[commands] Update Subsystem factories and example to return CommandBase (#4729)

Also update rapidreactcommandbot example factories to fit this convention (as in #4655).

C++ does not need an update as CommandPtr already uses CommandBase (#4677).

wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/rapidreactcommandbot/RapidReactCommandBot.java

@@ -13,7 +13,7 @@ import edu.wpi.first.wpilibj.examples.rapidreactcommandbot.subsystems.Drive;
 import edu.wpi.first.wpilibj.examples.rapidreactcommandbot.subsystems.Intake;
 import edu.wpi.first.wpilibj.examples.rapidreactcommandbot.subsystems.Shooter;
 import edu.wpi.first.wpilibj.examples.rapidreactcommandbot.subsystems.Storage;
-import edu.wpi.first.wpilibj2.command.Command;
+import edu.wpi.first.wpilibj2.command.CommandBase;
 import edu.wpi.first.wpilibj2.command.button.CommandXboxController;
 import edu.wpi.first.wpilibj2.command.button.Trigger;
 
@@ -76,7 +76,7 @@ public class RapidReactCommandBot {
    *
    * <p>Scheduled during {@link Robot#autonomousInit()}.
    */
-  public Command getAutonomousCommand() {
+  public CommandBase getAutonomousCommand() {
     // Drive forward for 2 meters at half speed with a 3 second timeout
     return m_drive
         .driveDistanceCommand(AutoConstants.kDriveDistanceMeters, AutoConstants.kDriveSpeed)

wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/rapidreactcommandbot/subsystems/Drive.java

@@ -9,7 +9,7 @@ import edu.wpi.first.wpilibj.drive.DifferentialDrive;
 import edu.wpi.first.wpilibj.examples.rapidreactcommandbot.Constants.DriveConstants;
 import edu.wpi.first.wpilibj.motorcontrol.MotorControllerGroup;
 import edu.wpi.first.wpilibj.motorcontrol.PWMSparkMax;
-import edu.wpi.first.wpilibj2.command.Command;
+import edu.wpi.first.wpilibj2.command.CommandBase;
 import edu.wpi.first.wpilibj2.command.SubsystemBase;
 import java.util.function.DoubleSupplier;
 
@@ -61,7 +61,7 @@ public class Drive extends SubsystemBase {
    * @param fwd the commanded forward movement
    * @param rot the commanded rotation
    */
-  public Command arcadeDriveCommand(DoubleSupplier fwd, DoubleSupplier rot) {
+  public CommandBase arcadeDriveCommand(DoubleSupplier fwd, DoubleSupplier rot) {
     // A split-stick arcade command, with forward/backward controlled by the left
     // hand, and turning controlled by the right.
     return run(() -> m_drive.arcadeDrive(fwd.getAsDouble(), rot.getAsDouble()))
@@ -74,7 +74,7 @@ public class Drive extends SubsystemBase {
    * @param distanceMeters The distance to drive forward in meters
    * @param speed The fraction of max speed at which to drive
    */
-  public Command driveDistanceCommand(double distanceMeters, double speed) {
+  public CommandBase driveDistanceCommand(double distanceMeters, double speed) {
     return runOnce(
             () -> {
               // Reset encoders at the start of the command

wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/rapidreactcommandbot/subsystems/Intake.java

@@ -9,7 +9,7 @@ import static edu.wpi.first.wpilibj.examples.rapidreactcommandbot.Constants.Inta
 import edu.wpi.first.wpilibj.DoubleSolenoid;
 import edu.wpi.first.wpilibj.PneumaticsModuleType;
 import edu.wpi.first.wpilibj.motorcontrol.PWMSparkMax;
-import edu.wpi.first.wpilibj2.command.Command;
+import edu.wpi.first.wpilibj2.command.CommandBase;
 import edu.wpi.first.wpilibj2.command.SubsystemBase;
 
 public class Intake extends SubsystemBase {
@@ -21,14 +21,14 @@ public class Intake extends SubsystemBase {
           IntakeConstants.kSolenoidPorts[2]);
 
   /** Returns a command that deploys the intake, and then runs the intake motor indefinitely. */
-  public Command intakeCommand() {
+  public CommandBase intakeCommand() {
     return runOnce(() -> m_pistons.set(DoubleSolenoid.Value.kForward))
         .andThen(run(() -> m_motor.set(1.0)))
         .withName("Intake");
   }
 
   /** Returns a command that turns off and retracts the intake. */
-  public Command retractCommand() {
+  public CommandBase retractCommand() {
     return runOnce(
             () -> {
               m_motor.disable();

wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/rapidreactcommandbot/subsystems/Shooter.java

@@ -12,7 +12,7 @@ import edu.wpi.first.math.controller.SimpleMotorFeedforward;
 import edu.wpi.first.wpilibj.Encoder;
 import edu.wpi.first.wpilibj.examples.frisbeebot.Constants.ShooterConstants;
 import edu.wpi.first.wpilibj.motorcontrol.PWMSparkMax;
-import edu.wpi.first.wpilibj2.command.Command;
+import edu.wpi.first.wpilibj2.command.CommandBase;
 import edu.wpi.first.wpilibj2.command.SubsystemBase;
 
 public class Shooter extends SubsystemBase {
@@ -50,7 +50,7 @@ public class Shooter extends SubsystemBase {
    *
    * @param setpointRotationsPerSecond The desired shooter velocity
    */
-  public Command shootCommand(double setpointRotationsPerSecond) {
+  public CommandBase shootCommand(double setpointRotationsPerSecond) {
     return parallel(
             // Run the shooter flywheel at the desired setpoint using feedforward and feedback
             run(

wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/rapidreactcommandbot/subsystems/Storage.java

@@ -8,7 +8,7 @@ import static edu.wpi.first.wpilibj.examples.rapidreactcommandbot.Constants.Stor
 
 import edu.wpi.first.wpilibj.DigitalInput;
 import edu.wpi.first.wpilibj.motorcontrol.PWMSparkMax;
-import edu.wpi.first.wpilibj2.command.Command;
+import edu.wpi.first.wpilibj2.command.CommandBase;
 import edu.wpi.first.wpilibj2.command.SubsystemBase;
 
 public class Storage extends SubsystemBase {
@@ -27,7 +27,7 @@ public class Storage extends SubsystemBase {
   }
 
   /** Returns a command that runs the storage motor indefinitely. */
-  public Command runCommand() {
+  public CommandBase runCommand() {
     return run(() -> m_motor.set(1)).withName("run");
   }
 }