Package org.eclipse.core.runtime.jobs

Interface IJobManager

public interface IJobManager
The job manager provides facilities for scheduling, querying, and maintaining jobs and locks. In particular, the job manager provides the following services:
  • Maintains a queue of jobs that are waiting to be run. Items can be added to the queue using the schedule method.
  • Allows manipulation of groups of jobs called job families. Job families can be canceled, put to sleep, or woken up atomically. There is also a mechanism for querying the set of known jobs in a given family.
  • Allows listeners to find out about progress on running jobs, and to find out when jobs have changed states.
  • Provides a factory for creating lock objects. Lock objects are smart monitors that have strategies for avoiding deadlock.
  • Provide feedback to a client that is waiting for a given job or family of jobs to complete.
Since:
3.0
See Also:
Restriction:
This interface is not intended to be implemented by clients.
Restriction:
This interface is not intended to be extended by clients.

  • Field Details

    • PROP_USE_DAEMON_THREADS

      static final String PROP_USE_DAEMON_THREADS
      A system property key indicating whether the job manager should create job threads as daemon threads. Set to true to force all worker threads to be created as daemon threads. Set to false to force all worker threads to be created as non-daemon threads.
      Since:
      3.3
      See Also:

  • Method Details

    • addJobChangeListener

      void addJobChangeListener(IJobChangeListener listener)
      Registers a job listener with the job manager. Has no effect if an identical listener is already registered.
      Parameters:
      listener - the listener to be added
      See Also:

    • beginRule

      void beginRule(ISchedulingRule rule, IProgressMonitor monitor)
      Begins applying this rule in the calling thread. If the rule conflicts with another rule currently running in another thread, this method blocks until there are no conflicting rules. Calls to beginRule must eventually be followed by a matching call to endRule in the same thread and with the identical rule instance.

      Rules can be nested only if the rule for the inner beginRule is contained within the rule for the outer beginRule. Rule containment is tested with the API method ISchedulingRule.contains. Also, begin/end pairs must be strictly nested. Only the rule that has most recently begun can be ended at any given time.

      A rule of null can be used, but will be ignored for scheduling purposes. The outermost non-null rule in the thread will be used for scheduling. A null rule that is begun must still be ended.

      If this method is called from within a job that has a scheduling rule, the given rule must also be contained within the rule for the running job.

      Note that endRule must be called even if beginRule fails. The recommended usage is: 

       final ISchedulingRule rule = ...;
 try {
        manager.beginRule(rule, monitor);
 } finally {
        manager.endRule(rule);
 }
      Parameters:
      rule - the rule to begin applying in this thread, or null
      monitor - a progress monitor, or null if progress reporting and cancellation are not desired
      Throws:
      IllegalArgumentException - if the rule is not strictly nested within all other rules currently active for this thread
      OperationCanceledException - if the supplied monitor reports cancelation before the rule becomes available
      See Also:

    • cancel

      void cancel(Object family)
      Cancels all jobs in the given job family. Jobs in the family that are currently waiting will be removed from the queue. Sleeping jobs will be discarded without having a chance to wake up. Currently executing jobs will be asked to cancel but there is no guarantee that they will do so.
      Parameters:
      family - the job family to cancel, or null to cancel all jobs
      See Also:

    • createProgressGroup

      IProgressMonitor createProgressGroup()
      Returns a progress monitor that can be used to provide aggregated progress feedback on a set of running jobs. A user interface will typically group all jobs in a progress group together, providing progress feedback for individual jobs as well as aggregated progress for the entire group. Jobs in the group may be run sequentially, in parallel, or some combination of the two.

      Recommended usage (this snippet runs two jobs in sequence in a single progress group): 

       Job parseJob, compileJob;
 IProgressMonitor pm = Job.getJobManager().createProgressGroup();
 try {
        pm.beginTask("Building", 10);
        parseJob.setProgressGroup(pm, 5);
        parseJob.schedule();
        compileJob.setProgressGroup(pm, 5);
        compileJob.schedule();
        parseJob.join();
        compileJob.join();
 } finally {
        pm.done();
 }
      Returns:
      a progress monitor
      See Also:

    • currentRule

      ISchedulingRule currentRule()
      Returns the scheduling rule currently held by this thread, or null if the current thread does not hold any scheduling rule.

      If this method is called from within the scope of a running job with a non-null scheduling rule, then this method is equivalent to calling currentJob().getRule(). Otherwise, this method will return the first scheduling rule obtained by this thread via beginRule(ISchedulingRule, IProgressMonitor) that has not yet had a corresponding call to endRule(ISchedulingRule).

      Returns:
      the current rule or null
      Since:
      3.5

    • currentJob

      Job currentJob()
      Returns the job that is currently running in this thread, or null if there is no currently running job.
      Returns:
      the job or null

    • endRule

      void endRule(ISchedulingRule rule)
      Ends the application of a rule to the calling thread. Calls to endRule must be preceded by a matching call to beginRule in the same thread with an identical rule instance.

      Rules can be nested only if the rule for the inner beginRule is contained within the rule for the outer beginRule. Also, begin/end pairs must be strictly nested. Only the rule that has most recently begun can be ended at any given time.

      Parameters:
      rule - the rule to end applying in this thread
      Throws:
      IllegalArgumentException - if this method is called on a rule for which there is no matching begin, or that does not match the most recent begin.
      See Also:

    • find

      Job[] find(Object family)
      Returns all waiting, executing and sleeping jobs belonging to the given family. If no jobs are found, an empty array is returned.
      Parameters:
      family - the job family to find, or null to find all jobs
      Returns:
      the job array
      See Also:

    • isIdle

      boolean isIdle()
      Returns whether the job manager is currently idle. The job manager is idle if no jobs are currently running or waiting to run.
      Returns:
      true if the job manager is idle, and false otherwise
      Since:
      3.1

    • isSuspended

      boolean isSuspended()
      Returns whether the job manager is currently suspended.
      Returns:
      true if the job manager is suspended, and false otherwise
      Since:
      3.4
      See Also:

    • join

      void join(Object family, IProgressMonitor monitor) throws InterruptedException, OperationCanceledException
      Waits until all jobs of the given family are finished. This method will block the calling thread until all such jobs have finished executing, or until this thread is interrupted. If there are no jobs in the family that are currently waiting, running, or sleeping, this method returns immediately. Feedback on how the join is progressing is provided to a progress monitor.

      If this method is called while the job manager is suspended, only jobs that are currently running will be joined; Once there are no jobs in the family in the Job.RUNNING state, this method returns.

      Note that there is a deadlock risk when using join. If the calling thread owns a lock or object monitor that the joined thread is waiting for, deadlock will occur. This method can also result in starvation of the current thread if another thread continues to add jobs of the given family, or if a job in the given family reschedules itself in an infinite loop.

      Parameters:
      family - the job family to join, or null to join all jobs.
      monitor - Progress monitor for reporting progress on how the wait is progressing, or null if no progress monitoring is required.
      Throws:
      InterruptedException - if this thread is interrupted while waiting
      OperationCanceledException - if the progress monitor is canceled while waiting
      See Also:

    • newLock

      ILock newLock()
      Creates a new lock object. All lock objects supplied by the job manager know about each other and will always avoid circular deadlock amongst themselves.
      Returns:
      the new lock object

    • removeJobChangeListener

      void removeJobChangeListener(IJobChangeListener listener)
      Removes a job listener from the job manager. Has no effect if an identical listener is not already registered.
      Parameters:
      listener - the listener to be removed
      See Also:

    • resume

      @Deprecated void resume(ISchedulingRule rule)
      Deprecated.
      This method is not safe and should not be used. Suspending a scheduling rule violates the thread safety of clients that use scheduling rules as a mutual exclusion mechanism, and can result in concurrency problems in all clients that use the suspended rule.
      Resumes execution of jobs after a previous suspend. All jobs that were sleeping or waiting prior to the suspension, or that were scheduled while the job manager was suspended, will now be eligible for execution.

      Calling this method on a rule that is not suspended has no effect. If another thread also owns the rule at the time this method is called, then the rule will not be resumed until all threads have released the rule.

      See Also:

    • resume

      void resume()
      Resumes execution of jobs after a previous suspend. All jobs that were sleeping or waiting prior to the suspension, or that were scheduled while the job manager was suspended, will now be eligible for execution.

      Calling resume when the job manager is not suspended has no effect.

      See Also:

    • setLockListener

      void setLockListener(LockListener listener)
      Provides a hook that is notified whenever a thread is about to wait on a lock, or when a thread is about to release a lock. This hook must only be set once.

      This method is for internal use by the platform-related plug-ins. Clients should not call this method.

      See Also:

    • setProgressProvider

      void setProgressProvider(ProgressProvider provider)
      Registers a progress provider with the job manager. If there was a provider already registered, it is replaced.

      This method is intended for use by the currently executing Eclipse application. Plug-ins outside the currently running application should not call this method.

      Parameters:
      provider - the new provider, or null if no progress is needed

    • suspend

      void suspend()
      Suspends execution of all jobs. Jobs that are already running when this method is invoked will complete as usual, but all sleeping and waiting jobs will not be executed until the job manager is resumed.

      The job manager will remain suspended until a subsequent call to resume. Further calls to suspend when the job manager is already suspended are ignored.

      All attempts to join sleeping and waiting jobs while the job manager is suspended will return immediately.

      Note that this very powerful function should be used with extreme caution. Suspending the job manager will prevent all jobs in the system from executing, which may have adverse affects on components that are relying on execution of jobs. The job manager should never be suspended without intent to resume execution soon afterwards.

      See Also:

    • suspend

      @Deprecated void suspend(ISchedulingRule rule, IProgressMonitor monitor)
      Deprecated.
      This method is not safe and should not be used. Suspending a scheduling rule violates the thread safety of clients that use scheduling rules as a mutual exclusion mechanism, and can result in concurrency problems in all clients that use the suspended rule.
      Defers execution of all jobs with scheduling rules that conflict with the given rule. The caller will be blocked until all currently executing jobs with conflicting rules are completed. Conflicting jobs that are sleeping or waiting at the time this method is called will not be executed until the rule is resumed.

      While a rule is suspended, all calls to beginRule and endRule on a suspended rule will not block the caller. The rule remains suspended until a subsequent call to resume(ISchedulingRule) with the identical rule instance. Further calls to suspend with an identical rule prior to calling resume are ignored.

      This method is long-running; progress and cancelation are provided by the given progress monitor. In the case of cancelation, the rule will not be suspended.

      Note: this very powerful function should be used with extreme caution. Suspending rules will prevent jobs in the system from executing, which may have adverse effects on components that are relying on execution of jobs. The job manager should never be suspended without intent to resume execution soon afterwards. Deadlock will result if the thread responsible for resuming the rule attempts to join a suspended job.
      Parameters:
      rule - The scheduling rule to suspend. Must not be null.
      monitor - a progress monitor, or null if progress reporting is not desired
      Throws:
      OperationCanceledException - if the operation is canceled. Cancelation can occur even if no progress monitor is provided.
      See Also:

    • sleep

      void sleep(Object family)
      Requests that all jobs in the given job family be suspended. Jobs currently waiting to be run will be removed from the queue and moved into the SLEEPING state. Jobs that have been put to sleep will remain in that state until either resumed or canceled. This method has no effect on jobs that are not currently waiting to be run.

      Sleeping jobs can be resumed using wakeUp.

      Parameters:
      family - the job family to sleep, or null to sleep all jobs.
      See Also:

    • transferRule

      void transferRule(ISchedulingRule rule, Thread destinationThread)
      Transfers ownership of a scheduling rule to another thread. The identical scheduling rule must currently be owned by the calling thread as a result of a previous call to beginRule. The destination thread must not already own a scheduling rule.

      Calling this method is equivalent to atomically calling endRule in the calling thread followed by an immediate beginRule in the destination thread. The destination thread is responsible for subsequently calling endRule when it is finished using the rule.

      This method has no effect when the destination thread is the same as the calling thread.

      Parameters:
      rule - The scheduling rule to transfer
      destinationThread - The new owner for the transferred rule.
      Since:
      3.1

    • wakeUp

      void wakeUp(Object family)
      Resumes scheduling of all sleeping jobs in the given family. This method has no effect on jobs in the family that are not currently sleeping.
      Parameters:
      family - the job family to wake up, or null to wake up all jobs
      See Also: