CODEWITHSUNDEEP
javaconstructorfactory-pattern
VICKY-TSC
VICKY-TSC

Reputation: 415

Constructor Has many Elements. how to refactor (Factory pattern)

i am having a constructor with Factory pattern. i am passing to many parameters. how to refactor it.

ServerFactory serverFactory = new ServerFactory();
CalendarResults calResults= serverFactory.getResults(serverName,locale, Day, week,     
                            month,vdate,results,uri, EmailShare, inc, upperLimit, 
                            endLimit,exchWD, YearMonthDay,WeekMonthDate);
results=calResults.serverNameDay(serverName,locale, Day, week, month,vdate,
        results,uri, EmailShare, inc, upperLimit, endLimit, exchWD, YearMonthDay);

public class ServerFactory {
    public CalendarResults getResults(String serverName,String locale, String day,    
                     String week, String month, 
             boolean vdate, ArrayList<CalendarOutput> results, String uri, 
                     List<String> emailShare, int inc, int upperLimit, 
             int endLimit, NexWebDav exchWD, String yearMonth, boolean 
                     weekMonthDate){

        CalendarResults calresults=null;
        if(serverName.equals("www.google.com")){
            calresults=new Google();
        }else{
            calresults=new Exchange();
        }
        return calresults;
    }
 }

Upvotes: 0

Views: 162

Answers (5)

Jens Schauder
Jens Schauder

Reputation: 81882

Hard to tell since you don't show all the code (I assume) where all these parameters get used.

But here are some things to consider:

  • Replaces arguments of primitive type with value objects, this makes it much clearer what parameter is expected in what position.

  • combine multiple related arguments to value objects. One example that seems obvious is upperLimit, endLimit (and maybe inc) which might end up in an object called Intervall.

  • replace booleans with different methods. Often booleans are used to perform different algorithms. If that's the case drop the booleans an make seperate methods instead.

  • If you have still to many and to confusing arguments, you might want to go with a Builder Pattern. This and the following blog posts might be helpfull: http://blog.schauderhaft.de/2012/07/29/named-parameters-in-java/

Upvotes: 1

Yogendra Singh
Yogendra Singh

Reputation: 34367

One other way code be to use String[] for all String type parameters with little swap in the their position as below:

public CalendarResults getResults(boolean vdate, ArrayList<CalendarOutput> results,
                 List<String> emailShare, int inc, int upperLimit, 
                 int endLimit, NexWebDav exchWD, boolean weekMonthDate,
                 String... stringParams){
          //You may get your string params as
          //stringParams[0] -> serverName
          //stringParams[1] -> locale
          //stringParams[2] -> day
          //stringParams[3] -> week
          //stringParams[4] -> month
          //stringParams[5] -> uri
          //stringParams[6] -> yearMonth
          ....

While you can use the factory pattern as of now, with only change that all string type paramters are moved towards the end e.g.

   CalendarResults calResults= serverFactory.getResults(vdate,results, 
                   EmailShare, inc, upperLimit, endLimit,exchWD, WeekMonthDate,
                   serverName, locale, Day, week, month, uri,YearMonthDay);

Some level of simplification.

Upvotes: 0

Azodious
Azodious

Reputation: 13872

You can have multiple setter methods on serverFactory and those must be called before calling getResults.

If those are not called, getResults should throw an exception.

The sequence could be as follows:

serverFactory.setServerDetails(servername, locale);
serverFactory.setCalendarDetails(day, week, month, vdate, yearmonthday, weekmonthday);
...
...
serverFactory.getResults(results);

Upvotes: 1

Sujay
Sujay

Reputation: 6783

Instead of sending so many parameters, consider creating a Value Object class, instantiate that and send that instance as a parameter.

Upvotes: 0

TeaCupApp
TeaCupApp

Reputation: 11452

Stringify all of the String parameters and split them into the constructor. But I recommend the current way that you are doing it. It's more readable.

Upvotes: 0

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