Class ConfigurationService


public class ConfigurationService extends Object
A service which provides for the registration, retrieval and deregistration of objects related to library module configuration.

The service uses an internally-managed instance of Configuration to handle the registration, retrieval and deregistration of the configuration objects under its management.

The service first attempts to use the Java Services API to resolve the instance of Configuration to use. If multiple implementations of Configuration are registered via the Services API mechanism, the first one returned by the ServiceLoader iterator is used. If no Configuration implementation is declared or resolvable using the Services API, then it uses the default implementation MapBasedConfiguration.

The Configuration instance to use may also be set externally via setConfiguration(Configuration). This may be useful where an application-specific means such as Spring is used to configure the environment. This overrides the resolution process described above.

  • Field Details


      @Nonnull public static final String DEFAULT_PARTITION_NAME
      The default storage partition name, if none is specified using configuration properties.
      See Also:

      @Nonnull public static final String PROPERTY_PARTITION_NAME
      The configuration property name for the storage partition name to use.
      See Also:
    • LOG

      @Nonnull private static final org.slf4j.Logger LOG
    • configPropertiesLoader

      private static ServiceLoader<ConfigurationPropertiesSource> configPropertiesLoader
      The service loader used to locate registered implementations of ConfigurationPropertiesSource.
    • configuration

      private static Configuration configuration
      The configuration instance to use.
  • Constructor Details

    • ConfigurationService

      protected ConfigurationService()
  • Method Details

    • get

      public static <T> T get(@Nonnull Class<T> configClass)
      Obtain the registered configuration instance.
      Type Parameters:
      T - the type of configuration being retrieved
      configClass - the configuration class identifier
      the instance of the registered configuration object, or null
    • register

      public static <T, I extends T> void register(@Nonnull Class<T> configClass, @Nonnull I configInstance)
      Register a configuration instance.
      Type Parameters:
      T - the type of configuration being registered
      I - the configuration object instance type being registered, which must be an instance of T
      configClass - the type of configuration being registered
      configInstance - the configuration object instance being registered
    • deregister

      public static <T> T deregister(@Nonnull Class<T> configClass)
      Deregister a configuration instance.
      Type Parameters:
      T - the type of configuration being deregistered
      configClass - the type of configuration class being deregistered
      the configuration object instance which was deregistered, or null
    • getConfigurationProperties

      @Nullable public static Properties getConfigurationProperties()
      Get the set of configuration meta-properties, which determines the configuration of the configuration service itself.

      The properties set is obtained from the first registered instance of ConfigurationPropertiesSource which returns a non-null properties set. The implementations of properties sources to use are obtained via the Java Services API.

      Properties made available in this meta-properties set may also be used by Initializer implementations.

      the set of configuration meta-properties
    • setConfiguration

      public static void setConfiguration(@Nonnull Configuration newConfiguration)
      Set the Configuration instance to use.

      The configuration instance to use is normally resolved via the Java Services API, or is defaulted. However, this method is provided to allow the configuration instance to be supplied externally, perhaps using an application-specific means such as Spring dependency injection.

      newConfiguration - the Configuration instance to use
    • getPartitionName

      @Nonnull @NotEmpty protected static String getPartitionName()
      Return the partition name which will be used for storage of configuration objects.

      This partition name is obtained from the configuration meta-properties. If a value is not supplied via that mechanism, then an internal default value is used.

      the partition name
    • getConfiguration

      @Nonnull protected static Configuration getConfiguration()
      Get the Configuration instance to use.

      The implementation to return is first resolved using the Java Services API. If this produces no implementation, then an instance of the default implementation of MapBasedConfiguration is used.

      the Configuration implementation instance