> For the complete documentation index, see [llms.txt](https://docs.cb21829.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cb21829.org/ftc-java-advanced-guide/command-based-structure-with-nextftc.md).

# Command-based structure with NextFTC

Command-based structure splits the robot into **subsystems** and **commands**.

NextFTC is a popular FTC library for this pattern.

### Core concepts

* **Subsystem** — owns hardware for one mechanism.
* **Command** — a reusable action with a lifecycle.
* **Bindings** — connect buttons to commands.

### A subsystem

```java
public class Lift extends Subsystem {
    public static final Lift INSTANCE = new Lift();
    private Lift() { }

    private MotorEx motor;

    public final ControlSystem controlSystem = ControlSystem.builder()
            .posPid(0.005, 0.0, 0.0)
            .build();

    @Override
    public void initialize() {
        motor = new MotorEx("lift");
    }

    @Override
    public void periodic() {
        motor.setPower(controlSystem.calculate(motor.getState()));
    }

    public Command toHigh() {
        return new RunToPosition(controlSystem, 2200).requires(this);
    }
    public Command toLow() {
        return new RunToPosition(controlSystem, 0).requires(this);
    }
}
```

### A command-based TeleOp with bindings

```java
@TeleOp(name = "Command TeleOp")
public class CommandTeleOp extends NextFTCOpMode {

    public CommandTeleOp() {
        addComponents(
            new SubsystemComponent(Lift.INSTANCE),
            BulkReadComponent.INSTANCE
        );
    }

    @Override
    public void onStartButtonPressed() {
        gamepadManager.gamepad2().a().whenBecomesTrue(Lift.INSTANCE.toHigh());
        gamepadManager.gamepad2().b().whenBecomesTrue(Lift.INSTANCE.toLow());
    }
}
```

### When to adopt command-based

Use it when you feel the pain of large OpModes, complex autos, and hand-managed parallelism. For very small robots, plain structured OpModes are still fine.


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