[wpilib] Add IsJoystickConnected method (#2847)

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

@@ -594,6 +594,21 @@ public class DriverStation {
     return HAL.getJoystickAxisType((byte) stick, (byte) axis);
   }
 
+  /**
+   * Returns if a joystick is connected to the Driver Station.
+   *
+   * <p>This makes a best effort guess by looking at the reported number of axis,
+   * buttons, and POVs attached.
+   *
+   * @param stick The joystick port number
+   * @return true if a joystick is connected
+   */
+  public boolean isJoystickConnected(int stick) {
+    return getStickAxisCount(stick) > 0
+      || getStickButtonCount(stick) > 0
+      || getStickPOVCount(stick) > 0;
+  }
+
   /**
    * Gets a value indicating whether the Driver Station requires the robot to be enabled.
    *

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

@@ -217,6 +217,15 @@ public abstract class GenericHID {
     return m_ds.getStickButtonCount(m_port);
   }
 
+  /**
+   * Get if the HID is connected.
+   *
+   * @return true if the HID is connected
+   */
+  public boolean isConnected() {
+    return m_ds.isJoystickConnected(m_port);
+  }
+
   /**
    * Get the type of the HID.
    *