TaskSchedulerExample: Using Task Scheduler for Creating and Executing Tasks

Download

Click on the following link to download the examples:

TaskSchedulerExample.zip

Click the following links to view the example code.

TaskSchedulerExample

Purpose

The scheduler example has two applications; one to schedule the tasks, and the other to run the scheduled tasks. The scheduler application launches the application that runs the scheduled tasks, when the tasks are due to be completed.

The scheduler application is the client of the scheduler server. It connects and registers itself with the scheduler server using the RScheduler::Connect() and RScheduler::Register() methods, respectively. While registering itself with the scheduler server, the scheduler application provides the name of the application that runs the scheduled tasks, along with its complete path and its priority relative to other clients.

When a session with the scheduler server is started, the scheduler creates a persistent time-based schedule using the RScheduler::CreatePersistentSchedule() method. Then, it adds a task to the persistent schedule using the RScheduler::ScheduleTask()method.

The scheduler application also creates a transient time-based schedule using the RScheduler::ScheduleTask() method. The application passes the schedule information to the method using the TScheduleEntryInfo2andTTaskInfo objects. It also edits the transient schedule entry to change its validity using RScheduler::EditSchedule()

The scheduler application launches the executor application, which runs the scheduled tasks when they are due to be completed. The executor checks whether it has the necessary capability to run the scheduled tasks using the CScheduledTask::SecurityInfo() method. The executor application also checks whether the Secure ID (SID) is the same as that of the task requester, to be able to run the tasks. If these security checks pass, the executor prints the details of the scheduled task to the console.

Finally, the scheduled tasks are deleted using the RScheduler::DeleteSchedule() and RScheduler::DeleteTask()methods, respectively.

Class summary

The example shows the following APIs:

• RScheduler

• CScheduledTask

• TScheduleEntryInfo2

• TTaskInfo

• TSchedulerItemRef

• TSecurityInfo

Building and configuring

To build the example:

• You can build the example from the Carbide.c++ IDE or the command line.

  If you use an IDE, import the bld.inf file of the example into your IDE, and use the build command of the IDE. If you use the command line, open a command prompt, and set the current directory to examples\SysLibs\TaskSchedulerExample folder which contains the bld.inf file. You can then build the example with the following build commands:

  bldmake bldfiles
  abld build winsw (For WINSCW platforms)
  abld build ARMV5 (For hardware)

  for running the obtained .exe, go to epoc32\release\winscw\udeb\ (or urel\), launch taskexecutor.exe :

  taskexecutor.exe