quartz(二) 源码分析
// SimpleThreadPool——quartz里的工头儿
// WorkerThread——quartz里的工人
// QuartzSchedulerThread——Quartz里面的老板
public class SimpleExample {
public void run() throws Exception {
Logger log = LoggerFactory.getLogger(SimpleExample.class);
log.info("------- Initializing ----------------------");
// First we must get a reference to a scheduler
SchedulerFactory sf = new StdSchedulerFactory();
Scheduler sched = sf.getScheduler();
log.info("------- Initialization Complete -----------");
// computer a time that is on the next round minute
Date runTime = evenMinuteDate(new Date());
log.info("------- Scheduling Job -------------------");
// define the job and tie it to our HelloJob class
JobDetail job = newJob(HelloJob.class).withIdentity("job1", "group1").build();
// Trigger the job to run on the next round minute
Trigger trigger = newTrigger().withIdentity("trigger1", "group1").startAt(runTime).build();
// Tell quartz to schedule the job using our trigger
sched.scheduleJob(job, trigger);
log.info(job.getKey() + " will run at: " + runTime);
// Start up the scheduler (nothing can actually run until the
// scheduler has been started)
//sched.start();//里面修改pause为false，scheduledThread才退出暂停状态，真正开始工作。
sched.start();
log.info("------- Started Scheduler -----------------");
// wait long enough so that the scheduler as an opportunity to
// run the job!
log.info("------- Waiting 65 seconds... -------------");
try {
// wait 65 seconds to show job
Thread.sleep(65L * 1000L);
// executing...
} catch (Exception e) {
//
}
// shut down the scheduler
log.info("------- Shutting Down ---------------------");
sched.shutdown(true);
log.info("------- Shutdown Complete -----------------");
}
public static void main(String[] args) throws Exception {
SimpleExample example = new SimpleExample();
example.run();
}
}
以这个例子为例，分析一下源码，先说明一下，主要用到了三种类型的线程来执行任务。
SimpleThreadPool——quartz里的工头儿
WorkerThread——quartz里的工人
QuartzSchedulerThread——Quartz里面的老板
QuartzSchedulerThread首先负责轮询 数据库中的触发器，当发现有任务需要执行的时候，就把任务包装一下，分配给SimpleThreadPool，SimpleThreadPool再把任务具体下发给空闲的WorkerThread来执行。
SchedulerFactory sf = new StdSchedulerFactory();
Scheduler sched = sf.getScheduler();
先来分析下这里面主要做了啥，进入getScheduler()。
/**
*
* Returns a handle to the Scheduler produced by this factory.
*
*
*
* If one of the initialize methods has not be previously
* called, then the default (no-arg) initialize() method
* will be called by this method.
*
*/
public Scheduler getScheduler() throws SchedulerException {
if (cfg == null) {
initialize(); //主要是读取quartz.properties,初始化cfg
}
//获取scheruler的存储类，单利
SchedulerRepository schedRep = SchedulerRepository.getInstance();
//获取scheduler，第一次肯定为空
Scheduler sched = schedRep.lookup(getSchedulerName());
if (sched != null) {
if (sched.isShutdown()) {
schedRep.remove(getSchedulerName());
} else {
return sched;
}
}
//根据配置文件初始化scheduler
sched = instantiate();
return sched;
}
初始化scheduler就不细说了代码很长，主要看依一下与数据库连接池相关部分的代码
还有QuartzScheduler的初始化
private Scheduler instantiate() throws SchedulerException {
-------------
//主要就是初始化这些信息的
JobStore js = null;
ThreadPool tp = null;
QuartzScheduler qs = null;
DBConnectionManager dbMgr = null;
String instanceIdGeneratorClass = null;
Properties tProps = null;
String userTXLocation = null;
boolean wrapJobInTx = false;
boolean autoId = false;
long idleWaitTime = -1;
long dbFailureRetry = 15000L; // 15 secs
String classLoadHelperClass;
String jobFactoryClass;
ThreadExecutor threadExecutor;
// Get Scheduler Properties -----
-----
// If Proxying to remote scheduler, short-circuit here...
-----------
// Create class load helper
----------
// If Proxying to remote JMX scheduler, short-circuit here...
------------
// Get ThreadPool Properties 初始化线程池相关
---------
// Get JobStore Properties
------------
// Set up any DataSources 这里就是初始化数据库连接池的
String[] dsNames = cfg.getPropertyGroups(PROP_DATASOURCE_PREFIX);
for (int i = 0; i < dsNames.length; i++) {
PropertiesParser pp = new PropertiesParser(cfg.getPropertyGroup(
PROP_DATASOURCE_PREFIX + "." + dsNames[i], true));
String cpClass = pp.getStringProperty(PROP_CONNECTION_PROVIDER_CLASS, null);
// custom connectionProvider...
if(cpClass != null) {
ConnectionProvider cp = null;
try {
cp = (ConnectionProvider) loadHelper.loadClass(cpClass).newInstance();
} catch (Exception e) {
initException = new SchedulerException("ConnectionProvider class '" + cpClass
+ "' could not be instantiated.", e);
throw initException;
}
try {
// remove the class name, so it isn't attempted to be set
pp.getUnderlyingProperties().remove(
PROP_CONNECTION_PROVIDER_CLASS);
if (cp instanceof PoolingConnectionProvider) {
populateProviderWithExtraProps((PoolingConnectionProvider)cp, pp.getUnderlyingProperties());
} else {
setBeanProps(cp, pp.getUnderlyingProperties());
}
cp.initialize();
} catch (Exception e) {
initException = new SchedulerException("ConnectionProvider class '" + cpClass
+ "' props could not be configured.", e);
throw initException;
}
dbMgr = DBConnectionManager.getInstance();
dbMgr.addConnectionProvider(dsNames[i], cp);
} else {
String dsJndi = pp.getStringProperty(PROP_DATASOURCE_JNDI_URL, null);
if (dsJndi != null) {
//jndi相关
JNDIConnectionProvider cp = new JNDIConnectionProvider(dsJndi,
props, dsAlwaysLookup);
dbMgr = DBConnectionManager.getInstance();
dbMgr.addConnectionProvider(dsNames[i], cp);
} else {//获取数据库连接信息，并初始化数据库连接池
String dsDriver = pp.getStringProperty(PoolingConnectionProvider.DB_DRIVER);
String dsURL = pp.getStringProperty(PoolingConnectionProvider.DB_URL);
if (dsDriver == null) {
initException = new SchedulerException(
"Driver not specified for DataSource: "
+ dsNames[i]);
throw initException;
}
if (dsURL == null) {
initException = new SchedulerException(
"DB URL not specified for DataSource: "
+ dsNames[i]);
throw initException;
}
try {
PoolingConnectionProvider cp = new PoolingConnectionProvider(pp.getUnderlyingProperties());
dbMgr = DBConnectionManager.getInstance();
dbMgr.addConnectionProvider(dsNames[i], cp);
// Populate the underlying C3P0 data source pool properties //c3p0
populateProviderWithExtraProps(cp, pp.getUnderlyingProperties());
} catch (Exception sqle) {
initException = new SchedulerException(
"Could not initialize DataSource: " + dsNames[i],
sqle);
throw initException;
}
}
}
}
-------------
----------------------
//QuartzScheduler的初始化
qs = new QuartzScheduler(rsrcs, idleWaitTime, dbFailureRetry);
qsInited = true;
// Create Scheduler ref...
Scheduler scheduler = instantiate(rsrcs, qs);
// set job factory if specified
if(jobFactory != null) {
qs.setJobFactory(jobFactory);
}
// Initialize plugins now that we have a Scheduler instance.
for (int i = 0; i < plugins.length; i++) {
plugins[i].initialize(pluginNames[i], scheduler, loadHelper);
}
// add listeners
for (int i = 0; i < jobListeners.length; i++) {
qs.getListenerManager().addJobListener(jobListeners[i], EverythingMatcher.allJobs());
}
for (int i = 0; i < triggerListeners.length; i++) {
qs.getListenerManager().addTriggerListener(triggerListeners[i], EverythingMatcher.allTriggers());
}
// set scheduler context data...
for(Object key: schedCtxtProps.keySet()) {
String val = schedCtxtProps.getProperty((String) key);
scheduler.getContext().put((String)key, val);
}
// fire up job store, and runshell factory
js.setInstanceId(schedInstId);
js.setInstanceName(schedName);
js.setThreadPoolSize(tp.getPoolSize());
js.initialize(loadHelper, qs.getSchedulerSignaler());
jrsf.initialize(scheduler);
qs.initialize();
getLog().info(
"Quartz scheduler '" + scheduler.getSchedulerName()
+ "' initialized from " + propSrc);
getLog().info("Quartz scheduler version: " + qs.getVersion());
// prevents the repository from being garbage collected
qs.addNoGCObject(schedRep);
// prevents the db manager from being garbage collected
if (dbMgr != null) {
qs.addNoGCObject(dbMgr);
}
schedRep.bind(scheduler);
return scheduler;
}
进入 new QuartzScheduler(rsrcs, idleWaitTime, dbFailureRetry);
public QuartzScheduler(QuartzSchedulerResources resources, long idleWaitTime, @Deprecated long dbRetryInterval)
throws SchedulerException {
this.resources = resources;
if (resources.getJobStore() instanceof JobListener) {
addInternalJobListener((JobListener)resources.getJobStore());
}
//这里就是老板线程生产的地方
this.schedThread = new QuartzSchedulerThread(this, resources);
ThreadExecutor schedThreadExecutor = resources.getThreadExecutor();
//这里老板线程开始工作了，剥削底层劳动人民了
schedThreadExecutor.execute(this.schedThread);
if (idleWaitTime > 0) {
this.schedThread.setIdleWaitTime(idleWaitTime);
}
jobMgr = new ExecutingJobsManager();
addInternalJobListener(jobMgr);
errLogger = new ErrorLogger();
addInternalSchedulerListener(errLogger);
signaler = new SchedulerSignalerImpl(this, this.schedThread);
if(shouldRunUpdateCheck())
updateTimer = scheduleUpdateCheck();
else
updateTimer = null;
getLog().info("Quartz Scheduler v." + getVersion() + " created.");
}
看下
public class QuartzSchedulerThread extends Thread {
public void run() {
boolean lastAcquireFailed = false;
while (!halted.get()) {
try {
// check if we're supposed to pause...
synchronized (sigLock) {
while (paused && !halted.get()) {
try {
// wait until togglePause(false) is called...
sigLock.wait(1000L);
} catch (InterruptedException ignore) {
}
}
if (halted.get()) {
break;
}
}
int availThreadCount = qsRsrcs.getThreadPool().blockForAvailableThreads();
if(availThreadCount > 0) { // will always be true, due to semantics of blockForAvailableThreads...
List triggers = null;
long now = System.currentTimeMillis();
clearSignaledSchedulingChange();
try {
triggers = qsRsrcs.getJobStore().acquireNextTriggers(
now + idleWaitTime, Math.min(availThreadCount, qsRsrcs.getMaxBatchSize()), qsRsrcs.getBatchTimeWindow());
lastAcquireFailed = false;
if (log.isDebugEnabled())
log.debug("batch acquisition of " + (triggers == null ? 0 : triggers.size()) + " triggers");
} catch (JobPersistenceException jpe) {
if(!lastAcquireFailed) {
qs.notifySchedulerListenersError(
"An error occurred while scanning for the next triggers to fire.",
jpe);
}
lastAcquireFailed = true;
continue;
} catch (RuntimeException e) {
if(!lastAcquireFailed) {
getLog().error("quartzSchedulerThreadLoop: RuntimeException "
+e.getMessage(), e);
}
lastAcquireFailed = true;
continue;
}
if (triggers != null && !triggers.isEmpty()) {
now = System.currentTimeMillis();
long triggerTime = triggers.get(0).getNextFireTime().getTime();
long timeUntilTrigger = triggerTime - now;
while(timeUntilTrigger > 2) {
synchronized (sigLock) {
if (halted.get()) {
break;
}
if (!isCandidateNewTimeEarlierWithinReason(triggerTime, false)) {
try {
// we could have blocked a long while
// on 'synchronize', so we must recompute
now = System.currentTimeMillis();
timeUntilTrigger = triggerTime - now;
if(timeUntilTrigger >= 1)
sigLock.wait(timeUntilTrigger);
} catch (InterruptedException ignore) {
}
}
}
if(releaseIfScheduleChangedSignificantly(triggers, triggerTime)) {
break;
}
now = System.currentTimeMillis();
timeUntilTrigger = triggerTime - now;
}
// this happens if releaseIfScheduleChangedSignificantly decided to release triggers
if(triggers.isEmpty())
continue;
// set triggers to 'executing'
List bndles = new ArrayList();
boolean goAhead = true;
synchronized(sigLock) {
goAhead = !halted.get();
}
if(goAhead) {
try {
List res = qsRsrcs.getJobStore().triggersFired(triggers);
if(res != null)
bndles = res;
} catch (SchedulerException se) {
qs.notifySchedulerListenersError(
"An error occurred while firing triggers '"
+ triggers + "'", se);
//QTZ-179 : a problem occurred interacting with the triggers from the db
//we release them and loop again
for (int i = 0; i < triggers.size(); i++) {
qsRsrcs.getJobStore().releaseAcquiredTrigger(triggers.get(i));
}
continue;
}
}
for (int i = 0; i < bndles.size(); i++) {
TriggerFiredResult result = bndles.get(i);
TriggerFiredBundle bndle = result.getTriggerFiredBundle();
Exception exception = result.getException();
if (exception instanceof RuntimeException) {
getLog().error("RuntimeException while firing trigger " + triggers.get(i), exception);
qsRsrcs.getJobStore().releaseAcquiredTrigger(triggers.get(i));
continue;
}
// it's possible to get 'null' if the triggers was paused,
// blocked, or other similar occurrences that prevent it being
// fired at this time... or if the scheduler was shutdown (halted)
if (bndle == null) {
qsRsrcs.getJobStore().releaseAcquiredTrigger(triggers.get(i));
continue;
}
//这部分代码就是调用了，我们实现的那个job类，主要部分
JobRunShell shell = null;
try {
shell = qsRsrcs.getJobRunShellFactory().createJobRunShell(bndle);
shell.initialize(qs);
} catch (SchedulerException se) {
qsRsrcs.getJobStore().triggeredJobComplete(triggers.get(i), bndle.getJobDetail(), CompletedExecutionInstruction.SET_ALL_JOB_TRIGGERS_ERROR);
continue;
}
if (qsRsrcs.getThreadPool().runInThread(shell) == false) {
// this case should never happen, as it is indicative of the
// scheduler being shutdown or a bug in the thread pool or
// a thread pool being used concurrently - which the docs
// say not to do...
getLog().error("ThreadPool.runInThread() return false!");
qsRsrcs.getJobStore().triggeredJobComplete(triggers.get(i), bndle.getJobDetail(), CompletedExecutionInstruction.SET_ALL_JOB_TRIGGERS_ERROR);
}
}
continue; // while (!halted)
}
} else { // if(availThreadCount > 0)
// should never happen, if threadPool.blockForAvailableThreads() follows contract
continue; // while (!halted)
}
long now = System.currentTimeMillis();
long waitTime = now + getRandomizedIdleWaitTime();
long timeUntilContinue = waitTime - now;
synchronized(sigLock) {
try {
if(!halted.get()) {
// QTZ-336 A job might have been completed in the mean time and we might have
// missed the scheduled changed signal by not waiting for the notify() yet
// Check that before waiting for too long in case this very job needs to be
// scheduled very soon
if (!isScheduleChanged()) {
sigLock.wait(timeUntilContinue);
}
}
} catch (InterruptedException ignore) {
}
}
} catch(RuntimeException re) {
getLog().error("Runtime error occurred in main trigger firing loop.", re);
}
} // while (!halted)
// drop references to scheduler stuff to aid garbage collection...
qs = null;
qsRsrcs = null;
}
}
拿出主要部分，细看一下
JobRunShell shell = null;
try {
shell = qsRsrcs.getJobRunShellFactory().createJobRunShell(bndle);
shell.initialize(qs);
} catch (SchedulerException se) {
qsRsrcs.getJobStore().triggeredJobComplete(triggers.get(i), bndle.getJobDetail(), CompletedExecutionInstruction.SET_ALL_JOB_TRIGGERS_ERROR);
continue;
}
//这里将JobRunShell（实现了Runnable接口）交给workThread执行，后面看下该方法
if (qsRsrcs.getThreadPool().runInThread(shell) == false) {
// this case should never happen, as it is indicative of the
// scheduler being shutdown or a bug in the thread pool or
// a thread pool being used concurrently - which the docs
// say not to do...
getLog().error("ThreadPool.runInThread() return false!");
qsRsrcs.getJobStore().triggeredJobComplete(triggers.get(i), bndle.getJobDetail(), CompletedExecutionInstruction.SET_ALL_JOB_TRIGGERS_ERROR);
}
shell.initialize(qs); 进入方法
public void initialize(QuartzScheduler sched)
throws SchedulerException {
this.qs = sched;
Job job = null;
JobDetail jobDetail = firedTriggerBundle.getJobDetail();
try {
//这里就是实例化，我们实现的job类
job = sched.getJobFactory().newJob(firedTriggerBundle, scheduler);
} catch (SchedulerException se) {
sched.notifySchedulerListenersError(
"An error occured instantiating job to be executed. job= '"
+ jobDetail.getKey() + "'", se);
throw se;
} catch (Throwable ncdfe) { // such as NoClassDefFoundError
SchedulerException se = new SchedulerException(
"Problem instantiating class '"
+ jobDetail.getJobClass().getName() + "' - ", ncdfe);
sched.notifySchedulerListenersError(
"An error occured instantiating job to be executed. job= '"
+ jobDetail.getKey() + "'", se);
throw se;
}
//这里就是传入Job接口里面的方法的参数，后面会用到
this.jec = new JobExecutionContextImpl(scheduler, firedTriggerBundle, job);
}
qsRsrcs.getThreadPool().runInThread(shell) 进入该方法看下，其实就是我们的SimpleThreadPool,包工头
public class SimpleThreadPool implements ThreadPool {
------------
public boolean runInThread(Runnable runnable) {
if (runnable == null) {
return false;
}
synchronized (nextRunnableLock) {
handoffPending = true;
// Wait until a worker thread is available
while ((availWorkers.size() < 1) && !isShutdown) {
try {
nextRunnableLock.wait(500);
} catch (InterruptedException ignore) {
}
}
if (!isShutdown) {//如果没有暂停，获取一个空闲的WorkerThread,执行任务
WorkerThread wt = (WorkerThread)availWorkers.removeFirst();
busyWorkers.add(wt);
wt.run(runnable);
} else {//如果已经暂停，用一个单独的WorkerThread执行
// If the thread pool is going down, execute the Runnable
// within a new additional worker thread (no thread from the pool).
WorkerThread wt = new WorkerThread(this, threadGroup,
"WorkerThread-LastJob", prio, isMakeThreadsDaemons(), runnable);
busyWorkers.add(wt);
workers.add(wt);
wt.start();
}
nextRunnableLock.notifyAll();
handoffPending = false;
}
return true;
}
-----------------------
}
看看WorkerThread
class WorkerThread extends Thread {
@Override
public void run() {
boolean ran = false;
while (run.get()) {
try {
synchronized(lock) {
while (runnable == null && run.get()) {
lock.wait(500);
}
if (runnable != null) {
ran = true;
//这里的runnable就是刚刚的JobRunShell
runnable.run();
}
}
} catch (InterruptedException unblock) {
// do nothing (loop will terminate if shutdown() was called
try {
getLog().error("Worker thread was interrupt()'ed.", unblock);
} catch(Exception e) {
// ignore to help with a tomcat glitch
}
} catch (Throwable exceptionInRunnable) {
try {
getLog().error("Error while executing the Runnable: ",
exceptionInRunnable);
} catch(Exception e) {
// ignore to help with a tomcat glitch
}
} finally {
synchronized(lock) {
runnable = null;
}
// repair the thread in case the runnable mucked it up...
if(getPriority() != tp.getThreadPriority()) {
setPriority(tp.getThreadPriority());
}
if (runOnce) {
run.set(false);
clearFromBusyWorkersList(this);
} else if(ran) {
ran = false;
makeAvailable(this);
}
}
}
//if (log.isDebugEnabled())
try {
getLog().debug("WorkerThread is shut down.");
} catch(Exception e) {
// ignore to help with a tomcat glitch
}
}
}
public class JobRunShell extends SchedulerListenerSupport implements Runnable {
-----------------
public void run() {
qs.addInternalSchedulerListener(this);
try {
OperableTrigger trigger = (OperableTrigger) jec.getTrigger();
JobDetail jobDetail = jec.getJobDetail();
do {
JobExecutionException jobExEx = null;
Job job = jec.getJobInstance();
try {
begin();
} catch (SchedulerException se) {
qs.notifySchedulerListenersError("Error executing Job ("
+ jec.getJobDetail().getKey()
+ ": couldn't begin execution.", se);
break;
}
// notify job & trigger listeners...
try {
if (!notifyListenersBeginning(jec)) {
break;
}
} catch(VetoedException ve) {
try {
CompletedExecutionInstruction instCode = trigger.executionComplete(jec, null);
qs.notifyJobStoreJobVetoed(trigger, jobDetail, instCode);
// QTZ-205
// Even if trigger got vetoed, we still needs to check to see if it's the trigger's finalized run or not.
if (jec.getTrigger().getNextFireTime() == null) {
qs.notifySchedulerListenersFinalized(jec.getTrigger());
}
complete(true);
} catch (SchedulerException se) {
qs.notifySchedulerListenersError("Error during veto of Job ("
+ jec.getJobDetail().getKey()
+ ": couldn't finalize execution.", se);
}
break;
}
long startTime = System.currentTimeMillis();
long endTime = startTime;
// execute the job 执行我们实现的Job的方法，就是在这里
try {
log.debug("Calling execute on job " + jobDetail.getKey());
job.execute(jec);
endTime = System.currentTimeMillis();
} catch (JobExecutionException jee) {
endTime = System.currentTimeMillis();
jobExEx = jee;
getLog().info("Job " + jobDetail.getKey() +
" threw a JobExecutionException: ", jobExEx);
} catch (Throwable e) {
endTime = System.currentTimeMillis();
getLog().error("Job " + jobDetail.getKey() +
" threw an unhandled Exception: ", e);
SchedulerException se = new SchedulerException(
"Job threw an unhandled exception.", e);
qs.notifySchedulerListenersError("Job ("
+ jec.getJobDetail().getKey()
+ " threw an exception.", se);
jobExEx = new JobExecutionException(se, false);
}
jec.setJobRunTime(endTime - startTime);
// notify all job listeners
if (!notifyJobListenersComplete(jec, jobExEx)) {
break;
}
CompletedExecutionInstruction instCode = CompletedExecutionInstruction.NOOP;
// update the trigger
try {
instCode = trigger.executionComplete(jec, jobExEx);
} catch (Exception e) {
// If this happens, there's a bug in the trigger...
SchedulerException se = new SchedulerException(
"Trigger threw an unhandled exception.", e);
qs.notifySchedulerListenersError(
"Please report this error to the Quartz developers.",
se);
}
// notify all trigger listeners
if (!notifyTriggerListenersComplete(jec, instCode)) {
break;
}
// update job/trigger or re-execute job
if (instCode == CompletedExecutionInstruction.RE_EXECUTE_JOB) {
jec.incrementRefireCount();
try {
complete(false);
} catch (SchedulerException se) {
qs.notifySchedulerListenersError("Error executing Job ("
+ jec.getJobDetail().getKey()
+ ": couldn't finalize execution.", se);
}
continue;
}
try {
complete(true);
} catch (SchedulerException se) {
qs.notifySchedulerListenersError("Error executing Job ("
+ jec.getJobDetail().getKey()
+ ": couldn't finalize execution.", se);
continue;
}
qs.notifyJobStoreJobComplete(trigger, jobDetail, instCode);
break;
} while (true);
} finally {
qs.removeInternalSchedulerListener(this);
}
}
----------------------
}
完结