Command

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

All Implemented Interfaces:

NamedSendable, Sendable

Direct Known Subclasses:

CommandGroup, ConditionalCommand, InstantCommand, PIDCommand, TimedCommand, WaitForChildren, WaitUntilCommand
```
public abstract class Command
extends java.lang.Object
implements NamedSendable
```
The Command class is at the very core of the entire command framework. Every command can be started with a call to start(). Once a command is started it will call initialize(), and then will repeatedly call execute() until the isFinished() returns true. Once it does, end() will be called.
However, if at any point while it is running cancel() is called, then the command will be stopped and interrupted() will be called.
If a command uses a Subsystem, then it should specify that it does so by calling the requires(...) method in its constructor. Note that a Command may have multiple requirements, and requires(...) should be called for each one.
If a command is running and a new command with shared requirements is started, then one of two things will happen. If the active command is interruptible, then cancel() will be called and the command will be removed to make way for the new one. If the active command is not interruptible, the other one will not even be started, and the active one will continue functioning.

See Also:

Subsystem, CommandGroup, IllegalUseOfCommandException

Constructor Summary

Constructors
Constructor and Description
`Command()` Creates a new command.
`Command(double timeout)` Creates a new command with the given timeout and a default name.
`Command(java.lang.String name)` Creates a new command with the given name.
`Command(java.lang.String name, double timeout)` Creates a new command with the given name and timeout.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`cancel()` This will cancel the current command.
`protected void`	`clearRequirements()` Clears list of subsystem requirements.
`boolean`	`doesRequire(Subsystem system)` Checks if the command requires the given `Subsystem`.
`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.
`CommandGroup`	`getGroup()` Returns the `CommandGroup` that this command is a part of.
`java.lang.String`	`getName()` Returns the name of this command.
`java.lang.String`	`getSmartDashboardType()` The string representation of the named data type that will be used by the smart dashboard for this `Sendable`.
`ITable`	`getTable()` The table that is associated with this `Sendable`.
`protected void`	`initialize()` The initialize method is called the first time this Command is run after being started.
`void`	`initTable(ITable table)` Initializes a table for this `Sendable` object.
`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.
`boolean`	`isCanceled()` Returns whether or not this has been canceled.
`protected abstract boolean`	`isFinished()` Returns whether this command is finished.
`boolean`	`isInterruptible()` Returns whether or not this command can be interrupted.
`boolean`	`isRunning()` Returns whether or not the command is running.
`protected boolean`	`isTimedOut()` Returns whether or not the `timeSinceInitialized()` method returns a number which is greater than or equal to the timeout for the command.
`protected void`	`requires(Subsystem subsystem)` This method specifies that the given `Subsystem` is used by this command.
`protected void`	`setInterruptible(boolean interruptible)` Sets whether or not this command can be interrupted.
`void`	`setRunWhenDisabled(boolean run)` Sets whether or not this `Command` should run when the robot is disabled.
`protected void`	`setTimeout(double seconds)` Sets the timeout of this command.
`void`	`start()` Starts up the command.
`double`	`timeSinceInitialized()` Returns the time since this command was initialized (in seconds).
`java.lang.String`	`toString()` The string representation for a `Command` is by default its name.
`boolean`	`willRunWhenDisabled()` Returns whether or not this `Command` will run when the robot is disabled, or if it will cancel itself.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - Command
```
public Command()
```
    Creates a new command. The name of this command will be set to its class name.
  - Command
```
public Command(java.lang.String name)
```
    Creates a new command with the given name.
    
    Parameters:
    
    name - the name for this command
    
    Throws:
    
    java.lang.IllegalArgumentException - if name is null
  - Command
```
public Command(double timeout)
```
    Creates a new command with the given timeout and a default name. The default name is the name of the class.
    
    Parameters:
    
    timeout - the time (in seconds) before this command "times out"
    
    Throws:
    
    java.lang.IllegalArgumentException - if given a negative timeout
    
    See Also:
    
    isTimedOut()
  - Command
```
public Command(java.lang.String name,
               double timeout)
```
    Creates a new command with the given name and timeout.
    
    Parameters:
    
    name - the name of the command
    
    timeout - the time (in seconds) before this command "times out"
    
    Throws:
    
    java.lang.IllegalArgumentException - if given a negative timeout or name was null.
    
    See Also:
    
    isTimedOut()
- Method Detail
  - getName
```
public java.lang.String getName()
```
    Returns the name of this command. If no name was specified in the constructor, then the default is the name of the class.
    
    Specified by:
    
    getName in interface NamedSendable
    
    Returns:
    
    the name of this command
  - setTimeout
```
protected final void setTimeout(double seconds)
```
    Sets the timeout of this command.
    
    Parameters:
    
    seconds - the timeout (in seconds)
    
    Throws:
    
    java.lang.IllegalArgumentException - if seconds is negative
    
    See Also:
    
    isTimedOut()
  - timeSinceInitialized
```
public final double timeSinceInitialized()
```
    Returns the time since this command was initialized (in seconds). This function will work even if there is no specified timeout.
    
    Returns:
    
    the time since this command was initialized (in seconds).
  - requires
```
protected void requires(Subsystem subsystem)
```
    This method specifies that the given Subsystem is used by this command. This method is crucial to the functioning of the Command System in general.
    Note that the recommended way to call this method is in the constructor.
    
    Parameters:
    
    subsystem - the Subsystem required
    
    Throws:
    
    java.lang.IllegalArgumentException - if subsystem is null
    
    IllegalUseOfCommandException - if this command has started before or if it has been given to a CommandGroup
    
    See Also:
    
    Subsystem
  - initialize
```
protected void initialize()
```
    The initialize method is called the first time this Command is run after being started.
  - execute
```
protected void execute()
```
    The execute method is called repeatedly until this Command either finishes or is canceled.
  - isFinished
```
protected abstract boolean isFinished()
```
    Returns whether this command is finished. If it is, then the command will be removed and end() will be called.
    It may be useful for a team to reference the isTimedOut() method for time-sensitive commands.
    Returning false will result in the command never ending automatically. It may still be cancelled manually or interrupted by another command. Returning true will result in the command executing once and finishing immediately. We recommend using InstantCommand for this.
    
    Returns:
    
    whether this command is finished.
    
    See Also:
    
    isTimedOut()
  - end
```
protected void end()
```
    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.
  - interrupted
```
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.
    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, as done here.
  - isTimedOut
```
protected boolean isTimedOut()
```
    Returns whether or not the timeSinceInitialized() method returns a number which is greater than or equal to the timeout for the command. If there is no timeout, this will always return false.
    
    Returns:
    
    whether the time has expired
  - clearRequirements
```
protected void clearRequirements()
```
    Clears list of subsystem requirements. This is only used by ConditionalCommand so cancelling the chosen command works properly in CommandGroup.
  - start
```
public void start()
```
    Starts up the command. Gets the command ready to start.
    Note that the command will eventually start, however it will not necessarily do so immediately, and may in fact be canceled before initialize is even called.
    
    Throws:
    
    IllegalUseOfCommandException - if the command is a part of a CommandGroup
  - isRunning
```
public boolean isRunning()
```
    Returns whether or not the command is running. This may return true even if the command has just been canceled, as it may not have yet called interrupted().
    
    Returns:
    
    whether or not the command is running
  - cancel
```
public void cancel()
```
    This will cancel the current command.
    This will cancel the current command eventually. It can be called multiple times. And it can be called when the command is not running. If the command is running though, then the command will be marked as canceled and eventually removed.
    
    A command can not be canceled if it is a part of a command group, you must cancel the command group instead.
    
    Throws:
    
    IllegalUseOfCommandException - if this command is a part of a command group
  - isCanceled
```
public boolean isCanceled()
```
    Returns whether or not this has been canceled.
    
    Returns:
    
    whether or not this has been canceled
  - isInterruptible
```
public boolean isInterruptible()
```
    Returns whether or not this command can be interrupted.
    
    Returns:
    
    whether or not this command can be interrupted
  - setInterruptible
```
protected void setInterruptible(boolean interruptible)
```
    Sets whether or not this command can be interrupted.
    
    Parameters:
    
    interruptible - whether or not this command can be interrupted
  - doesRequire
```
public boolean doesRequire(Subsystem system)
```
    Checks if the command requires the given Subsystem.
    
    Parameters:
    
    system - the system
    
    Returns:
    
    whether or not the subsystem is required, or false if given null
  - getGroup
```
public CommandGroup getGroup()
```
    Returns the CommandGroup that this command is a part of. Will return null if this Command is not in a group.
    
    Returns:
    
    the CommandGroup that this command is a part of (or null if not in group)
  - setRunWhenDisabled
```
public void setRunWhenDisabled(boolean run)
```
    Sets whether or not this Command should run when the robot is disabled.
    By default a command will not run when the robot is disabled, and will in fact be canceled.
    
    Parameters:
    
    run - whether or not this command should run when the robot is disabled
  - willRunWhenDisabled
```
public boolean willRunWhenDisabled()
```
    Returns whether or not this Command will run when the robot is disabled, or if it will cancel itself.
    
    Returns:
    
    True if this command will run when the robot is disabled.
  - toString
```
public java.lang.String toString()
```
    The string representation for a Command is by default its name.
    
    Overrides:
    
    toString in class java.lang.Object
    
    Returns:
    
    the string representation of this object
  - getSmartDashboardType
```
public java.lang.String getSmartDashboardType()
```
    Description copied from interface: Sendable
    
    The string representation of the named data type that will be used by the smart dashboard for this Sendable.
    
    Specified by:
    
    getSmartDashboardType in interface Sendable
    
    Returns:
    
    The type of this Sendable.
  - initTable
```
public void initTable(ITable table)
```
    Description copied from interface: Sendable
    
    Initializes a table for this Sendable object.
    
    Specified by:
    
    initTable in interface Sendable
    
    Parameters:
    
    table - The table to put the values in.
  - getTable
```
public ITable getTable()
```
    Description copied from interface: Sendable
    
    The table that is associated with this Sendable.
    
    Specified by:
    
    getTable in interface Sendable
    
    Returns:
    
    the table that is currently associated with the Sendable.

Class Command

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Command

Command

Command

Command

Method Detail

getName

setTimeout

timeSinceInitialized

requires

initialize

execute

isFinished

end

interrupted

isTimedOut

clearRequirements

start

isRunning

cancel

isCanceled

isInterruptible

setInterruptible

doesRequire

getGroup

setRunWhenDisabled

willRunWhenDisabled

toString

getSmartDashboardType

initTable

getTable