1. Maven 2
The Maven Apache

2. ... and anything else you'd like to know about
Overview
What's new in Maven 2.0
Maven 2.0 and Ant
... and anything else you'd like to know about

3. Is a complete rewrite from Maven 1.0/1.1
Scheduled for beta testing in July, final release in August
Built around reusable libraries:
Artifact code used in Ant tasks
Wagon, SCM and project loading being used in Maven 1.1

4. More consistent definition of all parts of the system
Why rewrite Maven for 2.0?
Started parallel development in early 2003, well before Maven 1.0 final!
More consistent definition of all parts of the system
Architecture supports features and that the original couldn't
Faster, lighter, smaller - embeddable
Making it simpler to use required reworking many core concepts

5. Maven 2.0 Architecture

6. Maven 2.0 Architecture - Plexus
Based on Plexus – an IoC container supporting component oriented programming (COP) encouraging a clear Separation of Concerns (SoC)
Plugins are handled as Plexus components though plugins have no direct dependency on Plexus

7. Maven 2.0 Component Architecture

8. Maven 2.0 New Features (alpha-3)
Enhanced dependency support
Build life cycle
Unified project file
Enhanced plug-in support
Multi-module project support
Site and documentation enhancements
Release management
Archetypes - project templates
Build Profiles

9. Main hurdle is non-redistributable artifacts – manual installation
Adding Dependencies
Declaration will download it, add it to the classpaths, bundle it into the resulting distribution if appropriate, etc.
Main hurdle is non-redistributable artifacts – manual installation
Now transitive – dependencies of dependencies
Added transitiviity
<dependencies>
<dependency>
<groupId>org.apache.maven.wagon</groupId>
<artifactId>wagon-provider-api</artifactId>
<version>1.0-alpha-3</version>
</dependency>
</dependencies>

10. Transitive Dependencies
Always enabled in Maven 2.0
Don't need to declare dependencies of dependencies yourself
Frequently requested, but has more consequences than often realised...
Version conflicts
Unwanted dependencies
Bad published meta data – report at
Not a hard problem with good data

11. compile (default), runtime, test, provided
Dependency Scope
compile (default), runtime, test, provided
Control classpath and distribution bundling
Helpful for transitive dependencies (don't get test transitively)
Only need to specify one – others may be implied

12. Controlling Transitive Dependencies
Filter out dependencies
Preferably dependency would be split into isolated pieces, with one POM to aggregate back if needed
E.g. Velocity “depends” on JDBC, but only in some conditions
<dependency>
<groupId>org.apache.maven.wagon</groupId>
<artifactId>wagon-provider-api</artifactId>
<version>1.0-alpha-3</version>
<exclusions>
<exclusion>
<groupId>jdbc</groupId>
<artifactId>jdbc</artifactId>
</exclusion>
</exclusions>
</dependency>

13. Don’t need to update dependency version to get updated builds
Snapshot Handling
Deploying to a shared repository gives a version with a time stamp and build #
Don’t need to update dependency version to get updated builds
Updates daily, on-demand, or at a particular interval
Developers can get access to co- workers changes earlier without the need to update and build

14. Builds in Maven follow a pattern
Build Life cycle
Builds in Maven follow a pattern
Ensures developers moving between projects do not need to learn new processes

15. Plugins can augment the build life cycle For example:
JAXB could register an XSD to Java goal in generate-sources, then add it to the compilation list
Xdoclet could register a goal to create a Hibernate mapping in process-resources.
The builder still only needs to know to use m2 package
Replaces use of preGoal from Maven 1

16. Unified Project File
Self contained, and no file system references making it usable from the repository
project.properties and maven.xml replaced by custom plugins and configuration
parent element replaces extend
<parent>
<groupId>org.apache.maven</groupId>
<artifactId>maven</artifactId>
</parent>

17. Configure how your project is built
Configuring Plugins
Configure how your project is built
In Maven 1, project.properties file
Example: compile with JDK 5.0 options
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.5</source>
<target>1.5</target>
</configuration>
</plugin>
</plugins>
</build>

18. Plugins can be requested on-demand from the command line
On-demand Features
Plugins can be requested on-demand from the command line
In Maven 1, this required manual installation
For example, idea:idea will generate an IDEA project file without modifications to your project

19. Plugin Version Discovery
Can opt not to declare a plugin version in your project
Will regularly check for a new release, and download it if desired
Users can opt to get prompted for new releases of plugins
Release tool will record the active version for reproducible builds

20. Java, Beanshell, Marmalade Java is the most common
Plugin Languages
Java, Beanshell, Marmalade
Java is the most common
Beanshell is new, useful for rapid prototyping
Marmalade is primarily to ease porting of Jelly-based plugins, and to make available Ant tasks in an XML syntax
Can support others with a small amount of work if there is demand
For example: Jython, Groovy, JRuby

21. Java Plugin import org.apache.maven.plugin.AbstractMojo;
import org.apache.maven.plugin.MojoExecutionException;
...
/**
* Goal which cleans the build.
touch
process-sources */
public class CoreItMojo extends AbstractMojo {
expression="${project.build.directory}"
* @required
private File outputDirectory;
/** Whether it is enabled.
private boolean enabled;
public void execute() throws MojoExecutionException {
if ( enabled )
getLog().info( “Path is ” + outputDirectory ); }

22. Beanshell Plugin /** * Beanshell mojo integration test. * @goal it0020*/
import org.apache.maven.plugin.Mojo;
import org.apache.maven.script.beanshell.BeanshellMojoAdapter;
import org.codehaus.plexus.util.FileUtils;
execute() {
logger.info( "Executing it " );
print( "info level?" );
FileUtils.fileWrite( outDir.getAbsolutePath() + "/out.txt",
"This is a Beanshell test" ); }
* Output directory for files. *
expression="${project.build.directory}" type="java.io.File"
setOutDir( file )
outDir = file;
return new BeanshellMojoAdapter( (Mojo) this, this.interpreter );

23. Marmalade <mojo xmlns="marmalade:mojo"> <metadata>
<goal>it0015</goal>
<description>
Output a file with specified contents to [outDir]
</description>
<parameters>
<parameter>
<name>outDir</name>
<type>java.lang.String</type>
<expression>${project.build.directory}</expression>
<description>Output directory for files.</description>
</parameter>
</parameters>
</metadata>
<execute>
<it0015:writeFile
xmlns:it0015="marmalade:it0015"
path="${outDir}/out.txt">
This is a test.
</it0015:writeFile>
</execute>
</mojo>

24. Maven 2 natively deals with multi- module builds
Multiple Modules
Maven 2 natively deals with multi- module builds
A module refers to another project in the build tree
Goals are performed on all found modules by default, so m2 install will perform an install for all found modules
Modules can in turn have modules
<modules>
<module>wagon-provider-api</module>
<module>wagon-providers</module>
</module>

25. Site and Documentation
A lot faster than previously
Accepts several input formats
Almost Plain Text (Wiki like)
Xdoc (Maven 1.0 compatible)
FAQ (Maven 1.0 compatible)
Docbook
Presently outputs XHTML, Xdoc, Docbook, Latex and RTF
PDF also planned

26. Example APT Document ------ Generating a Site Brett Porter 13 May 2005
Building a Site
* Creating Content
The first step to creating your site is to create some content. In
Maven 2.0, the site content is separated by format, as there are several
available.
+- src/
+- site/
+- apt/
| +- index.apt
+- site.xml
The Xdoc format is the same as
{{{ used in Maven 1.0}}.
However, <<<navigation.xml>>> has been replaced by the site descriptor
(see below).

27. Example APT Document

28. Improvement on the tasks from the SCM plugin in Maven 1.0
Release Assistance
Improvement on the tasks from the SCM plugin in Maven 1.0
Resolves information in the project to make the release reproducible
Updates the version information, commits and tags a release
Does a clean checkout and builds the release
Can be in the same environment, or a dedicated known build environment

29. Generates a template project for you Currently archetypes for:
Project Archetypes
m2 archetype:create
Generates a template project for you
Currently archetypes for:
JAR/WAR
Site
Java and Marmalade Plugins
Can easily create your own archetypes
Uses Velocity
Downloaded from the repository so they are easily shared

30. Change the build depending on the environment
Build Profiles
Change the build depending on the environment
Dependencies, repositories, plugins and configuration
Trigger by operating system, JDK, extistence of software, and so on, as well as command line parameter
Per user or per project
Used to set up standard environments:
Development, Test, QA and Production

31. Maven 2.0 Features Coming (July)
More on dependency mediation
Other languages (maybe beyond 2.0)

32. Allows specification of a range of versions for a dependency
Dependency Mediation
Allows specification of a range of versions for a dependency
Maven will help resolve the best version available
Techniques for handling conflicts
Fail, Newest, Nearest
Release tool fills in versions later
<dependency>
<groupId>jaxb</groupId>
<artifactId>jaxb-api</artifactId>
<version>[1.0.1,)</version>
</dependency>

33. Support for Other Languages
Being implemented as plugins
Currently have seen work on a C# compiler, and plan to support C/C++ environments on Unix and Windows
May not be available at Maven 2.0 final release

34. Moving from Ant to Maven 2
Identify sections of build.xml that are standard functionality
Build Maven 2 projects from scratch
Use m2 ant:ant to generate and use from master Ant script
Create Maven plugins for custom functionality, wrap them as Ant tasks
If Ant already works fine for you, you can still use some Maven features from Ant 1.6 today

35. Currently exposes the dependency and artifact handling as Ant tasks
Using Maven 2 From Ant
Currently exposes the dependency and artifact handling as Ant tasks
Ant 1.7 will utilise the artifact antlib for dependency management
Download dependencies (all features)
Share a local Maven repository
Install and deploy artifacts to a repository
Expose a POM as Ant properties

36. The Artifact Antlib
<project ... xmlns:artifact="antlib:org.apache.maven.artifact.ant">
<target name="...">
<artifact:localRepository id="local.repository"
location="${basedir}/target/local-repo" />
<artifact:dependencies
pathId="dependency.classpath" filesetId="dependency.fileset">
<dependency groupId="org.apache.maven.wagon"
artifactId="wagon-provider-test" version="1.0-alpha-2"/>
<dependency groupId="org.codehaus.modello"
artifactId="modello-core" version="1.0-alpha-2-SNAPSHOT"/>
<localRepository refid="local.repository"/>
</artifact:dependencies>
<!-- Can reuse POM -->
<artifact:pom id=“maven.project” file=“pom.xml”/>
<artifact:dependencies filesetId=“pom.dependencies”>
<pom refid=“maven.project”/>
<!-- Access to POM as properties -->
<echo>Now building ${maven.project.name}</echo>
...

37. The Artifact Antlib
...
<artifact:remoteRepository id="deploy.repository"
url="file://${basedir}/target/deployment-repo" layout="legacy"/>
<artifact:install file="target/maven-artifact-ant-2.0-SNAPSHOT.jar">
<localRepository refid="local.repository"/>
<pom refid="maven.project"/>
</artifact:install>
<artifact:deploy file="target/maven-artifact-ant-2.0-SNAPSHOT.jar">
<remoteRepository url="scp://localhost/tmp/deployment-repo">
<authentication username="brett"
privateKey="${user.home}/.ssh/id_dsa"/>
</remoteRepository>
</artifact:deploy>

38. Maven has project generation for several IDEs for one way creation
Maven and the IDE
MevenIDE project
Started out with NetBeans, Eclipse
Relatively new Jbuilder and IDEA plugins
Shared base code
Changes reflect in project and IDE
Planning support for embedded Maven 2 and remote Continuum
Independent of the Maven project
Maven has project generation for several IDEs for one way creation

39. Maven site and lists Maven Blogs Resources http://maven.apache.org/

40. Getting Involved
As with any open source project, there are several ways you can get involved
Join the mailing list and answer other user's questions
Report bugs, feature requests and other issues in the issue tracking application.
Submit patches to reported issues (both those you find, or that others have filed)

41. Questions?
Thanks for listening!