org.apache.commons.configuration2.builder.combined

Class FileExtensionConfigurationBuilderProvider

java.lang.Object

org.apache.commons.configuration2.builder.combined.BaseConfigurationBuilderProvider

org.apache.commons.configuration2.builder.combined.FileExtensionConfigurationBuilderProvider

All Implemented Interfaces:

ConfigurationBuilderProvider

public class FileExtensionConfigurationBuilderProvider
extends BaseConfigurationBuilderProvider

A specialized implementation of ConfigurationBuilderProvider which determines the name of the result configuration class based on the extension of the file to load.

This class works analogously to its base class BaseConfigurationBuilderProvider; especially, the resulting builder is created based on reflection. It extends the super class's functionality by a specific mechanism for determining the resulting configuration class: At construction time two configuration class names and a file extension are passed in. If a file name is provided in the builder's initialization parameters and this file name has the specified extension, then the first configuration class name is used; otherwise the default configuration class name is selected.

There are some tags for CombinedConfigurationProvider which can produce different results depending on the configuration files they have to load. This class can be used to implement this feature in a generic way.

Since:

2.0

Constructor Summary

Constructors

Constructor and Description
FileExtensionConfigurationBuilderProvider(String bldrCls, String reloadBldrCls, String matchingConfigCls, String defConfigClass, String ext, Collection<String> paramCls) Creates a new instance of FileExtensionConfigurationBuilderProvider.

Method Summary

Modifier and Type	Method and Description
protected String	determineConfigurationClass(ConfigurationDeclaration decl, Collection<BuilderParameters> params) Determines the name of the configuration class produced by the builder.
String	getExtension() Returns the file extension of this provider.
String	getMatchingConfigurationClass() Returns the name of the matching configuration class.

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

configureBuilder, createBuilder, createParameterObjects, determineBuilderClass, getBuilderClass, getConfigurationBuilder, getConfigurationClass, getParameterClasses, getReloadingBuilderClass, inheritParentBuilderProperties, initializeParameterObjects, isAllowFailOnInit

Methods inherited from class java.lang.Object

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

Constructor Detail

FileExtensionConfigurationBuilderProvider

public FileExtensionConfigurationBuilderProvider(String bldrCls,
                                                 String reloadBldrCls,
                                                 String matchingConfigCls,
                                                 String defConfigClass,
                                                 String ext,
                                                 Collection<String> paramCls)

Creates a new instance of FileExtensionConfigurationBuilderProvider.

Parameters:

bldrCls - the name of the builder class

reloadBldrCls - the name of a builder class to be used if reloading support is required (null if reloading is not supported)

matchingConfigCls - the name of the configuration class to be used if the provided file extension matches (must not be null)

defConfigClass - the name of the configuration class to be used if the provided file extension does not match (must not be null)

ext - the file extension to select the configuration class (must not be null)

paramCls - a collection with the names of parameters classes; an instance of a parameters object with basic properties is created automatically and does not need to be contained in this list; the collection can be null if no additional parameter objects are needed

Throws:

IllegalArgumentException - if a required parameter is missing

Method Detail

getMatchingConfigurationClass

public String getMatchingConfigurationClass()

Returns the name of the matching configuration class. This class is used if the file extension matches the extension of this provider.

Returns:

the matching configuration class

getExtension

public String getExtension()

Returns the file extension of this provider.

Returns:

the file extension to match

determineConfigurationClass

protected String determineConfigurationClass(ConfigurationDeclaration decl,
                                             Collection<BuilderParameters> params)
                                      throws ConfigurationException

Determines the name of the configuration class produced by the builder. This method is called when obtaining the arguments for invoking the constructor of the builder class. This implementation just returns the pre-configured configuration class name. Derived classes may determine this class name dynamically based on the passed in parameters. This implementation tries to find a FileBasedBuilderParametersImpl object in the parameter objects. If one is found, the extension of the file name is obtained and compared against the stored file extension. In case of a match, the matching configuration class is selected, otherwise the default one.

Overrides:

determineConfigurationClass in class BaseConfigurationBuilderProvider

Parameters:

decl - the current ConfigurationDeclaration

params - the collection with parameter objects

Returns:

the name of the builder's result configuration class

Throws:

ConfigurationException - if an error occurs