XML-based module descriptor
This page is about the XML-based module descriptor file which identifies and defines a Magnolia Maven module. If you are using a Magnolia light module, you should use a YAML-based module descriptor.
The XML file:
-
Conforms to module.dtd.
-
Is stored in
src/main/resources/META-INF/magnolia/<module-name>.xml
-
Can refer to nodes of the module pom file.
When you start Magnolia, the system identifies available modules by locating each module’s descriptor file.
Benefits of a module descriptor
The XML-based module descriptor has a number of benefits:
-
Dependency injection: Inject components into the module.
-
Module version handling: Smoother version changes with Maven.
-
Dependencies: Define runtime and install time dependencies to other modules.
-
Servlets: Register servlets in your module.
-
Workspaces: Create workspaces.
-
Module class: Register a module class that allows you to define module specific properties.
Example module descriptor
Here is an example XML Maven module descriptor that defines a module
class (class
element), a module version handler (versionHandler
element), an IoC component and a dependency on the ui-admincentral
module.
Note how you can refer to Maven properties within the module descriptor.
<!DOCTYPE module SYSTEM "module.dtd">
<module>
<name>acme-geotagging-module</name>
<displayName>Acme geotagging module.</displayName>
<class>com.acme.GeotaggingModule</class>
<versionHandler>com.acme.GeotaggingModuleVersionHandler</versionHandler>
<version>${project.version}</version>
<components>
<id>app-geotagging</id>
</components>
<components>
<id>app-geotagging-main</id>
<component>
<type>com.acme.geo.app.main.GeoTaggingMainSubappView</type>
<implementation>com.acme.geo.app.main.GeoTaggingMainSubappViewImpl</implementation>
</component>
</components>
<dependencies>
<dependency>
<name>ui-admincentral</name>
<version>${project.version}</version>
</dependency>
</dependencies>
</module>
Module descriptor elements
Element | Description |
---|---|
|
required Functional name of the module in the |
|
required Module version. |
|
optional Name of the module class. |
|
optional Full description of the module. |
|
optional Display name of the module. |
|
optional Name of the version handler class. |
|
optional Properties used with the version handler. |
|
optional Dependencies installed for the module. |
|
optional Servlets included in the servlet filter. |
|
optional Repositories used by the module. |
|
optional Injected components used by the module. |
Module naming
For each module you have to provide:
-
artifactId
andgroupId
to the identify the Maven artifact -
Name of the module descriptor file.
-
<name>
of the module in the module descriptor file.
There are no strict naming conventions. You should give a name that reflects the purpose of the module. The name may also contain the name of your company.
Depending on the module purpose it might be a good idea to use the same value for the artifact ID and module name.
It is definitively good practice to name the module descriptor file by
the pattern <module-name>.xml
.
- Example
-
-
Module name:
Social Media Hub
-
Artifact ID:
social-media-hub
-
Group ID:
com.tinext.magnolia
(contains the name of the creator Tinext.com) -
Module descriptor file:
social-media-hub.xml
-
Module versions
The syntax for a version is
from version / to version
where the version number consists of three parts: x.y.z
. The x.y
parts denote a major version
and the z
part a maintenance release. The y.z
parts are optional. For a strict version
dependency, use just one version string.
The info.magnolia.module.model.VersionRange class supports the following syntax to indicate version dependencies. Only three parts are supported: major, minor and security versions. The build number is not supported. See Runtime.Version for more information.
-
*
: all versions.In a YAML file, make sure to wrap *
with quotes (version: "*"
). -
1.2
: version 1.2 only. -
1.2/*
: version 1.2 or higher. -
1.2/1.2.9
or[1.2,1.2.9]
: all versions between 1.2 and 1.2.9 (including 1.2 and 1.2.9). -
[1.2,1.2.9[
or[1.2,1.2.9)
: all versions between 1.2 and 1.2.9 (including 1.2 but excluding 1.2.9).
Example | Description |
---|---|
|
Major version 3. |
|
Major version 3.6. |
|
Major version 3.6 and maintenance version 3. |
|
Major version 3 or higher. |
|
Major version 3.6 or higher. |
|
Major version 3.6 and maintenance version 3 or higher. |
|
Major version 3 or earlier. |
|
Major version 3.6 or earlier. |
|
Major version 3.6 and maintenance version 3 or earlier. |
|
All versions between 3.5 and 3.6.2 (including 3.5 and 3.6.2). |
|
All versions between 3.5 and 3.6.2 (including 3.5 but excluding 3.6.2). |
Module dependencies
You can define runtime or install time dependencies (not build dependencies). If you define a dependency on a module, then this module will be installed and started before your module. A dependency can be optional. Optional in this context means that if an optional module is not present, installation will proceed, but if the optional module is present, this module will be installed first. The dependencies could look like this:
<dependencies>
<dependency>
<name>core</name>
<version>3.6.0/*</version>
</dependency>
<!-- in case cache module is present,
make sure we install after so we can add a bypass -->
<dependency>
<name>cache</name>
<version>3.6.0/*</version>
<optional>true</optional>
</dependency>
</dependencies>
Module dependencies define module loading order
The module dependencies define the order in which modules are loaded
during startup. For example, if module-a
depends on module-b
,
module-b
will be loaded before module-a.
The order becomes
important, for example, if both module-a
and module-b
decorate the
same definition or if module-a
inherits a definition from module-b
.
Decorations are applied in the module load order. |
Workspaces
Workspaces can be defined in the module descriptor. If necessary Magnolia initializes these workspaces before the installation starts. As an example look at the data module:
<repositories>
<repository>
<name>magnolia</name>
<workspaces>
<workspace>data</workspace>
</workspaces>
<nodeTypeFile>/mgnl-nodetypes/magnolia-module-data-nodetypes.xml</nodeTypeFile>
</repository>
</repositories>
Under the hood, these repository workspaces are registered and initialized by info.magnolia.module.delta.SetupModuleRepositoriesTask when the module is installed.
If you are using the Magnolia Content Types module, you can define workspaces (and node types) also in light modules.
Please read the page Defining JCR node types and workspaces, which provides an overview of all ways to define custom JCR node types and create new workspaces with Magnolia. |