Connections

1
Connections

• Karl Lieberherr

2
Sources of Information

• Textbook The Pragmatic Programmer (TPP)
• My book AP book lecture notes
• Java Data Binding Technology
• Tools we use DJ, later we use DemeterJ

3
TPP section The Evils of Duplication

• Tip 11 DRY Dont Repeat Yourself
• Imposed duplication without tool support

4
Connections

• TPP Tip 11 DRY
• Dont duplicate class graph information in
  programs and in inputs
• Programs traversal strategies
• Inputs parsing
• TPP Tip 17
• Program close to problem domain
• Use class dictionary describing application
  objects

5
Connections

• TPP Tip 36 LoD
• Minimize coupling between modules avoid coupling
  by writing shy code
• traversal strategies
• TPP Tip 20 Keep knowledge in plain text
• Java data binding class dictionary and sentences

6
TPP section Decoupling and the Law of Demeter

• Write shy code
• A shy person does not interact with too many
  people.
• A shy method does not interact with too many
  classes/objects.

7
Connections

• TPP Tip 37"Configure, Don't Integrate
• We configure programs with class graphs,
  traversal graphs or object graph slices and we
  dont integrate those structures into the program
  manually.

8
Connections

• TPP Tip 38 "Put Abstractions in Code, Details in
  Metadata
• We put abstractions like ClassGraph.traverse(Objec
  t, Strategy, Visitor) into code and details like
  whereToGo into metadata.

9
TPP Tip 53 Abstractions Live Longer than Details

• Is in the Requirements Pit section
• Also applies to code dont overspecify!

10
TPP Tip 54 Dont Program by Coincidence

• Dont confuse a happy coicidence with a
  purposeful plan.