My experience with managing chaos in a large project

1
My experience with managing chaos in a large
project

• By Daniil Kigelman

2
Vlab portal
3
What is VLab?

• Dont ask me--Im just a developer
• Ive 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

4
My visible work
5
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• Outdated code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

6
Priceless tool Eclipse IDE

• Rapid development
• Code search, highlighting, code insight

• Refactoring, code generation tools
• Much, much more

7
Attempted Solutionusing more of maven 2s
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

8
Another solutionasking for advice from
co-workers

• Benefits
• More fun to workmuch
• More insight into design (I dont know which
  parts are confusingI wrote them)
• More wisdom
• Relevant eXtreme Programming principles
• Work together
• Pair programming
• Code review

9
Better Objects, cleaner code

• Assertion good object-oriented 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

10
Examples in context

• Idioms
• small method sizes with descriptive names
• focus on readability, not efficiency
• Assumption test suite present

11
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 pagesis
  anything broken?
• automated execute test suite, take coffee break.
  Is anything broken?

12
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/testFir
  stGuidelines.htm

13
Incremental Changes

• Refactor, test, code, test
• Small changes first
• Refactor to understand

14
Overview

• The following I found helpful in keeping my
  sanity
• Eclipse IDE
• Maven (project organization)
• Refactoring
• Testing
• (especially automated)
• Small, incremental changes
• Co-workers

• Source forget project http//sourceforge.net/proj
  ects/vlab
• svn repository url
• https//vlab.svn.sourceforge.net/svnroot/vlab/bran
  ches/demo_with_maven2

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/testFirstGuideli
nes.htm