1. HIGH MAINTAINABLE SOFTWARE
Nguyen Cuong viet
@ Septeni Technology
Ha noi - 12/2013
make it changeable

2. ABOUT ME
 8 years- experiences software developer, basically
base on LAMP environment
 ..
 Tratu.soha.vn
 Go.vn
 Pyxis-social.com

3. AGENDA
1. Understanding the important of “maintainability”
2. How to improve
 Design patterns
 Code refactor
 Jenkins
3. Discussion

4. I. WHAT, WHO, WHEN, WHY

5. THE MAINTAINABILITY PROBLEM
 Software systems are built under high pressure to meet
deadlines, and with initial emphasis on performance,
reliability, and usability.
 The software attributes relating to later changes in the
software => maintainability

6. SOFTWARE QUALITY FACTORS
 ISO 9126

7. SOFTWARE QUALITY FACTORS
 ISO 9126
->WHO ?

8. WHEN - DEPENDENCIES
 Do you need to care about Maintainability?
It depend on:
Project size
Life time of project
Quality of code
Design

9. THE MAINTAINABLE CODE CHECKLIST..

10. PYXIS USECASE
 20 developers
 +2 years
 10 lines of code/days x 20 x365 = 70.000 line of code/ year?

11. COMPLAINS..
 Bug fixes: ask Mr.A because he developed it!!
 Readable: New Member?
 understand project business by researching source
code ?
 everyone is new member with other modules!
 Simple development still has a lot of bugs!
 Throw it away, let rebuild this function!

12. SO..
• Imagine about our source code this
time next year..
READABLE?
CHANGEABLE?

13. HOW TO
Design pattern
Refactoring source code
Jenkins..

14. DESIGN PATTERNS
Design patterns can speed up the development process by
providing tested, proven development paradigms

15. PATTERNS

16. CODE REVIEW
Bad Smells in Code ..

17. CODE SMELLS ..
 Duplicated Code
 Long Method
 Large Class
 Long Parameter list
 Divergent Change
 Shotgun Surgery
 Feature Envy
 Feature Envy
 Data Clumn ..
 Primitive bsession
 Switch tatements
 Parallel
 Inheritance
 Hierarchies Lazy
 Class Speculative
 Generality
 Temporary Field
 Message Chains ..

18. REFACTOR - EXAMPLE
String foundPerson(String[] people){
for (int i = 0; i < people.length; i++) {
if (people[i].equals ("Don")){
return "Don";
}
if (people[i].equals ("John")){
return "John";
}
if (people[i].equals ("Kent")){
return "Kent";
}
}
return "";
}
String foundPerson(String[] people){
List candidates = Arrays.asList(new
String[] {"Don", "John", "Kent"});
for (int i=0; i &lt; people.length; i++)
if (candidates.contains(people[i]))
return people[i];
return "";
}
source refactored

19. REFACTOR - EXAMPLE
void printOwing(double amount) {
printBanner();
//print details
System.out.println ("name:" +
_name);
System.out.println ("amount" +
amount);
}
void printOwing(double amount) {
printBanner();
printDetails(amount);
}
void printDetails (double amount) {
System.out.println ("name:" +
_name);
System.out.println ("amount" +
amount);
}
source refactored

20. JENKINS
Automation tool..

21. JENKINS
 CHECKSTYLE(for processing PHP_CodeSniffer logfiles in
Checkstyle format)
 CLOVER(for processing PHPUnit code coverage xml output)
 DRY(for processing phpcpd logfiles in PMD-CPD format)
 JDepend (for processing PHP_Depend logfiles in JDepend
format)
 PMD (for processing PHPMD logfiles in PMD format)
 Violations (for processing various logfiles)
 xUnit (for processing PHPUnit logfiles in JUnit format)

22. JENKINS - SAMPLE
 Duplication

23. JENKINS - SAMPLE
 Duplication

24. JENKINS- SAMPLE: JDEPEND
 JDepend traverses Java class file directories and
generates design quality metrics for each Java
package. JDepend allows you to automatically measure
the quality of a design in terms of its extensibility,
reusability, and maintainability to manage package
dependencies effectively.

25. JDEPEND REPORT

26. REFERENCE
 Maintainbility in software engineering
 http://codebetter.com/jeremymiller/2006/12/06/on-
writing-maintainable-code/ (check list)
 A practice model for mesuaring maintainability
 http://sourcemaking.com/ very good resource for high
quality code
 http://jenkins-php.org/

27. THANK YOU!
Discussion..