This is the presentation I will be giving at GLASScon 2.5 on how to combine the Mikado Method with Kanban to help folks manage changes to their legacy software. This has also been proposed for the Saturn Conference as well.

1. M
I
k
a
d
o
Using Japanese to
save your Legacy S/W
K
a
n
b
a
n
+

2. Mikado Method  Mikado Game
Making a change to your legacy code is not
unlike picking out the Mikado from the other
sticks in the pile.
Removing one impacts the others.
And not in a good way…
What is the biggest difference?

3. We can
Revertour
code!

4. The Guts of the Mikado Method
• Make the ONE change you need/want to make
• See what broke – these are pre-requisites (the
next set of changes to make before doing this
one)
• Visualize (add to graph)
• REVERT !!
Repeat until no breakages occur.

5. Decouple
Content Edit &
Publishing
Servers
Create
Standalone
Publish
Server
Reimplement
DB Interface
Remove
Methods from
Edit Server
Code
Separate
Storage
Interface
Discovery
Refactor
✓ ✓
✓
✓
✓
✓ ✓
✓
Move
Check User
Permissions
Separate
Approval
Logic
Move
Publish-Reject
Code
Change
Deployment
Properties
✓

6. For Defects…
• Need to use exploratory and regression testing
to ID the next items to be graphed
• If not present, wrap unit tests around what
you are touching
• Have testing occur in an environment that
mimics as close to production as possible

7. Real Mikado Power
• Comes when you have unit, integration, and
acceptance tests
• These help reveal necessary refactors by
showing failures that the change creates
• Safer than exploration to find breakages

8. Some Restructuring Considerations
• Refactor Before Adding Functionality
• Separate Bulky Interfaces (limiting the
consumers it serves)
• Extract Methods/Classes into Common
Libraries
Let’s look at the first one…

9. Refactor Before Adding Functionality
• Suppose -
. . .
public static final int FIVE_CARD_POKER = 0;
public static final int INDIAN_POKER = 1;
. . .
Public class CardGameEngine {
. . .
public void deal (Game game, User user, Dealer dealer) {
if (game.getType() == FIVE_CARD_POKER {
user.setCards(dealer.deal(5));
} else if (game.getType() == INDIAN_POKER {
user.setCards(dealer.deal(1));
} else {
// else what?
}
}
• Want to add War (each player is dealt 26 cards)
• Could add it to the If-Then-Else logic, but this will get
messy, especially if I wanted to add more…

10. Mikado Graph for Refactor
Add War
card game
Refactor
If statements to extract
game-specific logic
Move 5 Card Poker
Logic to FiveCardPoker
class
Move Indian Poker
Logic to IndianPoker
class
Implement War
Logic to War class

11. Triage ReadyIntake
Update
Tests FIX Re-Test Deploy DONE
Done Done Done
✓✓

12. T
H
A
N
K
Y
O
U
あ
り
が
と
う
ご
ざ
い
ま
し
た