Implementation

---

Usage

Battleaid offers LoadableConfig to make defining and loading configuration files simple. LoadableConfig will automatically initialize class fields when an instance of the configuration is created. This encourages reuse and supports scalability.

---

I. Defining Configurations

To define a configuration, you must create a class that meets these requirements:

1. The class shall extend LoadableConfig.

2. All fields in the class shall be declared public and uninitialized.

3. Fields shall be typed as one of the following:

int	long	short	byte	char
float	double	boolean	String	LoadableConfig
int[]	long[]	short[]	byte[]	char[]
float[]	double[]	boolean[]	String[]	LoadableConfig[]

3. The class shall contain a public constructor with a single parameter String filename that calls super.load(this, filename).

4. Nested config definitions shall have an empty, public constructor and no other constructors.

5. Nested config definitions shall be outside the scope of the encompassing config definition.

6. Non-optional fields shall be annotated @Required.

For example:

// CarConfig.java
public class CarConfig extends LoadableConfig {
    public int mpg;
    public long odometer_measurement;
    @Required public Engine some_engine;
    @Required public boolean is_manual_transmission;
    @Required public Wheel the_wheels[];

    public CarConfig(String filename) {
        super.load(this, filename);
    }
}

In this case, the Engine and Wheel are nested LoadableConfigs:

// Engine.java
public class Engine extends LoadableConfig {
    @Required public int number_of_cylinders;
    public float liters;
    public String style;
    public short horsepower;

    public Engine(){};
}

// Wheel.java
public class Wheel extends LoadableConfig {
    @Required public float radius;
    @Required public String position;
    public int number_of_lugs;

    public Wheel(){};
}

Note

Optionally, one can call LoadableConfig.print(this) to view the class contents.

II. Creating Configuration Files

LoadableConfig uses TOML for configuration files. To make a configuration file, you must create a file that meets these requirements:

1. The file shall be located under src/main/deploy/configuration and have the extension .toml.

2. The identifier shall be identical to the identifier of the class field.

Using the CarConfig from above, a configuration file might be the following:

# example-car.toml
mpg = 32
odometer_measurement = 151_000
is_manual_transmission = true

the_wheels = [
    { radius = 18.0, position = "front right" },
    { radius = 18.0, position = "front left" },
    { radius = 22.0, position = "back left" },
    { radius = 22.0, position = "back right" }
]

[some_engine]
number_of_cylinders = 8
style = "Inline"
liters = 5.7
horsepower = 381

III. Utilizing the Config

Time to use our config!

// RobotContainer.java
public class RobotContainer { 
    public RobotContainer(){
        CarConfig cfg = new CarConfig("example-config.toml");

        // this subsystem needs that config!
        SomeSubsystem ss = new SomeSubsystem(cfg);
    }
}

---

Making Changes

Steps

1. Make a change in your *.toml.

2. Run ./gradlew deployStandalonefrcStaticFileDeployroborio in your terminal.

3. Restart robot code:

---

Notes

I.

An effective strategy is to combine a subsystem with a configuration. You can nest the config class in a subsystem class by adding the static modifier:

// ExampleSubsystem.java
public class ExampleSubsystem {
    private ExampleSubsystem.Config cnfg;

    public static class Config {
        public int some_data; 

        public Config(String filename){
            super.load(this, filename);
        }
    }

    public ExampleSubsystem(ExampleSubsystem.Config cnfg)
    {
        this.cnfg = cnfg;
    }
}

// RobotContainer.java
public class RobotContainer { 
    public RobotContainer(){
        // now the semantic meaning of the config is embedded
        // into the namespacing of our program 
        ExampleSubsystem.Config cnfg = new ExampleSubsystem.Config("config.toml");
        ExampleSubsystem ss = new ExampleSubsystem(cnfg);
    }
}