Strategy Pattern
Define a family of algorithms,
encapsulate each one, and make them interchangeable. Strategy lets the
algorithm vary independently from clients that use it.
The multiple strategies that we will be using are to define the quality of the output. The user could choose to convert to a low quality output (perhaps because it is fast and is of small size). The user could choose to convert to a high quality output (perhaps because he wants to use it on high-end audio products from BOSE or B&O), or he could just choose an average quality output (perhaps to put it on his cell phone). We implement all these as separate strategies so that the client code can be independent of the implementation details of these different strategies and will work in the same fashion for any selected strategy.
interface IStrategy
{
void
Convert();
}
class FileConverter
{
int quality;
public FileConverter(int
qual)
{
quality = qual;
}
public void
FileConvert()
{
if (quality < 100)
{
Console.WriteLine("Low Quality");
}
else if (quality >
100 && quality < 200)
{
Console.WriteLine("Medium Quality ");
}
else
{
Console.WriteLine("High Quality");
}
}
}
class LowQualityConversion:IStrategy
{
const int QUALITY =
50;
public void Convert()
{
FileConverter fcon = new
FileConverter(QUALITY);
fcon.FileConvert();
}
}
class MediumQualityConversion
: IStrategy
{
const int QUALITY =
150;
public void Convert()
{
FileConverter fcon = new
FileConverter(QUALITY);
fcon.FileConvert();
}
}
class HighQualityConversion
: IStrategy
{
const int QUALITY =
250;
public void Convert()
{
FileConverter fcon = new
FileConverter(QUALITY);
fcon.FileConvert();
}
}
Calling…
IStrategy selectStratergy = null;
int choice = Console.Read();
if (choice == '1')
{
selectStratergy = new LowQualityConversion();
}
else if (choice == '2')
{
selectStratergy = new MediumQualityConversion();
}
else if (choice == '3')
{
selectStratergy = new HighQualityConversion();
}
if (selectStratergy != null)
{
selectStratergy.Convert();
}
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