Package edu.wpi.first.wpilibj.command

Class Subsystem

java.lang.Object
edu.wpi.first.wpilibj.command.Subsystem
Direct Known Subclasses:
DriveBase
public abstract class Subsystem
extends java.lang.Object
This class defines a major component of the robot.

A good example of a subsystem is the driveline, or a claw if the robot has one.

All motors should be a part of a subsystem. For instance, all the wheel motors should be a part of some kind of "Driveline" subsystem.

Subsystems are used within the command system as requirements for Command. Only one command which requires a subsystem can run at a time. Also, subsystems can have default commands which are started if there is no command running which requires this subsystem.

See Also:
Command

  • Constructor Summary

    Constructors 
    Constructor Description
    Subsystem()  

  • Method Summary

    Modifier and Type Method Description
    Command getCurrentCommand()
    Returns the command which currently claims this subsystem.
    Command getDefaultCommand()
    Returns the default command (or null if there is none).
    void periodic()
    When the run method of the scheduler is called this method will be called.
    void setDefaultCommand​(Command command)
    Sets the default command.

    Methods inherited from class java.lang.Object

    equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

  • Method Details

    • periodic

      public void periodic()
      When the run method of the scheduler is called this method will be called.

    • setDefaultCommand

      public void setDefaultCommand​(Command command)
      Sets the default command. If this is not called or is called with null, then there will be no default command for the subsystem.

      WARNING: This should NOT be called in a constructor if the subsystem is a singleton.

      Parameters:
      command - the default command (or null if there should be none)
      Throws:
      IllegalUseOfCommandException - if the command does not require the subsystem

    • getDefaultCommand

      public Command getDefaultCommand()
      Returns the default command (or null if there is none).
      Returns:
      the default command

    • getCurrentCommand

      public Command getCurrentCommand()
      Returns the command which currently claims this subsystem.
      Returns:
      the command which currently claims this subsystem