Question

In my code I have a List<Person>. Attributes to the objects in this list may include something along the lines of:

• ID
• First Name
• Last Name

In a part of my application, I will be allowing the user to search for a specific person by using any combination of those three values. At the moment, I have a switch statement simply checking which fields are filled out, and calling the method designated for that combination of values.

i.e.:

switch typeOfSearch    
if 0, lookById()    
if 1, lookByIdAndName()  
if 2, lookByFirstName()

and so on. There are actually 7 different types.

This makes me have one method for each statement. Is this a ‘good’ way to do this? Is there a way that I should use a parameter or some sort of ‘filter’? It may not make a difference, but I’m coding this in Java.

Answer 1

You can do something more elgant with maps and interfaces. Try this for example,

interface LookUp{
    lookUpBy(HttpRequest req);
}

Map<Integer, LookUp> map = new HashMap<Integer, LookUp>();

map.put(0, new LookUpById());
map.put(1, new LookUpByIdAndName());

…

in your controller then you can do

int type = Integer.parseInt(request.getParameter(type));
Person person = map.get(type).lookUpBy(request);

This way you can quickly look up the method with a map. Of course you can also use a long switch but I feel this is more manageable.