edu.wpi.first.wpilibj.command
Class CommandGroup

java.lang.Object
  edu.wpi.first.wpilibj.command.Command
      edu.wpi.first.wpilibj.command.CommandGroup

All Implemented Interfaces:

SmartDashboardData, SmartDashboardNamedData

public class CommandGroup
extends Command

A CommandGroup is a list of commands which are executed in sequence.

Commands in a CommandGroup are added using the addSequential(...) method and are called sequentially. CommandGroups are themselves commands and can be given to other CommandGroups.

CommandGroups will carry all of the requirements of their subcommands. Additional requirements can be specified by calling requires(...) normally in the constructor.

CommandGroups can also execute commands in parallel, simply by adding them using addParallel(...).

Author:

Brad Miller, Joe Grinstead

See Also:

Command, Subsystem, IllegalUseOfCommandException

Constructor Summary

CommandGroup()
Creates a new CommandGroup.

CommandGroup(java.lang.String name)
Creates a new CommandGroup with the given name.

Method Summary

void	addParallel(Command command) Adds a new child Command to the group.
void	addParallel(Command command, double timeout) Adds a new child Command to the group with the given timeout.
void	addSequential(Command command) Adds a new Command to the group.
void	addSequential(Command command, double timeout) Adds a new Command to the group with a given timeout.
protected void	end() Called when the command ended peacefully.
protected void	execute() The execute method is called repeatedly until this Command either finishes or is canceled.
protected void	initialize() The initialize method is called the first time this Command is run after being started.
protected void	interrupted() Called when the command ends because somebody called cancel() or another command shared the same requirements as this one, and booted it out.
protected boolean	isFinished() Returns true if all the Commands in this group have been started and have finished.
boolean	isInterruptible() Returns whether or not this group is interruptible.

Methods inherited from class edu.wpi.first.wpilibj.command.Command

cancel, doesRequire, getGroup, getName, getTable, getType, grabTable, isCanceled, isRunning, isTimedOut, requires, setInterruptible, setRunWhenDisabled, setTimeout, start, timeSinceInitialized, toString, willRunWhenDisabled

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

CommandGroup

public CommandGroup()

Creates a new CommandGroup. The name of this command will be set to its class name.

CommandGroup

public CommandGroup(java.lang.String name)

Creates a new CommandGroup with the given name.

Parameters:

name - the name for this command group

Throws:

java.lang.IllegalArgumentException - if name is null

Method Detail

addSequential

public final void addSequential(Command command)

Adds a new Command to the group. The Command will be started after all the previously added Commands.

Note that any requirements the given Command has will be added to the group. For this reason, a Command's requirements can not be changed after being added to a group.

It is recommended that this method be called in the constructor.

Parameters:

command - The Command to be added

Throws:

IllegalUseOfCommandException - if the group has been started before or been given to another group

java.lang.IllegalArgumentException - if command is null

addSequential

public final void addSequential(Command command,
                                double timeout)

Adds a new Command to the group with a given timeout. The Command will be started after all the previously added commands.

Once the Command is started, it will be run until it finishes or the time expires, whichever is sooner. Note that the given Command will have no knowledge that it is on a timer.

Note that any requirements the given Command has will be added to the group. For this reason, a Command's requirements can not be changed after being added to a group.

It is recommended that this method be called in the constructor.

Parameters:

command - The Command to be added

timeout - The timeout (in seconds)

Throws:

IllegalUseOfCommandException - if the group has been started before or been given to another group or if the Command has been started before or been given to another group

java.lang.IllegalArgumentException - if command is null or timeout is negative

addParallel

public final void addParallel(Command command)

Adds a new child Command to the group. The Command will be started after all the previously added Commands.

Instead of waiting for the child to finish, a CommandGroup will have it run at the same time as the subsequent Commands. The child will run until either it finishes, a new child with conflicting requirements is started, or the main sequence runs a Command with conflicting requirements. In the latter two cases, the child will be canceled even if it says it can't be interrupted.

Note that any requirements the given Command has will be added to the group. For this reason, a Command's requirements can not be changed after being added to a group.

It is recommended that this method be called in the constructor.

Parameters:

command - The command to be added

Throws:

IllegalUseOfCommandException - if the group has been started before or been given to another command group

java.lang.IllegalArgumentException - if command is null

addParallel

public final void addParallel(Command command,
                              double timeout)

Adds a new child Command to the group with the given timeout. The Command will be started after all the previously added Commands.

Once the Command is started, it will run until it finishes, is interrupted, or the time expires, whichever is sooner. Note that the given Command will have no knowledge that it is on a timer.

Instead of waiting for the child to finish, a CommandGroup will have it run at the same time as the subsequent Commands. The child will run until either it finishes, the timeout expires, a new child with conflicting requirements is started, or the main sequence runs a Command with conflicting requirements. In the latter two cases, the child will be canceled even if it says it can't be interrupted.

Note that any requirements the given Command has will be added to the group. For this reason, a Command's requirements can not be changed after being added to a group.

It is recommended that this method be called in the constructor.

Parameters:

command - The command to be added

timeout - The timeout (in seconds)

Throws:

IllegalUseOfCommandException - if the group has been started before or been given to another command group

java.lang.IllegalArgumentException - if command is null

isFinished

protected boolean isFinished()

Returns true if all the Commands in this group have been started and have finished.

Teams may override this method, although they should probably reference super.isFinished() if they do.

Specified by:

isFinished in class Command

Returns:

whether this CommandGroup is finished

See Also:

isTimedOut()

initialize

protected void initialize()

Description copied from class: Command

The initialize method is called the first time this Command is run after being started.

Specified by:

initialize in class Command

execute

protected void execute()

Description copied from class: Command

The execute method is called repeatedly until this Command either finishes or is canceled.

Specified by:

execute in class Command

end

protected void end()

Description copied from class: Command

Called when the command ended peacefully. This is where you may want to wrap up loose ends, like shutting off a motor that was being used in the command.

Specified by:

end in class Command

interrupted

protected void interrupted()

Description copied from class: Command

Called when the command ends because somebody called cancel() or another command shared the same requirements as this one, and booted it out.

This is where you may want to wrap up loose ends, like shutting off a motor that was being used in the command.

Generally, it is useful to simply call the end() method within this method

Specified by:

interrupted in class Command

isInterruptible

public boolean isInterruptible()

Returns whether or not this group is interruptible. A command group will be uninterruptible if setInterruptable(false) was called or if it is currently running an uninterruptible command or child.

Overrides:

isInterruptible in class Command

Returns:

whether or not this CommandGroup is interruptible.