Package edu.wpi.first.wpilibj2.command
Class CommandScheduler
- java.lang.Object
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- edu.wpi.first.wpilibj2.command.CommandScheduler
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- All Implemented Interfaces:
NTSendable
,Sendable
,AutoCloseable
public final class CommandScheduler extends Object implements NTSendable, AutoCloseable
The scheduler responsible for runningCommand
s. A Command-based robot should callrun()
on the singleton instance in its periodic block in order to run commands synchronously from the main loop. Subsystems should be registered with the scheduler usingregisterSubsystem(Subsystem...)
in order for theirSubsystem.periodic()
methods to be called and for their default commands to be scheduled.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description void
addButton(Runnable button)
Adds a button binding to the scheduler, which will be polled to schedule commands.void
cancel(Command... commands)
Cancels commands.void
cancelAll()
Cancels all commands that are currently scheduled.void
clearButtons()
Removes all button bindings from the scheduler.void
close()
void
disable()
Disables the command scheduler.void
enable()
Enables the command scheduler.Command
getDefaultCommand(Subsystem subsystem)
Gets the default command associated with this subsystem.static CommandScheduler
getInstance()
Returns the Scheduler instance.void
initSendable(NTSendableBuilder builder)
Initializes thisSendable
object.boolean
isScheduled(Command... commands)
Whether the given commands are running.void
onCommandExecute(Consumer<Command> action)
Adds an action to perform on the execution of any command by the scheduler.void
onCommandFinish(Consumer<Command> action)
Adds an action to perform on the finishing of any command by the scheduler.void
onCommandInitialize(Consumer<Command> action)
Adds an action to perform on the initialization of any command by the scheduler.void
onCommandInterrupt(Consumer<Command> action)
Adds an action to perform on the interruption of any command by the scheduler.void
registerSubsystem(Subsystem... subsystems)
Registers subsystems with the scheduler.Command
requiring(Subsystem subsystem)
Returns the command currently requiring a given subsystem.void
run()
Runs a single iteration of the scheduler.void
schedule(boolean interruptible, Command... commands)
Schedules multiple commands for execution.void
schedule(Command... commands)
Schedules multiple commands for execution, with interruptible defaulted to true.void
setDefaultCommand(Subsystem subsystem, Command defaultCommand)
Sets the default command for a subsystem.void
setPeriod(double period)
Changes the period of the loop overrun watchdog.double
timeSinceScheduled(Command command)
Returns the time since a given command was scheduled.void
unregisterSubsystem(Subsystem... subsystems)
Un-registers subsystems with the scheduler.-
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface edu.wpi.first.networktables.NTSendable
initSendable
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Method Detail
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getInstance
public static CommandScheduler getInstance()
Returns the Scheduler instance.- Returns:
- the instance
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setPeriod
public void setPeriod(double period)
Changes the period of the loop overrun watchdog. This should be be kept in sync with the TimedRobot period.- Parameters:
period
- Period in seconds.
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close
public void close()
- Specified by:
close
in interfaceAutoCloseable
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addButton
public void addButton(Runnable button)
Adds a button binding to the scheduler, which will be polled to schedule commands.- Parameters:
button
- The button to add
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clearButtons
public void clearButtons()
Removes all button bindings from the scheduler.
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schedule
public void schedule(boolean interruptible, Command... commands)
Schedules multiple commands for execution. Does nothing if the command is already scheduled. If a command's requirements are not available, it will only be started if all the commands currently using those requirements have been scheduled as interruptible. If this is the case, they will be interrupted and the command will be scheduled.- Parameters:
interruptible
- whether the commands should be interruptiblecommands
- the commands to schedule
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schedule
public void schedule(Command... commands)
Schedules multiple commands for execution, with interruptible defaulted to true. Does nothing if the command is already scheduled.- Parameters:
commands
- the commands to schedule
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run
public void run()
Runs a single iteration of the scheduler. The execution occurs in the following order:Subsystem periodic methods are called.
Button bindings are polled, and new commands are scheduled from them.
Currently-scheduled commands are executed.
End conditions are checked on currently-scheduled commands, and commands that are finished have their end methods called and are removed.
Any subsystems not being used as requirements have their default methods started.
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registerSubsystem
public void registerSubsystem(Subsystem... subsystems)
Registers subsystems with the scheduler. This must be called for the subsystem's periodic block to run when the scheduler is run, and for the subsystem's default command to be scheduled. It is recommended to call this from the constructor of your subsystem implementations.- Parameters:
subsystems
- the subsystem to register
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unregisterSubsystem
public void unregisterSubsystem(Subsystem... subsystems)
Un-registers subsystems with the scheduler. The subsystem will no longer have its periodic block called, and will not have its default command scheduled.- Parameters:
subsystems
- the subsystem to un-register
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setDefaultCommand
public void setDefaultCommand(Subsystem subsystem, Command defaultCommand)
Sets the default command for a subsystem. Registers that subsystem if it is not already registered. Default commands will run whenever there is no other command currently scheduled that requires the subsystem. Default commands should be written to never end (i.e. theirCommand.isFinished()
method should return false), as they would simply be re-scheduled if they do. Default commands must also require their subsystem.- Parameters:
subsystem
- the subsystem whose default command will be setdefaultCommand
- the default command to associate with the subsystem
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getDefaultCommand
public Command getDefaultCommand(Subsystem subsystem)
Gets the default command associated with this subsystem. Null if this subsystem has no default command associated with it.- Parameters:
subsystem
- the subsystem to inquire about- Returns:
- the default command associated with the subsystem
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cancel
public void cancel(Command... commands)
Cancels commands. The scheduler will only callCommand.end(boolean)
method of the canceled command withtrue
, indicating they were canceled (as opposed to finishing normally).Commands will be canceled even if they are not scheduled as interruptible.
- Parameters:
commands
- the commands to cancel
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cancelAll
public void cancelAll()
Cancels all commands that are currently scheduled.
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timeSinceScheduled
public double timeSinceScheduled(Command command)
Returns the time since a given command was scheduled. Note that this only works on commands that are directly scheduled by the scheduler; it will not work on commands inside of commandgroups, as the scheduler does not see them.- Parameters:
command
- the command to query- Returns:
- the time since the command was scheduled, in seconds
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isScheduled
public boolean isScheduled(Command... commands)
Whether the given commands are running. Note that this only works on commands that are directly scheduled by the scheduler; it will not work on commands inside of CommandGroups, as the scheduler does not see them.- Parameters:
commands
- the command to query- Returns:
- whether the command is currently scheduled
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requiring
public Command requiring(Subsystem subsystem)
Returns the command currently requiring a given subsystem. Null if no command is currently requiring the subsystem- Parameters:
subsystem
- the subsystem to be inquired about- Returns:
- the command currently requiring the subsystem, or null if no command is currently scheduled
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disable
public void disable()
Disables the command scheduler.
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enable
public void enable()
Enables the command scheduler.
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onCommandInitialize
public void onCommandInitialize(Consumer<Command> action)
Adds an action to perform on the initialization of any command by the scheduler.- Parameters:
action
- the action to perform
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onCommandExecute
public void onCommandExecute(Consumer<Command> action)
Adds an action to perform on the execution of any command by the scheduler.- Parameters:
action
- the action to perform
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onCommandInterrupt
public void onCommandInterrupt(Consumer<Command> action)
Adds an action to perform on the interruption of any command by the scheduler.- Parameters:
action
- the action to perform
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onCommandFinish
public void onCommandFinish(Consumer<Command> action)
Adds an action to perform on the finishing of any command by the scheduler.- Parameters:
action
- the action to perform
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initSendable
public void initSendable(NTSendableBuilder builder)
Description copied from interface:NTSendable
Initializes thisSendable
object.- Specified by:
initSendable
in interfaceNTSendable
- Parameters:
builder
- sendable builder
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