A.3. Mvn URL Handler

Overview

If you use Maven to build your bundles or if you know that a particular bundle is available from a Maven repository, you can use the Mvn handler scheme to locate the bundle.
Note
To ensure that the Mvn URL handler can find local and remote Maven artifacts, you might find it necessary to customize the Mvn URL handler configuration. For details, see the section called “Configuring the Mvn URL handler”.

Syntax

An Mvn URL has the following syntax:
mvn:[repositoryUrl!]groupId/artifactId[/[version][/[packaging][/[classifier]]]]
Where repositoryUrl optionally specifies the URL of a Maven repository. The groupId, artifactId, version, packaging, and classifier are the standard Maven coordinates for locating Maven artifacts (see the section called “Maven coordinates”).

Omitting coordinates

When specifying an Mvn URL, only the groupId and the artifactId coordinates are required. The following examples reference a Maven bundle with the groupId, org.fusesource.example, and with the artifactId, bundle-demo:
mvn:org.fusesource.example/bundle-demo
mvn:org.fusesource.example/bundle-demo/1.1
When the version is omitted, as in the first example, it defaults to LATEST, which resolves to the latest version based on the available Maven metadata.
In order to specify a classifier value without specifying a packaging or a version value, it is permissible to leave gaps in the Mvn URL. Likewise, if you want to specify a packaging value without a version value. For example:
mvn:groupId/artifactId///classifier
mvn:groupId/artifactId/version//classifier
mvn:groupId/artifactId//packaging/classifier
mvn:groupId/artifactId//packaging

Specifying a version range

When specifying the version value in an Mvn URL, you can specify a version range (using standard Maven version range syntax) in place of a simple version number. You use square brackets—[ and ]—to denote inclusive ranges and parentheses—( and )—to denote exclusive ranges. For example, the range, [1.0.4,2.0), matches any version, v, that satisfies 1.0.4 <= v < 2.0. You can use this version range in an Mvn URL as follows:
mvn:org.fusesource.example/bundle-demo/[1.0.4,2.0)

Configuring the Mvn URL handler

Before using Mvn URLs for the first time, you might need to customize the Mvn URL handler settings, as follows:

Check the Mvn URL settings

The Mvn URL handler resolves a reference to a local Maven repository and maintains a list of remote Maven repositories. When resolving an Mvn URL, the handler searches first the local repository and then the remote repositories in order to locate the specified Maven artifiact. If there is a problem with resolving an Mvn URL, the first thing you should do is to check the handler settings to see which local repository and remote repositories it is using to resolve URLs.
To check the Mvn URL settings, enter the following commands at the console:
JBossFuse:karaf@root> config:edit org.ops4j.pax.url.mvn
JBossFuse:karaf@root> config:proplist
The config:edit command switches the focus of the config utility to the properties belonging to the org.ops4j.pax.url.mvn persistent ID. The config:proplist command outputs all of the property settings for the current persistent ID. With the focus on org.ops4j.pax.url.mvn, you should see a listing similar to the following:
   org.ops4j.pax.url.mvn.localRepository = file:E:/Data/.m2/repository
   service.pid = org.ops4j.pax.url.mvn
   org.ops4j.pax.url.mvn.defaultRepositories = file:E:/Programs/FUSE/apache-serv
icemix-4.2.0-fuse-SNAPSHOT/system@snapshots
   felix.fileinstall.filename = org.ops4j.pax.url.mvn.cfg
   org.ops4j.pax.url.mvn.repositories = http://repo1.maven.org/maven2, http://re
po.fusesource.com/maven2, http://repo.fusesource.com/maven2-snapshot@snapshots@n
oreleases, http://repository.apache.org/content/groups/snapshots-group@snapshots
@noreleases, http://repository.ops4j.org/maven2, http://svn.apache.org/repos/asf
/servicemix/m2-repo, http://repository.springsource.com/maven/bundles/release, h
ttp://repository.springsource.com/maven/bundles/external
Where the localRepository setting shows the local repository location currently used by the handler and the repositories setting shows the remote repository list currently used by the handler.

Edit the configuration file

To customize the property settings for the Mvn URL handler, edit the following configuration file:
InstallDir/etc/org.ops4j.pax.url.mvn.cfg
The settings in this file enable you to specify explicitly the location of the local Maven repository, remove Maven repositories, Maven proxy server settings, and more. Please see the comments in the configuration file for more details about these settings.

Customize the location of the local repository

In particular, if your local Maven repository is in a non-default location, you might find it necessary to configure it explicitly in order to access Maven artifacts that you build locally. In your org.ops4j.pax.url.mvn.cfg configuration file, uncomment the org.ops4j.pax.url.mvn.localRepository property and set it to the location of your local Maven repository. For example:
# Path to the local maven repository which is used to avoid downloading
# artifacts when they already exist locally.
# The value of this property will be extracted from the settings.xml file
# above, or defaulted to:
#     System.getProperty( "user.home" ) + "/.m2/repository"
#
org.ops4j.pax.url.mvn.localRepository=file:E:/Data/.m2/repository

Reference

For more details about the mvn URL syntax, see the original Pax URL Mvn Protocol documentation.