Package edu.wpi.first.wpilibj2.command

Interface Command

All Known Implementing Classes:
CommandBase, CommandGroupBase, ConditionalCommand, FunctionalCommand, InstantCommand, MecanumControllerCommand, NotifierCommand, ParallelCommandGroup, ParallelDeadlineGroup, ParallelRaceGroup, PerpetualCommand, PIDCommand, PrintCommand, ProfiledPIDCommand, ProxyCommand, ProxyScheduleCommand, RamseteCommand, RepeatCommand, RunCommand, ScheduleCommand, SelectCommand, SequentialCommandGroup, StartEndCommand, SwerveControllerCommand, TrapezoidProfileCommand, WaitCommand, WaitUntilCommand, WrapperCommand
public interface Command
A state machine representing a complete action to be performed by the robot. Commands are run by the CommandScheduler, and can be composed into CommandGroups to allow users to build complicated multi-step actions without the need to roll the state machine logic themselves.

Commands are run synchronously from the main robot loop; no multithreading is used, unless specified explicitly from the command implementation.

This class is provided by the NewCommands VendorDep

  • Method Details

    • initialize

      default void initialize()
      The initial subroutine of a command. Called once when the command is initially scheduled.

    • execute

      default void execute()
      The main body of a command. Called repeatedly while the command is scheduled.

    • end

      default void end​(boolean interrupted)
      The action to take when the command ends. Called when either the command finishes normally, or when it interrupted/canceled.

      Do not schedule commands here that share requirements with this command. Use andThen(Command...) instead.

      Parameters:
      interrupted - whether the command was interrupted/canceled

    • isFinished

      default boolean isFinished()
      Whether the command has finished. Once a command finishes, the scheduler will call its end() method and un-schedule it.
      Returns:
      whether the command has finished.

    • getRequirements

      Set<Subsystem> getRequirements()
      Specifies the set of subsystems used by this command. Two commands cannot use the same subsystem at the same time. If another command is scheduled that shares a requirement, getInterruptionBehavior() will be checked and followed. If no subsystems are required, return an empty set.

      Note: it is recommended that user implementations contain the requirements as a field, and return that field here, rather than allocating a new set every time this is called.

      Returns:
      the set of subsystems that are required
      See Also:
      Command.InterruptionBehavior

    • withTimeout

      default ParallelRaceGroup withTimeout​(double seconds)
      Decorates this command with a timeout. If the specified timeout is exceeded before the command finishes normally, the command will be interrupted and un-scheduled. Note that the timeout only applies to the command returned by this method; the calling command is not itself changed.

      Note: This decorator works by adding this command to a composition. The command the decorator was called on cannot be scheduled independently or be added to a different composition (namely, decorators), unless it is manually cleared from the list of composed commands with CommandScheduler.removeComposedCommand(Command). The command composition returned from this method can be further decorated without issue.

      Parameters:
      seconds - the timeout duration
      Returns:
      the command with the timeout added

    • until

      default ParallelRaceGroup until​(BooleanSupplier condition)
      Decorates this command with an interrupt condition. If the specified condition becomes true before the command finishes normally, the command will be interrupted and un-scheduled. Note that this only applies to the command returned by this method; the calling command is not itself changed.

      Note: This decorator works by adding this command to a composition. The command the decorator was called on cannot be scheduled independently or be added to a different composition (namely, decorators), unless it is manually cleared from the list of composed commands with CommandScheduler.removeComposedCommand(Command). The command composition returned from this method can be further decorated without issue.

      Parameters:
      condition - the interrupt condition
      Returns:
      the command with the interrupt condition added

    • withInterrupt

      @Deprecated(since="2023") default ParallelRaceGroup withInterrupt​(BooleanSupplier condition)
      Deprecated.
      Replace with until(BooleanSupplier)
      Decorates this command with an interrupt condition. If the specified condition becomes true before the command finishes normally, the command will be interrupted and un-scheduled. Note that this only applies to the command returned by this method; the calling command is not itself changed.

      Note: This decorator works by adding this command to a composition. The command the decorator was called on cannot be scheduled independently or be added to a different composition (namely, decorators), unless it is manually cleared from the list of composed commands with CommandScheduler.removeComposedCommand(Command). The command composition returned from this method can be further decorated without issue.

      Parameters:
      condition - the interrupt condition
      Returns:
      the command with the interrupt condition added

    • beforeStarting

      default SequentialCommandGroup beforeStarting​(Runnable toRun, Subsystem... requirements)
      Decorates this command with a runnable to run before this command starts.

      Note: This decorator works by adding this command to a composition. The command the decorator was called on cannot be scheduled independently or be added to a different composition (namely, decorators), unless it is manually cleared from the list of composed commands with CommandScheduler.removeComposedCommand(Command). The command composition returned from this method can be further decorated without issue.

      Parameters:
      toRun - the Runnable to run
      requirements - the required subsystems
      Returns:
      the decorated command

    • beforeStarting

      default SequentialCommandGroup beforeStarting​(Command before)
      Decorates this command with another command to run before this command starts.

      Note: This decorator works by adding this command to a composition. The command the decorator was called on cannot be scheduled independently or be added to a different composition (namely, decorators), unless it is manually cleared from the list of composed commands with CommandScheduler.removeComposedCommand(Command). The command composition returned from this method can be further decorated without issue.

      Parameters:
      before - the command to run before this one
      Returns:
      the decorated command

    • andThen

      default SequentialCommandGroup andThen​(Runnable toRun, Subsystem... requirements)
      Decorates this command with a runnable to run after the command finishes.

      Note: This decorator works by adding this command to a composition. The command the decorator was called on cannot be scheduled independently or be added to a different composition (namely, decorators), unless it is manually cleared from the list of composed commands with CommandScheduler.removeComposedCommand(Command). The command composition returned from this method can be further decorated without issue.

      Parameters:
      toRun - the Runnable to run
      requirements - the required subsystems
      Returns:
      the decorated command

    • andThen

      default SequentialCommandGroup andThen​(Command... next)
      Decorates this command with a set of commands to run after it in sequence. Often more convenient/less-verbose than constructing a new SequentialCommandGroup explicitly.

      Note: This decorator works by adding this command to a composition. The command the decorator was called on cannot be scheduled independently or be added to a different composition (namely, decorators), unless it is manually cleared from the list of composed commands with CommandScheduler.removeComposedCommand(Command). The command composition returned from this method can be further decorated without issue.

      Parameters:
      next - the commands to run next
      Returns:
      the decorated command

    • deadlineWith

      default ParallelDeadlineGroup deadlineWith​(Command... parallel)
      Decorates this command with a set of commands to run parallel to it, ending when the calling command ends and interrupting all the others. Often more convenient/less-verbose than constructing a new ParallelDeadlineGroup explicitly.

      Note: This decorator works by adding this command to a composition. The command the decorator was called on cannot be scheduled independently or be added to a different composition (namely, decorators), unless it is manually cleared from the list of composed commands with CommandScheduler.removeComposedCommand(Command). The command composition returned from this method can be further decorated without issue.

      Parameters:
      parallel - the commands to run in parallel
      Returns:
      the decorated command

    • alongWith

      default ParallelCommandGroup alongWith​(Command... parallel)
      Decorates this command with a set of commands to run parallel to it, ending when the last command ends. Often more convenient/less-verbose than constructing a new ParallelCommandGroup explicitly.

      Note: This decorator works by adding this command to a composition. The command the decorator was called on cannot be scheduled independently or be added to a different composition (namely, decorators), unless it is manually cleared from the list of composed commands with CommandScheduler.removeComposedCommand(Command). The command composition returned from this method can be further decorated without issue.

      Parameters:
      parallel - the commands to run in parallel
      Returns:
      the decorated command

    • raceWith

      default ParallelRaceGroup raceWith​(Command... parallel)
      Decorates this command with a set of commands to run parallel to it, ending when the first command ends. Often more convenient/less-verbose than constructing a new ParallelRaceGroup explicitly.

      Note: This decorator works by adding this command to a composition. The command the decorator was called on cannot be scheduled independently or be added to a different composition (namely, decorators), unless it is manually cleared from the list of composed commands with CommandScheduler.removeComposedCommand(Command). The command composition returned from this method can be further decorated without issue.

      Parameters:
      parallel - the commands to run in parallel
      Returns:
      the decorated command

    • perpetually

      @Deprecated(forRemoval=true, since="2023") default PerpetualCommand perpetually()
      Deprecated, for removal: This API element is subject to removal in a future version.
      PerpetualCommand violates the assumption that execute() doesn't get called after isFinished() returns true -- an assumption that should be valid. This was unsafe/undefined behavior from the start, and RepeatCommand provides an easy way to achieve similar end results with slightly different (and safe) semantics.
      Decorates this command to run perpetually, ignoring its ordinary end conditions. The decorated command can still be interrupted or canceled.

      Note: This decorator works by adding this command to a composition. The command the decorator was called on cannot be scheduled independently or be added to a different composition (namely, decorators), unless it is manually cleared from the list of composed commands with CommandScheduler.removeComposedCommand(Command). The command composition returned from this method can be further decorated without issue.

      Returns:
      the decorated command

    • repeatedly

      default RepeatCommand repeatedly()
      Decorates this command to run repeatedly, restarting it when it ends, until this command is interrupted. The decorated command can still be canceled.

      Note: This decorator works by adding this command to a composition. The command the decorator was called on cannot be scheduled independently or be added to a different composition (namely, decorators), unless it is manually cleared from the list of composed commands with CommandScheduler.removeComposedCommand(Command). The command composition returned from this method can be further decorated without issue.

      Returns:
      the decorated command

    • asProxy

      default ProxyCommand asProxy()
      Decorates this command to run "by proxy" by wrapping it in a ProxyCommand. This is useful for "forking off" from command compositions when the user does not wish to extend the command's requirements to the entire command composition.
      Returns:
      the decorated command

    • unless

      default ConditionalCommand unless​(BooleanSupplier condition)
      Decorates this command to only run if this condition is not met. If the command is already running and the condition changes to true, the command will not stop running. The requirements of this command will be kept for the new conditonal command.
      Parameters:
      condition - the condition that will prevent the command from running
      Returns:
      the decorated command

    • ignoringDisable

      default WrapperCommand ignoringDisable​(boolean doesRunWhenDisabled)
      Decorates this command to run or stop when disabled.
      Parameters:
      doesRunWhenDisabled - true to run when disabled.
      Returns:
      the decorated command

    • withInterruptBehavior

      default WrapperCommand withInterruptBehavior​(Command.InterruptionBehavior interruptBehavior)
      Decorates this command to have a different interruption behavior.
      Parameters:
      interruptBehavior - the desired interrupt behavior
      Returns:
      the decorated command

    • finallyDo

      default WrapperCommand finallyDo​(BooleanConsumer end)
      Decorates this command with a lambda to call on interrupt or end, following the command's inherent end(boolean) method.
      Parameters:
      end - a lambda accepting a boolean parameter specifying whether the command was interrupted.
      Returns:
      the decorated command

    • handleInterrupt

      default WrapperCommand handleInterrupt​(Runnable handler)
      Decorates this command with a lambda to call on interrupt, following the command's inherent end(boolean) method.
      Parameters:
      handler - a lambda to run when the command is interrupted
      Returns:
      the decorated command

    • schedule

      default void schedule()
      Schedules this command.

    • cancel

      default void cancel()
      Cancels this command. Will call end(true). Commands will be canceled regardless of interruption behavior.
      See Also:
      CommandScheduler.cancel(Command...)

    • isScheduled

      default boolean isScheduled()
      Whether or not the command is currently scheduled. Note that this does not detect whether the command is in a composition, only whether it is directly being run by the scheduler.
      Returns:
      Whether the command is scheduled.

    • hasRequirement

      default boolean hasRequirement​(Subsystem requirement)
      Whether the command requires a given subsystem.
      Parameters:
      requirement - the subsystem to inquire about
      Returns:
      whether the subsystem is required

    • getInterruptionBehavior

      default Command.InterruptionBehavior getInterruptionBehavior()
      How the command behaves when another command with a shared requirement is scheduled.
      Returns:
      a variant of Command.InterruptionBehavior, defaulting to kCancelSelf.

    • runsWhenDisabled

      default boolean runsWhenDisabled()
      Whether the given command should run when the robot is disabled. Override to return true if the command should run when disabled.
      Returns:
      whether the command should run when the robot is disabled

    • getName

      default String getName()
      Gets the name of this Command. Defaults to the simple class name if not overridden.
      Returns:
      The display name of the Command

    • setName

      default void setName​(String name)
      Sets the name of this Command. Nullop if not overridden.
      Parameters:
      name - The display name of the Command.

    • withName

      default WrapperCommand withName​(String name)
      Decorates this Command with a name.
      Parameters:
      name - name
      Returns:
      the decorated Command