It is "bad practice" to pass argument to module

[Mashrur Mia]

Hi All,

Checking out Guice and I love it. I currently have problem where guice solved it by injecting all the required dependencies I need. But I wonder if I am using Guice in the wrong way. What I require though is define bindings depending on specific instance. And to achieve this I passed the instance in the module.

For instance, consider the following (somewhat similar to my problem):

public class CustomerModule extends AbstractModule {
   private Customer customer;
   
   public CustomerModule(Customer customer){
       this.customer = customer;
   }  

   @Override
   public void configure() {
      bind(ReportGenerator.class).to(HtmlReportGenerator.class);
   }

   @Provides
   Account providePurchasingAccount() {
      return customer.getPurchasingAccount();
   }
}

And I use this module to get Account dependency injected to the report generator class that needs the account of a specific customer. For example, a user chooses a specific customer and say, wants to show a generated report. I have method like

public void printReport (Customer customer){
   Injector injector = Guice.createInjector(new CustomerModule(customer));
   ReportGenerator reportGenerator  = injector.getInstance(ReportGenerator.class);

   showReport(reportGenerator.generate())

}

Once the work is done, I am done with this module. 

Is this a ok use of guice?

BTW the above example was inspired by https://github.com/google/guice/wiki/InjectOnlyDirectDependencies but perhaps my related question is, how does the "providePurchasingAccount" gets a specific Customer?

thanks for you help guys!

Mashrur

[Mashrur Mia]

Sorry, the original subject should be "Is it "bad practice" to pass argument to module"

[Fred Faber]

In general lean against that type of design in favor of designing a contextual aware app based on Scopes, or by using ephemeral scopes with AssistedInject. One reason is, if your app is a long running process, then you don't want the expense of creating an Injector with each request.

Fred

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[Brian Pontarelli]

This specific use case feels more like business logic than injection. The Customer and Account both appear to be request scoped business objects that should be looked up from places like the database and passed to services. 

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