Department of Computer Science and Software Engineering Concordia University E NTERPRISE A...

Department of Computer Science and Software

EngineeringConcordia University

ENTERPRISE APPLICATION DESIGN PATTERNS:IMPROVED AND APPLIED

Stuart Thielsthiel@cs.concordia.ca

February 11, 2010

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Enterprise Application Design Patterns: Improved and Applied

Outline

A Brief Overview of Development

Problems for Software Engineers

A Progression Through Fowler’s Patterns

Domain Objects and Improved Patterns

Applying Patterns with the SoenEA

Framework

February 2010 Stuart Thiel

Outline

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Enterprise Application Design Patterns: Improved and Applied

Developers Work With Software

Design

Implement

Test

Maintain

February 2010 Stuart Thiel

Developers Work With Software

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Enterprise Application Design Patterns: Improved and Applied

Developer Aids/Tools• Programming Languages

• Integrated Development Environments

• Processes / Artifacts

• Patterns / Styles

February 2010 Stuart Thiel

Developer Tools

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Enterprise Application Design Patterns: Improved and Applied

Problems

Fowler describes architectural patterns, but no overall

usage guidelines

• High level patterns lack broad examples

• Guidance on interrelation of patterns is sparse

• Pattern theory / implementation separation ambiguous

Cooking Analogy

February 2010 Stuart Thiel

Problems

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Enterprise Application Design Patterns: Improved and Applied

Problems:: Few Simple Examples

Trivial examples for Fowler’s patterns, usually

covering only a piece of functionality

February 2010 Stuart Thiel

P. Few Simple Examples

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Enterprise Application Design Patterns: Improved and Applied

Problems:: Interrelation Not

Described

Not usually covering more than one or two

patterns at a time

Discussion of interrelation limited

February 2010 Stuart Thiel

P. Interrelation Not Described

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Enterprise Application Design Patterns: Improved and Applied

Problems:: Theory Mixes with

Implementation, or is Kept Apart

Lazy Load

Unit of Work

February 2010 Stuart Thiel

P. Theory Implementation

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Enterprise Application Design Patterns: Improved and Applied

Problems Summary

The components of a solution are available

We can readily identify patterns in existing

software

There is no description of what to

do

February 2010 Stuart Thiel

Problem Summary

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Enterprise Application Design Patterns: Improved and AppliedSolutions

Solutions

Review of Existing Patterns

An Additional Patterns

Refined Patterns

SoenEA

February 2010 Stuart Thiel

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Enterprise Application Design Patterns: Improved and AppliedExisting Patterns

Review of Existing Patterns

Fowler identifies important patterns

They need context wrt each other

Transaction Script to complex Domain Model

February 2010 Stuart Thiel

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Enterprise Application Design Patterns: Improved and AppliedAdditional Patterns

Additional Pattern

Domain Object

Front Command

Dispatcher

List Proxy

February 2010 Stuart Thiel

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Enterprise Application Design Patterns: Improved and AppliedRefined Patterns:: Mappers

Refined Patterns

Data Mapper / Table Data GatewayInput MapperOutput MapperTable Data GatewayFinder

February 2010 Stuart Thiel

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Enterprise Application Design Patterns: Improved and AppliedRefined Patterns:: Others

Refined Patterns

Front Controller

Lazy Load

Identity Map

Unit of Work

February 2010 Stuart Thiel

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Enterprise Application Design Patterns: Improved and AppliedSoenEA:: advantages

SoenEA

help eliminate tedious tasks,

help programmers to make fewer mistakes, and

give guidance on proper practices.

February 2010 Stuart Thiel

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Enterprise Application Design Patterns: Improved and AppliedSoenEA:: provides

SoenEA

Patterns

Utility components

Default Implementations of Typical Components (DITCs)

Test components

February 2010 Stuart Thiel

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Enterprise Application Design Patterns: Improved and Applied

SoenEA Summary• Developers can use our contribution to build on their

understanding of existing patterns• They can use SoenEA to quickly develop software• SoenEA is like a jigsaw puzzle

February 2010 Stuart Thiel

Summary

February 2010 Stuart Thiel

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Enterprise Application Design Patterns: Improved and Applied

Conclusion

We have brought together a lot of other people’s good ideas

Our approach has been used in commercial applications

Our approach has allowed consistent and reliable

development

Our approach is readily communicable

February 2010 Stuart Thiel

Conclusion

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Enterprise Application Design Patterns: Improved and Applied

Future Work

Code Generation

Testing

Application Level Patterns

Validator Pattern

Refining Data Gateway Implementations

Integration with other artefacts0

February 2010 Stuart Thiel

Future Work

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Enterprise Application Design Patterns: Improved and Applied

Thank You!

Thank You

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Enterprise Application Design Patterns: Improved and Applied

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Enterprise Application Design Patterns: Improved and Applied

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Enterprise Application Design Patterns: Improved and Applied

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Enterprise Application Design Patterns: Improved and Applied

An Analogy

Software Development -> Cooking

WEA Development -> Baking

February 2010 Stuart Thiel

An Analogy

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Enterprise Application Design Patterns: Improved and Applied

An Analogy:: Styles

Layered Style, Event-based Style, Process

Control, Blackboard

Cakes/Pizza, Cookies/Muffins, Souflé,

Omlette/Pancake

February 2010 Stuart Thiel

An Analogy:: Styles

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Enterprise Application Design Patterns: Improved and Applied

An Analogy:: Design Patterns

Command, Factory, Adapter, Proxy

Mixing, Chopping, Heating, Greasing,

Measuring

February 2010 Stuart Thiel

An Analogy:: Design Patterns

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Enterprise Application Design Patterns: Improved and Applied

An Analogy:: Architectural

Patterns

Lazy Load, Pessimistic Offline Lock , Unit Of

Work

Mixing Dry Ingredients vs. Wet, Checking That

All Ingredients Are Available Before Starting,

Preparing All Ingredients

February 2010 Stuart Thiel

An Analogy:: Architectural Patterns

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Enterprise Application Design Patterns: Improved and Applied

An Analogy:: Frameworks

Struts 1.0 - > Waffle Iron

Hibernate -> Bread Maker

February 2010 Stuart Thiel

Analogy:: Frameworks

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Enterprise Application Design Patterns: Improved and Applied

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Enterprise Application Design Patterns: Improved and Applied

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Enterprise Application Design Patterns: Improved and Applied

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Enterprise Application Design Patterns: Improved and Applied

Cyclic Reference

Where to solve it?

• Input Mapper

Common Alternatives

• Loading other Domain Objects after

February 2010 Stuart Thiel

Cyclic Reference Solution

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Enterprise Application Design Patterns: Improved and Applied

Cyclic Reference alternative

Easy:

February 2010 Stuart Thiel

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Enterprise Application Design Patterns: Improved and Applied

public Person find(long id) {

//Check Identity Map and return if found

if(IdentityMap.has(id,Person.class))

return IdentityMap.get(id,Person.class);

//Not in Identity Map

ResultSet rs = PersonFinder.find(id);

if(!rs.next) ;//

Person p = new Person(id);

UoW.getCurrent.registerClean(p);

Person buddy = find(rs.getLong("buddy"));

p.setBuddy(buddy);

}

February 2010 Stuart Thiel

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Enterprise Application Design Patterns: Improved and Applied

Cyclic Reference alternative

Harder

February 2010 Stuart Thiel

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Enterprise Application Design Patterns: Improved and Applied

public Person find(long id) {

//Check Identity Map and return if found

if(IdentityMap.has(id,Person.class))

return IdentityMap.get(id,Person.class);

//Not in Identity Map

ResultSet rs = PersonFinder.find(id);

if(!rs.next) ;//

Person p = new Person(id);

UoW.getCurrent.registerClean(p);

Pet pet = find(rs.getLong("pet"));

p.setPet(pet);

}

February 2010 Stuart Thiel

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Enterprise Application Design Patterns: Improved and Applied

Proxy

public Person find(long id) {

//Check Identity Map and return if found

if(IdentityMap.has(id,Person.class))

return IdentityMap.get(id,Person.class);

//Not in Identity Map

ResultSet rs = PersonFinder.find(id);

if(!rs.next) ;//

Person p = new Person(id,

new PersonProxy(rs.getLong("buddy")));

UoW.getCurrent.registerClean(p);

}

February 2010 Stuart Thiel