org.objectweb.jonathan.resources.api

Interface Scheduler

Known Implementing Classes:
JScheduler

public interface Scheduler

Schedulers are used to create and schedule Jobs.

To allow application programmers to change the default scheduling used by Java, and to implement some resource management policy on activity resources (threads), Jonathan introduces abstractions to represent activities (interface Job) and schedulers (interface Scheduler).

A Job is the abstraction of an activity in the system. When this activity is sequential (the usual case), it may be thought of as a thread. The role of a scheduler is to create Jobs (a scheduler is a job factory), and to manage them according to their properties (a priority, a deadline, ...). A scheduler has thus the responsibility to associate a Job with some processing resource (which may be a processor, or more simply a Java thread) when it is entitled to run.

Method Summary

void
enter()
Causes a job "escaped" from the scheduler to be re-admitted in the set of jobs managed by the target scheduler.
void
escape()
Causes the calling job to be removed from the set of jobs managed by the target scheduler.
Job
getCurrent()
Returns the currently executing job (the job performing the call).
Job
newJob()
Returns a new job created by the scheduler.
void
notify(Object lock)
Unblocks a job waiting on the lock.
void
notifyAll(Object lock)
Unblocks all jobs waiting on the lock.
void
wait(Object lock)
Blocks the calling job until the notify or notifyAll method is called providing the same lock identifier.
void
wait(Object lock, long millis)
Blocks the calling job until the notify or notifyAll method is called providing the same lock identifier.
void
yield()
Calling this method gives the opportunity to the scheduler to re-schedule the currently executing jobs.

Method Details

enter

public void enter()
Causes a job "escaped" from the scheduler to be re-admitted in the set of jobs managed by the target scheduler.


escape

public void escape()
Causes the calling job to be removed from the set of jobs managed by the target scheduler. It is necessary to call this method before every possibly blocking method so that the scheduler can give a chance to run to another job.


getCurrent

public Job getCurrent()
Returns the currently executing job (the job performing the call).

Returns:
the currently executing job.


newJob

public Job newJob()
Returns a new job created by the scheduler.

Returns:
a new job created by the scheduler.


notify

public void notify(Object lock)

Parameters:
lock - the lock identifier.


notifyAll

public void notifyAll(Object lock)

Parameters:
lock - the lock identifier.


wait

public void wait(Object lock)
            throws InterruptedException
Blocks the calling job until the notify or notifyAll method is called providing the same lock identifier.

Parameters:
lock - the lock identifier.


wait

public void wait(Object lock,
                 long millis)
            throws InterruptedException
Blocks the calling job until the notify or notifyAll method is called providing the same lock identifier.

Parameters:
lock - the lock identifier.


yield

public void yield()
Calling this method gives the opportunity to the scheduler to re-schedule the currently executing jobs.