Preferences Overview

The java.util.prefs.Preferences API provides a generic mechanism for storing user and system preferences, as well as configuration data. Jetspeed 2 relies on this API to provide a wide ranging of functionality to higher level services. Some of the Jetspeed components leveraging the java.util.prefs.Preferences API are:

  • Portlet Preferences: Portlet preferences are stored in the system preferences tree. The following path structure is used to establish the location of a given portlet preference in the preferences tree: /portlet_application/${Portlet Application Name}/portlets/${Portlet Name}/preferences/${Preference Name}/values . The preferences values are stored under the values node as a map of key/values.
  • User Attributes: User attributes are stored in the user preferences tree as follow. The following path structure is used to stored a user's attributes: /user/${User Name}/userinfo . The user attributes are stored as a preferences key/values map under the userinfo node.
  • Roles and groups hierarchy: Documentation on how roles and groups hierarchy use the Preferences model can be found in the security section of the documentation.

Preferences Goals

The Preferences API provides a generic implementation for organizing properties as illustrated below: 

<preferences EXTERNAL_XML_VERSION="1.0">
<root type="user">
  <map />
  <node name="user">
    <map />
	<node name="principal1">
      <map />
    <node name="propertyset1">
      <map>
        <entry key="set1prop1" value="256" />
        <entry key="set1prop2" value="314" />
      </map>
    </node>
  </node>
</root>

A good reference article can be found at ONJava.com.

Preferences Implementation Overview

Jetspeed 2 Preferences implementation leverages the following classes:

Class Description
PreferencesFactoryImpl Implements the java.util.prefs.PreferencesFactory that generates Preferences objects. The PreferencesFactoryImpl is configured through spring assembly (prefs.xml) to use a PreferencesProvider that encapsalutes the backing store implementation.
PreferencesImpl Extends the java.util.prefs.AbstractPreferences and implements the SPI by leveraging the PreferencesProvider API. Jetspeed Preferences implementation can be configured to validate that preferences map key/values are created for predefined keys. A PropertyManager enforces the checks if enabled.
PreferencesProvider Encapsulates the preferences implementation again a specific backing store. In Jetspeed 2, the default implementation is provided by org.apache.jetspeed.prefs.impl.PersistenceBrokerPreferencesProvider

Preferences Database Schema

The following database schema is being used in Jetspeed 2 to store Preferences in a relational database model.