Refactoring Day 29 : Remove Middle Man
Today’s refactoring comes from Fowler’s refactoring catalog and can be found here.
Sometimes in code you may have a set of “Phantom” or “Ghost” classes. Fowler calls these “Middle Men”. Middle Men classes simply take calls and forward them on to other components without doing any work. This is an unneeded layer and can be removed completely with minimal effort.
1: public class Consumer
2: {
3: public AccountManager AccountManager { get; set; }
4:
5: public Consumer(AccountManager accountManager)
6: {
7: AccountManager = accountManager;
8: }
9:
10: public void Get(int id)
11: {
12: Account account = AccountManager.GetAccount(id);
13: }
14: }
15:
16: public class AccountManager
17: {
18: public AccountDataProvider DataProvider { get; set; }
19:
20: public AccountManager(AccountDataProvider dataProvider)
21: {
22: DataProvider = dataProvider;
23: }
24:
25: public Account GetAccount(int id)
26: {
27: return DataProvider.GetAccount(id);
28: }
29: }
30:
31: public class AccountDataProvider
32: {
33: public Account GetAccount(int id)
34: {
35: // get account
36: }
37: }
The end result is straightforward enough. We just remove the middle man object and point the original call to the intended receiver.
1: public class Consumer
2: {
3: public AccountDataProvider AccountDataProvider { get; set; }
4:
5: public Consumer(AccountDataProvider dataProvider)
6: {
7: AccountDataProvider = dataProvider;
8: }
9:
10: public void Get(int id)
11: {
12: Account account = AccountDataProvider.GetAccount(id);
13: }
14: }
15:
16: public class AccountDataProvider
17: {
18: public Account GetAccount(int id)
19: {
20: // get account
21: }
22: }
This is part of the 31 Days of Refactoring series. For a full list of Refactorings please see the original introductory post.