org.apache.commons.configuration2.builder

Class FileBasedConfigurationBuilder<T extends FileBasedConfiguration>

java.lang.Object

org.apache.commons.configuration2.builder.BasicConfigurationBuilder<T>

org.apache.commons.configuration2.builder.FileBasedConfigurationBuilder<T>

Type Parameters:

T - the concrete type of Configuration objects created by this builder

All Implemented Interfaces:

ConfigurationBuilder<T>, EventSource

Direct Known Subclasses:

ReloadingFileBasedConfigurationBuilder

public class FileBasedConfigurationBuilder<T extends FileBasedConfiguration>
extends BasicConfigurationBuilder<T>

A specialized ConfigurationBuilder implementation which can handle configurations read from a FileHandler.

This class extends its base class by the support of a FileBasedBuilderParametersImpl object, and especially of the FileHandler contained in this object. When the builder creates a new object the resulting Configuration instance is associated with the FileHandler. If the FileHandler has a location set, the Configuration is directly loaded from this location.

The FileHandler is kept by this builder and can be queried later on. It can be used for instance to save the current Configuration after it was modified. Some care has to be taken when changing the location of the FileHandler: The new location is recorded and also survives an invocation of the resetResult() method. However, when the builder's initialization parameters are reset by calling resetParameters() the location is reset, too.

Since:

2.0

Constructor Summary

Constructors

Constructor and Description
FileBasedConfigurationBuilder(Class<? extends T> resCls) Creates a new instance of FileBasedConfigurationBuilder which produces result objects of the specified class.
FileBasedConfigurationBuilder(Class<? extends T> resCls, Map<String,Object> params) Creates a new instance of FileBasedConfigurationBuilder which produces result objects of the specified class and sets initialization parameters.
FileBasedConfigurationBuilder(Class<? extends T> resCls, Map<String,Object> params, boolean allowFailOnInit) Creates a new instance of FileBasedConfigurationBuilder which produces result objects of the specified class and sets initialization parameters and the allowFailOnInit flag.

Method Summary

Modifier and Type	Method and Description
FileBasedConfigurationBuilder<T>	configure(BuilderParameters... params) Appends the content of the specified BuilderParameters objects to the current initialization parameters.
static String	getDefaultEncoding(Class<?> configClass) Returns the default encoding for the specified configuration class.
FileHandler	getFileHandler() Returns the FileHandler associated with this builder.
protected void	initFileHandler(FileHandler handler) Initializes the new current FileHandler.
protected void	initResultInstance(T obj) Initializes a newly created result object.
boolean	isAutoSave() Returns a flag whether auto save mode is currently active.
void	save() Convenience method which saves the associated configuration.
void	setAutoSave(boolean enabled) Enables or disables auto save mode.
static void	setDefaultEncoding(Class<?> configClass, String encoding) Sets a default encoding for a specific configuration class.
BasicConfigurationBuilder<T>	setParameters(Map<String,Object> params) Sets the initialization parameters of this builder.

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

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

Methods inherited from class java.lang.Object

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

Constructor Detail

FileBasedConfigurationBuilder

public FileBasedConfigurationBuilder(Class<? extends T> resCls)

Creates a new instance of FileBasedConfigurationBuilder which produces result objects of the specified class.

Parameters:

resCls - the result class (must not be null

Throws:

IllegalArgumentException - if the result class is null

FileBasedConfigurationBuilder

public FileBasedConfigurationBuilder(Class<? extends T> resCls,
                                     Map<String,Object> params)

Creates a new instance of FileBasedConfigurationBuilder which produces result objects of the specified class and sets initialization parameters.

Parameters:

resCls - the result class (must not be null

params - a map with initialization parameters

Throws:

IllegalArgumentException - if the result class is null

FileBasedConfigurationBuilder

public FileBasedConfigurationBuilder(Class<? extends T> resCls,
                                     Map<String,Object> params,
                                     boolean allowFailOnInit)

Creates a new instance of FileBasedConfigurationBuilder which produces result objects of the specified class and sets initialization parameters and the allowFailOnInit flag.

Parameters:

resCls - the result class (must not be null

params - a map with initialization parameters

allowFailOnInit - the allowFailOnInit flag

Throws:

IllegalArgumentException - if the result class is null

Method Detail

getDefaultEncoding

public static String getDefaultEncoding(Class<?> configClass)

Returns the default encoding for the specified configuration class. If an encoding has been set for the specified class (or one of its super classes), it is returned. Otherwise, result is null.

Parameters:

configClass - the configuration class in question

Returns:

the default encoding for this class (may be null)

setDefaultEncoding

public static void setDefaultEncoding(Class<?> configClass,
                                      String encoding)

Sets a default encoding for a specific configuration class. This encoding is used if an instance of this configuration class is to be created and no encoding has been set in the parameters object for this builder. The encoding passed here not only applies to the specified class but also to its sub classes. If the encoding is null, it is removed.

Parameters:

configClass - the name of the configuration class (must not be null)

encoding - the default encoding for this class

Throws:

IllegalArgumentException - if the class is null

configure

public FileBasedConfigurationBuilder<T> 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 here to change the result type.

Overrides:

configure in class BasicConfigurationBuilder<T extends FileBasedConfiguration>

Parameters:

params - an arbitrary number of objects with builder parameters

Returns:

a reference to this builder for method chaining

getFileHandler

public FileHandler getFileHandler()

Returns the FileHandler associated with this builder. If already a result object has been created, this FileHandler can be used to save it. Otherwise, the FileHandler from the initialization parameters is returned (which is not associated with a FileBased object). Result is never null.

Returns:

the FileHandler associated with this builder

setParameters

public BasicConfigurationBuilder<T> setParameters(Map<String,Object> params)

Sets the initialization parameters of this builder. Already existing parameters are replaced by the content of the given map. This implementation just records the fact that new parameters have been set. This means that the next time a result object is created, the FileHandler has to be initialized from initialization parameters rather than reusing the existing one.

Overrides:

setParameters in class BasicConfigurationBuilder<T extends FileBasedConfiguration>

Parameters:

params - the new initialization parameters of this builder; can be null, then all initialization parameters are removed

Returns:

a reference to this builder for method chaining

save

public void save()
          throws ConfigurationException

Convenience method which saves the associated configuration. This method expects that the managed configuration has already been created and that a valid file location is available in the current FileHandler. The file handler is then used to store the configuration.

Throws:

ConfigurationException - if an error occurs

isAutoSave

public boolean isAutoSave()

Returns a flag whether auto save mode is currently active.

Returns:

true if auto save is enabled, false otherwise

setAutoSave

public void setAutoSave(boolean enabled)

Enables or disables auto save mode. If auto save mode is enabled, every update of the managed configuration causes it to be saved automatically; so changes are directly written to disk.

Parameters:

enabled - true if auto save mode is to be enabled, false otherwise

initResultInstance

protected void initResultInstance(T obj)
                           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 deals with the creation and initialization of a FileHandler associated with the new result object.

Overrides:

initResultInstance in class BasicConfigurationBuilder<T extends FileBasedConfiguration>

Parameters:

obj - the object to be initialized

Throws:

ConfigurationException - if an error occurs

initFileHandler

protected void initFileHandler(FileHandler handler)
                        throws ConfigurationException

Initializes the new current FileHandler. When a new result object is created, a new FileHandler is created, too, and associated with the result object. This new handler is passed to this method. If a location is defined, the result object is loaded from this location. Note: This method is called from a synchronized block.

Parameters:

handler - the new current FileHandler

Throws:

ConfigurationException - if an error occurs