Dependency Injection for objects that require parameters
- by Andrew
All of our reports are created from object graphs that are translated from our domain objects. To enable this, we have a Translator class for each report, and have been using Dependency Injection for passing in dependencies.
This worked great, and would yield nice classes structured like this:
public class CheckTranslator : ICheckTranslator
{
public CheckTranslator (IEmployeeService empSvc
, IPaycheckService paySvc)
{
_empSvc = empSvc;
_paySvc = paySvc;
}
public Check CreateCheck()
{
//do the translation...
}
}
However, in some cases the mapping has many different grouping options. As a result, the c-tor would turn into a mix of class dependencies and parameters.
public class CheckTranslator : ICheckTranslator
{
public CheckTranslator (IEmployeeService empSvc
, IPaycheckService paySvc
, bool doTranslateStubData
, bool doAttachLogo)
{
_empSvc = empSvc;
_paySvc = paySvc;
_doTranslateStubData = doTranslateStubData;
_doAttachLogo = doAttachLogo;
}
public Check CreateCheck()
{
//do the translation...
}
}
Now, we can still test it, but it no longer really works with an IoC container, at least in a clean fashion. Plus, we can no longer call the CreateCheck twice if the settings are different for each check.
While I recognize it's a problem, I don't necessarily see the right solution. It seems kind of strange to create a Factory for each class ... or is this the best way?
