Class CompositeConfiguration
- java.lang.Object
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- org.apache.commons.configuration2.event.BaseEventSource
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- org.apache.commons.configuration2.AbstractConfiguration
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- org.apache.commons.configuration2.CompositeConfiguration
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- All Implemented Interfaces:
java.lang.Cloneable
,Configuration
,EventSource
,ImmutableConfiguration
,SynchronizerSupport
public class CompositeConfiguration extends AbstractConfiguration implements java.lang.Cloneable
CompositeConfiguration
allows you to add multipleConfiguration
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.
This configuration class uses a
Synchronizer
to control concurrent access. While all methods for reading and writing configuration properties make use of thisSynchronizer
per default, the methods for managing the list of child configurations and the in-memory configuration (addConfiguration(), getNumberOfConfigurations(), removeConfiguration(), getConfiguration(), getInMemoryConfiguration()
) are guarded, too. Because most methods for accessing configuration data delegate to the list of child configurations, the thread-safety of aCompositeConfiguration
object also depends on theSynchronizer
objects used by these children.- Version:
- $Id: CompositeConfiguration.java 1790899 2017-04-10 21:56:46Z ggregory $
- Author:
- Eric Pugh, Henning P. Schmiedehausen
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Constructor Summary
Constructors Constructor Description CompositeConfiguration()
Creates an empty CompositeConfiguration object which can then be added some other Configuration filesCompositeConfiguration(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.
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Method Summary
All Methods Instance Methods Concrete Methods 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 in-memory Configuration.protected void
clearInternal()
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.protected boolean
containsKeyInternal(java.lang.String key)
Actually checks whether the specified key is contained in this configuration.Configuration
getConfiguration(int index)
Return the configuration at the specified index.Configuration
getInMemoryConfiguration()
Returns the "in memory configuration".protected java.util.Iterator<java.lang.String>
getKeysInternal()
Actually creates an iterator for iterating over the keys in this configuration.protected java.util.Iterator<java.lang.String>
getKeysInternal(java.lang.String key)
Returns anIterator
with all property keys starting with 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.protected java.lang.Object
getPropertyInternal(java.lang.String key)
Read property from underlying compositeConfiguration
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.protected boolean
isEmptyInternal()
Actually checks whether this configuration contains data.void
removeConfiguration(Configuration config)
Remove a configuration.void
setListDelimiterHandler(ListDelimiterHandler listDelimiterHandler)
Sets theListDelimiterHandler
to be used by this instance.-
Methods inherited from class org.apache.commons.configuration2.AbstractConfiguration
addErrorLogListener, addProperty, addPropertyInternal, append, beginRead, beginWrite, clear, clearProperty, cloneInterpolator, containsKey, copy, endRead, endWrite, get, get, getArray, getArray, getBigDecimal, getBigDecimal, getBigInteger, getBigInteger, getBoolean, getBoolean, getBoolean, getByte, getByte, getByte, getCollection, getCollection, getConfigurationDecoder, getConversionHandler, getDouble, getDouble, getDouble, getEncodedString, getEncodedString, getFloat, getFloat, getFloat, getInt, getInt, getInteger, getInterpolator, getKeys, getKeys, getList, getList, getList, getListDelimiterHandler, getLogger, getLong, getLong, getLong, getProperties, getProperties, getProperty, getShort, getShort, getShort, getString, getString, getSynchronizer, immutableSubset, initLogger, installInterpolator, interpolate, interpolate, interpolatedConfiguration, isEmpty, isScalarValue, isThrowExceptionOnMissing, lock, setConfigurationDecoder, setConversionHandler, setDefaultLookups, setInterpolator, setLogger, setParentInterpolator, setPrefixLookups, setProperty, setPropertyInternal, setSynchronizer, setThrowExceptionOnMissing, size, sizeInternal, subset, unlock
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Methods inherited from class org.apache.commons.configuration2.event.BaseEventSource
addEventListener, clearErrorListeners, clearEventListeners, copyEventListeners, createErrorEvent, createEvent, fireError, fireEvent, getEventListenerRegistrations, getEventListeners, isDetailEvents, removeEventListener, setDetailEvents
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Constructor Detail
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CompositeConfiguration
public CompositeConfiguration()
Creates an empty CompositeConfiguration object which can then be added some other Configuration files
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CompositeConfiguration
public CompositeConfiguration(Configuration inMemoryConfiguration)
Creates a CompositeConfiguration object with a specified in-memory configuration. This configuration will store any changes made to theCompositeConfiguration
. 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, useaddConfiguration(Configuration, boolean)
with a value of true instead.- Parameters:
inMemoryConfiguration
- the in memory configuration to use
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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
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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 useconfigurations
- the collection of configurations to add- See Also:
CompositeConfiguration(Configuration)
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Method Detail
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addConfiguration
public void addConfiguration(Configuration config)
Add a configuration.- Parameters:
config
- the configuration to add
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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 addedasInMemory
- true if this configuration becomes the new in-memory configuration, false otherwise- Since:
- 1.8
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removeConfiguration
public void removeConfiguration(Configuration config)
Remove a configuration. The in memory configuration cannot be removed.- Parameters:
config
- The configuration to remove
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getNumberOfConfigurations
public int getNumberOfConfigurations()
Return the number of configurations.- Returns:
- the number of configuration
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clearInternal
protected void clearInternal()
Removes all child configurations and reinitializes the in-memory configuration. Attention: A new in-memory configuration is created; the old one is lost.- Overrides:
clearInternal
in classAbstractConfiguration
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addPropertyDirect
protected void addPropertyDirect(java.lang.String key, java.lang.Object token)
Add this property to the in-memory Configuration.- Specified by:
addPropertyDirect
in classAbstractConfiguration
- Parameters:
key
- The Key to add the property to.token
- The Value to add.
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getPropertyInternal
protected java.lang.Object getPropertyInternal(java.lang.String key)
Read property from underlying composite- Specified by:
getPropertyInternal
in classAbstractConfiguration
- Parameters:
key
- key to use for mapping- Returns:
- object associated with the given configuration key.
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getKeysInternal
protected java.util.Iterator<java.lang.String> getKeysInternal()
Description copied from class:AbstractConfiguration
Actually creates an iterator for iterating over the keys in this configuration. This method is called bygetKeys()
, it has to be defined by concrete subclasses.- Specified by:
getKeysInternal
in classAbstractConfiguration
- Returns:
- an
Iterator
with all property keys in this configuration
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getKeysInternal
protected java.util.Iterator<java.lang.String> getKeysInternal(java.lang.String key)
Description copied from class:AbstractConfiguration
Returns anIterator
with all property keys starting with the specified prefix. This method is called byAbstractConfiguration.getKeys(String)
. It is fully implemented by delegating togetKeysInternal()
and returning a special iterator which filters for the passed in prefix. Subclasses can override it if they can provide a more efficient way to iterate over specific keys only.- Overrides:
getKeysInternal
in classAbstractConfiguration
- Parameters:
key
- the prefix for the keys to be taken into account- Returns:
- an
Iterator
returning the filtered keys
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isEmptyInternal
protected boolean isEmptyInternal()
Description copied from class:AbstractConfiguration
Actually checks whether this configuration contains data. This method is called byisEmpty()
. It has to be defined by concrete subclasses.- Specified by:
isEmptyInternal
in classAbstractConfiguration
- Returns:
- true if this configuration contains no data, false otherwise
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clearPropertyDirect
protected void clearPropertyDirect(java.lang.String key)
Description copied from class:AbstractConfiguration
Removes the specified property from this configuration. This method is called byclearProperty()
after it has done some preparations. It must be overridden in sub classes.- Specified by:
clearPropertyDirect
in classAbstractConfiguration
- Parameters:
key
- the key to be removed
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containsKeyInternal
protected boolean containsKeyInternal(java.lang.String key)
Description copied from class:AbstractConfiguration
Actually checks whether the specified key is contained in this configuration. This method is called bycontainsKey()
. It has to be defined by concrete subclasses.- Specified by:
containsKeyInternal
in classAbstractConfiguration
- Parameters:
key
- the key in question- Returns:
- true if this key is contained in this configuration, false otherwise
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getList
public java.util.List<java.lang.Object> getList(java.lang.String key, java.util.List<?> defaultValue)
Description copied from interface:ImmutableConfiguration
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 interfaceImmutableConfiguration
- Overrides:
getList
in classAbstractConfiguration
- Parameters:
key
- The configuration key.defaultValue
- The default value.- Returns:
- The associated List of strings.
- See Also:
ImmutableConfiguration.getList(Class, String, List)
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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. When 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 the associationListDelimiterHandler
is consulted to find out whether the string can be split into multiple values.- Specified by:
getStringArray
in interfaceImmutableConfiguration
- Overrides:
getStringArray
in classAbstractConfiguration
- Parameters:
key
- The configuration key.- Returns:
- The associated string array if key is found.
- See Also:
AbstractConfiguration.setListDelimiterHandler(ListDelimiterHandler)
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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
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getInMemoryConfiguration
public Configuration getInMemoryConfiguration()
Returns the "in memory configuration". In this configuration changes are stored.- Returns:
- the in memory configuration
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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 classBaseEventSource
- Returns:
- the copy
- Since:
- 1.3
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setListDelimiterHandler
public void setListDelimiterHandler(ListDelimiterHandler listDelimiterHandler)
Sets the
ListDelimiterHandler
to be used by this instance. This object is invoked every time when dealing with string properties that may contain a list delimiter and thus have to be split to multiple values. Per default, aListDelimiterHandler
implementation is set which does not support list splitting. This can be changed for instance by setting aDefaultListDelimiterHandler
object.Warning: Be careful when changing the list delimiter handler when the configuration has already been loaded/populated. List handling is typically applied already when properties are added to the configuration. If later another handler is set which processes lists differently, results may be unexpected; some operations may even cause exceptions.
This implementation ensures that the in memory configuration is correctly initialized.- Overrides:
setListDelimiterHandler
in classAbstractConfiguration
- Parameters:
listDelimiterHandler
- theListDelimiterHandler
to be used (must not be null)
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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
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