Pure Ejb Within An Agile Context

Pure EJB within an Agile ContextAtlanta BEA dev2dev User Group

Monday. October 10, 2005

Presented by:

Noam Bunder

Sekhar Atteri

Larry Williams

Version 3.0

04/13/23

Atlanta BEA User Group 2

Questions:What do we mean by Pure EJBs?Can you make EJBs work in an Agile Methodology?Where do new frameworks fit in (Spring, etc.)?Can you use Eclipse and Workshop in harmony?What benefits do you get from Continuous Builds?How does Hibernate fit in?What does Maven bring to the table?

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Overview

Overview:Combining a plain-vanilla Enterprise Java implementation, with the processes and tools common to Agile methods. Based upon WebLogic Portal, this session shows how to leverage Eclipse, Maven, CruiseControl and Hibernate for efficient development. We will review the architecture and development process, as well address challenges with the approach.

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Agenda

Agenda:7:00pm – 7:30pm: Review the Architecture7:30pm – 7:45pm: Present Development Tool Set7:45pm – 8:00pm: Describe Continuous Build Process8:00pm – 8:30pm: Q & A / Open Discussion

ArchitectureArchitecture

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Architecture – Assumptions, Drivers, Constraints and Challenges

ArchitectureAssumptions

Will be hosted as an ASP model, thus it must server multiple customers, with different load and customization demandsMust be understood, will be adopted company wide for new product suite

DriversKeep it Simple and FlexibleLeverage Existing, Proven Technology and DesignProvide a Foundation that is Extensible

ConstraintsInteroperability with Legacy SystemTime – Product to be delivered to customer for UAT within 5 monthsManagement Directive: Scrum Process

ChallengesRamp Up and Integration of Tool Set and Deployment ModelManaging Risks with Key Partners/Software Vendors

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Architecture - Components

Architecture – Component View

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Architecture – Design Patterns

Key Design PatternsProxy Pattern

Client Agent hides EJB Invocation

Session Facade Aggregates Business Services

DAO Pattern Abstracts Persistence Strategy

Presentation Tier

Middle Tier

Data Tier

Portal

Portal

Servlet

Java

PageFlows

JSPs

Client

Agent

Client

Agent

Factory

Business

Services

Data

Access Object

Value

Objects Oracle

Hibernate

Data

Access Object

Factory

Session

Facade

(EJB)

DataTransferObjects

Application Server

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Architecture – Proxy Pattern and Session Facade

Facades add a layer of abstraction to the architecture allowing application and business semantics to be reflected in the Façade’s public methodsA Façade is an “agent” of the client running co-resident with servicesProvide an application-friendly broker that will aggregate service invocationsAlthough they execute on the server within the EJB Container, Facades are designed to serve as brokers for the web-tier clients (i.e., client agents)Facades can be an effective tool to minimize web-tier calls into the EJB-tierFacades should only contain lightweight logic delegating heavy-weight logic to collaborating business service componentFacades should have some structural form to provide standard processing for each method

Pre-Call ValidationCall SequencingPost-Call ValidationDTO Building

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Architecture – Data Access Object with Hibernate

Resource access objects must accommodate both transactional and non-transaction semanticsResource access objects should serve the purpose of insulating the architecture from the technical nuances of the external resourcesResource Access Objects vend business objects to the services layer and interact with RDBMS systems or web service providers using the native protocols of the external resource

Resource access objects come is different typesDatabase Access ObjectsWeb Service Access ObjectsJMS Access Objects

Access objects should be hidden behind a service object, Façade components and presentation-tier components should never create direct references to access objectsDAOs are implemented using HibernateHibernate manages the mapping between the business domain model and the underlying relational database structureHibernate exposes a suite of CRUD APIs to the service layer allowing service methods to create, retrieve, update, or delete business objects as needed

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Architecture – Sequence Diagram

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Architecture – Key Success Factors

Begin Early with Domain ModelFit Database Schema to Object Model in a reasonable fashion

Both a blessing (huge time saving) and a curse (making changes to the db model to make it work for java applications)

Partner with BEA Professional ServicesEarly for prototype, Midway for review and End for deployment

Leverage BEA SupportGet the best developers you can find

Three or Four Senior Leads

Have finely controlled Architectural Constraints. Clear cut responsibilities for each package means faster time from use case to implementation

Invest Time enforcing Code Reviews

Development Tool Set

Development Tool Set

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Development Tool Set – Assumptions, Drivers, Constraints

AssumptionsProvide Developers with a Productive Development Environment without compromising the End Product ArchitectureLeverage Tools associated with Agile Methodologies (i.e. Scrum)Development Tools will provide “easy-entry” for new Developers

DriversSupport largest range of possible Java related technologies, while staying as close as possible to mainstream Enterprise JavaLeverage WebLogic Portal for Branding and PersonalizationLeverage Eclipse for Development Ease and SpeedLeverage Hibernate for Time to Market and Reduced Database DependencyLeverage Cactus for In-Container TestingScript and Automate as much as possible to reduce human errorProvide visibility to Development to close loop - MTTBF (Mean Time to Bug Fix)

ConstraintsMinimize reliance on WebLogic Workshop to be replaced by Eclipse by Q4 2005Scrum process does not allow for abundance of documentation

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Development Tool Set – Challenges

ChallengesDevelopment Environment requires precise configurationBig lettered Slides have been successful in assuring compliance½ Day walkthrough required to get new developers up and runningA “Development Core Image” does not provide everythingThe installation of Maven (1st running) must occur within the User Profile, where it builds its local repositoryWorking with a WebLogic Portal Project required some components to not be checked in to StarTeam, complicating a fresh-pull of codeDevelopers can “debug through” Back End code when exercised by Unit Tests, however Front End developers cannot debug Back End code, for it is compiled and copied into APP-INF/libUnit Tests are insufficient and can be sloppy. Although Code compiles, Unit Tests hog memory and can interrupt continuous build cycle

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Development Tools

EclipseMultiple ProjectsUsing Mevenide Plug-in

MavenManages DependenciesProduces Web SitesRuns Build, Tests and Metrics

WebLogic WorkshopUsing JARs copied by MavenPageFlows expose Business Logic

HibernateHBM files with associated code

CactusExercised by Maven Plug-In

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Development Tool Set - Lifecycle

Lifecycle: Code > Build > Test > DeployEclipse

Code, Build and Test

MavenBuild, Test and Deploy

Code Build Test Deploy

Eclipse Responsibility Space

Maven Responsibility Space

• Source Generation• Compilation• Dependant Projects• Resource Dependencies• Artifact Generation

• Cactus Unit Testing• Integration Testing• Profiling

• Doc. Generation• Artifact Trending• Project Website• Notification

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MavenActs like a “Container” providing Services

Services for Build = Goals and Plug-Ins

Maven does not equal ANT ANT is not multi-project and dependency aware

Goes Beyond ANT to Provide a Multi-Project Build ScriptManages Dependencies via Local and Remote RepositoriesIntegrates into Eclipse (Development IDE)Provides Automated Quality and Unit TestsProvides a Multitude of Plug-InsGenerates Reports (Web Site)

Development Tool Set - Maven

Build

Build

Maven

Developed ANT Tasks

Task Calls

Maven Built-In Goals and Plug-Ins

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Development Tool Set – Maven and ANT

ANT and Maven within the Build Process

coreejbcoreejb

infrinfr

corecore

coresupportcoresupport

MA

VEN

/ Cactu

s

pageflowspageflows

portalportal

Copy to web

project

BUILD EAR

StarTeam

EA

R FILE

Back End Code

Back End Code

Front End Code

Front End Code

Label StarTeam

Label StarTeam Un-deployUn-deploy Deploy/

Configure

Deploy/Configure

Development QA Smoke

QA Smoke QA Server

ANT

ANT

ANT ANT

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Development Tool Set – Maven Website Screen Shot

Cactus Unit Test Cases Report

Continuous Build ProcessContinuous

Build Process

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Continuous Build Process – Assumptions, Drivers, Constraints and Challenges

AssumptionsAgile Methodology (Scrum) to be followed, requiring daily statusDevelopment will include Iterative Integration and Testing

DriversProvide visibility and proper focus to developmentReduce down time between compile-breakagesFocus improvement upon realistic and objective metrics

ConstraintsTools do not extend fully into Workshop files (JPF, etc.)Unit Testing not emphasized (green = good compile only)

ChallengesLack of discipline around Cactus Tests made for long-build times (~15 minutes)Stability issues

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Continuous Build Process

Separate Developer WorkstationRunning SimpleHTTP ServerWebLogic Portal

CruiseControl scheduledto kick-off build every20 minutesGreen Light / Red Light

via X10 devices

Scheduled Build at 2:00 AM Prepares build for QA (optional)

Timed to run every 20 minutes, 6:00am – 10:00pm

SummarySummary

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Partner with BEA Professional ServicesLeverage BEA SupportSend folks to BEA Educational Services classesVisit dev2dev often for articles and code libraryGet the best developers you can – at least 3 seasoned leadsFocus on what works, take risks where they are manageableIntegrate BEA with other departments early (IT, Support, etc.)Design, Code and Lead by Example

Take AwayTips/HintsTake AwayTips/Hints

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Maven Details

Maven in 3 concepts:POM (Project Object Model)Plugins

Made of Goals = Actions

Repositories

Maven files (in 3):project.xml

POM

maven.xmlCustom goals in JellyGoal, preGoal, postGoal

Configurationproject.propertiesbuild.properties

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Maven POM Example

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Cruise Control Details

CruiseControl Configurationconfig.xml – CruiseControl Configuration (see next slide)

Build Filesbuild.xml – Full Clean and Full Check Out (Get Latest)

ant – (default target)Calls the Clean and StCheckout Targets

build-cc.xml – Full Build and (Separately) Deployant –f build-cc.xml scheduled –Dlabel=build.xx

1. Full Build2. Update the Footer with the Label3. Label StarTeam

Separate Deployment Targets for each Environment

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Cruise Control Sample Configuration File

<project name=“project"><bootstrappers>

<antbootstrapper /></bootstrappers> <modificationset><alwaysbuild/></modificationset> <schedule interval="600">

<maven goal="multiproject:install cleanDB multiproject:site" projectfile="C:/_project/source/server/project.xml“ mavenscript="C:\Maven_1.0.2/bin/maven.bat"/> <pause starttime="2200" endtime="0530"/> <pause day="sunday" starttime="0001" endtime="2400"/> <pause day="saturday" starttime="0001" endtime="2400"/>

</schedule> <publishers>

<email buildresultsurl="http://buildmachine:8080/cruisecontrol/index.jsp" defaultsuffix="@mailserver.com" mailhost=“IPADDRESS" reportsuccess="fixes" returnaddress="buildmachine" subjectprefix="Integration build - "> <always address=“developer"/>

</email> <x10publisher port="COM1" passDeviceCode="A3" failDeviceCode="A2"/> <x10publisher port="COM1" passDeviceCode="B3" failDeviceCode="B2"/> <artifactspublisher dir="C:/_project/source/server/target/docs“ dest="artifacts/project"/></publishers>

</project>

Pure Ejb Within An Agile Context

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