BunyipsLib/au.edu.sa.mbhs.studentrobotics.bunyipslib.tasks.bases/Task

Task

abstract class Task : BunyipsComponent, Runnable, Action

A task, or command is an action that can be performed by a robot. This has been designed to reflect closely the command-based programming style used in FRC, while still being reflective of the past nature of how the Task system was implemented in BunyipsLib.

The task system in BunyipsLib has been constructed from the ground-up with a more lightweight ecosystem where Tasks are at their core stripped into running some code for some time, somewhere. The original behaviour of tasks running outright used to be the legacy roots of how Tasks worked, and since has adopted some command-based structures that work by running them in the contexts of other subsystems.

Task extends BunyipsComponent to allow for simpler integration with accessing the OpMode, and was a legacy feature that was kept for the sake of simplicity, more pedantic exception handling, and ease of use.

As of 6.0.0, the Task system now implements the Action interface for seamless compatibility with RoadRunner v1.0.0. The ActionTask may be used to convert a pure Action into a task, however, writing a task directly using a Task is encouraged for more control and flexibility, due to there being no downsides to doing so and the exposure of the same accessors. Additional changes have also been made to allow for simpler construction of tasks, and the introduction of a new DynamicTask class to allow for more flexible task construction.

Author

Lucas Bubner, 2024

Since

1.0.0-pre

Inheritors

Constructors

Task

constructor()

Types

Companion

object Companion

Properties

deltaTime

val deltaTime: Measure<Time>

Time since the task was started.

dependency

val dependency: Optional<BunyipsSubsystem>

Get the subsystem reference that this task has elected a dependency on. Will return an Optional where if it is not present, this task is not dependent on any subsystem.

fieldOverlay

protected lateinit var fieldOverlay: Canvas

Convenience field to get a reference to FtcDashboard's field overlay for drawing on the field. Available as soon as init has been called for this task.

isFinished

val isFinished: Boolean

Query (but not update) the finished state of the task. This will return true if the task is finished and the finisher has been fired.

isPriority

var isPriority: Boolean

Whether this task should override other tasks in the queue if they conflict with this task. Will only apply if this task has a dependency to run on (see dependency).

isRunning

val isRunning: Boolean

Whether the task is currently running (i.e. has been started (init called) and not finished).

protected lateinit var p: TelemetryPacket

Convenience field to get a reference to a TelemetryPacket for sending telemetry to the dashboard. Available as soon as init has been called for this task.

timeout

@JvmField

var timeout: Measure<Time>

Maximum timeout of the task. If set to 0 magnitude (or a timeout-less constructor) this will serve as an indefinite task, and will only finish when isTaskFinished returns true, or this task is manually interrupted via finish/finishNow.

Inherited properties

opMode

@Nullable

protected val opMode: BunyipsOpMode?

Get a reference to the currently running BunyipsOpMode.

Functions

after

infix fun after(waitTime: Measure<Time>): SequentialTaskGroup

fun after(waitDuration: Double, unit: Time): SequentialTaskGroup

Composes a WaitTask to run before this task.

infix fun after(otherTask: Task): SequentialTaskGroup

Compose this task into a SequentialTaskGroup with the supplied task to run before this one.

infix fun after(runnable: Runnable): SequentialTaskGroup

Implicitly run a SequentialTaskGroup with this supplied Runnable, queued to run before this task starts.

fun after(vararg otherTasks: Task): SequentialTaskGroup

Compose this task into a SequentialTaskGroup with the supplied tasks to run before this one.

during

infix fun during(otherTask: Task): DeadlineTaskGroup

Compose this task into a DeadlineTaskGroup with the supplied task to run alongside this one until this task is done.

fun during(vararg otherTasks: Task): DeadlineTaskGroup

Compose this task into a DeadlineTaskGroup with the supplied tasks to run these extra tasks until this task is done.

finish

fun finish()

Tell a task to finish on the next iteration of poll.

finishNow

fun finishNow()

Force a task to finish immediately, and fire the onFinish method without waiting for the next polling loop.

forAtLeast

infix fun forAtLeast(waitTime: Measure<Time>): ParallelTaskGroup

fun forAtLeast(waitDuration: Double, unit: Time): ParallelTaskGroup

Composes a ParallelTaskGroup with a WaitTask to run before this task. This will ensure the task runs for at least the specified time, and no-ops until the duration if it finishes early.

init

protected open fun init()

Define code to run once, when the task is started. Override to implement.

isTaskFinished

protected open fun isTaskFinished(): Boolean

Return a boolean to this method to add custom criteria if a task should be considered finished.

named

open infix fun named(name: String?): Task

Set the name of this task to be displayed in the OpMode. You may override this method if required to enforce a naming convention/prefix.

infix fun on(subsystem: BunyipsSubsystem): Task

Set the subsystem you want to elect this task to run on, notifying the runner that this task should run there. This task is scheduled with default override behaviour (where this task is not priority).

open fun on(subsystem: BunyipsSubsystem, override: Boolean): Task

Set the subsystem you want to elect this task to run on, notifying the runner that this task should run there.

onFinish

protected open fun onFinish()

Finalising function to run once the task is finished. This will always run regardless of whether the task was ended because of an interrupt or the task naturally finishing. Override to add your own callback.

onInterrupt

protected open fun onInterrupt()

Finalising function that will be called after onFinish in the event this task is finished via a call to finish or finishNow. Override to add your own callback.

onReset

protected open fun onReset()

Called when the task is resetting now. Override this method to add custom reset behaviour, such as resetting any internal state variables such as iterators or lists.

periodic

protected open fun periodic()

To run as an active loop during this task's duration. Override to implement.

poll

fun poll(): Boolean

Update and query the state of the task if it is finished. This will return true if the task is fully completed with all callbacks processed.

preview

override fun preview(fieldOverlay: Canvas)

RoadRunner Action implementation to preview the action on the field overlay. This method no-ops as previews are done via DualTelemetry and the Drawing util.

race

infix fun race(otherTask: Task): RaceTaskGroup

Compose this task into a RaceTaskGroup with the supplied task to run alongside this one until one finishes.

fun race(vararg otherTasks: Task): RaceTaskGroup

Compose this task into a RaceTaskGroup with the supplied tasks to run all of these tasks until one finishes.

repeatedly

fun repeatedly(): Task

Wrap this task in a RepeatTask where finish conditions are reset immediately.

reset

fun reset()

Reset a task to an uninitialised and unfinished state. Will no-op if the task is already fully reset.

run

override fun run()

Execute one cycle of this task. The finish condition is separately polled in the poll method.

override fun run(p: TelemetryPacket): Boolean

RoadRunner Action implementation to run this Task.

then

infix fun then(otherTask: Task): SequentialTaskGroup

Compose this task into a SequentialTaskGroup with the supplied task to follow after this one.

infix fun then(runnable: Runnable): SequentialTaskGroup

Implicitly run a SequentialTaskGroup with this supplied Runnable, queued to run when this task finishes.

fun then(vararg otherTasks: Task): SequentialTaskGroup

Compose this task into a SequentialTaskGroup with the supplied tasks to follow after this one.

timeout

infix fun timeout(timeout: Measure<Time>): Task

Set the timeout of this task dynamically and return the task.

toString

override fun toString(): String

Get the name of this task. By default, it will be the class simple name, but you can call named to set a custom name.

toVerboseString

fun toVerboseString(): String

Get a verbose string representation of this task, including all of its properties.

until

infix fun until(condition: BooleanSupplier): RaceTaskGroup

Compose this task into a RaceTaskGroup with a wait condition based on this condition.

with

infix fun with(otherTask: Task): ParallelTaskGroup

Compose this task into a ParallelTaskGroup with the supplied task to run alongside this one.

fun with(vararg otherTasks: Task): ParallelTaskGroup

Compose this task into a ParallelTaskGroup with the supplied tasks to run all of these tasks at once.

Inherited functions

opMode

protected fun opMode(@NonNull ifRunning: Consumer<BunyipsOpMode>)

Null check consumer for the opMode field which will no-op the given consumer if an active BunyipsOpMode is not present (i.e. the opMode field is null). This method is the same to the BunyipsOpMode.ifRunning method, and is supplied here for convenience.

require

@NonNull

protected fun require(@Nullable nullableOpMode: BunyipsOpMode?): BunyipsOpMode

Null assertion for the opMode field which throws a NullPointerException if an active BunyipsOpMode is not present (i.e. the supplied field is null). This method replicates Objects.requireNonNull but has a built-in message to alert the user of a non-active OpMode.