This document provides an overview of advanced topics in Apache Maven 2, including working with multi-module projects, Maven inheritance and aggregation, profiles, properties, plugins, and configuring a Nexus repository. It discusses how Maven can be used to build projects with multiple modules and dependencies by defining a parent pom that inherits common configuration and defines child modules. It also describes features like profiles, properties, and plugins that add flexibility and customization to Maven builds. Finally, it provides guidance on configuring a Nexus repository for artifact storage and management.

1. Apache Maven 2 Overview
Part 2
Advanced Topics of Apache Maven 2
Anatoly Kondratyev
September 2012
30 January 2013
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2. The Goal
• Understand several Maven capabilities
• Build multi-module project with Maven
• Some special pom blocks
• Nexus configuration notes
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3. Maven in real world
WORKING WITH MULTI-MODULE
PROJECTS
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4. Project contents
GWT
application
EJB A EJB B
My Library
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5. What to do with Maven?
• 4 independent artifacts with dependencies
• Build in one step?
• Organize versioning?
• Keeping up to date?
• Wrong!
• Maven Inheritance and Aggregation
• Solves the above problems
• Right!
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6. Maven Inheritance & Aggregation
• <packaging>pom</packaging>
• Super pom
• Data in parent pom is inherited
• Maven dependency reactor
• Notes
• No cyclic dependencies
• No same modules
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7. Maven Inheritance & Aggregation
Parent
pom
EJB A EJB B Gwt My library
ejb ejb war jar
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8. Maven in action
<project …>
<modelVersion>4.0.0</modelVersion>
<groupId>ru.exigenservices</groupId>
<artifactId>my-parent</artifactId>
<version>1.0.1-SNAPSHOT</version>
<packaging>pom</packaging>
<modules>
<module>EJB-A</module>
<module>EJB-B</module>
<module>Gwt</module>
<module>MyLibrary</module>
</modules>
</project>
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9. Maven in action
• What about deployment?
• EAR needed
• Special step needed
• Maybe divide frontend and backend?
• NB! One pom – one artifact
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10. Maven in action
Parent
pom
Frontend Backend
pom pom
Frontend Backend
Gwt EJB A EJB B My library
wrapper wrapper jar
war ear ejb ejb ear
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11. Multimodal hierarchy
• Parent pom
<project …>
<groupId>exigen</groupId>
<artifactId>parent</artifactId>
<version>1.0.1-SNAPSHOT</version>
<packaging>pom</packaging>
<modules>
<module>backend</module>
<module>frontend</module>
</modules>
</project>
• Frontend pom
<project …>
<parent>
<groupId>exigen</groupId>
<artifactId>parent</artifactId>
<version>1.0.1-SNAPSHOT</version>
</parent>
<artifactId>frontend</artifactId>
<packaging>pom</packaging>
<modules>
<module>Gwt</module>
</modules>
</project>
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12. Dependency&Plugin management
• Changeable, overriddable and inheritable
• In parent
• GroupId & ArtifactId
• Version
• Everything you can configure
• Type, packaging
• In child
• GroupId & ArtifactId
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13. Dependency&Plugin Management
Parent:
<dependencyManagement>
<dependencies>
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-api</artifactId>
<version>6.0</version>
<scope>provided</scope>
</dependency>
</dependencies>
</dependencyManagement>
Child:
<dependencies>
<dependency>
<groupId>javax</groupId>
<artifactId>javaee-api</artifactId>
</dependency>
</dependencies>
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14. Flat vs Tree, Flat
.
|-- my-module
| `-- pom.xml
`--parent
`--pom.xml
• Pom.xml for my-module:
<project>
<parent>
<groupId>com.mycompany.app</groupId>
<artifactId>my-app</artifactId>
<version>1</version>
<relativePath>.../parent/pom.xml</relativePath>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>my-module</artifactId>
</project>
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15. Maven reactor
• Collects all the available modules to build
• Sorts the projects into the correct build order
• a project dependency on another module in the build
• different rules with plugins dependencies
• the order declared in the <modules> element (if no other rule
applies)
• Builds the selected projects in order
• Be aware of cycles and same modules on different
parents
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16. Conclusion
• Inheritance and aggregation
• Flat/Tree structure
• Maven reactor
• Dependency&Plugin management
• Deploy to Nexus/Weblogic problem
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17. What will help you
PROPERTIES, PROFILES,
EXECUTION BLOCKS
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18. Maven properties
• Just as common Ant properties
• ${property_name}
• Case sensitive
• Upper case for environment variables
• Dot(.) notated path
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19. Predefined properties
• Build in properties
• ${basedir} – directory with pom
• ${version} – artifact version
• Project properties
• ${project.build.directory}
• ${project.build.outputDirectory} (target/classes)
• ${project.name}
• ${project.version}
• Local user settings
• ${settings.localRepository}
• Environment properties
• ${env.M2_HOME}
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20. Maven profiles
• Maven profile – special way for configuring
build
• Different environments – different results
• Renaming
• Different build cycles
• Special plugin configuration
• Just different targets
• For different users
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21. Maven profiles
• Per project
• pom.xml
• Per user
• %USER_HOME%/.m2/settings.xml
• Per computer (Global)
• %M2_HOME%/conf/settings.xml
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22. Maven profiles
• Activation
• By hand (-P profile1,profile2)
• <activeProfiles>
• <activation>
• By environment settings
• By properties
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23. Maven profiles
<profiles>
<profile>
<activation>
<jdk>[1.3,1.6)</jdk>
</activation>
...
</profile>
<profile>
<activation>
<property>
<name>environment</name>
<value>test</value>
</property>
</activation>
...
</profile>
</profiles>
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24. Mojo
• Plugin
• Executing action
• Mojo – magical charm in hoodoo
• Just a Goal
• Plugin consists of Mojos
• Some parameters
• MOJO aka POJO (Plain-old-Java-object)
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25. Mojo
• When we should use mojos?
• Run from command line
• Different execution parameters for different
configurations
• Group of mojos from same plugin with
different configuration
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26. Execution blocks
Plugin:time
<plugin>
<groupId>com.mycompany.example</groupId>
<artifactId>plugin</artifactId>
<version>1.0</version>
<executions>
<execution>
<id>first</id>
<phase>test</phase>
<goals>
<goal>time</goal>
</goals>
<configuration> … </configuration>
</execution>
<execution>
<id>default</id>
…
<!– No phase block -->
</execution>
</executions>
</plugin>
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27. SCM SourceCodeManagement
• CVS, Mercurial, Perforce, Subversion, etc.
• Commit/update
• scm:bootstrap – build project
• Maven Release Plugin
• Snapshot  Version
• Check everything
• Commit
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28. Maven archetypes
• Create folders, poms, general stuff
• Archetype  Project
• For creating project:
• archetype:generate
• Select archetype from list
• Set up groupId, artifactId, version, …
• Get all project structure and draft files
• maven-archetype-quickstart
• For creating archetype:
• archetype:create-from-project
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29. Provided Arhetypes
• maven-archetype-archetype
• Sample archetype
• maven-archetype-j2ee-simple
• Simplified sample J2EE application
• maven-archetype-plugin
• Sample Maven plugin
• maven-archetype-quickstart
• Sample Maven project
• maven-archetype-webapp
• Sample Maven Webapp project
• More information:
http://maven.apache.org/archetype/maven-archetype-bundles/
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30. archetype:create-from-project
• Sample project
• mvn archetype:create-from-project
• src catalog
• Pom.xml (maven-archetype)
• Some resources
• Modify code (…targetgenerated-sourcesarchetype)
• archetype-metadata.xml
• Update properties and default values; review
• Go to target, run “mvn install”
• To test archetype
“mvn archetype:generate -DarchetypeCatalog=local”
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31. Good configuration - great advantage
NEXUS
SETTING.XML
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32. Sonatype Nexus
• Artifact repository
• Nexus and Nexus Pro
• Rather simple
• Widely used
• Other Maven Repository Managers
• Apache Archiva
• Artifactory
• Comparison
http://docs.codehaus.org/display/MAVENUSER/Maven+Repository+Manager+Fe
ature+Matrix
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33. Nexus hints
• Nexus configuration + local configuration
• Proxy repositories
• Add everything and cache it!
• Add to Public Repositories group
• Restrictions on uploading artifacts
• UI: Artifact Upload
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34. Settings.xml
• Servers • Profile
<servers>
<profiles>
<server>
<profile>
<id>nexus</id>
<id>nexus</id>
<username>…</username>
<repositories>
<password>…</password>
<repository>
</server>
<id>central</id>
</servers>
<url>http://central</url>
• Mirrors (2.0.9) <releases>
<mirrors> <enabled>true</enabled>
<mirror> <updatePolicy>never</updatePolicy>
<id>nexus</id> </releases>
<mirrorOf>*</mirrorOf> <snapshots>
<url>http://localserver:8081/nexus/content/groups/public/ <enabled>true</enabled>
</url> </snapshots>
</mirror> </repository>
</mirrors> </repositories>
• Active Profile <pluginRepositories>
<activeProfiles> …
</pluginRepositories>
<activeProfile>nexus</activeProfile>
</profile>
</activeProfiles>
</profiles>
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35. updatePolicy
• UpdatePolicy
• Always
• Daily (default)
• Interval:X (X – integer in minutes)
• Never
• Repository Snapshots
• Enabled true/false
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36. When you have free time…
LICENSE, ORGANIZATION, DEVELOPER
S, CONTRIBUTORS
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37. Licenses
• How your project could be used?
<licenses>
<license>
<name>The Apache Software License, Version 2.0</name>
<url>http://www.apache.org/licenses/LICENSE-2.0.txt</url>
<distribution>repo</distribution>
<comments>A business-friendly OSS license</comments>
</license>
</licenses>
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38. Organization
• Just tell everybody!
<organization>
<name>Exigen Services</name>
<url>http://www.exigenservices.ru/</url>
</organization>
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39. Developers & Contributors block
• Id, name, email
• Organization, organizationUrl
• Roles
• Timezone
• Properties
• Contributors don’t have Id
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40. Developers block
<developers>
<developer>
<id>anatoly.k</id>
<name>Anatoly</name>
<email>Anatoly.Kondratiev@exigenservices.com</email>
<organization>Exigen</organization>
<organizationUrl>http://www.exigenservices.ru/</organizationUrl>
<roles>
<role>Configuration Manager</role>
<role>Developer</role>
</roles>
<timezone>+3</timezone>
<properties>
<skype>anatoly.kondratyev</skype>
</properties>
</developer>
</developers>
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41. Final notes
• A great amount of plugins
• Ant-run
• Mirrors on local repo, not on computer
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42. Now it’s your turn…
QUESTIONS
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