cf.objective (anz)
DESCRIPTION
Design Patterns and Form Processing Jaime Metcher Software Architect, Centre for Innovation in Professional Learning, University of Queensland. cf.OBJECTIVE (ANZ). B.Sc (maths) Aerial survey software (in the 80's!) Kids LAN wrangler at UQ Coldfusioneer at Med-E-Serv - PowerPoint PPT PresentationTRANSCRIPT
cf.OBJECTIVE(ANZ)
Design Patterns and Form ProcessingJaime Metcher
Software Architect, Centre for Innovation in Professional Learning, University of Queensland
About me
B.Sc (maths)
Aerial survey software (in the 80's!)
Kids
LAN wrangler at UQ
Coldfusioneer at Med-E-Serv
Archi-thingie back at UQ
B.Sc (maths)
Aerial survey software (in the 80's!)
Kids
LAN wrangler at UQ
Coldfusioneer at Med-E-Serv
Archi-thingie back at UQ
OUTPUT 2500ADORG 2000HMOV DX,0FFE6HMOV AX,82HOUT DX,ALNEXT:MOV AX,3000HMOV BX,0000HCALL DISPNOT ALMOV 3001H,ALMOV BX,0100HCALL DISPJMP SHORT NEXTDISP:PUSH AXMOV CX,1CALL FAR 0FF00:0B12HPOP AXRETEND
About youYour team lead is bugging you
You are the team lead and you want to bug your juniors:
What do you do that's so great?How do you teach that?
You want to pad your CV
You know all about patterns and you're here to heckle
You thought this was the Railo talk
OutlineDesign Patterns by Example
Template methodComposite
Design Patterns World TourArchitectureSoftware engineeringEducation
ConclusionMotherhood statementsResourcesQuestions
Example – form processing
SimpleSee code sample - simple
Example – form processing
Let's componentize a bit...See code sample - simple.cfc
Example – form processing
Add some functionality:Support multiple forms on a pageDetect incomplete form transmission
See code sample - bettercfc
Example – form processing
Now refactor out some common functionality:See code sample - bettercfcrefactored
Example – form processing
A little less procedural, just for fun:See code sample - templatemethod
Template method
if (isSubmitted() and validated()) {
commit();
}
Other ways to do this?
Define the skeleton of an algorithm in an operation, deferring some steps to subclasses. Template Method lets subclasses redefine certain steps of an algorithm without changing the algorithm's structure.- Design Patterns: Gamma et al. (aka GoF)
Example – form processing
OK, let's separate some concerns:See code sample - templatemethodrefactored
Example – form processing
More guts, more glorySee code sample – composite
Composite
Compose objects into tree structures to represent part-whole hierarchies. Composite lets clients treat individual objects and compositions of objects uniformly
- Design Patterns: Gamma et al. (aka GoF)
myCompositeFormGuts = CreateObject("component", "compositeFormGuts").init("puttin_it_togetha");
myCompositeFormGuts.addChild(myFormGuts1);myCompositeFormGuts.addChild(myFormGuts2);
What's a pattern?
NameIntent
ContextHow it works
Trade-offs
And why should I care?
Prevent 'defactoring'“Hey, I noticed there was this totally unnecessary inheritance lying around so I
refactored it out”
Communication“Why do we have this one crazy class that has the same interface as all the
others but is completely different under the hood?”
Education
World tour - architecture
Alexander's “A Pattern Language” - read it!
Light on two sides:When they have a choice, people will always gravitate to those rooms which
have light on two sides, and leave the rooms which are lit only from one side unused and empty.
Therefore:
Locate each room so that it has outdoor space outside it on at least two sides, and then place windows in these outdoor walls so that natural light falls into
every room from more than one direction.
World Tour – Software Engineering
GoF – Design PatternsSingletonIterator
Decorator
Martin Fowler – PoEAAFront Controller
GatewaySingle Table Inheritance
Gregor Hohpe – Enterprise Integration PatternsMessage Endpoint
Publish-Subscribe ChannelGuaranteed Delivery
World tour - education
CIPL (my lot)Chunking & toggling
Peer leaderHypothetical professionals
E-LEN projectCoherence principle
Provide personal identity information
Motherhood statements
Patterns are primarily about communication
Patterns are not templates or rules
Pattern use is all about professional judgement
A pattern by definition is not new
Resources
Books
A Pattern Language: Towns, Buildings, ConstructionChristopher Alexander, Sara Ishikawa, Murry SilversteinISBN 978-0195019193
Design Patterns: Elements of Reusable Object-Oriented SoftwareErich Gamma, Richard Helm, Ralph Johnson, John M. VlissidesISBN 978-0201633610
Enterprise Integration Patterns: Designing, Building, and Deploying Messaging SolutionsGregor Hohpe & Bobby WoolfISBN 978-0321200686
Patterns of Enterprise Application ArchitectureMartin FowlerISBN 978-0321127426
Applying UML and Patterns: An Introduction to Object-Oriented Analysis and Design and Iterative DevelopmentCraig LarmanISBN 978-013148906
Websites
E-LEN http://www2.tisip.no/E-LEN/patterns_info.phpSome patterns in the education field
CIPL http://www.uq.edu.au/ciplNo patterns here yet :(
http://www.daimi.au.dk/~apaipi/workshop/nyartikel.pdfArticle by Aino Corry on patterns vs language constructs. See also her talk on patterns in functional languages on InfoQ.
