[sim] Add AnalogEncoderSim (#2647)

wpilibj/src/main/java/edu/wpi/first/wpilibj/AnalogEncoder.java

@@ -1,5 +1,5 @@
 /*----------------------------------------------------------------------------*/
-/* Copyright (c) 2019 FIRST. All Rights Reserved.                             */
+/* Copyright (c) 2019-2020 FIRST. All Rights Reserved.                        */
 /* Open Source Software - may be modified and shared by FRC teams. The code   */
 /* must be accompanied by the FIRST BSD license file in the root directory of */
 /* the project.                                                               */
@@ -132,6 +132,15 @@ public class AnalogEncoder implements Sendable, AutoCloseable {
     return get() * getDistancePerRotation();
   }
 
+  /**
+   * Get the channel number.
+   *
+   * @return The channel number.
+   */
+  public int getChannel() {
+    return m_analogInput.getChannel();
+  }
+
   /**
    * Reset the Encoder distance to zero.
    */

wpilibj/src/main/java/edu/wpi/first/wpilibj/simulation/AnalogEncoderSim.java

@@ -0,0 +1,59 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2020 FIRST. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+package edu.wpi.first.wpilibj.simulation;
+
+import edu.wpi.first.hal.SimDouble;
+import edu.wpi.first.wpilibj.AnalogEncoder;
+import edu.wpi.first.wpilibj.geometry.Rotation2d;
+
+/**
+ * Class to control a simulated analog encoder.
+ */
+public class AnalogEncoderSim {
+  private final SimDouble m_simPosition;
+
+  /**
+   * Constructs from an AnalogEncoder object.
+   *
+   * @param encoder AnalogEncoder to simulate
+   */
+  public AnalogEncoderSim(AnalogEncoder encoder) {
+    SimDeviceSim wrappedSimDevice = new SimDeviceSim("AnalogEncoder" + "[" + encoder.getChannel() + "]");
+    m_simPosition = wrappedSimDevice.getDouble("Position");
+  }
+
+  /**
+   * Set the position using an {@link Rotation2d}.
+   */
+  public void setPosition(Rotation2d angle) {
+    setTurns(angle.getDegrees() / 360.0);
+  }
+
+  /**
+   * Set the position of the encoder.
+   *
+   * @param turns The position.
+   */
+  public void setTurns(double turns) {
+    m_simPosition.set(turns);
+  }
+
+  /**
+   * Get the simulated position.
+   */
+  public double getTurns() {
+    return m_simPosition.get();
+  }
+
+  /**
+   * Get the position as a {@link Rotation2d}.
+   */
+  public Rotation2d getPosition() {
+    return Rotation2d.fromDegrees(getTurns() * 360.0);
+  }
+}