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

Field Summary

Fields inherited from class org.apache.commons.configuration2.builder.combined.CombinedConfigurationBuilder

ADDITIONAL_NAME

Constructor Summary

Constructors

Constructor and Description
ReloadingCombinedConfigurationBuilder() Creates a new instance of ReloadingCombinedConfigurationBuilder.
ReloadingCombinedConfigurationBuilder(Map<String,Object> params) Creates a new instance of ReloadingCombinedConfigurationBuilder and sets the specified initialization parameters.
ReloadingCombinedConfigurationBuilder(Map<String,Object> params, boolean allowFailOnInit) Creates a new instance of ReloadingCombinedConfigurationBuilder and sets the specified initialization parameters and the allowFailOnInit flag.

Method Summary

Modifier and Type	Method and Description
ReloadingCombinedConfigurationBuilder	configure(BuilderParameters... params) Appends the content of the specified BuilderParameters objects to the current initialization parameters.
protected ReloadingController	createReloadingController() Creates the ReloadingController for this builder.
protected ConfigurationBuilder<? extends HierarchicalConfiguration<?>>	createXMLDefinitionBuilder(BuilderParameters builderParams) Creates a default builder for the definition configuration and initializes it with a parameters object.
CombinedConfiguration	getConfiguration() Returns the configuration provided by this builder.
ReloadingController	getReloadingController() Returns the ReloadingController associated with this object.
protected void	initResultInstance(CombinedConfiguration result) Initializes a newly created result object.
static void	obtainReloadingController(Collection<ReloadingController> subControllers, Object builder) Checks whether the passed in builder object supports reloading.

Methods inherited from class org.apache.commons.configuration2.builder.combined.CombinedConfigurationBuilder

builderNames, configureEntityResolver, createAdditionalsConfiguration, createResultDeclaration, getChildBuilders, getDefinitionBuilder, getDefinitionConfiguration, getNamedBuilder, initChildBuilderParameters, initFileSystem, initSystemProperties, providerForTag, registerConfiguredLookups, resetParameters, setupDefinitionBuilder

Methods inherited from class org.apache.commons.configuration2.builder.BasicConfigurationBuilder

addEventListener, addParameters, connectToReloadingController, copyEventListeners, copyEventListeners, createResult, createResultInstance, fetchBeanHelper, fireBuilderEvent, getParameters, getResultClass, getResultDeclaration, installEventListener, isAllowFailOnInit, removeEventListener, reset, resetResult, setParameters

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ReloadingCombinedConfigurationBuilder

public ReloadingCombinedConfigurationBuilder()

Creates a new instance of ReloadingCombinedConfigurationBuilder. No parameters are set.

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

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

Method Detail

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

getReloadingController

public ReloadingController getReloadingController()

Returns 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

getConfiguration

public CombinedConfiguration getConfiguration()
                                       throws ConfigurationException

Returns 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

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

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

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

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