Mach II at MacromediaSean Corfield

Director, ArchitectureAn introduction to Mach II and its

use on macromedia.com

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Overview

• An introduction to Mach II

• What Macromedia is doing with Mach II

• Lessons Learned - Good & Bad

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Introduction

• What is Mach II?Definitions & BuzzwordsAn overview of how it works

• Why use Mach II?Pros & ConsAlternatives

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What is Mach II? /i

• "Mach-II is a web-application framework focused on easing software development and maintenance."mach-ii.com (official Mach II website)

• It's code that we can use as a foundation for our applications

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What is Mach II? /ii

• Object-Oriented

• Strict Model View Controller structure

• Event-Based Implicit Invocation Architecture

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What is Mach II? /iii

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What is Mach II? /iv

• EventsGenerated by user (links, forms)Generated by application code

• ExampleUser tries to login (event=login)Login success (event=login_ok)Login failure (event=login_bad)

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What is Mach II? /v

• Event HandlersSpecified in XML (mach-ii.xml)Can notify "listener" CFCsCan render views (HTML)Can announce new eventsCan use filters to process data and affect

the flow of control

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What is Mach II? /vi

• A simple event handler:<event-handler event="showHome" access="public"><notify listener="newsManager" method="getNews" resultKey="request.news" />

<view-page name="homePage" /></event-handler>

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What is Mach II? /vii

• Model - ColdFusion ComponentsBusiness Domain Objects"listeners" (for handling events)

• View - CFML pagesAlso layout templates, "pods" etc

• Controller - Mach IIXML configuration fileCore framework files

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What is Mach II? /viii

Mach II Application Structure

Application.cfm index.cfm

CFCs

/model

.cfm pages

/view

mach-ii.xml

/config

/appname

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What is Mach II? /ix

• ExtensibilityFilters

• CFCs that process data, announce events, change flow of control

• Invoked explicitly by event handlersPlugins

• CFCs that process data, announce events, change flow of control

• Invoked implicitly at key points in the event lifecycle

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Why use Mach II? /i

• "It helps ColdFusion developers build maintainable applications by allowing them to focus separately on the independent parts of their applications: the business model, the presentation layer, the connecting logic - the flow of the application."corfield.org (unofficial Mach II website)

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Why use Mach II? /ii

• Good frameworks provide a "head start"• Based on sound engineering principles

MVC design patternImplicit Invocation Architecture

• StandardizationCommon structure for applications

• It supports "best practices"Good OO design / heavy use of CFCsLoose coupling / high cohesion

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Why use Mach II? /iii

• But . . .

• FrameworksRequire you use their style / idiomConstrain how you develop applications

• Mach II requires you use CFCs / OO / MVC / CFMX6.1

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Why use Mach II? /iv

• Alternatives?Struts (built for Java)

• http://jakarta.apache.org/struts/Fusebox (procedural, explicit)

• http://www.fusebox.org/onTap (procedural, implicit)

• http://www.turnkey.to/ontap/

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Macromedia & Mach II

• Why did we choose Mach II?

• How are we contributing to Mach II?

• What applications use Mach II?

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Why we chose Mach II

• The macromedia.com team hadHeavy use of ColdFusion ComponentsInformal MVC approach in some apps

• But we wanted more standards and more structure in our applications

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Contributing to Mach II

• Macromedia was an early adopterDiscovered bugs (& provided fixes)Submitted enhancements (based on real-

world usage scenarios)Load testing & stability improvements

• Published Mach II Development Guide

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Applications using Mach II /i

• We started smallActive Content Resources administrator

• 6 filters, 14 event handlers, 2 listeners, 7 viewsBreeze Leads application

• 4 filters, 13 event handlers, 2 listeners, 6 viewsSome internal content management

applications• This proved the framework for us

without taking much of a risk

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Applications using Mach II /ii

• Product Showcase [link]6 filters, 81 event handlers, 16 listeners, 1 plugin,

42 views

• European Online Stores (HTML version) [link]7 filters, 78 event handlers, 1 listener, 1 plugin, 45

views

• 14 Mach II applications in production or in development…

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Lessons Learned

• Benefits of using Mach II

• Downsides to using Mach II

• Freedom within the framework

• Load testing & thread safety

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Benefits of using Mach II /i

• Able to leverage existing CFCsBuilt an HTML version of Flash / CFC store in a

short space of time• Implicit Invocation

Reduced coupling & dependenciesEasier to change application flow

• Strict MVCSeparation of presentation and logicDeclarative controller (XML)

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Benefits of using Mach II /ii

• What our engineers sayMach II provides a head start on codingCommon code structure and very modular

nature of code make it easier to maintain than ad hoc applications

Plugins and filters make it easy to extend functionality

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Benefits of using Mach II /iii

• What our engineers sayGood MVC implementation allowing

application to be built views-first or business-model-first as needed

XML controller makes incremental development & testing easier

• Overall, a big win - Mach II is well-liked"two enthusiastic thumbs up!"

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Downsides to using Mach II

• What our engineers sayLack of documentationDebugging / Tool support

• Some community tools are now appearingPoor white space management

• Improved in 1.0.9Thread safety is big, big issue

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Freedom within the framework /i

• There's more than one way to do thingsFilters vs PluginsLayouts, PodsForm handlingRequest scope vs Event objectListener style

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Freedom within the framework /ii

• We used filters forSecurity / login authenticationPersistenceForm handlingLocalizationCachingOmniture click-stream tracking

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Freedom within the framework /iii

• We used plugins forApplication initialization / parametersLocalizationTracing / debugging / performance

analysis

• Note: two approaches to localization!

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Freedom within the framework /iv

• Layouts & PodsPortal / Grid LayoutsLots of small views, rendered to contentKey

variables (pods)Use layout template views to assemble pageUsually announce event to assemble pageCompositeView design pattern

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Freedom within the framework /v

• Form handlingBeaner filter

• Code was written before <event-bean> command was added!

Validation filter

• No custom form handling:All basic bean-based code

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Freedom within the framework /vi

• Request scope vs Event objectWe mostly follow the (original) Mach II

Development Guide recommendationsMostly use a few request scope variables

as the API to viewsUse a few event arguments where it is

clearer and more maintainable to do soThis is no longer considered best practice

for Mach II!

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Freedom within the framework /vii

• We have yet to choose one listener styleSome applications use a single listener as

a facade for the business modelSome applications use one or two simple

"manager" listenersSome applications use a lot of small,

single-function listeners

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Load testing & thread safety /i

• Mach II 1.0.9 is thread safeEarlier versions of the framework were not!Load testing highlighted random errors

• All CFCs are stored in application scopeNeed to use 'var' scope for all local

declarations in all functions!

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Load testing & thread safety /ii

• You must also 'var' declare implicitly created variables (from cfquery, cffile etc)

• Example:<cfset var results = 0 /><cfquery name="results" …>

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Summary

• Mach II……is a good fit for the way we develop

applications: OO, MVC…is based on a solid software

architecture: Implicit Invocation…provides a common structure for our

applications that reduces coupling, increases cohesion, eases maintenance

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Resources

• The official Mach II websitehttp://www.mach-ii.com/

• The unofficial Mach II websitehttp://www.corfield.org/machii/

• Mach II Development Guidehttp://livedocs.macromedia.com/wtg/

public/machiidevguide/

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Mach II at Macromedia

• Questions & Answers?

• Sean A Corfield• scorfield@macromedia.com