BindingScope.java

// Copyright (c) FIRST and other WPILib contributors.
// Open Source Software; you can modify and/or share it under the terms of
// the WPILib BSD license file in the root directory of this project.
 
package org.wpilib.command3;
 
import org.wpilib.hardware.hal.RobotMode;

@SuppressWarnings("PMD.ImplicitFunctionalInterface")
interface BindingScope {
  boolean active();

  static BindingScope createNarrowestScope(Scheduler scheduler) {
    Command currentCommand = scheduler.currentCommand();
    RobotStateFetcher fetcher = RobotStateFetcher.getFetcher();
    long currentOpMode = fetcher.getOpModeId();
    RobotMode currentRobotMode = fetcher.getRobotMode();
 
    if (currentCommand != null) {
      // Commands are the narrowest scope, so prioritize them first.
      return new ForCommand(scheduler, currentCommand);
    } else if (currentOpMode != 0) {
      // Opmodes are more specific than general robot mode bindings.
      return new ForOpmode(currentOpMode);
    } else {
      // Not in a command and not in an opmode. Use a robot mode scope, if applicable,
      // or fall back to the global scope if the robot is disabled or in an unrecognized mode.
      // The switch statement deliberately does not have a default case. We want the compiler to
      // tell us to update the switch statement if the enum changes.
      return switch (currentRobotMode) {
        case AUTONOMOUS -> AutonomousMode.INSTANCE;
        case TELEOPERATED -> TeleopMode.INSTANCE;
        case UTILITY -> UtilityMode.INSTANCE;
        case UNKNOWN -> Global.INSTANCE;
      };
    }
  }

  final class Global implements BindingScope {
    // No reason not to be a singleton.
    public static final Global INSTANCE = new Global();
 
    @Override
    public boolean active() {
      return true;
    }
  }

  record ForCommand(Scheduler scheduler, Command command) implements BindingScope {
    @Override
    public boolean active() {
      return scheduler.isRunning(command);
    }
  }

  record ForOpmode(long opmodeId) implements BindingScope {
    @Override
    public boolean active() {
      return RobotStateFetcher.getFetcher().getOpModeId() == opmodeId;
    }
  }
 
  interface RobotModeScope extends BindingScope {}

  final class AutonomousMode implements RobotModeScope {
    public static final AutonomousMode INSTANCE = new AutonomousMode();
 
    @Override
    public boolean active() {
      return RobotStateFetcher.getFetcher().getRobotMode() == RobotMode.AUTONOMOUS;
    }
  }

  final class TeleopMode implements RobotModeScope {
    public static final TeleopMode INSTANCE = new TeleopMode();
 
    @Override
    public boolean active() {
      return RobotStateFetcher.getFetcher().getRobotMode() == RobotMode.TELEOPERATED;
    }
  }

  final class UtilityMode implements RobotModeScope {
    public static final UtilityMode INSTANCE = new UtilityMode();
 
    @Override
    public boolean active() {
      return RobotStateFetcher.getFetcher().getRobotMode() == RobotMode.UTILITY;
    }
  }
 
  // There is no scope for the "disabled" mode, since it would interfere with the global scope
}