Package org.apache.commons.configuration

Class CompositeConfiguration

java.lang.Object

org.apache.commons.configuration.event.EventSource

org.apache.commons.configuration.AbstractConfiguration

org.apache.commons.configuration.CompositeConfiguration

All Implemented Interfaces:

java.lang.Cloneable, Configuration

public class CompositeConfiguration
extends AbstractConfiguration
implements java.lang.Cloneable

CompositeConfiguration allows you to add multiple Configuration objects to an aggregated configuration. If you add Configuration1, and then Configuration2, any properties shared will mean that the value defined by Configuration1 will be returned. If Configuration1 doesn't have the property, then Configuration2 will be checked. You can add multiple different types or the same type of properties file.

When querying properties the order in which child configurations have been added is relevant. To deal with property updates, a so-called in-memory configuration is used. Per default, such a configuration is created automatically. All property writes target this special configuration. There are constructors which allow you to provide a specific in-memory configuration. If used that way, the in-memory configuration is always the last one in the list of child configurations. This means that for query operations all other configurations take precedence.

Alternatively it is possible to mark a child configuration as in-memory configuration when it is added. In this case the treatment of the in-memory configuration is slightly different: it remains in the list of child configurations at the position it was added, i.e. its priority for property queries can be defined by adding the child configurations in the correct order.

Version:

$Id: CompositeConfiguration.java 1534064 2013-10-21 08:44:33Z henning $

Author:

Eric Pugh, Henning P. Schmiedehausen

Field Summary

Fields inherited from class org.apache.commons.configuration.AbstractConfiguration

END_TOKEN, EVENT_ADD_PROPERTY, EVENT_CLEAR, EVENT_CLEAR_PROPERTY, EVENT_READ_PROPERTY, EVENT_SET_PROPERTY, START_TOKEN

Constructor Summary

Constructors

Constructor	Description
CompositeConfiguration()	Creates an empty CompositeConfiguration object which can then be added some other Configuration files
CompositeConfiguration(java.util.Collection<? extends Configuration> configurations)	Create a CompositeConfiguration with an empty in memory configuration and adds the collection of configurations specified.
CompositeConfiguration(Configuration inMemoryConfiguration)	Creates a CompositeConfiguration object with a specified in-memory configuration.
CompositeConfiguration(Configuration inMemoryConfiguration, java.util.Collection<? extends Configuration> configurations)	Creates a CompositeConfiguration with a specified in-memory configuration, and then adds the given collection of configurations.

Method Summary

Modifier and Type	Method	Description
void	addConfiguration(Configuration config)	Add a configuration.
void	addConfiguration(Configuration config, boolean asInMemory)	Adds a child configuration and optionally makes it the in-memory configuration.
protected void	addPropertyDirect(java.lang.String key, java.lang.Object token)	Add this property to the inmemory Configuration.
void	clear()	Removes all child configurations and reinitializes the in-memory configuration.
protected void	clearPropertyDirect(java.lang.String key)	Removes the specified property from this configuration.
java.lang.Object	clone()	Returns a copy of this object.
boolean	containsKey(java.lang.String key)	Check if the configuration contains the specified key.
Configuration	getConfiguration(int index)	Return the configuration at the specified index.
Configuration	getInMemoryConfiguration()	Returns the "in memory configuration".
java.util.Iterator<java.lang.String>	getKeys()	Get the list of the keys contained in the configuration.
java.util.Iterator<java.lang.String>	getKeys(java.lang.String key)	Get the list of the keys contained in the configuration that match the specified prefix.
java.util.List<java.lang.Object>	getList(java.lang.String key, java.util.List<?> defaultValue)	Get a List of strings associated with the given configuration key.
int	getNumberOfConfigurations()	Return the number of configurations.
java.lang.Object	getProperty(java.lang.String key)	Read property from underlying composite
Configuration	getSource(java.lang.String key)	Returns the configuration source, in which the specified key is defined.
java.lang.String[]	getStringArray(java.lang.String key)	Get an array of strings associated with the given configuration key.
boolean	isEmpty()	Check if the configuration is empty.
void	removeConfiguration(Configuration config)	Remove a configuration.
void	setDelimiterParsingDisabled(boolean delimiterParsingDisabled)	Sets a flag whether added values for string properties should be checked for the list delimiter.
void	setListDelimiter(char listDelimiter)	Sets the character that is used as list delimiter.

Methods inherited from class org.apache.commons.configuration.AbstractConfiguration

addErrorLogListener, addProperty, append, clearProperty, copy, createInterpolator, getBigDecimal, getBigDecimal, getBigInteger, getBigInteger, getBoolean, getBoolean, getBoolean, getByte, getByte, getByte, getDefaultListDelimiter, getDelimiter, getDouble, getDouble, getDouble, getFloat, getFloat, getFloat, getInt, getInt, getInteger, getInterpolator, getList, getListDelimiter, getLogger, getLong, getLong, getLong, getProperties, getProperties, getShort, getShort, getShort, getString, getString, getSubstitutor, interpolate, interpolate, interpolatedConfiguration, interpolateHelper, isDelimiterParsingDisabled, isScalarValue, isThrowExceptionOnMissing, resolveContainerStore, setDefaultListDelimiter, setDelimiter, setLogger, setProperty, setThrowExceptionOnMissing, subset

Methods inherited from class org.apache.commons.configuration.event.EventSource

addConfigurationListener, addErrorListener, clearConfigurationListeners, clearErrorListeners, createErrorEvent, createEvent, fireError, fireEvent, getConfigurationListeners, getErrorListeners, isDetailEvents, removeConfigurationListener, removeErrorListener, setDetailEvents

Methods inherited from class java.lang.Object

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

Constructor Detail

CompositeConfiguration

public CompositeConfiguration()

Creates an empty CompositeConfiguration object which can then be added some other Configuration files

CompositeConfiguration

public CompositeConfiguration(Configuration inMemoryConfiguration)

Creates a CompositeConfiguration object with a specified in-memory configuration. This configuration will store any changes made to the CompositeConfiguration. Note: Use this constructor if you want to set a special type of in-memory configuration. If you have a configuration which should act as both a child configuration and as in-memory configuration, use addConfiguration(Configuration, boolean) with a value of true instead.

Parameters:

inMemoryConfiguration - the in memory configuration to use

CompositeConfiguration

public CompositeConfiguration(java.util.Collection<? extends Configuration> configurations)

Create a CompositeConfiguration with an empty in memory configuration and adds the collection of configurations specified.

Parameters:

configurations - the collection of configurations to add

CompositeConfiguration

public CompositeConfiguration(Configuration inMemoryConfiguration,
                              java.util.Collection<? extends Configuration> configurations)

Creates a CompositeConfiguration with a specified in-memory configuration, and then adds the given collection of configurations.

Parameters:

inMemoryConfiguration - the in memory configuration to use

configurations - the collection of configurations to add

See Also:

CompositeConfiguration(Configuration)

Method Detail

addConfiguration

public void addConfiguration(Configuration config)

Add a configuration.

Parameters:

config - the configuration to add

addConfiguration

public void addConfiguration(Configuration config,
                             boolean asInMemory)

Adds a child configuration and optionally makes it the in-memory configuration. This means that all future property write operations are executed on this configuration. Note that the current in-memory configuration is replaced by the new one. If it was created automatically or passed to the constructor, it is removed from the list of child configurations! Otherwise, it stays in the list of child configurations at its current position, but it passes its role as in-memory configuration to the new one.

Parameters:

config - the configuration to be added

asInMemory - true if this configuration becomes the new in-memory configuration, false otherwise

Since:

1.8

removeConfiguration

public void removeConfiguration(Configuration config)

Remove a configuration. The in memory configuration cannot be removed.

Parameters:

config - The configuration to remove

getNumberOfConfigurations

public int getNumberOfConfigurations()

Return the number of configurations.

Returns:

the number of configuration

clear

public void clear()

Removes all child configurations and reinitializes the in-memory configuration. Attention: A new in-memory configuration is created; the old one is lost.

Specified by:

clear in interface Configuration

Overrides:

clear in class AbstractConfiguration

addPropertyDirect

protected void addPropertyDirect(java.lang.String key,
                                 java.lang.Object token)

Add this property to the inmemory Configuration.

Specified by:

addPropertyDirect in class AbstractConfiguration

Parameters:

key - The Key to add the property to.

token - The Value to add.

getProperty

public java.lang.Object getProperty(java.lang.String key)

Read property from underlying composite

Specified by:

getProperty in interface Configuration

Parameters:

key - key to use for mapping

Returns:

object associated with the given configuration key.

getKeys

public java.util.Iterator<java.lang.String> getKeys()

Description copied from interface: Configuration

Get the list of the keys contained in the configuration. The returned iterator can be used to obtain all defined keys. Note that the exact behavior of the iterator's remove() method is specific to a concrete implementation. It may remove the corresponding property from the configuration, but this is not guaranteed. In any case it is no replacement for calling Configuration.clearProperty(String) for this property. So it is highly recommended to avoid using the iterator's remove() method.

Specified by:

getKeys in interface Configuration

Returns:

An Iterator.

getKeys

public java.util.Iterator<java.lang.String> getKeys(java.lang.String key)

Description copied from class: AbstractConfiguration

Get the list of the keys contained in the configuration that match the specified prefix. For instance, if the configuration contains the following keys:
db.user, db.pwd, db.url, window.xpos, window.ypos,
an invocation of getKeys("db");
will return the keys below:
db.user, db.pwd, db.url.
Note that the prefix itself is included in the result set if there is a matching key. The exact behavior - how the prefix is actually interpreted - depends on a concrete implementation. This implementation returns keys that either match the prefix or start with the prefix followed by a dot ('.'). So the call getKeys("db"); will find the keys db, db.user, or db.password, but not the key dbdriver.

Specified by:

getKeys in interface Configuration

Overrides:

getKeys in class AbstractConfiguration

Parameters:

key - The prefix to test against.

Returns:

An Iterator of keys that match the prefix.

See Also:

Configuration.getKeys()

isEmpty

public boolean isEmpty()

Description copied from interface: Configuration

Check if the configuration is empty.

Specified by:

isEmpty in interface Configuration

Returns:

true if the configuration contains no property, false otherwise.

clearPropertyDirect

protected void clearPropertyDirect(java.lang.String key)

Description copied from class: AbstractConfiguration

Removes the specified property from this configuration. This method is called by clearProperty() after it has done some preparations. It should be overridden in sub classes. This base implementation is just left empty.

Overrides:

clearPropertyDirect in class AbstractConfiguration

Parameters:

key - the key to be removed

containsKey

public boolean containsKey(java.lang.String key)

Description copied from interface: Configuration

Check if the configuration contains the specified key.

Specified by:

containsKey in interface Configuration

Parameters:

key - the key whose presence in this configuration is to be tested

Returns:

true if the configuration contains a value for this key, false otherwise

getList

public java.util.List<java.lang.Object> getList(java.lang.String key,
                                                java.util.List<?> defaultValue)

Description copied from interface: Configuration

Get a List of strings associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned.

Specified by:

getList in interface Configuration

Overrides:

getList in class AbstractConfiguration

Parameters:

key - The configuration key.

defaultValue - The default value.

Returns:

The associated List of strings.

getStringArray

public java.lang.String[] getStringArray(java.lang.String key)

Description copied from class: AbstractConfiguration

Get an array of strings associated with the given configuration key. If the key doesn't map to an existing object, an empty array is returned. If a property is added to a configuration, it is checked whether it contains multiple values. This is obvious if the added object is a list or an array. For strings it is checked whether the string contains the list delimiter character that can be specified using the setListDelimiter() method. If this is the case, the string is split at these positions resulting in a property with multiple values.

Specified by:

getStringArray in interface Configuration

Overrides:

getStringArray in class AbstractConfiguration

Parameters:

key - The configuration key.

Returns:

The associated string array if key is found.

See Also:

AbstractConfiguration.setListDelimiter(char), AbstractConfiguration.setDelimiterParsingDisabled(boolean)

getConfiguration

public Configuration getConfiguration(int index)

Return the configuration at the specified index.

Parameters:

index - The index of the configuration to retrieve

Returns:

the configuration at this index

getInMemoryConfiguration

public Configuration getInMemoryConfiguration()

Returns the "in memory configuration". In this configuration changes are stored.

Returns:

the in memory configuration

clone

public java.lang.Object clone()

Returns a copy of this object. This implementation will create a deep clone, i.e. all configurations contained in this composite will also be cloned. This only works if all contained configurations support cloning; otherwise a runtime exception will be thrown. Registered event handlers won't get cloned.

Overrides:

clone in class EventSource

Returns:

the copy

Since:

1.3

setDelimiterParsingDisabled

public void setDelimiterParsingDisabled(boolean delimiterParsingDisabled)

Sets a flag whether added values for string properties should be checked for the list delimiter. This implementation ensures that the in memory configuration is correctly initialized.

Overrides:

setDelimiterParsingDisabled in class AbstractConfiguration

Parameters:

delimiterParsingDisabled - the new value of the flag

Since:

1.4

setListDelimiter

public void setListDelimiter(char listDelimiter)

Sets the character that is used as list delimiter. This implementation ensures that the in memory configuration is correctly initialized.

Overrides:

setListDelimiter in class AbstractConfiguration

Parameters:

listDelimiter - the new list delimiter character

Since:

1.4

getSource

public Configuration getSource(java.lang.String key)

Returns the configuration source, in which the specified key is defined. This method will iterate over all existing child configurations and check whether they contain the specified key. The following constellations are possible:

• If exactly one child configuration contains the key, this configuration is returned as the source configuration. This may be the in memory configuration (this has to be explicitly checked by the calling application).
• If none of the child configurations contain the key, null is returned.
• If the key is contained in multiple child configurations or if the key is null, a IllegalArgumentException is thrown. In this case the source configuration cannot be determined.

Parameters:

key - the key to be checked

Returns:

the source configuration of this key

Throws:

java.lang.IllegalArgumentException - if the source configuration cannot be determined

Since:

1.5