Maven

Building and Managing
Projects with Maven

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

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).

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

Under the Hood
forehead classloader util launcher
maven core, jelly, werkz
Maven
pluginsjava jar war ejb
ear gump xdoclet javadoc
test
jalopy
cactus artifact xdoc
site junit etc…
ant

Architecture Overview
Build System
Local
Repo
Remote
Repo
maven
project.xml (pom)
maven.xml (goals) http
Site

Artifact Repository
The Most Important Feature
• Remote Repository
…
<dependencies>
<dependency>
<groupId>xalan</groupId>
<artifactId>xalan</artifactId>
<version>2.5.1</version>
<type>jar</type>
</dependency>
…
</dependencies>
…
${mave.repo.remote}/<groupId>/<type>s/<artifactId>-<version>.<type>
- repository
- […]
- xalan
- jars
- xalan-2.5.0.jar
- xalan-2.5.1.jar
- […]
- […]

Artifact Repository
• Local Repository
– A local mirror/cache of downloaded
artifacts from remote repositories.
– Located at $
{user.home}/.maven/repository
${mave.repo.local}/<groupId>/<type>s/<artifactId>-<version>.<type>

Implementing an Example
• Get Started
– Download from
• http://maven.apache.org/start/download.html
– Current version: 1.0rc1
– Environment setup
• export MAVEN_HOME=c:/maven-1.0rc1
• export PATH=“$MAVEN_HOME/bin;$PATH”
(or set MAVEN_HOME = c:maven-1.0rc1
set PATH = %MAVEN_HOME%bin;%PATH% )
– run install_repo.sh to populate the local
repository

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

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
– …

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
…

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

Project Object Model (POM)
• Project Dependency
– Libraries needed for build and runtime.
• Project Reports
– Junit reports
– Javadoc reports
– Checkstyle reports, ….etc

Project Management Section
<project>
<pomVersion>3</pomVersion>
<groupId>sampleservice</groupId>
<name>Sample Service</name> 
<id>sampleservice</id>
<currentVersion>1.0</currentVersion>

<organization>
<name>My, Inc.</name>
<url>http://www.myinc.com</url>
<logo>/images/logo.gif</logo>
</organization>
… (elements in bold are required)

<project>
[…]
<inceptionYear>2003</inceptionYear> 
<shortDescription>Demo to use maven</shortDescription> 

<description>
A detailed description about this demo
</description>
<url>http://www.myinc.com/sampleservice/</url>
<issueTrackingUrl/>
<siteAddress>dev.myinc.com</siteAddress> 
<siteDirectory>/www/sampleservice/</siteDirectory> 

<distributionSite>/www/dist/sampleservice</distributionSite>

<distributionDirectory>/www/www.myinc.com/somedir</distributionDirectory>

<project>
[…]
<repository>
<connection>scm:cvs:pserver:anoncvs@cvs.myinc.com:/cvsroot:samples
ervice</connection>
<developerConnection>scm:cvs:pserver:$
{maven.username}@cvs.myinc.com:/cvsroot:sampleservice</develop
erConnection>
<url>http://cvs.myinc.org/viewcvs/sampleservice/</url>
</repository>

<versions>
<version>
<id>1.0-beta-1</id>
<name>1.0-beta-1</name>
<tag>1.0-beta-1</tag>
</version>
</versions>
<branches/>
[…]
…
<mailingLists/>
<contributors/>
<developers/>
…

Project Dependency Section
<project>
[…]
<dependencies>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<properties>
<ear.bundle>true</ear.bundle>
<ejb.manifest.classpath>true</ejb.manifest.classpa
th>
</properties>
</dependency>
</dependencies>
[…]
Special Dependency:
SNAPSHOT

Dependency Classloader
[…]
<dependency>
<groupId>bcel</groupId>
<artifactId>bcel</artifactId>
<version>5.1</version>
<properties>
<classloader>root</classloader>
</properties>
</dependency>
[…]
Maven has three classloaders:
root -- ant classloader
root.maven – maven core classloader
default – plugin classloader

Dependency Override
project.xml
…
<dependency>
<groupId>weblogic</groupId>
<artifactId>weblogic</artifactId>
<properties>
<classloader>root</classloader>
</properties>
</dependency>
project.properties
…
## Dependency override
maven.jar.override = on
maven.jar.weblogic = ${weblogic.home}/lib/weblogic.jar
maven.jar.webservices = ${weblogic.home}/lib/webservices.jar

Project Build Section
Defines the location of source, test and resource files.
[…]
<build>
<nagEmailAddress>buildmaster@myinc.com</nagEmailAddress>
<sourceDirectory>${src.java.dir}</sourceDirectory>
<unitTestSourceDirectory>${src.test.dir}</unitTestSourceDirectory>
<aspectSourceDirectory/>
[…]
src/aspect
src/test
src/java

Project Build Section
<unitTest>
<includes>
<include>**/*Test.java</include>
</includes>
<resources/>
</unitTest>
<resources>
<resource>
<directory>${src.conf.dir}</directory>
<targetPath/>
<includes>
<include>**/*.properties</include>
</includes>
</resource>
</resources>
src/conf
prefix package name,
e.g. com.myinc.
sampleservice

Project Report Section
Defines various reports to be generated
<reports>
<report>maven-jdepend-plugin</report>
<report>maven-checkstyle-plugin</report>
<report>maven-changelog-plugin</report>
<report>maven-developer-activity-plugin</report>
<report>maven-file-activity-plugin</report>
<report>maven-javadoc-plugin</report>
<report>maven-jxr-plugin</report>
<report>maven-junit-report-plugin</report>
<report>maven-linkcheck-plugin</report>
<report>maven-tasklist-plugin</report>
</reports>

Project Report - Example
Jakarta Turbine

Project Report - XDoc
xdocs/navigation.xml
…
<menu name="General Information">
<item name="Overview" href="/index.html"/>
<item name="Features" href="/features.html"/>
<item name="Specification" href="/fsd.html"/>
<item name="Getting Started" href="/getting-started.html"/>
</menu>
xdocs/features.xml
<document>
<properties>
<title>Turbine Features</title>
<author email="">Jon S. Stevens</author>
</properties>
<body>
<section name="Features">
<p>This document is for bragging about all of Turbine's ….
…
</document>

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 –Dfoo=bar
The last definition wins
Sample build.properties:
…
bea.home=c:/bea81sp1
oracle.home=c:/oracle/ora9i

Build Process Design
Sample Service project components
Common data module
EJBs
Web Application
Data
(jar)
EJB
(jar)
Webapp
(war)
EAR

Subproject: service-data
sampleservice
–project.xml
–maven.xml
–application/
–service-data/
–project.xml
–maven.xml
–src/
–service-ejb/
–service-web/
–xdocs/
project.xml (POM)
<project>
<extend>../project.xml</extend>
<name>Sample Service Data
Module</name>
<id>sampleservice-data</id>
</project>
Note: POM can be inherited.

Subproject: service-data
sampleservice
–project.xml
–maven.xml
–application/
–service-data/
–project.xml
–maven.xml
–src/
–service-ejb/
–service-web/
–xdocs/
maven.xml (Goals)
<project default="build"
xmlns:j="jelly:core"
xmlns:maven="jelly:maven"
xmlns:ant="jelly:ant">
<goal name="build"
prereqs="jar:install"/>
</project>
Note: Goals can also be inherited
Make jar Local
Repo

Subproject: service-ejb
sampleservice
–project.xml
–maven.xml
–application/
–service-data/
–service-ejb/
–project.xml
–maven.xml
–src/
–service-web/
–xdocs/
project.xml (POM)
<project>
<name>Sample Service EJB</name>
<id>sampleservice-ejb</id>
<dependency>
<groupId>${pom.groupId}</groupId>
<artifactId>sampleservice-data</artifactId>
<version>${pom.currentVersion}</version>
<properties>
<ejb.manifest.classpath>true</ejb.manifest
.classpath>
</properties>
</dependency>
</project> Local
Repoxdoclet compile ws-gen ejb-jar

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)

Maven XDoclet Plugin - Properties
## EJBDoclet
maven.xdoclet.ejbdoclet.fileset.0.include=**/ejb/**/*Bean.java
maven.xdoclet.ejbdoclet.ejbSpec=2.0
maven.xdoclet.ejbdoclet.verbose=true
maven.xdoclet.ejbdoclet.session.0=false
maven.xdoclet.ejbdoclet.localhomeinterface.0=true
maven.xdoclet.ejbdoclet.localinterface.0=true
maven.xdoclet.ejbdoclet.utilobject.0=true
## EJBDoclet WebLogic Nested Element
maven.xdoclet.ejbdoclet.weblogic.0=true
maven.xdoclet.ejbdoclet.weblogic.0.mergeDir=${src.dir}/ejbdoclet
maven.xdoclet.ejbdoclet.weblogic.0.destDir=$
{maven.xdoclet.ejbdoclet.deploymentdescriptor.0.destDir}

Web Services
– Currently Maven has no container specific plugins
<goal name="wsgen" prereqs="wsgen.autotype, wsgen.source2wsdd"/>
<goal name="wsgen.autotype">
<taskdef name="autotype"
classname="weblogic.ant.taskdefs.webservices.javaschema.JavaSchema"/>
….
</goal>
<goal name=“wsgen.source2wsdd”>
…
</goal> project.properties
## Web Services
maven.webservice.javaComponents=
com.myinc.sampleservice.ejb.BasicAccountInquiry,
com.myinc.sampleservice.ejb.ExpandedAccountInquiry,
com.myinc.sampleservice.ejb.DetailedAccountInquiry
maven.webservice.autotype.package=com.myinc.sampleservice.autotype
maven.webservice.autotype.keepgenerated=false
Use tag:
@wlws

sampleservice
–project.xml
–maven.xml
–application/
–service-data/
–service-ejb/
–project.xml
–maven.xml
–src/
–service-web/
–xdocs/
Maven EJB Plugin
– Currently no container specific ejb-jar
<goal name="ejbjar" prereqs="java:compile">
<path id="ejb.classpath">
<pathelement location="${maven.build.dest}"/>
<path refid="maven.dependency.classpath"/>
</path>
<j:set var="maven.ejb.descriptordir"
value="${pom.getPluginContext('maven-xdoclet-plugin')
…./>
<ejbjar srcdir="${maven.build.dest}"
descriptordir="${maven.ejb.descriptordir}"
flatdestdir="true"
basejarname="${pom.artifactId}-${pom.currentVersion}">
<classpath refid="ejb.classpath"/>
<weblogic destdir="${maven.build.dir}“newCMP="true"
outputdir="${maven.build.dir}/ejb" rebuild="false"
ejbcclass="weblogic.ejbc"
</weblogic>
…

sampleservice
–project.xml
–maven.xml
–application/
–service-data/
–service-ejb/
–project.xml
–maven.xml
–src/
–service-web/
–xdocs/
Making the Final EJB Jar
<project default="build“>
<goal name="build" prereqs="ejb:install"/>
<preGoal name="java:compile">
<attainGoal name="xdoclet:ejbdoclet"/>
</preGoal>
<postGoal name="java:compile">
<attainGoal name="wsgen"/>
<attainGoal name="java:jar-resources"/>
</postGoal>
<preGoal name="ejb:ejb">
<attainGoal name="ejbjar"/>
</preGoal>
<postGoal name="ejb:install">
<artifact:install
artifact="${maven.build.dir}/${pom.artifactId}-${pom.currentVersion}.xml"
type="xml“ project="${pom}"/>
</postGoal>

Subproject: service-web
sampleservice
–project.xml
–maven.xml
–application/
–service-data/
–service-ejb/
–service-web/
–project.xml
–maven.xml
–src/
–xdocs/
project.xml (POM)
<project>
<name>Sample Service Web Application</name>
<id>sampleservice-web</id>
…
<dependency>
</dependency>
<dependency>
<artifactId>sampleservice-ejb</artifactId>
<type>ejb</type>
<properties>
<web-service>true</web-service>
</properties>
</dependency>
custom
property

Subproject: service-web
maven.xml (goals)
<project default=“build”>
<goal name="build" prereqs="war:install"/>
<preGoal name="war:war">
<j:forEach var="dep" items="${pom.dependencies}">
<j:if test="${dep.getProperty('web-service')=='true'}">
<util:file var="xmlFile"
name="${maven.repo.local}/${dep.groupId}/xmls/${dep.artifactId}-
${dep.version}.xml"/>
<j:if test="${xmlFile.exists()}">
<x:parse var="xml" xml="${xmlFile}"/>
<x:forEach var="node" select="$xml/*/*">
<j:set var="temp" value="${root.add(node.detach())}"/>
</x:forEach>
</j:if>
</j:if>
</j:forEach>
<j:if test="${!root.elements().isEmpty()}">
<!– output the “web-services.xml” -->
</j:if>
</preGoal>
preGoal is
used to generate
web services DD
file if defined

Subproject: application
sampleservice
–project.xml
–maven.xml
–application/
–project.xml
–maven.xml
–src/
–service-data/
–service-ejb/
–service-web/
–xdocs/
EAR Packaging
<project>
<name>Sample Service Application</name>
<id>sampleservice</id>

<dependency> <groupId>$
{pom.groupId}</groupId>
<type>jar</type>
<properties>
</properties>
</dependency>

<dependency>
<artifactId>sampleservice-ejb</artifactId>
<type>ejb</type>
<properties>
</properties>
</dependency>

<dependency>
<artifactId>sampleservice-web</artifactId>
<type>war</type>
<properties>
<ear.appxml.war.context-root>
/${pom.artifactId}
</ear.appxml.war.context-root>
</properties>
</dependency>

Subproject: application
sampleservice
–project.xml
–maven.xml
–application/
–project.xml
–maven.xml
–src/
–service-data/
–service-ejb/
–service-web/
–xdocs/
EAR Packaging
<project default=“build”>
<goal name="build" prereqs="ear"/>
<preGoal name="ear:generate-ear-descriptor">
<mkdir dir="${maven.ear.appxml.dir}"/>
</preGoal>
</project>
project.properties
…
## Ear related
maven.ear.appxml.dir = ${maven.build.dir}/application/META-INF
maven.ear.appxml = ${maven.ear.appxml.dir}/application.xml
maven.ear.appxml.generate = true
Tip: container specific DD files can be stored at src/application/META-INF

Putting It Together: Reactor
<goal name="build">
<maven:reactor
basedir="${basedir}"
postProcessing="true"
includes="*/project.xml"
excludes=""
goals="build"
banner="Building"
ignoreFailures="false"/>
</goal>
…
sampleservice
–project.xml
–maven.xml
–application/
–service-data/
–service-ejb/
–service-web/
–xdocs/
<project default=“build”
xmlns:j="jelly:core"
xmlns:maven="jelly:maven"
xmlns:ant="jelly:ant">
….

Putting It Together: Reactor
/c/dev/sampleservice/>maven
__ __
| / |__ _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:
java:prepare-filesystem:
[mkdir] Created dir: C:devsampleserviceservice-datatargetclasses
java:compile:
….

Customizing Maven
• Override plugin properties in
– project.properties
– build.properties
• Use maven.xml
– Override plugin goals
– Intercept plugin goals with <preGoal/>
and <postGoal/>
• Write you own plugin
– In Java, Jelly, or other scripting language.

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

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.

Get More
• http://maven.apache.org
• http://www.onjava.com/pub/a/onjava/2003/10/22/maven.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?
l=MavenMagic
• http://blogs.codehaus.org/people/vmassol/archives/000080.ht
ml
• http://www.javaworld.com/javaworld/jw-10-2002/jw-1011-
maven.html

Maven

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