I have a job scheduled in Liferay, if for example this job is running every 5 minutes and needs more than 5 minutes to complete, how is it handled in Liferay?
What I have observed is that the job will just start again, this could result in problems for me.
Is it somehow possible to not trigger a job, when it is already running?
*using liferay 6.0.6
Thanks
Try LockLocalServiceUtil and its methods lock(), unlock() and isLocked(). Something like this:
try {
if (LockLocalServiceUtil.isLocked()) {
return;
}
LockLocalServiceUtil.lock();
// do your job
} finally {
LockLocalServiceUtil.unlock();
}
Locks are stored in database so there will be no problem in a cluster environment.
This might not be the best practice but here goes
private static boolean runningJob = false;
#Override
public void receive(Message arg0) throws MessageListenerException {
if(runningJob)
return;
runningJob = true; //marking that a job just started
//Do stuff { ....... } // this might take a while
runningJob = false;
}
Related
i am making cron job like loop to do something using new thread.
when module stop, this thread keeps running, so when i deployed updated module, i'm afraid it will make duplicate thread doing similar task
#Component(immediate = true, service = ExportImportLifecycleListener.class)
public class StaticUtils extends Utils{
private StaticUtils() {}
private static class SingletonHelper{
private static final StaticUtils INSTANCE = new StaticUtils();
}
public static StaticUtils getInstance() {
return SingletonHelper.INSTANCE;
}
}
public class Utils extends BaseExportImportLifecycleListener{
public Utils() {
startTask();
}
protected Boolean CRON_START = true;
private void startTask() {
new Thread(new Runnable() {
public void run() {
while (CRON_START) {
System.out.println("test naon bae lah ");
}
}
}).start();
}
#Deactivate
protected void deactivate() {
CRON_START = false;
System.out.println(
"cron stop lah woooooooooooooooooy");
}
}
i'm using liferay 7
I have populated task that i store from db, so this thread is checking is there a task that it must do, then if it exist execute it.
I'm quite new in osgi and liferay. i've try to use scheduler and failed and also exportimportlifecycle listener but dont really get it yet
think again: Do you really need something to run all the time in the background, or do you just need some asynchronous processing in the background, when triggered? It might be better to start a background task as a one-off, that automatically terminates
Liferay provides an internal MessageBus, that you can utilize to listen to events and implement background processing, without the need for a custom thread
You're in the OSGi world, so you can utilize #Activate, #Modified, #Deactivate (from org.osgi.service.component.annotations) or use a org.osgi.framework.BundleActivator.
But, in general, it's preferable if you don't start your own thread
I have been having trouble for a while with two recurring jobs (the ones at the top of this list) that don't get run even though they are scheduled.
I can trigger them just fine, and they get rescheduled, but when the schedule time comes around they don't run, and the "Next Execution" time just slips into the past.
Now there are a bunch of other jobs that are having the same problem. These are supposed to run hourly, but if they get past the schedule time they just don't run.
Visiting the dashboard makes no difference. The web app is always on. Hangfire will never run these jobs unless I trigger them manually. Jobs that AREN'T in this state still run just fine as scheduled every day or every hour.
What would cause this?
My hangfire instance (version 1.7.6) is in an Azure WebApp that is set to be always running. It uses an Azure-sql database for its data store.
Here's my Bootstrapper.cs code:
using System.Configuration;
using System.Web.Hosting;
using Hangfire;
namespace MyApi
{
public class HangfireBootstrapper : IRegisteredObject
{
public static readonly HangfireBootstrapper Instance = new HangfireBootstrapper();
private readonly object _lockObject = new object();
private bool _started;
private BackgroundJobServer _backgroundJobServer;
private HangfireBootstrapper()
{
}
public void Start()
{
lock (_lockObject)
{
if (_started) return;
_started = true;
HostingEnvironment.RegisterObject(this);
var jobOptions = new BackgroundJobServerOptions();
jobOptions.ServerName = ConfigurationManager.AppSettings.Get("hangfire:servername");
jobOptions.Queues = new[] {"k1"};
GlobalConfiguration.Configuration
.UseSqlServerStorage("Kdb");
_backgroundJobServer = new BackgroundJobServer(jobOptions);
}
}
public void Stop()
{
lock (_lockObject)
{
if (_backgroundJobServer != null)
{
_backgroundJobServer.Dispose();
}
HostingEnvironment.UnregisterObject(this);
}
}
void IRegisteredObject.Stop(bool immediate)
{
Stop();
}
}
}
Here's code that is used to queue the majority of the jobs:
jobMgr.AddOrUpdate($"Script.{i1}.{name}", Job.FromExpression(() => HangfireJobs.ReplayQueue.EnqueueScript(scriptId, i1, null)),cronExpression);
Here's how my EnqueueScript method is defined:
[Queue("k1")]
public static void EnqueueScript(Guid scriptId, int env, PerformContext context)
{
try
{
...
This issue was resolved by upgrading Hangfire to version 1.7.8.
The Hangfire bug report is viewable at https://github.com/HangfireIO/Hangfire/issues/1459
It appears to have been introduced around version 1.7.4 (maybe earlier, but certainly by then) and fixed with version 1.7.8.
I'm developing an android app that receives and processes mail messages. The app must be connected to an IMAP server and keep the connection alive, so it can see and process new mail messages instantly (mails contains json data from a mail api server). The app have two modes, manual and live connection. Here is some of my code:
class Idler {
Thread th;
volatile Boolean isIdling=false;
boolean shouldsync=false;//we need to see if we have unseen mails
Object idleLock;
Handler handler=new Handler();
IMAPFolder inbox;
public boolean keppAliveConnection;//keep alive connection, or manual mode
//This thread should keep the idle connection alive, or in case it's set to manual mode (keppAliveConnection=false) get new mail.
Thread refreshThread;
synchronized void refresh()
{
if(isIdling)//if already idling, just keep connection alive
{
refreshThread =new Thread(new Runnable() {
#Override
public void run() {
try {
inbox.doCommand(new IMAPFolder.ProtocolCommand() {
#Override
public Object doCommand(IMAPProtocol protocol) throws ProtocolException {
//Why not noop?
//any call to IMAPFolder.doCommand() will trigger waitIfIdle, this
//issues a "DONE" command and waits for idle to return(ideally with a DONE server response).
// So... I think NOOP is unnecessary
//protocol.simpleCommand("NOOP",null); I'm not issuing noop due to what I said ^
//PD: if connection was broken, then server response will never arrive, and idle will keep running forever
//without triggering messagesAdded event any more :'( I see any other explanation to this phenomenon
return null;
}
});
} catch (MessagingException e) {
e.printStackTrace();
}
}
},"SyncThread");
refreshThread.start();
}
else
{
getNewMail();//If manual mode keppAliveConnection=false) get the new mail
}
}
public Idler()
{
th=new Thread(new Runnable() {
#SuppressWarnings("InfiniteLoopStatement")
#Override
public void run() {
while (true)
{
try {
if(refreshThread !=null && refreshThread.isAlive())
refreshThread.interrupt();//if the refresher thread is active: interrupt. I thing this is not necessary at this point, but not shure
initIMAP();//initializes imap store
try {
shouldsync=connectIMAP()||shouldsync;//if was disconnected or ordered to sync: needs to sync
}
catch (Exception e)
{
Thread.sleep(5000);//if can't connect: wait some time and throw
throw e;
}
shouldsync=initInbox()||shouldsync;//if inbox was null or closed: needs to sync
if(shouldsync)//if needs to sync
{
getNewMail();//gets new unseen mail
shouldsync=false;//already refreshed, clear sync "flag"
}
while (keppAliveConnection) {//if sould keep idling "forever"
synchronized (idleLock){}//MessageCountListener may be doing some work... wait for it
isIdling = true; //set isIdling "flag"
handler.removeCallbacksAndMessages(null);//clears refresh scheduled tasks
handler.postDelayed(new Runnable() {
#Override
public void run() {
refresh();
}
},1200000);//Schedule a refresh in 20 minutes
inbox.idle();//start idling
if(refreshThread !=null && refreshThread.isAlive())
refreshThread.interrupt();//if the refresher thread is active: interrupt. I thing this is not necessary at this point, but not shure
handler.removeCallbacksAndMessages(null);//clears refresh scheduled tasks
isIdling=false;//clear isIdling "flag"
if(shouldsync)
break;//if ordered to sync... break. The loop will handle it upstairs.
synchronized (idleLock){}//MessageCountListener may be doing some work... wait for it
}
}
catch (Exception e) {
//if the refresher thread is active: interrupt
//Why interrupt? refresher thread may be waiting for idle to return after "DONE" command, but if folder was closed and throws
//a FolderClosedException, then it could wait forever...., so... interrupt.
if (refreshThread != null && refreshThread.isAlive())
refreshThread.interrupt();
handler.removeCallbacksAndMessages(null);//clears refresh scheduled tasks
}
}
}
},"IdlerThread");
th.start();
}
private synchronized void getNewMail()
{
shouldsync=false;
long uid=getLastSeen();//get last unprocessed mail
SearchTerm searchTerm=new UidTerm(uid,Long.MAX_VALUE);//search from las processed message to the las one.
IMAPSearchOperation so=new IMAPSearchOperation(searchTerm);
try {
so.run();//search new messages
final long[] is=so.uids();//get unprocessed messages count
if (is.length > 0) {//if some...
try {
//there are new messages
IMAPFetchMessagesOperation fop=new IMAPFetchMessagesOperation(is);
fop.run();//fetch new messages
if(fop.messages.length>0)
{
//process fetched messages (internally sets the last seen uid value & delete some...)
processMessages(fop.messages);
}
inbox.expunge();//expunge deleted messages if any
}
catch (Exception e)
{
//Do something
}
}
else
{
//Do something
}
}
catch (Exception e)
{
//Do something
}
}
private synchronized void initIMAP()
{
if(store==null)
{
store=new IMAPStore(mailSession,new URLName("imap",p.IMAPServer,p.IMAPPort,null,p.IMAPUser,p.IMAPPassword));
}
}
private boolean connectIMAP() throws MessagingException {
try {
store.connect(p.IMAPServer, p.IMAPPort, p.IMAPUser, p.IMAPPassword);
return true;
}
catch (IllegalStateException e)
{
return false;
}
}
//returns true if the folder was closed or null
private synchronized boolean initInbox() throws MessagingException {
boolean retVal=false;
if(inbox==null)
{//if null, create. This is called after initializing store
inbox = (IMAPFolder) store.getFolder("INBOX");
inbox.addMessageCountListener(countListener);
retVal=true;//was created
}
if(!inbox.isOpen())
{
inbox.open(Folder.READ_WRITE);
retVal=true;//was oppened
}
return retVal;
}
private MessageCountListener countListener= new MessageCountAdapter() {
#Override
public void messagesAdded(MessageCountEvent ev) {
synchronized (idleLock)
{
try {
processMessages(ev.getMessages());//process the new messages, (internally sets the last seen uid value & delete some...)
inbox.expunge();//expunge deleted messajes if any
} catch (MessagingException e) {
//Do something
}
}
}
};
}
The problem is: Sometimes when the user is refreshing or the app auto-refreshes, in the Alive Connection mode, one or both of this conditions keeps my app from getting new messages. This is from the javamail source code.
1: The IdlerThread enters monitor state in:
//I don't know why sometimes it enters monitor state here.
private synchronized void throwClosedException(ConnectionException cex)
throws FolderClosedException, StoreClosedException {
// If it's the folder's protocol object, throw a FolderClosedException;
// otherwise, throw a StoreClosedException.
// If a command has failed because the connection is closed,
// the folder will have already been forced closed by the
// time we get here and our protocol object will have been
// released, so if we no longer have a protocol object we base
// this decision on whether we *think* the folder is open.
if ((protocol != null && cex.getProtocol() == protocol) ||
(protocol == null && !reallyClosed))
throw new FolderClosedException(this, cex.getMessage());
else
throw new StoreClosedException(store, cex.getMessage());
}
2: The "refresherThread" enters wait state in:
void waitIfIdle() throws ProtocolException {
assert Thread.holdsLock(messageCacheLock);
while (idleState != RUNNING) {
if (idleState == IDLE) {
protocol.idleAbort();
idleState = ABORTING;
}
try {
// give up lock and wait to be not idle
messageCacheLock.wait();//<-----This is the line is driving me crazy.
} catch (InterruptedException ex) { }
}
}
As one of both of this threads "stops" running (wait & monitor state) my app is useless when reach this condition. In my country the mobile data network is very unstable, slow & expensive(GSM) So it must be failure resilient and take care about every transferred bit.
I guess the problem arises when the connection silently fails and the refresherThread starts to do its job. It issues a DONE command if idle is active, but, as the connection is gone, when idle tries to throw a FolderClosedException, one or both threads gets locked indefinitely.
So, my question is: Why is this situation arising and how to prevent it? How can I keep the idle loop securely running without getting locked?
I've tried a lot of things till exhaustion with no results.
Here are some threads I've read without getting a solution to my problem. In my country internet is EXTREMELY expensive too, so I can't research as much as I want, nor list all the urls I've visited looking for information.
JavaMail: Keeping IMAPFolder.idle() alive
JavaMail: Keeping IMAPFolder.idle() alive
Javamail : Proper way to issue idle() for IMAPFolder
Please, excuse my english. Any suggestion will be greatly appreciated. I've heard about this site strictness, so please be gentle, I'm new over here.
Be sure to set the timeout properties to make sure you don't hang waiting for a dead connection or server.
Instead of issuing a nop command directly, you should call Folder.isOpen or Folder.getMessageCount; they'll issue the nop command if needed.
If the folder is closed asynchronously (FolderClosedException), you'll need to restart the idle loop.
We are launching a website that will have a very heavy volume for a short period of time. It is basically giving tickets. The code is written in Java, Spring & Hibernate. I want to mimic the high volume by spawning multiple threads and trying to get the ticket using JUnit test case. The problem is that in my DAO class the code just simply dies after I begin transaction. I mean there is no error trace in the log file or anything like that. Let me give some idea about the way my code is.
DAO code:
#Repository("customerTicketDAO")
public class CustomerTicketDAO extends BaseDAOImpl {// BaseDAOImpl extends HibernateDaoSupport
public void saveCustomerTicketUsingJDBC(String customerId) {
try{
getSession().getTransaction().begin(); //NOTHING HAPPENS AFTER THIS LINE OF CODE
// A select query
Query query1 = getSession().createSQLQuery("my query omitted on purpose");
.
.
// An update query
Query query2 = getSession().createSQLQuery("my query omitted on purpose");
getSession().getTransaction().commite();
} catch (Exception e) {
}
}
Runnable code:
public class InsertCustomerTicketRunnable implements Runnable {
#Autowired
private CustomerTicketDAO customerTicketDAO;
public InsertCustomerTicketRunnable(String customerId) {
this.customerId = customerId;
}
#Override
public void run() {
if (customerTicketDAO != null) {
customerTicketDAO.saveCustomerTicketUsingJDBC(customerId);
}
}
}
JUnit method:
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(locations={"file:src/test/resources/applicationContext-test.xml"})
public class DatabaseTest {
#Before
public void init() {
sessionFactory = (SessionFactory)applicationContext.getBean("sessionFactory");
Session session = SessionFactoryUtils.getSession(sessionFactory, true);
TransactionSynchronizationManager.bindResource(sessionFactory, new SessionHolder(session));
customerTicketDAO = (CustomerTicketDAO)applicationContext.getBean("customerTicketDAO");
}
#After
public void end() throws Exception {
SessionHolder sessionHolder = (SessionHolder) TransactionSynchronizationManager.unbindResource(sessionFactory);
SessionFactoryUtils.closeSession(session);
}
#Test
public void saveCustomerTicketInMultipleThreads () throws Exception {
ExecutorService executor = Executors.newFixedThreadPool(NTHREDS);
for (int i=0; i<1000; i++) {
executor.submit(new InsertCustomerTicketRunnable(i));
}
// This will make the executor accept no new threads
// and finish all existing threads in the queue
executor.shutdown();
// Wait until all threads are finish
executor.awaitTermination(1, TimeUnit.SECONDS);
}
I see no data being inserted into the database. Can someone please point me as to where I am going wrong?
Thanks
Raj
SessionFactory is thread safe but Session is not. So my guess is that you need to call SessionFactoryUtils.getSession() from within each thread, so that each thread gets its own instance. You are currently calling it from the main thread, so all children threads try to share the same instance.
Naughty, naughty!
public void saveCustomerTicketUsingJDBC(String customerId) {
try {
getSession().getTransaction().begin(); //NOTHING HAPPENS AFTER THIS LINE OF CODE
.
.
} catch (Exception e) {
}
}
You should never (well, hardly ever) have an empty catch block, if there is a problem you will find that your code 'just simply dies' with no log messages. Oh look, that's what's happening ;)
At the very minimum you should log the exception, that will go a long way towards you helping you find what the problem is (and from there, the solution).
I am learning creating windows services and threading. I am using a library provided by fellow worker that aids in building threaded service but this is not giving me the knowledge at the basic level.
Lets say i will have a service that will be long running (little advance than the basic example available on the net), needs to wake up every 15 seconds and then perform its action (basically will be always running). Action involves looking for a status in the DB and then performing actions.
How should the following be handled in such cases:
1. disposing the thread
2. in cases where action takes longer to execute than the interval.
I have found the following example but i am having problems with the above 2 points. Please do keep in mind that the service will be running always.
http://www.java2s.com/Tutorial/CSharp/0280__Development/CreatethedelegatethattheTimerwillcall.htm
using System;
using System.Threading;
class MainClass
{
public static void CheckTime(Object state)
{
Console.WriteLine(DateTime.Now);
}
public static void Main()
{
TimerCallback tc = new TimerCallback(CheckTime);
Timer t = new Timer(tc, null, 1000, 500);
Console.WriteLine("Press Enter to exit");
int i = Console.Read();
// clean up the resources
t.Dispose();
t = null;
}
}
So in my example, what will go in
1. stop event
2. Does start event looks good?
3. what should happen if nothing found in the queue?
4. What if the actions take longer than the interval?
public partial class QueueService : ServiceBase
{
public QueueService()
{
InitializeComponent();
}
protected override void OnStart(string[] args)
{
try
{
TimerCallback tc = new TimerCallback(CheckQueue);
Timer t = new Timer(tc, null, 10000, 15000); //first time wait for 10seconds and then execte every 15seconds
}
catch (Exception ex)
{
what should i be checking here and then also make sure that the threading/timer doesn't stop. It should still execute every 15 seconds
}
}
protected override void OnStop()
{
what needs to go here...
}
private static void CheckQueue(Object state)
{
... Connect to the DB
... Check status
... if queue status found then perform actions
. A
. C
. T
. I
. O
. N
. S
... if end
}
}
Thanks for looking!
Disposing the timer.
Not completely. You need to declare the timer at class level otherwise it will be collected after few iterations.
Nothing.
Stop the timer before you check the queue and start it again after you finish with it. This way you won't get into troubles of shared memory or other collisions.
public partial class QueueService : ServiceBase
{
Timer timer;
public QueueService()
{
InitializeComponent();
}
protected override void OnStart(string[] args)
{
try
{
TimerCallback tc = new TimerCallback(CheckQueue);
timer = new Timer(tc, null, 10000, 15000);
}
catch (Exception ex)
{
}
}
protected override void OnStop()
{
if (timer != null)
timer.Dispose();
}
private static void CheckQueue(Object state)
{
timer.Change(Timeout.Infinite, 0);
... Connect to the DB
... Check status
... if queue status found then perform actions
. A
. C
. T
. I
. O
. N
. S
... if end
timer.Change(10000, 15000);
}
}