Package org.apache.commons.configuration2.builder.combined

Class ReloadingCombinedConfigurationBuilder

java.lang.Object
org.apache.commons.configuration2.builder.BasicConfigurationBuilder<CombinedConfiguration>
org.apache.commons.configuration2.builder.combined.CombinedConfigurationBuilder
org.apache.commons.configuration2.builder.combined.ReloadingCombinedConfigurationBuilder
All Implemented Interfaces:
ConfigurationBuilder<CombinedConfiguration>, EventSource, ReloadingControllerSupport
public class ReloadingCombinedConfigurationBuilder extends CombinedConfigurationBuilder implements ReloadingControllerSupport

An extension of CombinedConfigurationBuilder which also supports reloading operations.

This class differs from its super class in the following aspects:

  • A ReloadingController is created which manages all child configuration builders supporting reloading operations.
  • If no ConfigurationBuilder is provided for the definition configuration, a builder with reloading support is created.

This class can be used exactly as its super class for creating combined configurations from multiple configuration sources. In addition, the combined reloading controller managed by an instance can be used to react on changes in one of these configuration sources or in the definition configuration.

Since:
2.0

  • Constructor Details

    • ReloadingCombinedConfigurationBuilder

      public ReloadingCombinedConfigurationBuilder()
      Creates a new instance of ReloadingCombinedConfigurationBuilder. No parameters are set.

    • ReloadingCombinedConfigurationBuilder

      public ReloadingCombinedConfigurationBuilder(Map<String,Object> params)
      Creates a new instance of ReloadingCombinedConfigurationBuilder and sets the specified initialization parameters.
      Parameters:
      params - a map with initialization parameters

    • ReloadingCombinedConfigurationBuilder

      public ReloadingCombinedConfigurationBuilder(Map<String,Object> params, boolean allowFailOnInit)
      Creates a new instance of ReloadingCombinedConfigurationBuilder and sets the specified initialization parameters and the allowFailOnInit flag.
      Parameters:
      params - a map with initialization parameters
      allowFailOnInit - the allowFailOnInit flag

  • Method Details

    • obtainReloadingController

      public static void obtainReloadingController(Collection<ReloadingController> subControllers, Object builder)
      Checks whether the passed in builder object supports reloading. If yes, its reloading controller is obtained and added to the given list.
      Parameters:
      subControllers - the list with sub controllers
      builder - the builder object to be checked

    • configure

      public ReloadingCombinedConfigurationBuilder configure(BuilderParameters... params)
      Appends the content of the specified BuilderParameters objects to the current initialization parameters. Calling this method multiple times will create a union of the parameters provided. This method is overridden to adapt the return type. This method is overridden to adapt the return type.
      Overrides:
      configure in class CombinedConfigurationBuilder
      Parameters:
      params - an arbitrary number of objects with builder parameters
      Returns:
      a reference to this builder for method chaining

    • createReloadingController

      protected ReloadingController createReloadingController() throws ConfigurationException
      Creates the ReloadingController for this builder. This method is called after the result configuration has been created and initialized. It is called from a synchronized block. This implementation creates a CombinedReloadingController.
      Returns:
      the ReloadingController for this builder
      Throws:
      ConfigurationException - if an error occurs

    • createXMLDefinitionBuilder

      protected ConfigurationBuilder<? extends HierarchicalConfiguration<?>> createXMLDefinitionBuilder(BuilderParameters builderParams)
      Creates a default builder for the definition configuration and initializes it with a parameters object. This method is called if no definition builder is defined in this builder's parameters. This implementation creates a default file-based builder which produces an XMLConfiguration; it expects a corresponding file specification. Note: This method is called in a synchronized block. This implementation creates a builder for XML configurations with reloading support.
      Overrides:
      createXMLDefinitionBuilder in class CombinedConfigurationBuilder
      Parameters:
      builderParams - the parameters object for the builder
      Returns:
      the standard builder for the definition configuration

    • getConfiguration

      public CombinedConfiguration getConfiguration() throws ConfigurationException
      Gets the configuration provided by this builder. An implementation has to perform all necessary steps for creating and initializing a ImmutableConfiguration object. This implementation creates the result configuration on first access. Later invocations return the same object until this builder is reset. The double-check idiom for lazy initialization is used (Bloch, Effective Java, item 71). This implementation makes sure that the reloading state of the managed reloading controller is reset. Note that this has to be done here and not in initResultInstance(CombinedConfiguration) because it must be outside of a synchronized block; otherwise, a dead-lock situation can occur.
      Specified by:
      getConfiguration in interface ConfigurationBuilder<CombinedConfiguration>
      Overrides:
      getConfiguration in class BasicConfigurationBuilder<CombinedConfiguration>
      Returns:
      the configuration
      Throws:
      ConfigurationException - if an error occurs

    • getReloadingController

      public ReloadingController getReloadingController()
      Gets the ReloadingController associated with this object. This implementation returns a CombinedReloadingController which contains sub controllers for all child configuration sources with reloading support. If the definition builder supports reloading, its controller is contained, too. Note that the combined reloading controller is initialized when the result configuration is created (i.e. when calling getConfiguration() for the first time). So this method does not return a meaningful result before.
      Specified by:
      getReloadingController in interface ReloadingControllerSupport
      Returns:
      the associated ReloadingController

    • initResultInstance

      protected void initResultInstance(CombinedConfiguration result) throws ConfigurationException
      Initializes a newly created result object. This is the second step of the process of producing a result object for this builder. This implementation uses the BeanHelper class to initialize the object's property based on the BeanDeclaration returned by BasicConfigurationBuilder.getResultDeclaration(). Note: This method is invoked in a synchronized block. This is required because internal state is accessed. Sub classes must not call this method without proper synchronization. This implementation processes the definition configuration in order to
      • initialize the resulting CombinedConfiguration
      • determine the builders for all configuration sources
      • populate the resulting CombinedConfiguration
      This implementation first calls the super method to actually initialize the result configuration. Then it creates the CombinedReloadingController for all child configuration sources with reloading support.
      Overrides:
      initResultInstance in class CombinedConfigurationBuilder
      Parameters:
      result - the object to be initialized
      Throws:
      ConfigurationException - if an error occurs