static void Main(string[] args)
{
string strTextGettterClass = ConfigurationSettings.AppSettings["TextGetterClass"]; //get name of TextGetter concrete class from web config (GetText classes are apis that produce "hello World text")
// there are different versions of concrete class. One returns text approp. for web, one for console. Additional concrete classes can be written as needed.
string strPrintTextClass = ConfigurationSettings.AppSettings["PrintTextClass"]; //get name of PrintText concrete class from web.config (PrintText classes print the text given to it)
// there are different versions of the concrete class. One writes out to a console window, one writes to DB. Additional concrete classes can be written as needed.
//The design patterns used here are 2 Factory Design patterns (one to get a concrete instance of the TextGetter and one to get a concrete instance of the TextPrinter class)
// The second, less obvious design pattern used here is the Bridge pattern: notice that the concrete impl. of TextGetter is passed to the concrete impl. of TextPrinter. (Double abstraction - loosely coupled)
IGetText textGetterClass = HelloWorldTextFactory.GetHelloWorldTextClass(strTextGettterClass); // use factory method to return correct concrete class
IPrintText textPrinterClass = PrintHelloWorldFactory.GetPrintHelloWorldClass(strPrintTextClass, textGetterClass); //use factory method to return concrete class
//the factory is also passed the concrete class of TextGetter
textPrinterClass.PrintHelloWorldBold();
textPrinterClass.PrintHelloWorldPlain();
textPrinterClass.PrintHelloWorldLight();
//The purpose of the Bridge Pattern is that any TextGetter implementation can be combined with any TextPrinter implementation.
// so that for instance you can use a TextPrinter for Database (DBPrinter concrete class) with TextGetter for web (GetWebText concrete class) (end result: text appropriate for web is written to database)
// or you can use a TextPrinter for Console (ConsolePrinter) and a TextGetter for web (GetWebText) (end result: text appropriate for web is written to console)
// note: some of these combinations may not be practical - but any combination of TextGetter and TextPrinter can be used, and new concrete classes can be written
// here are some commented out examples that show how easy the Bridge pattern makes combining the two:
//Additional Example #1
//IGetText textGetterClass = HelloWorldTextFactory.GetHelloWorldTextClass("Web"); // use factory method to return correct concrete class
//IPrintText textPrinterClass = PrintHelloWorldFactory.GetPrintHelloWorldClass("PrintToDB", textGetterClass); //use factory method to return concrete class
// //the factory is also passed the concrete class of TextGetter
//textPrinterClass.PrintHelloWorldBold();
//textPrinterClass.PrintHelloWorldPlain();
//textPrinterClass.PrintHelloWorldLight();
//Additional Example #2
//IGetText textGetterClass = HelloWorldTextFactory.GetHelloWorldTextClass("Web"); // use factory method to return correct concrete class
//IPrintText textPrinterClass = PrintHelloWorldFactory.GetPrintHelloWorldClass("PrintToConsole", textGetterClass); //use factory method to return concrete class
// //the factory is also passed the concrete class of TextGetter
//textPrinterClass.PrintHelloWorldBold();
//textPrinterClass.PrintHelloWorldPlain();
//textPrinterClass.PrintHelloWorldLight();
//Additional Example #3
//IGetText textGetterClass = HelloWorldTextFactory.GetHelloWorldTextClass("Console"); // use factory method to return correct concrete class
//IPrintText textPrinterClass = PrintHelloWorldFactory.GetPrintHelloWorldClass("PrintToDB", textGetterClass); //use factory method to return concrete class
// //the factory is also passed the concrete class of TextGetter
//textPrinterClass.PrintHelloWorldBold();
//textPrinterClass.PrintHelloWorldPlain();
//textPrinterClass.PrintHelloWorldLight();
}
public static IPrintText GetPrintHelloWorldClass(string strPrintHelloWorldClass, IGetText textGetter) // returns concrete implementation of text printer based on string passed in.
{ //also accepts a parameter of type: concrete impl. of textGetter
if (strPrintHelloWorldClass.ToLower() == "printtoconsole")
{
return(new ConsolePrinter(textGetter));
}
else if (strPrintHelloWorldClass.ToLower() == "printtodb")
{
return(new DBPrinter(textGetter));
}
else
{
return(new ConsolePrinter(textGetter)); //default
}
}
public DBPrinter(IGetText theGetTextClass) //constructor is passed in a concrete implementation of 'Text Getter' could be the text getter for web or console etc.
{
getTextClass = theGetTextClass;
}
public TextController(IGetText iGetText)
{
_allText = iGetText;
}
public HomeController(ILogger <HomeController> logger, IGetText getTextService, IConfiguration configuration)
{
_logger = logger;
_getTextService = getTextService;
_configuration = configuration;
}
