Transcript My experience with managing chaos in a large project By Daniil Kigelman

My experience with managing
chaos in a large project
By Daniil Kigelman
Vlab portal
What is VLab?
Don’t ask me--I’m just a developer
I’ve heard it has to do with chemistry and planetary
materials
My work with VLab has been focused around portlets
– Portlets: small little creatures that live inside a portlet container
they sit behind the portal login mechanism
– The concept of a portal and its portlets is quite simple--its
implementation.. Not so much.
The VLab portal aids the user in creating PWscf input, submitting
jobs, monitoring the progress, and viewing the results
http://www.vlab.msi.umn.edu
My visible work
Difficulties
30,000+ lines of code
Outdated code
– Some need to be
deleted, some
changed/updated
Overgrown code
– Large objects, long
methods
Volatile code
– A small change in a
name, version, or in the
code may break the
portal
Numerous technologies
used
–
–
–
–
–
Web services
Castor
Gridsphere
JSF, JSP
Java Database
Connectivity (JDBC)
– Hibernate
– Connection Pooling
– Subversion, maven, ant,
etc…
Priceless tool: Eclipse IDE
Rapid development
Code search, highlighting, code insight
Refactoring, code generation tools
Much, much more
Attempted Solution:
using more of maven 2’s features
“Maven is a software project
management and
comprehension tool. Based
on the concept of a project
object model (POM), Maven
can manage a project's
build, reporting and
documentation from a
central piece of
information.”
(maven.apache.org)
Only for java-based
projects..
Benefits: divide, conquer, and
reuse:
– vlab-portal
|- vlab-base
|- vlab-common
|- vlab-portlets
|- pseudo-potential-webapp
`- input portlet
– (vlab-common and vlab-base
are reused by other modules)
Explicitly defines dependency
versions
Transitive dependency
management
Site generation
Another solution:
asking for advice from co-workers
Benefits:
–
More fun to work
^much
– More insight into design (I
don’t know which parts are
confusing—I wrote them)
– More wisdom
Relevant eXtreme
Programming principles:
– Work together
– Pair programming
– Code review
Better Objects, cleaner code
Assertion: good objectoriented code saves sanity
Tool: Refactoring by Martin
Fowler
– Objects and complexity naturally
grow to difficult proportions
– The original design, more often
than not, does not satisfy the
need of the growing code
– Hence, refactor as you code
• rename method
• rename class
• extract method
• extract class
Examples in context
• Idioms:
– small method sizes with descriptive
names
– focus on readability, not efficiency
• Assumption: test suite present
Testing
Unit testing
– code that tests the smallest
unit's proper functionality
– increases confidence in code,
trust
– facilitates refactoring and
other changes
Acceptance / functional testing
– manual: go to website, click
through pages—is anything
broken?
– automated: execute test
suite, take coffee break. Is
anything broken?
Test-first development
The name of the test should describe the requirement of the code
There should be at least one test for each requirement of the code.
Each possible path through of the code is a different requirement
Only write the simplest possible code to get the test to pass, if you
know this code to be incomplete, write another test that
demonstrates what else the code needs to do
If you are unsure about a piece of code, add a test you think might
break it
Do not fix a bug until you have written a test that demonstrates the
bug
– copied from: http://xprogramming.com/xpmag/testFirstGuidelines.htm
Incremental Changes
Refactor, test, code,
test
Small changes first
Refactor to
understand
Overview
The following I found helpful in
keeping my sanity:
–
–
–
–
Eclipse IDE
Maven (project organization)
Refactoring
Testing
Source forget project:
http://sourceforge.net/projects/vlab
svn repository url
https://vlab.svn.sourceforge.net/svnroot/vlab/br
anches/demo_with_maven2
• (especially automated)
– Small, incremental changes
– Co-workers
Beck, Kent. Extreme Programming Explained: Embrace Change. Addison-Wesley. Second Edition 2005 with
Cynthia Andres.
Fowler, Martin. Refactoring: improving the design of existing code. Addison-Wesley, 1999.
Shubin, Sean. Test First Guidelines. XProgramming.com: an Agile Software Development Resource. 2002.
http://www.xprogramming.com/xpmag/testFirstGuidelines.htm