Will this be a valid base class for IDisposable
IDisposable pattern is expensive to implement. I've counted 17 lines of code before even starting to actually dispose resources.
Eric Lippert recently wrote a blog post bringing up an interesting point: any time a finalizer runs, it is a bug. I think it make perfect sense. If the IDisposable pattern is always followed, Finalizer should always be suppressed. It will never have a chance to run. If we accept that finalizer run is a bug, then does it make sense to have a guideline to force developers to derive from the following abstract class and forbid directly implementing the IDisposable interface.
public abstract class AbstractDisaposableBase: IDisposable
{
~AbstractDisaposableBase()
{
ReportObjectLeak();
Dispose(false);
}
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
protected abstract void Dispose(bool disposing);
[Conditional("DEBUG")]
private void ReportObjectLeak()
{
//Debug.Assert(false, "leaked instance");
//throw new Exception("leaked instance");
}
}
The benefits are clear:
class MyClass1 : DisablableBase
{
protected override void Dispose(bool disposing)
{
//dispose both managed and unmamaged resources as though disposing==true
}
}
Not disposed object got reported
Disposable pattern is always followed
But, is there any problem with such a guideline?
One possible problem is that all disposable object will have a finalizer defined. But since the finalizer is always suppressed, there should not be any performance penalties.
What are your thoughts?
does it make sense to have a guideline to force developers to derive from the following abstract class
No, solely for the reason that C# doesn't have multiple inheritance. Interfaces describe behavior, inheritance dictates "is-a". You'll thoroughly limit the object-oriented design of your classes if you enforce this rule.
For example you can't introduce base classes for business objects that are not disposable, where a derived class would be.
But since the finalizer is always suppressed, there should not be any performance penalties.
Instances of the AbstractDisaposableBase subclasses will still be participating in the finalization queue management, so there will be a performance impact for this.
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