rspec/rules/S1694/csharp/rule.adoc

The purpose of an abstract class is to provide some heritable behaviors while also defining methods which must be implemented by sub-classes.

A ``class`` with no abstract methods that was made ``abstract`` purely to prevent instantiation should be converted to a concrete ``class`` (i.e. remove the ``abstract`` keyword) with a ``protected`` constructor.

A ``class`` with only ``abstract`` methods and no inheritable behavior should be converted to an ``interface``.

== Noncompliant Code Example

----
public abstract class Animal //Noncompliant; should be an interface
{
  abstract void Move();
  abstract void Feed();
}

public abstract class Color //Noncompliant; should be concrete with a private constructor
{
  private int red = 0;
  private int green = 0;
  private int blue = 0;

  public int GetRed()
  {
    return red;
  }
}
----

== Compliant Solution

----
public interface Animal
{
  void Move();
  void Feed();
}

public class Color
{
  private int red = 0;
  private int green = 0;
  private int blue = 0;

  protected Color()
  {}

  public int GetRed()
  {
    return red;
  }
}

public abstract class Lamp
{
  private bool switchLamp = false;

  public abstract void Glow();

  public void FlipSwitch()
  {
    switchLamp = !switchLamp;
    if (switchLamp)
    {
      Glow();
    }
  }
}
----