Task -Scheduler Overview

Required background

In a condition-based schedule, -a condition can be user-defined or system condition. User defined conditions -are published using Publish and Subscribe keys. For more information about -Publish and Subscribe concept refer Publish -and Subscribe.

Key concepts and terms

Task: The execution of an application or program.
Schedule: A plan for performing a task.
Persistent Schedule: The lifetime of a persistent schedule is not limited to the lifetime -of the tasks associated with it.
Transient Schedule: A Transient schedule is created with a new scheduled task and is destroyed -on task destruction. Transient schedules and tasks are not persisted on disk-based -storage.
Time-based Schedule: A Time-based schedule contains one or more tasks that are due for execution -at a specified time.
Condition-based Schedule: A condition-based schedule contains one or more tasks which are executed -when either a set of certin Publish and Subscribe conditions are met or a -default time-out is reached.
Home-Time based Schedule: A home-time based schedule occur at a given local time. Local time -typically includes changes for time zone and DST. These schedules are referred -to as ‘floating’ schedules.
Daylight Saving Time (DST): Daylight Saving Time (or summertime as it is called in many countries) -is a way of utilizing more daylight by advancing the local time by one hour -during the summer.
Coordinated Universal Time (UTC): UTC is independent of location. UTC-based schedules occur at a given -UTC time regardless of the local time.

Architecture

The task scheduler is a permanent -server. It is automatically started when the phone boots or reboots and does -not shutdown while the phone is running. If the server fails, and cannot be -automatically restarted, the phone restarts automatically. Persistent schedules -are stored the permanent file store. Transient schedules are lost if the server -fails.

A client must register with the task scheduler before it can -schedule a task.

APIs

The main APIs of the task scheduler are:

- - - -API -Description - - - - -

CScheduledTask

A scheduled task

- - -

RScheduler

The client side interface to the Task Scheduler.

- - - -

Typical uses

The main uses of the task scheduler -are:

Schedule a sequence -of tasks to be executed based on time.
Schedule a sequence -of tasks to be executed based on conditions.

For more information about using the task scheduler APIs, see the Developing Programs with -Task Scheduling Capabilities section.

See also

Backup -and Restore on Scheduled Tasks in Persistent Schedules

+ + + + + +Task +Scheduler Overview

The Task Scheduler enables clients to schedule tasks for time-based +and condition-based execution. The Task Scheduler is a Startup +State Aware component. This ensures no task is initiated +before all system-level services are up and running.

The time or condition +for task execution is defined in a schedule. Schedules and tasks can be persistent +or transient. Schedules can be created, edited and deleted.

The Task +Scheduler participates in a system-wide backup or restore operation initiated +by the Secure Backup Engine as a passive backup client. +This ensures the persistent schedules are backed up and restored.

Required background

In a condition-based schedule, +a condition can be user-defined or system condition. User defined conditions +are published using Publish and Subscribe keys. For more information about +Publish and Subscribe concept refer Publish +and Subscribe.

Key concepts and terms

Task: The execution of an application or program.
Schedule: A plan for performing a task.
Persistent Schedule: The lifetime of a persistent schedule is not limited to the lifetime +of the tasks associated with it.
Transient Schedule: A Transient schedule is created with a new scheduled task and is destroyed +on task destruction. Transient schedules and tasks are not persisted on disk-based +storage.
Time-based Schedule: A Time-based schedule contains one or more tasks that are due for execution +at a specified time.
Condition-based Schedule: A condition-based schedule contains one or more tasks which are executed +when either a set of certin Publish and Subscribe conditions are met or a +default time-out is reached.
Home-Time based Schedule: A home-time based schedule occur at a given local time. Local time +typically includes changes for time zone and DST. These schedules are referred +to as ‘floating’ schedules.
Daylight Saving Time (DST): Daylight Saving Time (or summertime as it is called in many countries) +is a way of utilizing more daylight by advancing the local time by one hour +during the summer.
Coordinated Universal Time (UTC): UTC is independent of location. UTC-based schedules occur at a given +UTC time regardless of the local time.

Architecture

The task scheduler is a permanent +server. It is automatically started when the phone boots or reboots and does +not shutdown while the phone is running. If the server fails, and cannot be +automatically restarted, the phone restarts automatically. Persistent schedules +are stored the permanent file store. Transient schedules are lost if the server +fails.

A client must register with the task scheduler before it can +schedule a task.

APIs

The main APIs of the task scheduler are:

+ + + +API +Description + + + + +

CScheduledTask

A scheduled task

+ + +

RScheduler

The client side interface to the Task Scheduler.

+ + + +

Typical uses

The main uses of the task scheduler +are:

Schedule a sequence +of tasks to be executed based on time.
Schedule a sequence +of tasks to be executed based on conditions.

For more information about using the task scheduler APIs, see the Developing Programs with +Task Scheduling Capabilities section.