Letting generics in with Template Method pattern
Maybe it sounds silly but I just discovered a way to allow generics fit naturally into the Factory code. Paired development has its own benefits - I constantly overlooked this trick before and as a result was forced to get rid of some neat (from my point of view) generics designs.
Imagine you have started with this kind of design (I had to remember my first experiment so I apologize if the code seems a little but rough):
public abstract class AbstractResult<T>
{
public T Value
{
get {return _value;}
set {_value=value;}
}
public abstract string RenderResult();
public static AbstractResult<T> ResultFactory() {...}
}
public class CarResult : AbstractResult<Car>
{
public override string RenderResult()
{
//life sucks
Value.Render()
}
}
Unless you put some constraints on the generic type, you can't nicely use Value property inside your child class' Render method:
public abstract class AbstractResult<T> where T : Vehicle
It is still may not be a bad way out but something tells me that it is unnecessary limitation. Let's rebuild our classes slightly with the Template Method pattern:
public abstract class AbstractResult<T>
{
public T Value
{
get {return _value;}
set {_value=value;}
}
public virtual string RenderResult()
{
return ConcreteRenderResult();
}
public abstract string ConcreteRenderResult();
public static AbstractResult<T> ResultFactory() {...}
}
public class CarResult : AbstractResult<Car>
{
public override string ConcreteRenderResult()
{
//... do whatever
Value.Render();
}
}
With this implementation you have much more flexibility for child classes as well as for the factory method itself.
And finally, the ingenious piece of corporate brainwork - Windows Genuine Software® checker. Great, - it didn't work for my perfectly LEGITIMATE Windows Server 2003®. I couldn't download an important patch, because it kept failing and complaining that this system is not supported. I saw this thing fly on pirated® systems (not mine, I've just cast a glance at computers of some naughty, naughty people, who had long since been cured and own legitimate copies now) but why it can't reward me® - such a genuine LEGITIMATE user?!
The graph (I like graphs!) represents a publishing dates of the first 20 books on multithreading from the Amazon.com. This is an interesting tendency - the peak is on the 1997-1999. Of course there are some distracting factors, like IDE standardization and Internet, - blogging seems to chock the life out the technology publishing.
The position of an architect is often misunderstood in organizations: very often they are expected to produce UML diagrams and command developer herds, coding to the specs. Some architects do not code at all but just sit in the white castle up in the sky and craft divine designs.
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