时间以后，按照Interval的依次执行剩下的频率 ——共执行RepeatCount+1次 //3 withMisfireHandlingInstructionNextWithExistingCount ---> misfireInstruction == 5 ——不触发立即执行 ——等待下次触发频率周期时刻，执行至FinalTime的剩余周期次数 ——以startTime为基准计算周期频率，并得到FinalTime ——即使中间出现pause，resume以后保持FinalTime时间不变 //4 withMisfireHandlingInstructionNextWithRemainingCount ---> misfireInstruction = 4 ——不触发立即执行 ——等待下次触发频率周期时刻，执行至FinalTime的剩余周期次数 ——以startTime为基准计算周期频率，并得到FinalTime ——即使中间出现pause，resume以后保持FinalTime时间不变 //5 withMisfireHandlingInstructionNowWithExistingCount ---> misfireInstruction = 2 ——以当前时间为触发频率立即触发执行 ——执行至FinalTIme的剩余周期次数 ——以调度或恢复调度的时刻为基准的周期频率，FinalTime根据剩余次数和当前时间计算得到 ——调整后的FinalTime会略大于根据starttime计算的到的FinalTime值 //6 withMisfireHandlingInstructionNowWithRemainingCount --- >misfireInstruction = 3 ——以当前时间为触发频率立即触发执行 ——执行至FinalTIme的剩余周期次数 ——以调度或恢复调度的时刻为基准的周期频率，FinalTime根据剩余次数和当前时间计算得到 ——调整后的FinalTime会略大于根据starttime计算的到的FinalTime值 MISFIRE_INSTRUCTION_RESCHEDULE_NOW_WITH_REMAINING_REPEAT_COUNT 值为 3 ——此指令导致trigger忘记原始设置的starttime和repeat-count ——触发器的repeat-count将被设置为剩余的次数 ——这样会导致后面无法获得原始设定的starttime和repeat-count值 

updateAfterMisfire 方法源码：

/** * <p> * Updates the <code>SimpleTrigger</code>'s state based on the * MISFIRE_INSTRUCTION_XXX that was selected when the <code>SimpleTrigger</code> * was created. * </p> * * <p> * If the misfire instruction is set to MISFIRE_INSTRUCTION_SMART_POLICY, * then the following scheme will be used: <br> * <ul> * <li>If the Repeat Count is <code>0</code>, then the instruction will * be interpreted as <code>MISFIRE_INSTRUCTION_FIRE_NOW</code>.</li> * <li>If the Repeat Count is <code>REPEAT_INDEFINITELY</code>, then * the instruction will be interpreted as <code>MISFIRE_INSTRUCTION_RESCHEDULE_NEXT_WITH_REMAINING_COUNT</code>. * <b>WARNING:</b> using MISFIRE_INSTRUCTION_RESCHEDULE_NEXT_WITH_REMAINING_COUNT * with a trigger that has a non-null end-time may cause the trigger to * never fire again if the end-time arrived during the misfire time span. * </li> * <li>If the Repeat Count is <code>> 0</code>, then the instruction * will be interpreted as <code>MISFIRE_INSTRUCTION_RESCHEDULE_NOW_WITH_EXISTING_REPEAT_COUNT</code>. * </li> * </ul> * </p> * */ /* 基于在创建SimpleTrigger时选择的MISFIRE_INSTRUCTION_XXX更新SimpleTrigger的状态。 如果失火指令设置为MISFIRE_INSTRUCTION_SMART_POLICY，则将使用以下方案： •如果重复计数为0，则指令将解释为MISFIRE_INSTRUCTION_FIRE_NOW。 •如果重复计数为REPEAT_INDEFINITELY，则指令将解释为MISFIRE_INSTRUCTION_RESCHEDULE_NEXT_WITH_REMAINING_COUNT。 警告：如果触发器具有非空的结束时间，则使用MISFIRE_INSTRUCTION_RESCHEDULE_NEXT_WITH_REMAINING_COUNT可能会导致触发器在失火时间范围内到达结束时，不会再次触发。 •如果重复计数大于0，则指令将解释为MISFIRE_INSTRUCTION_RESCHEDULE_NOW_WITH_EXISTING_REPEAT_COUNT。 */ @Override public void updateAfterMisfire(Calendar cal) { int instr = getMisfireInstruction();//获取misfire的值，默认为0 if(instr == Trigger.MISFIRE_INSTRUCTION_IGNORE_MISFIRE_POLICY)//instr == -1 return; if (instr == Trigger.MISFIRE_INSTRUCTION_SMART_POLICY) { //instr == 1 if (getRepeatCount() == 0) { instr = MISFIRE_INSTRUCTION_FIRE_NOW; //instr = 1 } else if (getRepeatCount() == REPEAT_INDEFINITELY) {//getRe..Count == -1 //instr = 4 instr = MISFIRE_INSTRUCTION_RESCHEDULE_NEXT_WITH_REMAINING_COUNT; } else { // if (getRepeatCount() > 0) instr = MISFIRE_INSTRUCTION_RESCHEDULE_NOW_WITH_EXISTING_REPEAT_COUNT;//instr == 2 } //instr == 1 } else if (instr == MISFIRE_INSTRUCTION_FIRE_NOW && getRepeatCount() != 0) { //instr == 3 instr = MISFIRE_INSTRUCTION_RESCHEDULE_NOW_WITH_REMAINING_REPEAT_COUNT; } if (instr == MISFIRE_INSTRUCTION_FIRE_NOW) { //instr == 1 setNextFireTime(new Date()); //instr == 5 } else if (instr == MISFIRE_INSTRUCTION_RESCHEDULE_NEXT_WITH_EXISTING_COUNT) { Date newFireTime = getFireTimeAfter(new Date()); while (newFireTime != null && cal != null && !cal.isTimeIncluded(newFireTime.getTime())) { newFireTime = getFireTimeAfter(newFireTime); if(newFireTime == null) break; //avoid infinite loop java.util.Calendar c = java.util.Calendar.getInstance(); c.setTime(newFireTime); if (c.get(java.util.Calendar.YEAR) > YEAR_TO_GIVEUP_SCHEDULING_AT) { newFireTime = null; } } setNextFireTime(newFireTime); //instr == 4 } else if (instr == MISFIRE_INSTRUCTION_RESCHEDULE_NEXT_WITH_REMAINING_COUNT) { Date newFireTime = getFireTimeAfter(new Date()); while (newFireTime != null && cal != null && !cal.isTimeIncluded(newFireTime.getTime())) { newFireTime = getFireTimeAfter(newFireTime); if(newFireTime == null) break; //avoid infinite loop java.util.Calendar c = java.util.Calendar.getInstance(); c.setTime(newFireTime); if (c.get(java.util.Calendar.YEAR) > YEAR_TO_GIVEUP_SCHEDULING_AT) { newFireTime = null; } } if (newFireTime != null) { int timesMissed = computeNumTimesFiredBetween(nextFireTime, newFireTime); setTimesTriggered(getTimesTriggered() + timesMissed); } setNextFireTime(newFireTime); } else if (instr == MISFIRE_INSTRUCTION_RESCHEDULE_NOW_WITH_EXISTING_REPEAT_COUNT) { //instr == 2 Date newFireTime = new Date(); if (repeatCount != 0 && repeatCount != REPEAT_INDEFINITELY) { setRepeatCount(getRepeatCount() - getTimesTriggered()); setTimesTriggered(0); } if (getEndTime() != null && getEndTime().before(newFireTime)) { setNextFireTime(null); // We are past the end time } else { setStartTime(newFireTime); setNextFireTime(newFireTime); } } else if (instr == MISFIRE_INSTRUCTION_RESCHEDULE_NOW_WITH_REMAINING_REPEAT_COUNT) { //instr == 3 Date newFireTime = new Date(); int timesMissed = computeNumTimesFiredBetween(nextFireTime, newFireTime); if (repeatCount != 0 && repeatCount != REPEAT_INDEFINITELY) { //repeatCount == -1 int remainingCount = getRepeatCount() - (getTimesTriggered() + timesMissed); if (remainingCount <= 0) { remainingCount = 0; } setRepeatCount(remainingCount); setTimesTriggered(0); } if (getEndTime() != null && getEndTime().before(newFireTime)) { setNextFireTime(null); // We are past the end time } else { setStartTime(newFireTime); setNextFireTime(newFireTime); } } } 

二、CronTrigger的misfire机制—-默认的 Trigger.MISFIREINSTRUCTIONSMART_POLICY !!!

trig.updateAfterMisfire(cal); getMisfireInstruction() —-> misfireInstruction == 0

CronScheduleBuilder csb = CronScheduleBuilder.cronSchedule("0/5 * * * * ?"); csb.withMisfireHandlingInstructionDoNothing(); csb.withMisfireHandlingInstructionFireAndProceed(); csb.withMisfireHandlingInstructionIgnoreMisfires(); withMisfireHandlingInstructionDoNothing ---> misfireInstruction = 2 ——不触发立即执行 ——等待下次Cron触发频率到达时刻开始按照Cron频率依次执行 withMisfireHandlingInstructionFireAndProceed ---> misfireInstruction = 1 ——以当前时间为触发频率立刻触发一次执行 ——然后按照Cron频率依次执行 withMisfireHandlingInstructionIgnoreMisfires ---> misfireInstruction = -1 ——以错过的第一个频率时间立刻开始执行 ——重做错过的所有频率周期后 ——当下一次触发频率发生时间大于当前时间后，再按照正常的Cron频率依次执行 

updateAfterMisfire 方法源码：

/** * <p> * Updates the <code>CronTrigger</code>'s state based on the * MISFIRE_INSTRUCTION_XXX that was selected when the <code>CronTrigger</code> * was created. * </p> * * <p> * If the misfire instruction is set to MISFIRE_INSTRUCTION_SMART_POLICY, * then the following scheme will be used: <br> * <ul> * <li>The instruction will be interpreted as <code>MISFIRE_INSTRUCTION_FIRE_ONCE_NOW</code> * </ul> * </p> */ /* 根据创建CronTrigger时选择的MISFIRE_INSTRUCTION_XXX更新CronTrigger的状态。 如果失火指令设置为MISFIRE_INSTRUCTION_SMART_POLICY，则将使用以下方案： •指令将解释为MISFIRE_INSTRUCTION_FIRE_ONCE_NOW */ @Override public void updateAfterMisfire(org.quartz.Calendar cal) { int instr = getMisfireInstruction();//获取misfire的值，默认为0 if(instr == Trigger.MISFIRE_INSTRUCTION_IGNORE_MISFIRE_POLICY)//instr == -1 return; if (instr == MISFIRE_INSTRUCTION_SMART_POLICY) {//instr == 0 instr = MISFIRE_INSTRUCTION_FIRE_ONCE_NOW;//instr = 1 } if (instr == MISFIRE_INSTRUCTION_DO_NOTHING) {//instr == 2 Date newFireTime = getFireTimeAfter(new Date()); while (newFireTime != null && cal != null && !cal.isTimeIncluded(newFireTime.getTime())) { newFireTime = getFireTimeAfter(newFireTime); } setNextFireTime(newFireTime); } else if (instr == MISFIRE_INSTRUCTION_FIRE_ONCE_NOW) {//instr == 1 setNextFireTime(new Date()); } } 

参考文章

Quartz的Misfire处理规则 Quartz-错过触发机制

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