Question

I would like to create an abstract class with an abstract method which can measure how long it takes to run.

public abstract class Monitor
{
    protected Stopwatch Timer = Stopwatch.StartNew();   
    public abstract void Run();
}

public class Concrete : Monitor
{
    public override void Run()
    {
        base.Timer.Start();
        //DoSomething
        base.Timer.Stop();
    }
}

However, implementers of the abstract class should not be calling the Start / Stop methods directly, so we can try to hide the implementation.

public abstract class Monitor
{
    private Stopwatch Timer = Stopwatch.StartNew(); 
    public virtual void Run()
        {
            Timer.Start();
            Timer.Stop();
        }
}

But as you can see this won’t work very well.

How can i ensure that all implementations of the base class will call Start /Stop and yet allow implementation code to run in between? Could events help me here, if so how?

Answer 1

Use the template method pattern:

public abstract class Monitor
{
    private readonly Stopwatch Timer = new Stopwatch(); 
    public void Run()
    {
        Timer.Start();
        DoRun();
        Timer.Stop();
    }

    protected abstract void DoRun();
}