How to avoid a lot of if else conditions

Question

I have read a lot of topics about code refactoring and avoiding of if else statements. Actually, I have a class where I am using a lot of if - else conditions.

More details: I am using the pull parser and on each line of my soap response, I will check if there is a tag I am interested on, if not, check another tag etc:

 if(eventType == XmlPullParser.START_TAG) {
            soapResponse= xpp.getName().toString();
            
            if (soapResponse.equals("EditorialOffice")){  
                eventType = xpp.next();
                if (xpp.getText()!=null){
                editorialOffice += xpp.getText();
                }
            }   
            else if (soapResponse.equals("EditorialBoard")){  
                eventType = xpp.next();
                if (xpp.getText()!=null){
                editorialBoard += xpp.getText();
                }
            }
            else if (soapResponse.equals("AdvisoryBoard")){  
                eventType = xpp.next();
                if (xpp.getText()!=null){
                advisoryBoard += xpp.getText();
                }
            }   
        }
        eventType = xpp.next();
     }

Now, I would like to use something else, instead of those if else conditions, but I don't know what.

Can you please give me an example?

Answer 1

Try to look at the strategy pattern.

• Make an interface class for handling the responses (IMyResponse)
  • Use this IMyResponse to create AdvisoryBoardResponse, EditorialBoardResponse classes
• Create an dictionary with the soapresponse value as key and your strategy as value
• Then you can use the methods of the IMyResponse class by getting it from the dictionary

Little Example:

// Interface
public interface IResponseHandler {
   public void handleResponse(XmlPullParser xxp);

}

// Concrete class for EditorialOffice response
private class EditorialOfficeHandler implements IResponseHandler {
   public void handleResponse(XmlPullParser xxp) {
       // Do something to handle Editorial Office response
   }
}

// Concrete class for EditorialBoard response
private class EditorialBoardHandler implements IResponseHandler {
   public void handleResponse(XmlPullParser xxp) {
       // Do something to handle Editorial Board response
   }
}

On a place you need to create the handlers:

Map<String, IResponseHandler> strategyHandlers = new HashMap<String,IResponseHandler>();
strategyHandlers.put("EditorialOffice", new EditorialOfficeHandler());
strategyHandlers.put("EditorialBoard", new EditorialBoardHandler());

Where you received the response:

IResponseHandler responseHandler = strategyHandlers.get(soapResponse);
responseHandler.handleResponse(xxp);