[wpiunits] Java units API rewrite (#6958)

Java generics are too limited to do what we need. This refactors generic code previously in Unit and Measure into unit-specific classes that can have unit-safe math operations (notably, times and divide) that can return values in known units instead of a wildcarded Measure<?>.

Unit-specific measure implementations are automatically generated by ./wpiunits/generate_units.py, which generates generic interfaces and mutable and immutable implementations of those interfaces. These make up the bulk of the diff of this PR (approximately 9300 LOC).

This also adds units for angular and linear velocities, accelerations, and momenta; moment of inertia; and torque.

wpiunits/src/main/java/edu/wpi/first/units/DimensionlessUnit.java

@@ -0,0 +1,99 @@
+// 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 edu.wpi.first.units;
+
+import edu.wpi.first.units.measure.Dimensionless;
+import edu.wpi.first.units.measure.ImmutableDimensionless;
+import edu.wpi.first.units.measure.MutDimensionless;
+
+/**
+ * A type of unit that corresponds to raw values and not any physical dimension, such as percentage.
+ */
+public final class DimensionlessUnit extends Unit {
+  /**
+   * Creates a new unit with the given name and multiplier to the base unit.
+   *
+   * @param baseUnitEquivalent the multiplier to convert this unit to the base unit of this type.
+   * @param name the name of the unit
+   * @param symbol the symbol of the unit
+   */
+  DimensionlessUnit(
+      DimensionlessUnit baseUnit, double baseUnitEquivalent, String name, String symbol) {
+    super(baseUnit, baseUnitEquivalent, name, symbol);
+  }
+
+  DimensionlessUnit(
+      DimensionlessUnit baseUnit,
+      UnaryFunction toBaseConverter,
+      UnaryFunction fromBaseConverter,
+      String name,
+      String symbol) {
+    super(baseUnit, toBaseConverter, fromBaseConverter, name, symbol);
+  }
+
+  @Override
+  public DimensionlessUnit getBaseUnit() {
+    return (DimensionlessUnit) super.getBaseUnit();
+  }
+
+  @Override
+  public Dimensionless of(double magnitude) {
+    return new ImmutableDimensionless(magnitude, toBaseUnits(magnitude), this);
+  }
+
+  @Override
+  public Dimensionless ofBaseUnits(double baseUnitMagnitude) {
+    return new ImmutableDimensionless(fromBaseUnits(baseUnitMagnitude), baseUnitMagnitude, this);
+  }
+
+  @Override
+  public Dimensionless zero() {
+    return (Dimensionless) super.zero();
+  }
+
+  @Override
+  public Dimensionless one() {
+    return (Dimensionless) super.one();
+  }
+
+  @Override
+  public MutDimensionless mutable(double initialMagnitude) {
+    return new MutDimensionless(initialMagnitude, toBaseUnits(initialMagnitude), this);
+  }
+
+  /**
+   * Converts a measurement value in terms of another dimensionless unit to this unit.
+   *
+   * @param magnitude the magnitude of the measurement in terms of the other dimensionless unit
+   * @param otherUnit the other dimensionless unit
+   * @return the value of the measurement in terms of this unit
+   */
+  public double convertFrom(double magnitude, DimensionlessUnit otherUnit) {
+    return fromBaseUnits(otherUnit.toBaseUnits(magnitude));
+  }
+
+  /**
+   * Creates a frequency unit as the ratio of this dimensionless unit to the period of time in which
+   * a single cycle is made.
+   *
+   * @param period the cycle period
+   * @return the combined frequency unit
+   */
+  @Override
+  public FrequencyUnit per(TimeUnit period) {
+    return FrequencyUnit.combine(this, period);
+  }
+
+  /**
+   * Creates a ratio unit between this unit and an arbitrary other unit.
+   *
+   * @param other the other unit
+   * @param <U> the type of the other unit
+   * @return the ratio unit
+   */
+  public <U extends Unit> PerUnit<DimensionlessUnit, U> per(U other) {
+    return PerUnit.combine(this, other);
+  }
+}