Building and Managing Java Projects with Maven

1
Building and Managing Java Projects with Maven

• Alan Wang
• Connectria

2
Agenda

• What is Maven?
• A J2EE example
• Customizing and extending Maven
• Tips and discussions

3
What is Maven?

• A Java project management and integration build
  tool.
• Based on the concept of XML Project Object Model
  (POM).
• Originally developed for building Turbine.
• A small core with numerous plugins (in Jelly).

4
Build Tools Retrospective

• One level above ant.
• Make ? ant ? Maven
• (Assembly ? C ? C)

Make makefile target
Ant build.xml target
Maven project.xml maven.xml goals
5
Under the Hood
jalopy
site
junit
etc
test
cactus
artifact
xdoc
ear
gump
xdoclet
javadoc
java
jar
war
ejb
plugins
maven core, jelly, werkz
ant
forehead classloader util launcher
Maven
6
Architecture Overview
Build System
project.xml (pom)
http
Remote Repo
maven.xml (goals)
Local Repo
maven
Site
7
Artifact Repository

• The Most Important Feature
• Remote Repository

mave.repo.remote/ltgroupIdgt/lttypegts/ltartifactIdgt
-ltversiongt.lttypegt

• repository
• xalan
• jars
• xalan-2.5.0.jar
• xalan-2.5.1.jar

ltdependenciesgt ltdependencygt
ltgroupIdgtxalanlt/groupIdgt
ltartifactIdgtxalanlt/artifactIdgt
ltversiongt2.5.1lt/versiongt lttypegtjarlt/typegt
lt/dependencygt lt/dependenciesgt
8
Artifact Repository

• Local Repository
• A local mirror/cache of downloaded artifacts from
  remote repositories.
• Located at user.home/.maven/repository

mave.repo.local/ltgroupIdgt/lttypegts/ltartifactIdgt-
ltversiongt.lttypegt
9
Implementing an Example

• Get Started
• Download from
• http//maven.apache.org/start/download.html
• Current version 1.0rc1
• Environment setup
• export MAVEN_HOMEc/maven-1.0rc1
• export PATHMAVEN_HOME/binPATH
• (or set MAVEN_HOME c\maven-1.0rc1
• set PATH MAVEN_HOME\binPATH )
• run install_repo.sh to populate the local
  repository

10
Create a New Project

• Type
• maven genapp
• It will prompt for
• project id
• project name
• project package name
• A Sample Service J2EE Project
• EJB (stateless session beans exposed as web
  services)
• Data components
• Web application

11
Directory Layout

• Project Directory Layout
• sampleservice
• project.xml - Master POM of the project
• maven.xml - Reactor definition
• project.properties - Properties related to the
  project
• application/ - Application component
• service-data/ - Common data component
• service-ejb/ - EJB/WS component
• service-web/ - Web Application component
• target/ - Generated artifact directory
• xdocs/ - Various documents in xml format

12
Directory Layout

• A Component Directory Layout
• service-data - Data component subproject
• project.xml - POM of the data project
• maven.xml - Goals definition
• project.properties - Properties related to the
  project
• src/ - Source directory
• conf/ - Configuration and resource files
• java/ - Java source files
• test/ - Test source files
• target/ - Generated artifact directory
• xdocs/ - Various documents in xml format

13
Project Object Model (POM)

• Projects are described as Project Object Model.
• Project Management
• Detailed description of the project.
• Company information.
• Developer roles and information.
• Mailing list and source control modules
  configuration.
• Project Build
• Source code and test code location.
• Resources location

14
Project Object Model (POM)

• Project Dependency
• Libraries needed for build and runtime.
• Project Reports
• Junit reports
• Javadoc reports
• Checkstyle reports, .etc

15
Project Management Section

• ltprojectgt
• ltpomVersiongt3lt/pomVersiongt
• ltgroupIdgtsampleservicelt/groupIdgt
• ltnamegtSample Servicelt/namegt lt!-- Used in
  Javadoc --gt
• ltidgtsampleservicelt/idgt
• ltcurrentVersiongt1.0lt/currentVersiongt
• lt!-- Used for document creation --gt
• ltorganizationgt
• ltnamegtMy, Inc.lt/namegt
• lturlgthttp//www.myinc.comlt/urlgt
• ltlogogt/images/logo.giflt/logogt
• lt/organizationgt

(elements in bold are required)
16
Project Management Section

• ltprojectgt
• ltinceptionYeargt2003lt/inceptionYeargt lt!-- Used in
  JavaDoc
• ltpackagegtcom.myinc.sampleservicelt/packagegt lt!--
  Used in JavaDoc --gt
• ltshortDescriptiongtDemo to use mavenlt/shortDescript
  iongt lt!-- one liner --gt
• lt!-- Used in front page--gt
• ltdescriptiongt
• A detailed description about this demo
• lt/descriptiongt
• lturlgthttp//www.myinc.com/sampleservice/lt/urlgt
• ltissueTrackingUrl/gt
• ltsiteAddressgtdev.myinc.comlt/siteAddressgt lt!--
  Used in deployment --gt
• ltsiteDirectorygt/www/sampleservice/lt/siteDirectorygt
  lt!-- Used in deployment --gt
• lt!-- Used in deployment. If defined, it overrides
  maven.repo.central --gt
• ltdistributionSitegt/www/dist/sampleservicelt/distrib
  utionSitegt
• lt!-- Used in deployment, final distribution
  directory --gt
• ltdistributionDirectorygt/www/www.myinc.com/somedirlt
  /distributionDirectorygt

17
Project Management Section

• ltprojectgt
• ltrepositorygt
• ltconnectiongtscmcvspserveranoncvs_at_cvs.myinc.com
  /cvsrootsampleservicelt/connectiongt
• ltdeveloperConnectiongtscmcvspservermaven.usern
  ame_at_cvs.myinc.com/cvsrootsampleservicelt/develop
  erConnectiongt
• lturlgthttp//cvs.myinc.org/viewcvs/sampleservice/lt/
  urlgt
• lt/repositorygt
• lt!-- Used in mavendist --gt
• ltversionsgt
• ltversiongt
• ltidgt1.0-beta-1lt/idgt
• ltnamegt1.0-beta-1lt/namegt
• lttaggt1.0-beta-1lt/taggt
• lt/versiongt
• lt/versionsgt
• ltbranches/gt

ltmailingLists/gt ltcontributors/gt ltdevelopers/gt
18
Project Dependency Section

• ltprojectgt
• ltdependenciesgt
• ltdependencygt
• ltgroupIdgtlog4jlt/groupIdgt
• ltartifactIdgtlog4jlt/artifactIdgt
• ltversiongt1.2.8lt/versiongt
• ltpropertiesgt
• ltear.bundlegttruelt/ear.bundlegt
• ltejb.manifest.classpathgttruelt/ejb.manifest.classpa
  thgt
• lt/propertiesgt
• lt/dependencygt
• lt/dependenciesgt

Special Dependency SNAPSHOT
19
Project Dependency Section

• Dependency Classloader
• ltdependencygt
• ltgroupIdgtbcellt/groupIdgt
• ltartifactIdgtbcellt/artifactIdgt
• ltversiongt5.1lt/versiongt
• ltpropertiesgt
• ltclassloadergtrootlt/classloadergt
• lt/propertiesgt
• lt/dependencygt

Maven has three classloaders root -- ant
classloader root.maven maven core
classloader default plugin classloader
20
Project Dependency Section

• Dependency Override
• project.xml
• ltdependencygt
• ltgroupIdgtweblogiclt/groupIdgt
• ltartifactIdgtweblogiclt/artifactIdgt
• ltversiongt8.1.1lt/versiongt
• ltpropertiesgt
• ltclassloadergtrootlt/classloadergt
• lt/propertiesgt
• lt/dependencygt
• project.properties
• Dependency override
• maven.jar.override on
• maven.jar.weblogic weblogic.home/lib/weblogic
  .jar
• maven.jar.webservices weblogic.home/lib/webse
  rvices.jar

21
Project Build Section

• Defines the location of source, test and resource
  files.
• ltbuildgt
• ltnagEmailAddressgtbuildmaster_at_myinc.comlt/nagEmailAd
  dressgt
• ltsourceDirectorygtsrc.java.dirlt/sourceDirectorygt
  
• ltunitTestSourceDirectorygtsrc.test.dirlt/unitTest
  SourceDirectorygt
• ltaspectSourceDirectory/gt

src/java
src/test
22
Project Build Section

• ltunitTestgt
• ltincludesgt
• ltincludegt/Test.javalt/includegt
• lt/includesgt
• ltresources/gt
• lt/unitTestgt
• ltresourcesgt
• ltresourcegt
• ltdirectorygtsrc.conf.dirlt/directorygt
• lttargetPath/gt
• ltincludesgt
• ltincludegt/.propertieslt/includegt
• lt/includesgt
• lt/resourcegt
• lt/resourcesgt

src/conf
prefix package name, e.g. com.myinc. sampleservice
23
Project Report Section

• Defines various reports to be generated
• ltreportsgt
• ltreportgtmaven-jdepend-pluginlt/reportgt
• ltreportgtmaven-checkstyle-pluginlt/reportgt
• ltreportgtmaven-changelog-pluginlt/reportgt
• ltreportgtmaven-developer-activity-pluginlt/reportgt
  
• ltreportgtmaven-file-activity-pluginlt/reportgt
• ltreportgtmaven-javadoc-pluginlt/reportgt
• ltreportgtmaven-jxr-pluginlt/reportgt
• ltreportgtmaven-junit-report-pluginlt/reportgt
• ltreportgtmaven-linkcheck-pluginlt/reportgt
• ltreportgtmaven-tasklist-pluginlt/reportgt
• lt/reportsgt

24
Project Report - Example
Jakarta Turbine
25
Project Report - XDoc
xdocs/navigation.xml ltmenu name"General
Information"gt ltitem name"Overview"
href"/index.html"/gt ltitem
name"Features" href"/features.htm
l"/gt ltitem name"Specification"
href"/fsd.html"/gt ltitem name"Getting
Started" href"/getting-started.html"/gt
lt/menugt
xdocs/features.xml ltdocumentgt
ltpropertiesgt lttitlegtTurbine
Featureslt/titlegt ltauthor
email""gtJon S. Stevenslt/authorgt
lt/propertiesgt ltbodygt
ltsection name"Features"gt ltpgtThis
document is for bragging about all of Turbine's
. lt/documentgt
26
Property Processing
project.home/project.properties Project scope properties
project.home/build.properties Properties specific to each build
user.home/build.properties Properties specific to each user
CLI Dfoobar
The last definition wins
Sample build.properties bea.homec/bea81sp1 or
acle.homec/oracle/ora9i
27
Build Process Design

• Sample Service project components

Common data module EJBs Web Application
Data (jar)
EJB (jar)
Webapp (war)
EAR
28
Subproject service-data
project.xml (POM) ltprojectgt ltextendgt../project.x
mllt/extendgt ltnamegtSample Service Data
Modulelt/namegt ltidgtsampleservice-datalt/idgt
lt/projectgt Note POM can be inherited.

• sampleservice
• project.xml
• maven.xml
• application/
• service-data/
• project.xml
• maven.xml
• src/
• service-ejb/
• service-web/
• xdocs/

29
Subproject service-data
maven.xml (Goals) ltproject default"build"
xmlnsj"jellycore" xmlnsmaven"jellymaven"
xmlnsant"jellyant"gt ltgoal
name"build" prereqs"jarinstall"/gt lt/projectgt
Note Goals can also be inherited

• sampleservice
• project.xml
• maven.xml
• application/
• service-data/
• project.xml
• maven.xml
• src/
• service-ejb/
• service-web/
• xdocs/

Make jar
Local Repo
30
Subproject service-ejb
project.xml (POM) ltprojectgt ltextendgt../project.x
mllt/extendgt ltnamegtSample Service EJBlt/namegt
ltidgtsampleservice-ejblt/idgt ltdependencygt
ltgroupIdgtpom.groupIdlt/groupIdgt
ltartifactIdgtsampleservice-datalt/artifactIdgt
ltversiongtpom.currentVersionlt/versiongt
ltpropertiesgt ltejb.manifest.classpathgttrue
lt/ejb.manifest.classpathgt lt/propertiesgt
lt/dependencygt lt/projectgt

• sampleservice
• project.xml
• maven.xml
• application/
• service-data/
• service-ejb/
• project.xml
• maven.xml
• src/
• service-web/
• xdocs/

Local Repo
xdoclet
compile
ws-gen
ejb-jar
31
Subproject service-ejb

• Maven XDoclet Plugin
• Support all standard tags
• Automatically includes generated src dir in
  compilation src set
• Support util class generation
• Dependencies
• xdoclet-ejb-module-1.2
• xdoclet-web-module-1.2
• xdoclet-bea-module-1.2
• (for WebLogic Server Deployment)

Note Current version 1.2 does not work
out-of-box (needed to fix the project.xml)
32
Subproject service-ejb
Maven XDoclet Plugin - Properties EJBDoclet
maven.xdoclet.ejbdoclet.fileset.0.include/ejb/
/Bean.java maven.xdoclet.ejbdoclet.ejbSpec2.0
maven.xdoclet.ejbdoclet.verbosetrue maven.xdoclet
.ejbdoclet.session.0false maven.xdoclet.ejbdoclet
.localhomeinterface.0true maven.xdoclet.ejbdoclet
.localinterface.0true maven.xdoclet.ejbdoclet.uti
lobject.0true EJBDoclet WebLogic Nested
Element maven.xdoclet.ejbdoclet.weblogic.0true ma
ven.xdoclet.ejbdoclet.weblogic.0.mergeDirsrc.di
r/ejbdoclet maven.xdoclet.ejbdoclet.weblogic.0.de
stDirmaven.xdoclet.ejbdoclet.deploymentdescript
or.0.destDir
33
Subproject service-ejb

• Web Services
• Currently Maven has no container specific plugins

ltgoal name"wsgen" prereqs"wsgen.autotype,
wsgen.source2wsdd"/gt ltgoal name"wsgen.autotype"
gt lttaskdef name"autotype"
classname"weblogic.ant.taskdefs.webservices.java
schema.JavaSchema"/gt . lt/goalgt ltgoal
namewsgen.source2wsddgt lt/goalgt
project.properties Web Services
maven.webservice.javaComponents\
com.myinc.sampleservice.ejb.BasicAccountInquiry,\
com.myinc.sampleservice.ejb.ExpandedAccountInq
uiry,\ com.myinc.sampleservice.ejb.DetailedAcc
ountInquiry maven.webservice.autotype.packagecom.
myinc.sampleservice.autotype maven.webservice.auto
type.keepgeneratedfalse
Use tag _at_wlws
34
Subproject service-ejb

• Maven EJB Plugin
• Currently no container specific ejb-jar

• sampleservice
• project.xml
• maven.xml
• application/
• service-data/
• service-ejb/
• project.xml
• maven.xml
• src/
• service-web/
• xdocs/

ltgoal name"ejbjar" prereqs"javacompile"gt
ltpath id"ejb.classpath"gt ltpathelement
location"maven.build.dest"/gt ltpath
refid"maven.dependency.classpath"/gt lt/pathgt
ltjset var"maven.ejb.descriptordir"
value"pom.getPluginContext('maven
-xdoclet-plugin')./gt ltejbjar
srcdir"maven.build.dest"
descriptordir"maven.ejb.descriptordir"
flatdestdir"true"
basejarname"pom.artifactId-pom.currentVers
ion"gt ltclasspath refid"ejb.classpath"/gt
ltweblogic destdir"maven.build.di
rnewCMP"true"
outputdir"maven.build.dir/ejb"
rebuild"false"
ejbcclass"weblogic.ejbc" lt/weblogicgt

35
Subproject service-ejb
Making the Final EJB Jar

• sampleservice
• project.xml
• maven.xml
• application/
• service-data/
• service-ejb/
• project.xml
• maven.xml
• src/
• service-web/
• xdocs/

ltproject default"buildgt ltgoal name"build"
prereqs"ejbinstall"/gt ltpreGoal
name"javacompile"gt ltattainGoal
name"xdocletejbdoclet"/gt lt/preGoalgt
ltpostGoal name"javacompile"gt ltattainGoal
name"wsgen"/gt ltattainGoal
name"javajar-resources"/gt lt/postGoalgt
ltpreGoal name"ejbejb"gt ltattainGoal
name"ejbjar"/gt lt/preGoalgt ltpostGoal
name"ejbinstall"gt ltartifactinstall
artifact"maven.build.dir/pom.artifactId
-pom.currentVersion.xml" type"xml
project"pom"/gt lt/postGoalgt
36
Subproject service-web
project.xml (POM)

• sampleservice
• project.xml
• maven.xml
• application/
• service-data/
• service-ejb/
• service-web/
• project.xml
• maven.xml
• src/
• xdocs/

ltprojectgt ltextendgt../project.xmllt/extendgt
ltnamegtSample Service Web Applicationlt/namegt
ltidgtsampleservice-weblt/idgt ltdependencygt
ltgroupIdgtpom.groupIdlt/groupIdgt
ltartifactIdgtsampleservice-datalt/artifactIdgt
ltversiongtpom.currentVersionlt/versiongt
lt/dependencygt ltdependencygt
ltgroupIdgtpom.groupIdlt/groupIdgt
ltartifactIdgtsampleservice-ejblt/artifactIdgt
ltversiongtpom.currentVersionlt/versiongt
lttypegtejblt/typegt ltpropertiesgt
ltweb-servicegttruelt/web-servicegt
lt/propertiesgt lt/dependencygt
custom property
37
Subproject service-web
maven.xml (goals)
ltproject defaultbuildgt ltgoal name"build"
prereqs"warinstall"/gt ltpreGoal name"warwar"gt
ltjforEach var"dep"
items"pom.dependencies"gt
ltjif test"dep.getProperty('web-service')'tr
ue'"gt ltutilfile var"xmlFile"
name"maven.repo.loca
l/dep.groupId/xmls/dep.artifactId-
dep.version.xml"/gt
ltjif test"xmlFile.exists()"gt
ltxparse var"xml"
xml"xmlFile"/gt
ltxforEach var"node" select"xml//"gt
ltjset var"temp" value"root.add(node.de
tach())"/gt lt/xforEachgt
lt/jifgt lt/jifgt
lt/jforEachgt ltjif
test"!root.elements().isEmpty()"gt
lt! output the web-services.xml --gt lt/jifgt
lt/preGoalgt
preGoal is used to generate web services DD
file if defined
38
Subproject application
lt!-- EJB Component --gt ltdependencygt
ltgroupIdgtpom.groupIdlt/groupIdgt
ltartifactIdgtsampleservice-ejblt/artifactIdgt
ltversiongtpom.currentVersionlt/versiongt
lttypegtejblt/typegt ltpropertiesgt
ltear.bundlegttruelt/ear.bundlegt
lt/propertiesgt lt/dependencygt lt!-- WAR
Component --gt ltdependencygt
ltgroupIdgtpom.groupIdlt/groupIdgt
ltartifactIdgtsampleservice-weblt/artifactIdgt
ltversiongtpom.currentVersionlt/versiongt
lttypegtwarlt/typegt ltpropertiesgt
ltear.bundlegttruelt/ear.bundlegt
ltear.appxml.war.context-rootgt
/pom.artifactId lt/ear.appxml.war.conte
xt-rootgt lt/propertiesgt lt/dependencygt
EAR Packaging ltprojectgt ltextendgt../project.
xmllt/extendgt ltnamegtSample Service
Applicationlt/namegt ltidgtsampleservicelt/idgt
lt!-- Data Component --gt ltdependencygt
ltgroupIdgtpom.groupIdlt/groupIdgt
ltartifactIdgtsampleservice-datalt/artifactIdgt
ltversiongtpom.currentVersionlt/versiongt
lttypegtjarlt/typegt ltpropertiesgt
ltear.bundlegttruelt/ear.bundlegt
lt/propertiesgt lt/dependencygt

• sampleservice
• project.xml
• maven.xml
• application/
• project.xml
• maven.xml
• src/
• service-data/
• service-ejb/
• service-web/
• xdocs/

39
Subproject application
EAR Packaging ltproject defaultbuildgt
ltgoal name"build" prereqs"ear"/gt ltpreGoal
name"eargenerate-ear-descriptor"gt ltmkdir
dir"maven.ear.appxml.dir"/gt
lt/preGoalgt lt/projectgt

• sampleservice
• project.xml
• maven.xml
• application/
• project.xml
• maven.xml
• src/
• service-data/
• service-ejb/
• service-web/
• xdocs/

project.properties Ear related maven.ear.appx
ml.dir maven.build.dir/application/META-INF m
aven.ear.appxml maven.ear.appxml.dir/applicat
ion.xml maven.ear.appxml.generate true
Tip container specific DD files can be stored at
src/application/META-INF
40
Putting It Together Reactor
ltproject defaultbuild xmlnsj"jellycore"
xmlnsmaven"jellymaven"
xmlnsant"jellyant"gt .

• sampleservice
• project.xml
• maven.xml
• application/
• service-data/
• service-ejb/
• service-web/
• xdocs/

ltgoal name"build"gt ltmavenreactor
basedir"basedir" postProcessing"true"
includes"/project.xml" excludes""
goals"build" banner"Building"
ignoreFailures"false"/gt lt/goalgt
41
Putting It Together Reactor
/c/dev/sampleservice/gtmaven __ __ \/ __
_Apache__ ___ \/ / _ \ V / -_) ' \
intelligent projects _ _\__,_\_/\_____
v. 1.0-rc1-SNAPSHOT Starting the reactor... Our
processing order Sample Service Data
Module Sample Service EJB Sample Service Web
Application Sample Service Application ----------
------------------------------ Building Sample
Service Data Module Memory 3M/4M -------------
--------------------------- build javaprepare-f
ilesystem mkdir Created dir
C\dev\sampleservice\service-data\target\classes
javacompile .
42
Customizing Maven

• Override plugin properties in
• project.properties
• build.properties
• Use maven.xml
• Override plugin goals
• Intercept plugin goals with ltpreGoal/gt and
  ltpostGoal/gt
• Write you own plugin
• In Java, Jelly, or other scripting language.

43
Real Life Maven

• Single artifact per project
• Can be tweaked to deliver multiple artifacts as
  long as no type conflicts
• Fine-grained design
• Project Migration/Mavenizing
• Can co-exist with ant
• May require different directory structure
• Too Slow?
• Use console plugin
• Are you ready for maven?
• Culture change

44
Summary

• Pros
• Work out-of-box for standard projects
• Build assets highly reusable, thanks to
  core/plugin architecture
• Build rules are more dynamic
• Best suited for project integration
• IDE friendly
• Cons
• Incomplete documentation
• Missing convenience details
• Not yet mature. Still waiting for the R1.

45
Get More

• http//maven.apache.org
• http//www.onjava.com/pub/a/onjava/2003/10/22/mave
  n.html
• http//www-106.ibm.com/developerworks/java/library
  /j-maven
• http//www.javausergroup.at/events/maven.pdf
• http//www.theserverside.com/articles/article.jsp?
  lMavenMagic
• http//blogs.codehaus.org/people/vmassol/archives/
  000080.html
• http//www.javaworld.com/javaworld/jw-10-2002/jw-1
  011-maven.html

46
Questions