Vara Framework

AgendaIntroductionBenefitsChallengesDemonstrationNext Steps

About Mike Merchant12+ Years in Software Development10 Years between KP and SCEDeveloped or managed on 50+ projectsExperience in Flex, Java, .NET and othersFounder and President of MCW Software, an RIA consulting firm in Lake Forest, CA

Introduction“What is this Vara Framework?”User workflow framework for FlexNew architecture? New use of patterns?Based on concepts I’ve been thinking about and working on for most of my software development careerDeveloped version for VB 6.0 around 2000Developed first Adobe Flex version last yearUsed and maintained by MCW Software

Introduction“How come I’ve never heard of it?”This is the first time we have presented it publicly (11/5/2009)“Why should I care?”Vara makes building large-scale, enterprise RIAs simpler, faster, easier to maintain, and more consistent.

ObservationsWe are going to talk about CRUD (a.k.a. Create, Read, Update, Delete)Applications handle CRUD similarlyForms should handle CRUD consistentlyApplications tend to repeat this logic for each and every screenLogic is very difficult to abstract

ObservationsViews have arbitrary complexityResources have arbitrary complexityMapping is usually not simpleSimple binding does not solve thisMVC does not go far enough

ObservationsAny widely used frameworks that concretely handle CRUD operations???Desire for frameworks is NOT to dumb down or eliminate the developer.Desire for frameworks comes from being pragmatic and the need to efficiently build applications that are easily maintainable and flexible.

Scenario #1: SDI ApplicationAssume we are building an application that shows one employee form at a time (i.e. single-document interface - SDI)Open an employee record from a listMake some changesOpen another employee record from listWhat actions need to take place?

Scenario #1: SDI ApplicationLoad new record…but wait…Clear existing record…but wait... Save existing record…but wait…Has existing record changed?Should the user be prompted to save changes?How did user respond to the prompt? Yes? No? Cancel?Is the data valid?

Scenario #1: SDI ApplicationSave existing recordHow to extract data to save from view?Where to send that data? Remote Object? Web Service?Was save successful?What to do after save? Update record in list?

Scenario #1: SDI ApplicationClear existing recordHow do we reset the form?Do we need to clear the resource?Load new recordWhere do we load from?How to populate the data onto the view?What to do after load?

Scenario #2: MDI ApplicationAssume we are building an application that uses multiple employee form at a time (i.e. multiple-document interface - MDI)Open an employee record from listMake some changesClose the form

Scenario #2: MDI ApplicationClose form… but wait…Clear form… but wait... Save existing record…but wait…Has existing record changed?Should the user be prompted to save changes?How did user respond to the prompt? Yes? No? Cancel?Is the data valid?Save recordHow to extract data to save from view?Where to send that data? Remote Object? Web Service?Was save successful?What to do after save? Update record in list?Clear recordHow do we reset the form?Do we need to clear the resource?Close form

Scenario #3: PITA ApplicationWrite an application that has 100 data entry forms of arbitrary complexity (trees, tabs, data grids, file uploads, custom components, etc.)Handle the loading, saving, closing, deleting, prompting, and validation consistently throughout the application

Scenario #3: PITA Application3 months into PITA project….PITA Boss read usability study about benefits of single-document interfaces (SDI)He wants you to convert those screens from MDI to SDIHe also wants prompting to occur only if the user has actually changed the recordDue to budget constraints, the timeline needs to be reduced

Core Ideas of VaraDeveloper should be able to handle…Design and development of viewsSelection and development of resourcesView/Model interactionResource/Model interactionUser prompting

Core Ideas of VaraActions always occur in a certain orderTop-level action can start other actionsWorkflow can orchestrate these actionsCommon workflow can be providedInteract with developer’s code in order to manage the views and resources

Flex ApplicationFlex MVC ArchitecturesLayersUser InterfaceNetworkServicesMiddlewareBusiness LogicData AccessDatabaseDatabase

Flex ApplicationResourceFlex MVC ArchitecturesLayersUser InterfaceServicesBusiness LogicData AccessDatabase

Flex MVC ArchitecturesLayersUser InterfaceViewModelControllerResourceWhat about the resource?ServicesBusiness LogicData AccessDatabase

Vara ArchitectureCreated by DeveloperProvided by FrameworkViewVara FrameworkModelResource

Vara ArchitectureCreated by DeveloperProvided by FrameworkViewActionsView Adapter ImplementationWorkflowView AdapterInitializeLoadClearModelSaveResource Adapter ImplementationResource AdapterUnloadCloseResource

Vara Workflow ActionsLoadUnloadCloseClearInitializeDestroySaveGeneric

Steps to Implement VaraStep 1: Include Vara.swc in Flex projectStep 2: Create View Adapter classStep 3: Create Resource Adapter classStep 4: Declare BasicWorkflowImplStep 5: Add calls to xxxxAction.start()Step 6: Override adapters as needed

Step 2: Create View AdapterStep 3: Create Resource Adapter

Step 6: Override as neededDeveloper extends and overrides…Vara provides…AdapterImplViewAdapterImpl

BenefitsConsistent handling of user workflow across an applicationMakes applications easier to maintainSpeeds up coding by reducing duplicationIncreases flexibility and agility in responding to customers demands

ChallengesRemember Flex applications are single-threaded and asynchronous

Integration with other frameworks?

Vara Framework

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Vara Framework