• Things maven needs are downloaded JIT
  • Plugins
  • Dependencies for projects
  • …
• From remote repositories on the 'net
• Cached in a local repository
  • ~/.m2/repository/

Remote Repositories

• Many repositories
  • Central repository
    • Under control of the maven team
    • Contains all known Java artifacts that they are allowed to distribute
      • Could not be served by Apache because of Apache license politics
    • http://www.ibiblio.org/maven2/
    • Mirrors
      • http://mirrors.dotsrc.org/maven2/
      • http://public.planetmirror.com/pub/maven2/
    • ibiblio is constantly under strain (servers, bandwith)
      • Mirrors are not really fast either
      • Request not to rsync central
      • Special maven-proxy exists
  • 3th party repositories
    • Some providers choose to distribute their artifacts themselves
  • Company-local repositories
    • Own artifacts
    • Private artifacts (access protection)
    • Missing artifacts
      • License issues (access protection)
      • Obscure artifacts
      • Solution to artifact naming problems
• Repositories can be accessed via any protocol supported by Wagon
  • HTTP, HTTPS, FTP, SFTP, SCP, WebDAV, …
    • In principle …
    • HTTP and HTTPS validated by the author
      • HTTPS issue: self-signed certificates
      • Can be configure to do authentification
• Our artifacts are also deployed to remote repositories for others to use
  • Private company release repository
    • Seperate snapshot repository: don't annoy other people with development versions
  • Public company release repository
  • Central repository

Typical setup

In practice, at PeopleWare

Project Server Layout

/

|-- ppw/
|    |-- projects/

|    |   |-- dgt/

|    |   |   |-- cvs_repository/

|    |   |   |   |-- CVSROOT/...

|    |   |   |   |-- OSMOT/...
|    |   |   |   |-- OSMOT2/...
|    |   |   |   |-- expertPoll/...
|    |   |   |   `-- expertPollWebapp/...

|    |   |   |-- public_html/

|    |   |   |   |-- .htaccess

|    |   |   |   |-- index.html
|    |   |   |   |-- installation.html
|    |   |   |   |-- contact.html
|    |   |   |   .
|    |   |   |   .
|    |   |   |   .

|    |   |   |   |-- developer/
|    |   |   |   |   |-- OSMOT/...
|    |   |   |   |   |-- OSMOT2/..
|    |   |   |   |   |-- expertPoll/...
|    |   |   |   |   `-- expertPollWebapp/...

|    |   |   |   `-- maven_repository/
|    |   |   |       `-- be/
|    |   |   |           `-- peopleware/
|    |   |   |               `-- dgt/
|    |   |   |                   |-- OSMOT/
|    |   |   |                   |   |-- 1.0.0/...
|    |   |   |                   |   .
|    |   |   |                   |   .
|    |   |   |                   |   .
|    |   |   |                   |
|    |   |   |                   |-- OSMOT2/...
|    |   |   |                   |-- expertPoll/...
|    |   |   |                   `-- expertPollWebapp/...

|    |   |   `-- share/
|    |   |       |-- public/...

|    |   .       .
|    |   .       .
|    |   .       .
.    |
.    |-- sysadmin/...
.    `-- training/...

• un*x group per client

Configuring Which Repositories to Use

• Most often project-related
  • All developers for a project need same setup
  • Project dependent settings go in pom.xml
• Authentification depends on particular user
  • Access settings (username, password) go in ~/.m2/settings.xml <servers />-element
• Setting up Multiple Repositories

Configuring Mirrors

• Depends on particular user
  • User-dependent settings go in ~/.m2/settings.xml <mirrors />-element
• Using Mirrors for Repositories

Configuring HTTP Proxies

• Depends on particular user
  • User-dependent settings go in ~/.m2/settings.xml <proxies />-element
• Configuring a proxy

Repository Layout

• Directory structure based on groupId
  • s/\./\//
  • Like Java package structure
  • Suggestion to use reverse domain name of issuing entity as part of groupId
    • Like Java package names
  • E.g., groupId=be.peopleware.training.maven2
    • be/peopleware/training/maven2/
• artifactId
  • be/peopleware/training/maven2/helloWorld/
• version
  • be/peopleware/training/maven2/helloWorld/1.2.3/
• Everything for this artifact/version in this directory
  • Artifact
    • be/peopleware/training/maven2/helloWorld/1.2.3/helloWorld-1.2.3.jar
  • Consolidated POM
    • be/peopleware/training/maven2/helloWorld/1.2.3/pom.xml
  • Potentially other assemblies
    • E.g., source zip
  • Checksums for each file
    • MD5
• Have a look at central

Abberations

Maven 1 legacy

• Directory structure based on groupId is new since maven 2
• To be backward compatible, old maven 1 structure is kept too
  • E.g., Apache Jakarta Commons
    • groupId=commons-XXX
    • groupId=org.apache.… ???
  • E.g., Hibernate
    • groupId=hibernate (Hibernate 1-3)
    • groupId=net.sf.hibernate (Hibernate 1-2)
    • groupId=org.hibernate (Hibernate 3)
• Migration is in progress

Standard Sun Specification API's

• Package javax.…
• Naming convention
  • Legacy issues
• Some cannot be stored in public repository because of licensing issues
  • Only POM in central
  • Says where to download artifact
  • E.g., javax.mail

    • […]
        <distributionManagement>
          <downloadUrl>http://java.sun.com/products/javamail/downloads/index.html</downloadUrl>
        </distributionManagement>
      […]
      

• Company missing-artifacts repository
  • Download artifact from given location
  • Install in company missing-artifacts repository, with POM, checksum

Local Installation

Try-out You're Own Stuff Locally First

• Run mvn install
  • Last-but-one phase in default build lifecycle
• Artifact is added correctly to local repository
  • With POM
  • With checksum

Solve Repository Problems

• Install artifacts in his local repository directly
• Do it by hand, or
• maven-install-plugin:install-file

  • mvn install:install-file -DgroupId=group-id \
                             -DartifactId=artifact-id \
                             -Dversion=version \
                             -Dpackaging=packaging \
                             -Dfile=fileToInstall
    

  • Copies the fileToInstall into the local repository, in the directory structure based on group-id, with file name artifcact-id-version.packaging
• You should provide a POM and checksum too (by hand for now)
• Bad practice in a group effort
  • The problem you are having, other people will encounter too
  • Better do it in a company repository from the start

This work is licensed under a Creative Commons Attribution 2.0 Belgium License.

Jan Dockx PeopleWare n.v., © 2005