Writing data to System.in

Question

In our application, we expect user input within a Thread as follows :

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
         


        

Answer 1

Instead of the suggestions above (edit: I noticed that Bart left this idea in a comment as well), I would suggest making your class more unit testable by making the class accept the input source as a constructor parameter or similar (inject the dependency). A class shouldn't be so coupled to System.in anyway.

If your class is constructed from a Reader, you can just do this:

class SomeUnit {
   private final BufferedReader br;
   public SomeUnit(Reader r) {
       br = new BufferedReader(r);
   }
   //...
}

//in your real code:
SomeUnit unit = new SomeUnit(new InputStreamReader(System.in));

//in your JUnit test (e.g.):
SomeUnit unit = new SomeUnit(new StringReader("here's the input\nline 2"));