CIYAWASAY

最近在看Big Ball of Mud
想到之前在Java 2005有去聽介紹AntiPattern的場次
故在此整理一下之前聽到有關Spaghetti Code的資料

何謂AntiPatterns?

• AntiPatterns are Negative Solutions that present more problems than they address
• AntiPatterns are a natural extension to design patterns
• AntiPatterns bridge the gap between architectural concepts and real-world implementations
• Understanding AntiPatterns provides the knowledge to prevent or recover from them

Spaghetti Code–雜亂無章的程式碼 (Development AntiPattern)

Symptoms

• Quick demonstration code that became operational
• "Lone Ranger" programmer (who was that masked man?)
• Obsolete or scanty documentation
• 50% of maintence spent on system rediscovery
• Hesitant Programmer Syndrome
  • More likely to break it than extend it
  • Easier to just rewrite it
• Cannot be reused
  • System software and COTS packages can't be upgraded
  • Performance cannot optimized
• User work around

Object-Oriented Spaghetti Code –非物件導向Code

• Many object methods with no parameters
• Suspicious class or global variables
• intertwined and unforeseen relationships between objects
• Process-oriented methods, objects with process-oriented names
• OO advantage lost - inheritance cannot be used to extend the system, polymorphism not effective either

Refactored Solution

• Refactor to generalize: Create an abstract superclass
  • Make subclass function signatures compatible
  • Add function signatures to the superclass
  • Make function bodies and variables compatible
  • Mirgate common code to the superclass
• Refactor to specialize: Simplify conditionals
  • For each condition, create a subclass with matching invariant
  • Copy the code into the subclass
  • Simplify code based upon invariant
  • Specialize the superclass constructor
• Refactor to combine: Capture aggregations and components
  • Type A: Move members from an aggregate class to a components class
  • Type B: Move members from component classes to aggregate class
  • Type C: Convert inheritance into an aggregation

Strategy: Reform the software process

• Refactoring as you program
  • incremental development
  • Refactoring to improve structure
  • Incremental test
  • Iterate
• Use programming discipline
  • Keep track of defects (metrics)
  • Learn to avoid programming defects
• Use Architecture-Centered development
  • Define enforceable system boundaried
  • Use design patterns to document software

# posted by Unknown @ 15:12