------
 Guide to Mirror Settings
 ------
 Jason van Zyl
 Brian Fox
 ------
 2008-09-01
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Using Mirrors for Repositories

 Repositories are declared inside a project, which means that if you have your own custom repositories, those sharing
 your project easily get the right settings out of the box. However, you may want to use an alternative mirror
 for a particular repository without changing the project files.

 Some reasons to use a mirror are:

    * There is a synchronized mirror on the internet that is geographically closer and faster

    * You want to replace a particular repository with your own internal repository which you have greater control over

    * You want to run a repository manager to provide a local cache to a mirror and need to use its URL instead

    []

 To configure a mirror of a given repository, you provide it in your settings file (<<<$\{user.home\}/.m2/settings.xml>>>),
 giving the new repository its
 own <<<id>>> and <<<url>>>, and specify the <<<mirrorOf>>> setting that is the ID of the repository you are using a
 mirror of. For example, the ID of the main Maven Central US repository included by default is <<<central>>>, so to use
 the European Central instance, you would configure the following:

+-----+
<settings>
  ...
  <mirrors>
    <mirror>
      <id>UK</id>
      <name>UK Central</name>
      <url>http://uk.maven.org/maven2</url>
      <mirrorOf>central</mirrorOf>
    </mirror>
  </mirrors>
  ...
</settings>
+-----+

  Note that there can be at most one mirror for a given repository. In other words, you cannot map a single
  repository to a group of mirrors that all define the same <<<\<mirrorOf\>>>> value. Maven will not aggregate the
  mirrors but simply picks the first match. If you want to provide a combined view of several repositories, use a
  {{{../../repository-management.html}repository manager}} instead.

 The settings descriptor documentation can be found on the {{{../../maven-settings/settings.html}Maven Local Settings
 Model Website}}.

 <<Note>>: The official Maven 2 repository is at <<<http://repo.maven.apache.org/maven2>>> hosted in the US, or <<<http://uk.maven.org/maven2>>> hosted in the UK. 
 
 A list of known mirrors is available in the {{{http://repo.maven.apache.org/maven2/.meta/repository-metadata.xml}Repository Metadata}}. These 
mirrors may not have the same contents and we don't support them in any way.

Using A Single Repository

  You can force Maven to use a single repository by having it mirror all repository requests. The repository must
  contain all of the desired artifacts, or be able to proxy the requests to other repositories. This setting is most
  useful when using an internal company repository with the Maven Repository Manager to proxy external requests.

  To achieve this, set <<<mirrorOf>>> to <<<*>>>.

  <<Note:>> This feature is only available in Maven 2.0.5+.

+-----+
<settings>
  ...
  <mirrors>
    <mirror>
      <id>internal-repository</id>
      <name>Maven Repository Manager running on repo.mycompany.com</name>
      <url>http://repo.mycompany.com/proxy</url>
      <mirrorOf>*</mirrorOf>
    </mirror>
  </mirrors>
  ...
</settings>
+-----+

Advanced Mirror Specification

  A single mirror can handle multiple repositories when used in conjunction with a repository manager.

  The syntax as of Maven 2.0.9:

 * <<<\*>>> matches all repo ids.

 * <<<external:\*>>> matches all repositories except those using localhost or file based repositories. This is used in conjunction
  with a repository manager when you want to exclude redirecting repositories that are defined for Integration Testing.

 * multiple repositories may be specified using a comma as the delimiter

 * an exclamation mark may be used in conjunction with one of the above wildcards to exclude a repository id

 []

  The position of wildcards within a comma separated list of repository identifiers is not important as the wildcards
  defer to further processing and explicit includes or excludes stop the processing, overruling any wildcard match.

  When you use the advanced syntax and configure multiple mirrors, keep in mind that their declaration order matters.
  When Maven looks for a mirror of some repository, it first checks for a mirror whose <<<\<mirrorOf\>>>> exactly
  matches the repository identifier. If no direct match is found, Maven picks the first mirror declaration that matches
  according to the rules above (if any). Hence, you may influence match order by changing the order of the definitions
  in the <<<settings.xml>>>

 Examples:

 *  <<<\*>>> = everything

 *  <<<external:\*>>> = everything not on the localhost and not file based.

 *  <<<repo,repo1>>> = repo or repo1

 *  <<<\*,!repo1>>> = everything except repo1

 []

 <<Note:>> This feature is only available in Maven 2.0.9+.

+-----+
<settings>
  ...
  <mirrors>
    <mirror>
      <id>internal-repository</id>
      <name>Maven Repository Manager running on repo.mycompany.com</name>
      <url>http://repo.mycompany.com/proxy</url>
      <mirrorOf>external:*,!foo</mirrorOf>
    </mirror>
    <mirror>
      <id>foo-repository</id>
      <name>Foo</name>
      <url>http://repo.mycompany.com/foo</url>
      <mirrorOf>foo</mirrorOf>
    </mirror>
  </mirrors>
  ...
</settings>
+-----+

Creating Your Own Mirror

  The size of the central repository is {{{http://search.maven.org/#stats}increasing steadily}}
  To save us bandwidth and you time, mirroring the entire central repository is not allowed. 
  (Doing so will get you automatically banned) Instead, we suggest you setup a
  {{{../../repository-management.html}repository manager}} as a proxy.

  If you really want to become an official mirror, contact us at {{{https://issues.sonatype.org/browse/MVNCENTRAL}MVNCENTRAL}} with your location and we'll work to get you setup.