To Be Explicit

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To Be Explicit

• Eric Avery
• 1.23.2003

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Software Design

• Classes, Objects, Instantiation clear as
  mud????????
• How easy can your design be changed?
• VERY IMPORTANT
• Durakon Purchase Requisition Approval Process
  Analogy

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Classes Explicit vs. Dictionary Design

• Explicit Design
• Less flexible class but easier to understand.
• Class is specific to what is stores
• Easier for the programmer to modify

• Dictionary Design
• Array like storage (or other methods)
• More flexible to use but difficult to understand.
• Class is not specific to what is stores
• Requires total system analysis to determine what
  the class does

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Classes Explicit vs. Dictionary DesignCODE

• Calling Methods
• objEmployee.FirstName Eric
• objEmployee.Title Ruler of the Universe
• vs
• objEmployee(PayRate) UNDERPAID
• objEmployee(Migraines) 4000

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Classes Event Handlers vs. Explicit Methods

• Event Handlers
• Quick and easy to extend behavior to module
  (object) interaction
• Difficult to understand Code is shorthand and
  not easily readable
• Programmer must search all the code for a handler
  to see what it does
• Debugging can be difficult

• Explicit Methods
• Clearly defines what happens for an event
• Must modify the class when a change in behavior
  is needed
• Primary practice at Durakon

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More on Event Handlers

• Not evil, actually very powerful (if used wisely)
• Click a button, you might have 50 objects that
  created and used. You would have to search the
  code for any handling/
• Basically, the framework of modern programming
  language will allow you to raise events based on
  an action of the object (an event) which calls
  another objects behavior.
• VB Form Example The Form_Load Event of the Form
  is fired automatically when a form loads. Events
  are inherent to Microsofts current developer
  tools

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Classes Event Handlers vs. Explicit MethodsCODE
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Classes Data-Driven vs. Explicit

• Data-Driven Classes
• Make new behaviors without modify or creating new
  classes if the logic fits

• Explicit Classes
• Again, Easier to read and understand
• You must edit the class in order to change
  behavior

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More on Data Driven Generic Classes

• Works well if there are several behaviors that
  follow the logic involved. Cuts down on the
  sheer volume of code.
• Trade off is again, difficulty to understand and
  thereby more difficult to change.
• Another Example

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Classes Data-Driven vs. Explicit CODE
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For me

• I agree with the author
• 90 of the code I have written is heavily
  explicit.
• It costs a little more time but it is clearer for
  other programmers(and the programmer writing the
  code) to debug.
• From my perspective, I believe using non-explicit
  codes will eventually cost you in the end
  (instead of upfront)
• Most used non-explicit Event handlers

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Links

• Microsoft Overview