Add support for enum logging as inputs and outputs

Closes #54

docs/DATA-FLOW.md

@@ -39,6 +39,10 @@ AdvantageKit also supports logging the state of a `Mechanism2d` object as an out
 
 WPILib includes a [units library](https://docs.wpilib.org/en/latest/docs/software/basic-programming/java-units.html) that can be used to simplify unit conversions. `Measure` objects can be logged and replayed by AdvantageKit. These values will be stored in the log as doubles using the [base unit](https://github.com/wpilibsuite/allwpilib/blob/main/wpiunits/src/main/java/edu/wpi/first/units/BaseUnits.java) for the measurement type (e.g. distances will always be logged in meters).
 
+### Enums
+
+[Enum](https://www.w3schools.com/java/java_enums.asp) values can be logged and replayed by AdvantageKit. These values will be stored in the log as string values (using the [`name()`](https://docs.oracle.com/javase/8/docs/api/java/lang/Enum.html#name--) method).
+
 ## Deterministic Timestamps
 
 ### The Problem

docs/RECORDING-INPUTS.md

@@ -52,7 +52,7 @@ public RobotContainer() {
 
 ## `AutoLog` Annotation & Data Types
 
-By adding the `@AutoLog` annotation to your inputs class, AdvantageKit will automatically generate implementations of `toLog` and `fromLog` for your inputs. All simple data types (including single values and arrays) are supported. [Structured data types](DATA-FLOW.md#structured-data-types) are also supported, so geometry objects like `Rotation2d` and `Pose3d` can be directly used as inputs.
+By adding the `@AutoLog` annotation to your inputs class, AdvantageKit will automatically generate implementations of `toLog` and `fromLog` for your inputs. All simple data types (including single values and arrays) are supported. [Structured data types](DATA-FLOW.md#structured-data-types) and enum values are also supported, so geometry objects like `Rotation2d` and `Pose3d` can be directly used as inputs.
 
 For example:
 
@@ -61,6 +61,7 @@ For example:
 public class MyInputs {
     public double myNumber = 0.0;
     public Pose2d myPose = new Pose2d();
+    public MyEnum myEnum = MyEnum.VALUE;
 }
 ```
 
@@ -71,11 +72,13 @@ class MyInputsAutoLogged extends MyInputs implements LoggableInputs {
     public void toLog(LogTable table) {
         table.put("MyNumber", myField);
         table.put("MyPose", myPose);
+        table.put("MyEnum", myEnum);
     }
 
     public void fromLog(LogTable table) {
         myNumber = table.get("MyNumber", myNumber);
         myPose = table.get("MyPose", myPose);
+        myEnum = table.get("MyEnum", myEnum);
     }
 }
 ```

docs/RECORDING-OUTPUTS.md

@@ -12,8 +12,8 @@ The logging framework supports recording this output data on the real robot and
 
 ```java
 Logger.recordOutput("Flywheel/Setpoint", setpointSpeed);
-Logger.recordOutput("FeederState", "IDLE");
-Logger.recordOutput("Drive/CalculatedLeftVolts", leftVolts);
+Logger.recordOutput("Drive/Pose", odometryPose);
+Logger.recordOutput("FeederState", FeederState.RUNNING);
 ```
 
 > Note: This data is automatically saved to the `RealOutputs` or `ReplayOutputs` table, and it can be divided further into subtables using slashes (as seen above).

junction/core/src/org/littletonrobotics/junction/AutoLogOutputManager.java

@@ -388,6 +388,14 @@ private static void registerField(String key, Class<?> type, Supplier<?> supplie
               if (value != null)
                 Logger.recordOutput(key, (String) value);
             });
+      } else if (type.isEnum()) {
+        callbacks.add(
+            () -> {
+              Object value = supplier.get();
+              if (value != null)
+                // Cannot cast to enum subclass, log the name directly
+                Logger.recordOutput(key, ((Enum<?>) value).name());
+            });
       } else if (type.equals(Measure.class)) {
         callbacks.add(
             () -> {

junction/core/src/org/littletonrobotics/junction/LogTable.java

@@ -231,6 +231,14 @@ public void put(String key, String value) {
     put(key, new LogValue(value, null));
   }
 
+  /**
+   * Writes a new enum value to the table. Skipped if the key already exists as
+   * a different type.
+   */
+  public <E extends Enum<E>> void put(String key, E value) {
+    put(key, new LogValue(value.name(), null));
+  }
+
   /**
    * Writes a new Measure value to the table. Skipped if the key already exists as
    * a different type.
@@ -532,6 +540,16 @@ public String get(String key, String defaultValue) {
     }
   }
 
+  /** Reads an enum value from the table. */
+  public <E extends Enum<E>> E get(String key, E defaultValue) {
+    if (data.containsKey(prefix + key)) {
+      String name = get(key).getString(defaultValue.name());
+      return (E) Enum.valueOf(defaultValue.getClass(), name);
+    } else {
+      return defaultValue;
+    }
+  }
+
   /** Reads a Measure value from the table. */
   public <U extends Unit<U>> Measure<U> get(String key, Measure<U> defaultValue) {
     if (data.containsKey(prefix + key)) {

junction/core/src/org/littletonrobotics/junction/Logger.java

@@ -503,6 +503,20 @@ public static void recordOutput(String key, String value) {
     }
   }
 
+  /**
+   * Records a single output field for easy access when viewing the log. On the
+   * simulator, use this method to record extra data based on the original inputs.
+   * 
+   * @param key   The name of the field to record. It will be stored under
+   *              "/RealOutputs" or "/ReplayOutputs"
+   * @param value The value of the field.
+   */
+  public static <E extends Enum<E>> void recordOutput(String key, E value) {
+    if (running) {
+      outputTable.put(key, value);
+    }
+  }
+
   /**
    * Records a single output field for easy access when viewing the log. On the
    * simulator, use this method to record extra data based on the original inputs.