#API #Jobs

Type: Interface
Extends: I_Debug
Description:
Represents an object responsible for scheduling and managing the execution of jobs.

Type: Method
Description:
Defers the job by moving it to the end of the queue.
Returns:

• Ok – Success
• Err.Itf0 – iJob = 0
• Err.NoMatch – iJob.Worker <> THIS^

Signature:

METHOD Defer : Result
VAR_INPUT
    iJob : I_Job;
END_VAR

Type: Method
Description:
Removes the job from the queue and resets it.
Returns:

• Ok – Success
• Err.Itf0 – iJob = 0
• Err.NoMatch – iJob.Worker <> THIS^
• Err.IncArg – iJob.State = TaskState.Idle

Signature:

METHOD Dequeue : Result
VAR_INPUT
    iJob : I_Job;
END_VAR

Type: Method
Description:
Adds a job to the queue.
Returns:

• Ok – Success
• Err.Itf0 – iJob = 0
• Err.NoMatch – iJob.Worker <> THIS^
• Err.IncArg – iJob.State <> TaskState.Idle

Signature:

METHOD Enqueue : Result
VAR_INPUT
    iJob : I_Job;
END_VAR

Type: Property
Accessors: Get
Description:
Returns the first job in the queue.
Signature: PROPERTY First : I_Job

Type: Function Block
Implements: I_Worker
Description: Manages adding, removing, deferring, and running I_Job instances. This function block is not intended for standalone use. It must be wrapped by a higher-level controller or scheduler that manages when jobs are enqueued, dequeued, deferred, or executed. See: LoopWorker, BlockingWorker.

Type: Property
Accessors: Get
Description: Returns the first job currently in the queue.
Signature: PROPERTY First : I_Job

Type: Method
Description:
Moves the given job to the end of the queue.
Returns:

• Ok – Success
• Err.Itf0 – iJob is null
• Err.NoMatch – iJob.Worker does not match THIS^

Signature:

METHOD Defer : Result
VAR_INPUT
    iJob : I_Job;
END_VAR

Type: Method
Description:
Removes a job from the queue and finalizes it depending on its state.
Returns:

• Ok – Success
• Err.Itf0 – iJob is null
• Err.NoMatch – iJob.Worker does not match THIS^
• Err.IncArg – iJob.State = JobState.Idle

Signature:

METHOD Dequeue : Result
VAR_INPUT
    iJob : I_Job;
END_VAR

Type: Method
Description:
Adds a job to the end of the queue.
Returns:

• Ok – Success
• Err.Itf0 – iJob is null
• Err.NoMatch – iJob.Worker does not match THIS^
• Err.IncArg – iJob.State <> JobState.Idle

Signature:

METHOD Enqueue : Result
VAR_INPUT
    iJob : I_Job;
END_VAR

Type: Method
Description:
Executes the Run method of a job if it is in the Ready state.
Returns:

• Ok – Success
• Err.Itf0 – iJob is null
• Err.IncArg – Invalid job state for execution (Error, Idle, Running)

Signature:

METHOD Run : Result
VAR_INPUT
    iJob : I_Job;
END_VAR

Type: Function Block
Description: A wrapper worker that runs a single Job per call and defers it, ensuring all enqueued jobs get a chance to execute. This distributes workload across multiple PLC cycles, with execution occurring once per cycle.

Type: Property
Accessors: Get
Description:
Returns the internal scheduler instance that manages job execution.
Signature: PROPERTY Base : I_Worker

Type: Method
Description:
Executes the first job in the queue. If the job is completed or aborted, it is removed.
Otherwise, it is executed and deferred for future cycles. Invalid states trigger a debug message.
Signature: METHOD Run

Type: Function Block
Description:
A worker wrapper that runs a Job continuously until it completes. It attempts to finish the active job before moving on, which may block execution for multiple cycles depending on job duration.

Type: Property
Accessors: Get
Description:
Returns the internal scheduler instance that manages job execution.
Signature: PROPERTY Base : I_Worker

Type: Method
Description:
Runs the first job in the queue until it completes. If the job is in a terminal state (Completed or Aborted), it is dequeued. Invalid job states trigger a debug message.
Signature: METHOD Run

Type: Enum
Description: Represents the various states a job can be in during its lifecycle.
Signature:

{attribute 'qualified_only'}
{attribute 'strict'}
TYPE JobState :
(
	Error,		// Incorrect state
	Idle,		// Not in queue
	Enqueue,	// Enqueued and wating for worker response
	Ready,		// Ready to be processed
	Running,	// Currently processed by worker
	Aborted,	// Aborted, wating to be dequeued
	Completed	// Completed, wating to be dequeued
) BYTE := Idle;
END_TYPE

Type: Interface
Extends: I_Debug
Description:
Provides an interface for starting and aborting jobs. Designed for external components to interact with the job scheduler.

Type: Method
Description:
Starts the job and adds it to the worker queue.
Results:

• Ok upon successful start.
• Err.IncArg if the job is not in the Idle state.
• Err.Itf0 if the worker is not assigned (Worker = 0).

Signature: METHOD Start : Result

Type: Method
Description:
Notifies the scheduler to abort the current job.
Results:

• Err.IncArg if the job is already in the Idle state.

Signature: METHOD Abort : Result

Type: Function Block
Implements: I_Job
Description:
An abstract representation of a system job, providing the foundation for implementing job-specific behaviour. Manages its state and offers default behaviour for its lifecycle methods, allowing overriding only where necessary.

Type: Property
Accessors: Get, Set
Description:
Gets or sets the I_Worker handling this job. Can only be set when the job is in Idle state.
Signature: PROPERTY Worker : I_Worker

Type: Property
Accessors: Get
Description:
Returns the current state of the job.

Signature: PROPERTY State : JobState

Type: Method
From: I_Job
Description:
Starts the job and queues it with the assigned worker.
Results:

• Ok upon success.
• Err.IncArg if state is not Idle.
• Err.Itf0 if worker is not assigned.

Signature: METHOD Start : Result

Type: Method
From: I_Job
Description:
Requests abortion of the job.
Results:

• Err.IncArg if the job is already in the Idle state.
  Signature: METHOD Abort : Result

Type: Method
Access: Protected
Description:
Notifies that the job has completed.
Results:

• Ok upon success.
• Err.IncArg if state is not Running.

Signature: METHOD PROTECTED Done : Result

Type: Method
Access: Protected
Description:
Executed when the job is started. Override for custom behaviour.
Signature: METHOD PROTECTED OnStart

Type: Method
Access: Protected
Description:
Executed when the job runs. Override for job-specific logic.
Signature: METHOD PROTECTED OnRun

Type: Method
Access: Protected
Description:
Executed when the job is marked as done.
Signature: METHOD PROTECTED OnDone

Type: Method
Access: Protected
Description:
Executed when the job is aborted.
Signature: METHOD PROTECTED OnAbort

Type: Method
Access: Protected
Description:
Executed when the job exits or is removed from the queue.
Signature: METHOD PROTECTED OnExit