AbstractConfiguration (Apache Commons Configuration 2.7 API)

java.lang.Object
- org.apache.commons.configuration2.event.BaseEventSource
- - org.apache.commons.configuration2.AbstractConfiguration

All Implemented Interfaces:

Configuration, EventSource, ImmutableConfiguration, SynchronizerSupport

Direct Known Subclasses:

AbstractHierarchicalConfiguration, AppletConfiguration, BaseConfiguration, CompositeConfiguration, DatabaseConfiguration, DataConfiguration, JNDIConfiguration, MapConfiguration, ServletConfiguration, ServletContextConfiguration, ServletFilterConfiguration, ServletRequestConfiguration, SubsetConfiguration
```
public abstract class AbstractConfiguration
extends BaseEventSource
implements Configuration
```
Abstract configuration class. Provides basic functionality but does not store any data.

If you want to write your own Configuration class then you should implement only abstract methods from this class. A lot of functionality needed by typical implementations of the Configuration interface is already provided by this base class. Following is a list of features implemented here:
- Data conversion support. The various data types required by the Configuration interface are already handled by this base class. A concrete sub class only needs to provide a generic getProperty() method.
- Support for variable interpolation. Property values containing special variable tokens (like ${var}) will be replaced by their corresponding values.
- Optional support for string lists. The values of properties to be added to this configuration are checked whether they contain a list delimiter character. If this is the case and if list splitting is enabled, the string is split and multiple values are added for this property. List splitting is controlled by a ListDelimiterHandler object which can be set using the setListDelimiterHandler(ListDelimiterHandler) method. It is disabled per default. To enable this feature, set a suitable ListDelimiterHandler, e.g. an instance of DefaultListDelimiterHandler configured with the desired list delimiter character.
- Allows specifying how missing properties are treated. Per default the get methods returning an object will return null if the searched property key is not found (and no default value is provided). With the setThrowExceptionOnMissing() method this behavior can be changed to throw an exception when a requested property cannot be found.
- Basic event support. Whenever this configuration is modified registered event listeners are notified. Refer to the various EVENT_XXX constants to get an impression about which event types are supported.
- Support for proper synchronization based on the Synchronizer interface.
Most methods defined by the Configuration interface are already implemented in this class. Many method implementations perform basic book-keeping tasks (e.g. firing events, handling synchronization), and then delegate to other (protected) methods executing the actual work. Subclasses override these protected methods to define or adapt behavior. The public entry point methods are final to prevent subclasses from breaking basic functionality.

Constructor Summary

Constructors
Constructor and Description

AbstractConfiguration()
Creates a new instance of AbstractConfiguration.

Constructors
Constructor and Description
`AbstractConfiguration()` Creates a new instance of `AbstractConfiguration`.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addErrorLogListener()` Adds a special `EventListener` object to this configuration that will log all internal errors.
`void`	`addProperty(String key, Object value)` Add a property to the configuration.
`protected abstract void`	`addPropertyDirect(String key, Object value)` Adds a key/value pair to the Configuration.
`protected void`	`addPropertyInternal(String key, Object value)` Actually adds a property to this configuration.
`void`	`append(Configuration c)` Appends the content of the specified configuration to this configuration.
`protected void`	`beginRead(boolean optimize)` Notifies this configuration's `Synchronizer` that a read operation is about to start.
`protected void`	`beginWrite(boolean optimize)` Notifies this configuration's `Synchronizer` that an update operation is about to start.
`void`	`clear()` Remove all properties from the configuration.
`protected void`	`clearInternal()` Clears the whole configuration.
`void`	`clearProperty(String key)` Removes the specified property from this configuration.
`protected abstract void`	`clearPropertyDirect(String key)` Removes the specified property from this configuration.
`protected void`	`cloneInterpolator(AbstractConfiguration orgConfig)` Creates a clone of the `ConfigurationInterpolator` used by this instance.
`boolean`	`containsKey(String key)` Check if the configuration contains the specified key.
`protected abstract boolean`	`containsKeyInternal(String key)` Actually checks whether the specified key is contained in this configuration.
`void`	`copy(Configuration c)` Copies the content of the specified configuration into this configuration.
`protected void`	`endRead()` Notifies this configuration's `Synchronizer` that a read operation has finished.
`protected void`	`endWrite()` Notifies this configuration's `Synchronizer` that an update operation has finished.
`<T> T`	`get(Class<T> cls, String key)` Get an object of the specified type associated with the given configuration key.
`<T> T`	`get(Class<T> cls, String key, T defaultValue)` Get an object of the specified type associated with the given configuration key using a default value.
`Object`	`getArray(Class<?> cls, String key)` Get an array of typed objects associated with the given configuration key.
`Object`	`getArray(Class<?> cls, String key, Object defaultValue)` Get an array of typed objects associated with the given configuration key.
`BigDecimal`	`getBigDecimal(String key)` Get a `BigDecimal` associated with the given configuration key.
`BigDecimal`	`getBigDecimal(String key, BigDecimal defaultValue)` Get a `BigDecimal` associated with the given configuration key.
`BigInteger`	`getBigInteger(String key)` Get a `BigInteger` associated with the given configuration key.
`BigInteger`	`getBigInteger(String key, BigInteger defaultValue)` Get a `BigInteger` associated with the given configuration key.
`boolean`	`getBoolean(String key)` Get a boolean associated with the given configuration key.
`boolean`	`getBoolean(String key, boolean defaultValue)` Get a boolean associated with the given configuration key.
`Boolean`	`getBoolean(String key, Boolean defaultValue)` Obtains the value of the specified key and tries to convert it into a `Boolean` object.
`byte`	`getByte(String key)` Get a byte associated with the given configuration key.
`byte`	`getByte(String key, byte defaultValue)` Get a byte associated with the given configuration key.
`Byte`	`getByte(String key, Byte defaultValue)` Get a `Byte` associated with the given configuration key.
`<T> Collection<T>`	`getCollection(Class<T> cls, String key, Collection<T> target)` Get a collection of typed objects associated with the given configuration key.
`<T> Collection<T>`	`getCollection(Class<T> cls, String key, Collection<T> target, Collection<T> defaultValue)` Get a collection of typed objects associated with the given configuration key using the values in the specified default collection if the key does not map to an existing object.
`ConfigurationDecoder`	`getConfigurationDecoder()` Returns the `ConfigurationDecoder` used by this instance.
`ConversionHandler`	`getConversionHandler()` Returns the `ConversionHandler` used by this instance.
`double`	`getDouble(String key)` Get a double associated with the given configuration key.
`double`	`getDouble(String key, double defaultValue)` Get a double associated with the given configuration key.
`Double`	`getDouble(String key, Double defaultValue)` Get a `Double` associated with the given configuration key.
`String`	`getEncodedString(String key)` Get the value of a string property that is stored in encoded form in this configuration using a default `ConfigurationDecoder`.
`String`	`getEncodedString(String key, ConfigurationDecoder decoder)` Get the value of a string property that is stored in encoded form in this configuration.
`float`	`getFloat(String key)` Get a float associated with the given configuration key.
`float`	`getFloat(String key, float defaultValue)` Get a float associated with the given configuration key.
`Float`	`getFloat(String key, Float defaultValue)` Get a `Float` associated with the given configuration key.
`int`	`getInt(String key)` Get a int associated with the given configuration key.
`int`	`getInt(String key, int defaultValue)` Get a int associated with the given configuration key.
`Integer`	`getInteger(String key, Integer defaultValue)` Get an `Integer` associated with the given configuration key.
`ConfigurationInterpolator`	`getInterpolator()` Returns the `ConfigurationInterpolator` object that manages the lookup objects for resolving variables.
`Iterator<String>`	`getKeys()` Get the list of the keys contained in the configuration.
`Iterator<String>`	`getKeys(String prefix)` Get the list of the keys contained in the configuration that match the specified prefix.
`protected abstract Iterator<String>`	`getKeysInternal()` Actually creates an iterator for iterating over the keys in this configuration.
`protected Iterator<String>`	`getKeysInternal(String prefix)` Returns an `Iterator` with all property keys starting with the specified prefix.
`<T> List<T>`	`getList(Class<T> cls, String key)` Get a list of typed objects associated with the given configuration key returning an empty list if the key doesn't map to an existing object.
`<T> List<T>`	`getList(Class<T> cls, String key, List<T> defaultValue)` Get a list of typed objects associated with the given configuration key returning the specified default value if the key doesn't map to an existing object.
`List<Object>`	`getList(String key)` Get a List of the values associated with the given configuration key.
`List<Object>`	`getList(String key, List<?> defaultValue)` Get a List of strings associated with the given configuration key.
`ListDelimiterHandler`	`getListDelimiterHandler()` Returns the `ListDelimiterHandler` used by this instance.
`ConfigurationLogger`	`getLogger()` Returns the logger used by this configuration object.
`long`	`getLong(String key)` Get a long associated with the given configuration key.
`long`	`getLong(String key, long defaultValue)` Get a long associated with the given configuration key.
`Long`	`getLong(String key, Long defaultValue)` Get a `Long` associated with the given configuration key.
`Properties`	`getProperties(String key)` Get a list of properties associated with the given configuration key.
`Properties`	`getProperties(String key, Properties defaults)` Get a list of properties associated with the given configuration key.
`Object`	`getProperty(String key)` Gets a property from the configuration.
`protected abstract Object`	`getPropertyInternal(String key)` Actually obtains the value of the specified property.
`short`	`getShort(String key)` Get a short associated with the given configuration key.
`short`	`getShort(String key, short defaultValue)` Get a short associated with the given configuration key.
`Short`	`getShort(String key, Short defaultValue)` Get a `Short` associated with the given configuration key.
`String`	`getString(String key)` Get a string associated with the given configuration key.
`String`	`getString(String key, String defaultValue)` Get a string associated with the given configuration key.
`String[]`	`getStringArray(String key)` Get an array of strings associated with the given configuration key.
`Synchronizer`	`getSynchronizer()` Returns the object responsible for synchronizing this configuration.
`ImmutableConfiguration`	`immutableSubset(String prefix)` Return a decorator immutable Configuration containing every key from the current Configuration that starts with the specified prefix.
`protected void`	`initLogger(ConfigurationLogger log)` Initializes the logger.
`void`	`installInterpolator(Map<String,? extends Lookup> prefixLookups, Collection<? extends Lookup> defLookups)` Creates and installs a new `ConfigurationInterpolator` for this `Configuration` based on the passed in arguments.
`protected Object`	`interpolate(Object value)` Returns the interpolated value.
`protected String`	`interpolate(String base)` interpolate key names to handle ${key} stuff
`Configuration`	`interpolatedConfiguration()` Returns a configuration with the same content as this configuration, but with all variables replaced by their actual values.
`boolean`	`isEmpty()` Check if the configuration is empty.
`protected abstract boolean`	`isEmptyInternal()` Actually checks whether this configuration contains data.
`protected boolean`	`isScalarValue(Object value)` Checks whether the specified object is a scalar value.
`boolean`	`isThrowExceptionOnMissing()` Returns true if missing values throw Exceptions.
`void`	`lock(LockMode mode)` Locks this object for the specified mode.
`void`	`setConfigurationDecoder(ConfigurationDecoder configurationDecoder)` Sets the `ConfigurationDecoder` for this configuration.
`void`	`setConversionHandler(ConversionHandler conversionHandler)` Sets the `ConversionHandler` to be used by this instance.
`void`	`setDefaultLookups(Collection<? extends Lookup> lookups)` Adds all `Lookup` objects in the given collection as default lookups (i.e.
`void`	`setInterpolator(ConfigurationInterpolator ci)` Sets the `ConfigurationInterpolator` object to be used by this `Configuration`.
`void`	`setListDelimiterHandler(ListDelimiterHandler listDelimiterHandler)` Sets the `ListDelimiterHandler` to be used by this instance.
`void`	`setLogger(ConfigurationLogger log)` Allows setting the logger to be used by this configuration object.
`void`	`setParentInterpolator(ConfigurationInterpolator parent)` Sets the specified `ConfigurationInterpolator` as the parent of this configuration's `ConfigurationInterpolator`.
`void`	`setPrefixLookups(Map<String,? extends Lookup> lookups)` Registers all `Lookup` objects in the given map at the current `ConfigurationInterpolator` of this configuration.
`void`	`setProperty(String key, Object value)` Set a property, this will replace any previously set values.
`protected void`	`setPropertyInternal(String key, Object value)` Actually sets the value of a property.
`void`	`setSynchronizer(Synchronizer synchronizer)` Sets the object responsible for synchronizing this configuration.
`void`	`setThrowExceptionOnMissing(boolean throwExceptionOnMissing)` Allows to set the `throwExceptionOnMissing` flag.
`int`	`size()` Returns the number of keys stored in this configuration.
`protected int`	`sizeInternal()` Actually calculates the size of this configuration.
`Configuration`	`subset(String prefix)` Return a decorator Configuration containing every key from the current Configuration that starts with the specified prefix.
`void`	`unlock(LockMode mode)` Releases a lock of this object that was obtained using the `SynchronizerSupport.lock(LockMode)` method.

Methods inherited from class org.apache.commons.configuration2.event.BaseEventSource
addEventListener, clearErrorListeners, clearEventListeners, clone, copyEventListeners, createErrorEvent, createEvent, fireError, fireEvent, getEventListenerRegistrations, getEventListeners, isDetailEvents, removeEventListener, setDetailEvents

Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - AbstractConfiguration
```
public AbstractConfiguration()
```
    Creates a new instance of AbstractConfiguration.
- Method Detail
  - getListDelimiterHandler
```
public ListDelimiterHandler getListDelimiterHandler()
```
    Returns the ListDelimiterHandler used by this instance.
    
    Returns:
    
    the ListDelimiterHandler
    
    Since:
    
    2.0
  - 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, a ListDelimiterHandler implementation is set which does not support list splitting. This can be changed for instance by setting a DefaultListDelimiterHandler 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.
    
    Parameters:
    
    listDelimiterHandler - the ListDelimiterHandler to be used (must not be null)
    
    Throws:
    
    IllegalArgumentException - if the ListDelimiterHandler is null
    
    Since:
    
    2.0
  - getConversionHandler
```
public ConversionHandler getConversionHandler()
```
    Returns the ConversionHandler used by this instance.
    
    Returns:
    
    the ConversionHandler
    
    Since:
    
    2.0
  - setConversionHandler
```
public void setConversionHandler(ConversionHandler conversionHandler)
```
    Sets the ConversionHandler to be used by this instance. The ConversionHandler is responsible for every kind of data type conversion. It is consulted by all get methods returning results in specific data types. A newly created configuration uses a default ConversionHandler implementation. This can be changed while initializing the configuration (e.g. via a builder). Note that access to this property is not synchronized.
    
    Parameters:
    
    conversionHandler - the ConversionHandler to be used (must not be null)
    
    Throws:
    
    IllegalArgumentException - if the ConversionHandler is null
    
    Since:
    
    2.0
  - setThrowExceptionOnMissing
```
public void setThrowExceptionOnMissing(boolean throwExceptionOnMissing)
```
    Allows to set the throwExceptionOnMissing flag. This flag controls the behavior of property getter methods that return objects if the requested property is missing. If the flag is set to false (which is the default value), these methods will return null. If set to true, they will throw a NoSuchElementException exception. Note that getter methods for primitive data types are not affected by this flag.
    
    Parameters:
    
    throwExceptionOnMissing - The new value for the property
  - isThrowExceptionOnMissing
```
public boolean isThrowExceptionOnMissing()
```
    Returns true if missing values throw Exceptions.
    
    Returns:
    
    true if missing values throw Exceptions
  - getInterpolator
```
public ConfigurationInterpolator getInterpolator()
```
    Returns the ConfigurationInterpolator object that manages the lookup objects for resolving variables.
    
    Specified by:
    
    getInterpolator in interface Configuration
    
    Returns:
    
    the ConfigurationInterpolator associated with this configuration
    
    Since:
    
    1.4
  - setInterpolator
```
public final void setInterpolator(ConfigurationInterpolator ci)
```
    Sets the ConfigurationInterpolator object to be used by this Configuration. This object is invoked for each access of a string property in order to substitute variables which may be contained. The argument can be null to disable interpolation at all. This implementation sets the passed in object without further modifications. A null argument is allowed; this disables interpolation.
    
    Specified by:
    
    setInterpolator in interface Configuration
    
    Parameters:
    
    ci - the new ConfigurationInterpolator
    
    Since:
    
    2.0
  - installInterpolator
```
public final void installInterpolator(Map<String,? extends Lookup> prefixLookups,
                                      Collection<? extends Lookup> defLookups)
```
    Creates and installs a new ConfigurationInterpolator for this Configuration based on the passed in arguments. This method creates a default ConfigurationInterpolator instance and initializes it with the passed in Lookup objects. It also adds a special default Lookup object that tries to resolve variables by matching them with properties contained in this Configuration. This is also the main difference to the Configuration.setInterpolator(ConfigurationInterpolator) method which sets the passed in object as is without adding this special lookup. This implementation creates a new ConfigurationInterpolator instance and initializes it with the given Lookup objects. In addition, it adds a specialized default Lookup object which queries this Configuration.
    
    Specified by:
    
    installInterpolator in interface Configuration
    
    Parameters:
    
    prefixLookups - the map with Lookup objects associated with specific prefixes (can be null)
    
    defLookups - a collection with default Lookup objects (can be null)
    
    Since:
    
    2.0
    
    See Also:
    
    ConfigurationInterpolator
  - setPrefixLookups
```
public void setPrefixLookups(Map<String,? extends Lookup> lookups)
```
    Registers all Lookup objects in the given map at the current ConfigurationInterpolator of this configuration. The set of default lookup objects (for variables without a prefix) is not modified by this method. If this configuration does not have a ConfigurationInterpolator, a new instance is created. Note: This method is mainly intended to be used for initializing a configuration when it is created by a builder. Normal client code should better call installInterpolator(Map, Collection) to define the ConfigurationInterpolator in a single step.
    
    Parameters:
    
    lookups - a map with new Lookup objects and their prefixes (may be null)
    
    Since:
    
    2.0
  - setDefaultLookups
```
public void setDefaultLookups(Collection<? extends Lookup> lookups)
```
    Adds all Lookup objects in the given collection as default lookups (i.e. lookups without a variable prefix) to the ConfigurationInterpolator object of this configuration. In addition, it adds a specialized default Lookup object which queries this Configuration. The set of Lookup objects with prefixes is not modified by this method. If this configuration does not have a ConfigurationInterpolator, a new instance is created. Note: This method is mainly intended to be used for initializing a configuration when it is created by a builder. Normal client code should better call installInterpolator(Map, Collection) to define the ConfigurationInterpolator in a single step.
    
    Parameters:
    
    lookups - the collection with default Lookup objects to be added
    
    Since:
    
    2.0
  - setParentInterpolator
```
public void setParentInterpolator(ConfigurationInterpolator parent)
```
    Sets the specified ConfigurationInterpolator as the parent of this configuration's ConfigurationInterpolator. If this configuration does not have a ConfigurationInterpolator, a new instance is created. Note: This method is mainly intended to be used for initializing a configuration when it is created by a builder. Normal client code can directly update the ConfigurationInterpolator.
    
    Parameters:
    
    parent - the parent ConfigurationInterpolator to be set
    
    Since:
    
    2.0
  - setConfigurationDecoder
```
public void setConfigurationDecoder(ConfigurationDecoder configurationDecoder)
```
    Sets the ConfigurationDecoder for this configuration. This object is used by getEncodedString(String).
    
    Parameters:
    
    configurationDecoder - the ConfigurationDecoder
    
    Since:
    
    2.0
  - getConfigurationDecoder
```
public ConfigurationDecoder getConfigurationDecoder()
```
    Returns the ConfigurationDecoder used by this instance.
    
    Returns:
    
    the ConfigurationDecoder
    
    Since:
    
    2.0
  - cloneInterpolator
```
protected void cloneInterpolator(AbstractConfiguration orgConfig)
```
    Creates a clone of the ConfigurationInterpolator used by this instance. This method can be called by clone() implementations of derived classes. Normally, the ConfigurationInterpolator of a configuration instance must not be shared with other instances because it contains a specific Lookup object pointing to the owning configuration. This has to be taken into account when cloning a configuration. This method creates a new ConfigurationInterpolator for this configuration instance which contains all lookup objects from the original ConfigurationInterpolator except for the configuration specific lookup pointing to the passed in original configuration. This one is replaced by a corresponding Lookup referring to this configuration.
    
    Parameters:
    
    orgConfig - the original configuration from which this one was cloned
    
    Since:
    
    2.0
  - getLogger
```
public ConfigurationLogger getLogger()
```
    Returns the logger used by this configuration object.
    
    Returns:
    
    the logger
    
    Since:
    
    2.0
  - setLogger
```
public void setLogger(ConfigurationLogger log)
```
    Allows setting the logger to be used by this configuration object. This method makes it possible for clients to exactly control logging behavior. Per default a logger is set that will ignore all log messages. Derived classes that want to enable logging should call this method during their initialization with the logger to be used. It is legal to pass a null logger; in this case, logging will be disabled.
    
    Parameters:
    
    log - the new logger
    
    Since:
    
    2.0
  - addErrorLogListener
```
public final void addErrorLogListener()
```
    Adds a special EventListener object to this configuration that will log all internal errors. This method is intended to be used by certain derived classes, for which it is known that they can fail on property access (e.g. DatabaseConfiguration).
    
    Since:
    
    1.4
  - getSynchronizer
```
public final Synchronizer getSynchronizer()
```
    Returns the object responsible for synchronizing this configuration. All access to this configuration - both read and write access - is controlled by this object. This implementation never returns null. If no Synchronizer has been set, a NoOpSynchronizer is returned. So, per default, instances of AbstractConfiguration are not thread-safe unless a suitable Synchronizer is set!
    
    Specified by:
    
    getSynchronizer in interface SynchronizerSupport
    
    Returns:
    
    the Synchronizer used by this instance
    
    Since:
    
    2.0
  - setSynchronizer
```
public final void setSynchronizer(Synchronizer synchronizer)
```
    Sets the object responsible for synchronizing this configuration. This method has to be called with a suitable Synchronizer object when initializing this configuration instance in order to make it thread-safe.
    
    Specified by:
    
    setSynchronizer in interface SynchronizerSupport
    
    Parameters:
    
    synchronizer - the new Synchronizer; can be null, then this instance uses a NoOpSynchronizer
    
    Since:
    
    2.0
  - lock
```
public final void lock(LockMode mode)
```
    Locks this object for the specified mode. This call may block until this object is released from other lock operations. When it returns the caller can access the object in a way compatible to the specified LockMode. When done the unlock() must be called with the same LockMode argument. In practice, a try-finally construct should be used as in the following example:
```
 SynchronizerSupport syncSupport = ...;
 syncSupport.lock(LockMode.READ);
 try
 {
     // read access to syncSupport
 }
 finally
 {
     syncSupport.unlock(LockMode.READ);
 }
 
```
    Note: Always use this method for obtaining a lock rather than accessing the object's Synchronizer directly. An implementation may perform additional actions which are not executed when only interacting with the Synchronizer. This implementation delegates to beginRead() or beginWrite(), depending on the LockMode argument. Subclasses can override these protected methods to perform additional steps when a configuration is locked.
    Specified by:
    
    lock in interface SynchronizerSupport
    
    Parameters:
    
    mode - the LockMode
    
    Throws:
    
    NullPointerException - if the argument is null
    
    Since:
    
    2.0
  - unlock
```
public final void unlock(LockMode mode)
```
    Releases a lock of this object that was obtained using the SynchronizerSupport.lock(LockMode) method. This method must always be called pair-wise with lock(). The argument must match to the one passed to the corresponding lock() call; otherwise, the behavior of the Synchronizer is unspecified. This implementation delegates to endRead() or endWrite(), depending on the LockMode argument. Subclasses can override these protected methods to perform additional steps when a configuration's lock is released.
    
    Specified by:
    
    unlock in interface SynchronizerSupport
    
    Parameters:
    
    mode - the LockMode
    
    Throws:
    
    NullPointerException - if the argument is null
  - beginRead
```
protected void beginRead(boolean optimize)
```
    Notifies this configuration's Synchronizer that a read operation is about to start. This method is called by all methods which access this configuration in a read-only mode. Subclasses may override it to perform additional actions before this read operation. The boolean optimize argument can be evaluated by overridden methods in derived classes. Some operations which require a lock do not need a fully initialized configuration object. By setting this flag to true, such operations can give a corresponding hint. An overridden implementation of beginRead() can then decide to skip some initialization steps. All basic operations in this class (and most of the basic Configuration implementations) call this method with a parameter value of false. In any case the inherited method must be called! Otherwise, proper synchronization is not guaranteed.
    
    Parameters:
    
    optimize - a flag whether optimization can be performed
    
    Since:
    
    2.0
  - endRead
```
protected void endRead()
```
    Notifies this configuration's Synchronizer that a read operation has finished. This method is called by all methods which access this configuration in a read-only manner at the end of their execution. Subclasses may override it to perform additional actions after this read operation. In any case the inherited method must be called! Otherwise, the read lock will not be released.
    
    Since:
    
    2.0
  - beginWrite
```
protected void beginWrite(boolean optimize)
```
    Notifies this configuration's Synchronizer that an update operation is about to start. This method is called by all methods which modify this configuration. Subclasses may override it to perform additional operations before an update. For a description of the boolean optimize argument refer to the documentation of beginRead(). In any case the inherited method must be called! Otherwise, proper synchronization is not guaranteed.
    
    Parameters:
    
    optimize - a flag whether optimization can be performed
    
    Since:
    
    2.0
    
    See Also:
    
    beginRead(boolean)
  - endWrite
```
protected void endWrite()
```
    Notifies this configuration's Synchronizer that an update operation has finished. This method is called by all methods which modify this configuration at the end of their execution. Subclasses may override it to perform additional operations after an update. In any case the inherited method must be called! Otherwise, the write lock will not be released.
    
    Since:
    
    2.0
  - addProperty
```
public final void addProperty(String key,
                              Object value)
```
    Description copied from interface: Configuration
    Add a property to the configuration. If it already exists then the value stated here will be added to the configuration entry. For example, if the property:
```
resource.loader = file
```
    is already present in the configuration and you call
```
addProperty("resource.loader", "classpath")
```
    Then you will end up with a List like the following:
```
["file", "classpath"]
```
    Specified by:
    
    addProperty in interface Configuration
    
    Parameters:
    
    key - The key to add the property to.
    
    value - The value to add.
  - addPropertyInternal
```
protected void addPropertyInternal(String key,
                                   Object value)
```
    Actually adds a property to this configuration. This method is called by addProperty(). It performs list splitting if necessary and delegates to addPropertyDirect(String, Object) for every single property value.
    
    Parameters:
    
    key - the key of the property to be added
    
    value - the new property value
    
    Since:
    
    2.0
  - addPropertyDirect
```
protected abstract void addPropertyDirect(String key,
                                          Object value)
```
    Adds a key/value pair to the Configuration. Override this method to provide write access to underlying Configuration store.
    
    Parameters:
    
    key - key to use for mapping
    
    value - object to store
  - interpolate
```
protected String interpolate(String base)
```
    interpolate key names to handle ${key} stuff
    
    Parameters:
    
    base - string to interpolate
    
    Returns:
    
    returns the key name with the ${key} substituted
  - interpolate
```
protected Object interpolate(Object value)
```
    Returns the interpolated value. This implementation delegates to the current ConfigurationInterpolator. If no ConfigurationInterpolator is set, the passed in value is returned without changes.
    
    Parameters:
    
    value - the value to interpolate
    
    Returns:
    
    the value with variables substituted
  - subset
```
public Configuration subset(String prefix)
```
    Description copied from interface: Configuration
    Return a decorator Configuration containing every key from the current Configuration that starts with the specified prefix. The prefix is removed from the keys in the subset. For example, if the configuration contains the following properties:
```
    prefix.number = 1
    prefix.string = Apache
    prefixed.foo = bar
    prefix = Jakarta
```
    the Configuration returned by subset("prefix") will contain the properties:
```
    number = 1
    string = Apache
    = Jakarta
```
    (The key for the value "Jakarta" is an empty string)
    Since the subset is a decorator and not a modified copy of the initial Configuration, any change made to the subset is available to the Configuration, and reciprocally.
    Specified by:
    
    subset in interface Configuration
    
    Parameters:
    
    prefix - The prefix used to select the properties.
    
    Returns:
    
    a subset configuration
    
    See Also:
    
    SubsetConfiguration
  - immutableSubset
```
public ImmutableConfiguration immutableSubset(String prefix)
```
    Description copied from interface: ImmutableConfiguration
    Return a decorator immutable Configuration containing every key from the current Configuration that starts with the specified prefix. The prefix is removed from the keys in the subset. For example, if the configuration contains the following properties:
```
    prefix.number = 1
    prefix.string = Apache
    prefixed.foo = bar
    prefix = Jakarta
```
    the immutable Configuration returned by subset("prefix") will contain the properties:
```
    number = 1
    string = Apache
    = Jakarta
```
    (The key for the value "Jakarta" is an empty string)
    Specified by:
    
    immutableSubset in interface ImmutableConfiguration
    
    Parameters:
    
    prefix - The prefix used to select the properties.
    
    Returns:
    
    a subset immutable configuration
  - setProperty
```
public final void setProperty(String key,
                              Object value)
```
    Description copied from interface: Configuration
    
    Set a property, this will replace any previously set values. Set values is implicitly a call to clearProperty(key), addProperty(key, value).
    
    Specified by:
    
    setProperty in interface Configuration
    
    Parameters:
    
    key - The key of the property to change
    
    value - The new value
  - setPropertyInternal
```
protected void setPropertyInternal(String key,
                                   Object value)
```
    Actually sets the value of a property. This method is called by setProperty(). It provides a default implementation of this functionality by clearing the specified key and delegating to addProperty(). Subclasses should override this method if they can provide a more efficient algorithm for setting a property value.
    
    Parameters:
    
    key - the property key
    
    value - the new property value
    
    Since:
    
    2.0
  - clearProperty
```
public final void clearProperty(String key)
```
    Removes the specified property from this configuration. This implementation performs some preparations and then delegates to clearPropertyDirect(), which will do the real work.
    
    Specified by:
    
    clearProperty in interface Configuration
    
    Parameters:
    
    key - the key to be removed
  - clearPropertyDirect
```
protected abstract void clearPropertyDirect(String key)
```
    Removes the specified property from this configuration. This method is called by clearProperty() after it has done some preparations. It must be overridden in sub classes.
    
    Parameters:
    
    key - the key to be removed
  - clear
```
public final void clear()
```
    Description copied from interface: Configuration
    
    Remove all properties from the configuration.
    
    Specified by:
    
    clear in interface Configuration
  - clearInternal
```
protected void clearInternal()
```
    Clears the whole configuration. This method is called by clear() after some preparations have been made. This base implementation uses the iterator provided by getKeys() to remove every single property. Subclasses should override this method if there is a more efficient way of clearing the configuration.
  - getKeys
```
public final Iterator<String> getKeys()
```
    Get the list of the keys contained in the configuration. The returned iterator can be used to obtain all defined keys. It does not allow removing elements from this configuration via its remove() method. Note that the keys of this configuration are returned in a form, so that they can be directly evaluated; escaping of special characters (if necessary) has already been performed. This implementation takes care of synchronization and then delegates to getKeysInternal() for obtaining the actual iterator. Note that depending on a concrete implementation, an iteration may fail if the configuration is updated concurrently.
    
    Specified by:
    
    getKeys in interface ImmutableConfiguration
    
    Returns:
    
    An Iterator.
  - getKeys
```
public final Iterator<String> getKeys(String prefix)
```
    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 ImmutableConfiguration
    
    Parameters:
    
    prefix - The prefix to test against.
    
    Returns:
    
    An Iterator of keys that match the prefix.
    
    See Also:
    
    ImmutableConfiguration.getKeys()
  - getKeysInternal
```
protected abstract Iterator<String> getKeysInternal()
```
    Actually creates an iterator for iterating over the keys in this configuration. This method is called by getKeys(), it has to be defined by concrete subclasses.
    
    Returns:
    
    an Iterator with all property keys in this configuration
    
    Since:
    
    2.0
  - getKeysInternal
```
protected Iterator<String> getKeysInternal(String prefix)
```
    Returns an Iterator with all property keys starting with the specified prefix. This method is called by getKeys(String). It is fully implemented by delegating to getKeysInternal() 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.
    
    Parameters:
    
    prefix - the prefix for the keys to be taken into account
    
    Returns:
    
    an Iterator returning the filtered keys
    
    Since:
    
    2.0
  - getProperty
```
public final Object getProperty(String key)
```
    Gets a property from the configuration. This is the most basic get method for retrieving values of properties. In a typical implementation of the Configuration interface the other get methods (that return specific data types) will internally make use of this method. On this level variable substitution is not yet performed. The returned object is an internal representation of the property value for the passed in key. It is owned by the Configuration object. So a caller should not modify this object. It cannot be guaranteed that this object will stay constant over time (i.e. further update operations on the configuration may change its internal state). This implementation ensures proper synchronization. Subclasses have to define the abstract getPropertyInternal() method which is called from here.
    
    Specified by:
    
    getProperty in interface ImmutableConfiguration
    
    Parameters:
    
    key - property to retrieve
    
    Returns:
    
    the value to which this configuration maps the specified key, or null if the configuration contains no mapping for this key.
  - getPropertyInternal
```
protected abstract Object getPropertyInternal(String key)
```
    Actually obtains the value of the specified property. This method is called by getProperty(). Concrete subclasses must define it to fetch the value of the desired property.
    
    Parameters:
    
    key - the key of the property in question
    
    Returns:
    
    the (raw) value of this property
    
    Since:
    
    2.0
  - isEmpty
```
public final boolean isEmpty()
```
    Check if the configuration is empty. This implementation handles synchronization and delegates to isEmptyInternal().
    
    Specified by:
    
    isEmpty in interface ImmutableConfiguration
    
    Returns:
    
    true if the configuration contains no property, false otherwise.
  - isEmptyInternal
```
protected abstract boolean isEmptyInternal()
```
    Actually checks whether this configuration contains data. This method is called by isEmpty(). It has to be defined by concrete subclasses.
    
    Returns:
    
    true if this configuration contains no data, false otherwise
    
    Since:
    
    2.0
  - size
```
public final int size()
```
    Returns the number of keys stored in this configuration. Note that a concrete implementation is not guaranteed to be efficient; for some implementations it may be expensive to determine the size. Especially, if you just want to check whether a configuration is empty, it is preferable to use the ImmutableConfiguration.isEmpty() method. This implementation handles synchronization and delegates to sizeInternal().
    
    Specified by:
    
    size in interface ImmutableConfiguration
    
    Returns:
    
    the number of keys stored in this configuration
  - sizeInternal
```
protected int sizeInternal()
```
    Actually calculates the size of this configuration. This method is called by size() with a read lock held. The base implementation provided here calculates the size based on the iterator returned by getKeys(). Sub classes which can determine the size in a more efficient way should override this method.
    
    Returns:
    
    the size of this configuration (i.e. the number of keys)
  - containsKey
```
public final boolean containsKey(String key)
```
    Check if the configuration contains the specified key. This implementation handles synchronization and delegates to containsKeyInternal().
    
    Specified by:
    
    containsKey in interface ImmutableConfiguration
    
    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
  - containsKeyInternal
```
protected abstract boolean containsKeyInternal(String key)
```
    Actually checks whether the specified key is contained in this configuration. This method is called by containsKey(). It has to be defined by concrete subclasses.
    
    Parameters:
    
    key - the key in question
    
    Returns:
    
    true if this key is contained in this configuration, false otherwise
    
    Since:
    
    2.0
  - getProperties
```
public Properties getProperties(String key)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a list of properties associated with the given configuration key. This method expects the given key to have an arbitrary number of String values, each of which is of the form key=value. These strings are split at the equals sign, and the key parts will become keys of the returned Properties object, the value parts become values.
    
    Specified by:
    
    getProperties in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    Returns:
    
    The associated properties if key is found.
  - getProperties
```
public Properties getProperties(String key,
                                Properties defaults)
```
    Get a list of properties associated with the given configuration key.
    
    Parameters:
    
    key - The configuration key.
    
    defaults - Any default values for the returned Properties object. Ignored if null.
    
    Returns:
    
    The associated properties if key is found.
    
    Throws:
    
    ConversionException - is thrown if the key maps to an object that is not a String/List of Strings.
    
    IllegalArgumentException - if one of the tokens is malformed (does not contain an equals sign).
  - getBoolean
```
public boolean getBoolean(String key)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a boolean associated with the given configuration key.
    
    Specified by:
    
    getBoolean in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    Returns:
    
    The associated boolean.
  - getBoolean
```
public boolean getBoolean(String key,
                          boolean defaultValue)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a boolean associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned.
    
    Specified by:
    
    getBoolean in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated boolean.
  - getBoolean
```
public Boolean getBoolean(String key,
                          Boolean defaultValue)
```
    Obtains the value of the specified key and tries to convert it into a Boolean object. If the property has no value, the passed in default value will be used.
    
    Specified by:
    
    getBoolean in interface ImmutableConfiguration
    
    Parameters:
    
    key - the key of the property
    
    defaultValue - the default value
    
    Returns:
    
    the value of this key converted to a Boolean
    
    Throws:
    
    ConversionException - if the value cannot be converted to a Boolean
  - getByte
```
public byte getByte(String key)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a byte associated with the given configuration key.
    
    Specified by:
    
    getByte in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    Returns:
    
    The associated byte.
  - getByte
```
public byte getByte(String key,
                    byte defaultValue)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a byte associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned.
    
    Specified by:
    
    getByte in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated byte.
  - getByte
```
public Byte getByte(String key,
                    Byte defaultValue)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a Byte associated with the given configuration key.
    
    Specified by:
    
    getByte in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated byte if key is found and has valid format, default value otherwise.
  - getDouble
```
public double getDouble(String key)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a double associated with the given configuration key.
    
    Specified by:
    
    getDouble in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    Returns:
    
    The associated double.
  - getDouble
```
public double getDouble(String key,
                        double defaultValue)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a double associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned.
    
    Specified by:
    
    getDouble in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated double.
  - getDouble
```
public Double getDouble(String key,
                        Double defaultValue)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a Double associated with the given configuration key.
    
    Specified by:
    
    getDouble in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated double if key is found and has valid format, default value otherwise.
  - getFloat
```
public float getFloat(String key)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a float associated with the given configuration key.
    
    Specified by:
    
    getFloat in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    Returns:
    
    The associated float.
  - getFloat
```
public float getFloat(String key,
                      float defaultValue)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a float associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned.
    
    Specified by:
    
    getFloat in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated float.
  - getFloat
```
public Float getFloat(String key,
                      Float defaultValue)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a Float associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned.
    
    Specified by:
    
    getFloat in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated float if key is found and has valid format, default value otherwise.
  - getInt
```
public int getInt(String key)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a int associated with the given configuration key.
    
    Specified by:
    
    getInt in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    Returns:
    
    The associated int.
  - getInt
```
public int getInt(String key,
                  int defaultValue)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a int associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned.
    
    Specified by:
    
    getInt in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated int.
  - getInteger
```
public Integer getInteger(String key,
                          Integer defaultValue)
```
    Description copied from interface: ImmutableConfiguration
    
    Get an Integer associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned.
    
    Specified by:
    
    getInteger in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated int if key is found and has valid format, default value otherwise.
  - getLong
```
public long getLong(String key)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a long associated with the given configuration key.
    
    Specified by:
    
    getLong in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    Returns:
    
    The associated long.
  - getLong
```
public long getLong(String key,
                    long defaultValue)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a long associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned.
    
    Specified by:
    
    getLong in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated long.
  - getLong
```
public Long getLong(String key,
                    Long defaultValue)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a Long associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned.
    
    Specified by:
    
    getLong in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated long if key is found and has valid format, default value otherwise.
  - getShort
```
public short getShort(String key)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a short associated with the given configuration key.
    
    Specified by:
    
    getShort in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    Returns:
    
    The associated short.
  - getShort
```
public short getShort(String key,
                      short defaultValue)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a short associated with the given configuration key.
    
    Specified by:
    
    getShort in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated short.
  - getShort
```
public Short getShort(String key,
                      Short defaultValue)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a Short associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned.
    
    Specified by:
    
    getShort in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated short if key is found and has valid format, default value otherwise.
  - getBigDecimal
```
public BigDecimal getBigDecimal(String key)
```
    Get a BigDecimal associated with the given configuration key.
    
    Specified by:
    
    getBigDecimal in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    Returns:
    
    The associated BigDecimal if key is found and has valid format
    
    See Also:
    
    setThrowExceptionOnMissing(boolean)
  - getBigDecimal
```
public BigDecimal getBigDecimal(String key,
                                BigDecimal defaultValue)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a BigDecimal associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned.
    
    Specified by:
    
    getBigDecimal in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated BigDecimal if key is found and has valid format, default value otherwise.
  - getBigInteger
```
public BigInteger getBigInteger(String key)
```
    Get a BigInteger associated with the given configuration key.
    
    Specified by:
    
    getBigInteger in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    Returns:
    
    The associated BigInteger if key is found and has valid format
    
    See Also:
    
    setThrowExceptionOnMissing(boolean)
  - getBigInteger
```
public BigInteger getBigInteger(String key,
                                BigInteger defaultValue)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a BigInteger associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned.
    
    Specified by:
    
    getBigInteger in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated BigInteger if key is found and has valid format, default value otherwise.
  - getString
```
public String getString(String key)
```
    Get a string associated with the given configuration key.
    
    Specified by:
    
    getString in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    Returns:
    
    The associated string.
    
    See Also:
    
    setThrowExceptionOnMissing(boolean)
  - getString
```
public String getString(String key,
                        String defaultValue)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a string associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned.
    
    Specified by:
    
    getString in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated string if key is found and has valid format, default value otherwise.
  - getEncodedString
```
public String getEncodedString(String key,
                               ConfigurationDecoder decoder)
```
    Get the value of a string property that is stored in encoded form in this configuration. This method obtains the value of the string property identified by the given key. This value is then passed to the provided ConfigurationDecoder. The value returned by the ConfigurationDecoder is passed to the caller. If the key is not associated with a value, the decoder is not invoked; depending on this configuration's settings either null is returned or an exception is thrown. This implementation delegates to getString(String) in order to obtain the value of the passed in key. This value is passed to the decoder. Because getString() is used behind the scenes all standard features like handling of missing keys and interpolation work as expected.
    
    Specified by:
    
    getEncodedString in interface ImmutableConfiguration
    
    Parameters:
    
    key - the configuration key
    
    decoder - the ConfigurationDecoder (must not be null)
    
    Returns:
    
    the plain string value of the specified encoded property
  - getEncodedString
```
public String getEncodedString(String key)
```
    Get the value of a string property that is stored in encoded form in this configuration using a default ConfigurationDecoder. This method works like the method with the same name, but it uses a default ConfigurationDecoder associated with this configuration. It depends on a specific implementation how this default decoder is obtained. This implementation makes use of the ConfigurationDecoder set for this configuration. If no such object has been set, an IllegalStateException exception is thrown.
    
    Specified by:
    
    getEncodedString in interface ImmutableConfiguration
    
    Parameters:
    
    key - the configuration key
    
    Returns:
    
    the plain string value of the specified encoded property
    
    Throws:
    
    IllegalStateException - if no ConfigurationDecoder is set
    
    See Also:
    
    setConfigurationDecoder(ConfigurationDecoder)
  - getStringArray
```
public String[] getStringArray(String key)
```
    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 association ListDelimiterHandler is consulted to find out whether the string can be split into multiple values.
    
    Specified by:
    
    getStringArray in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    Returns:
    
    The associated string array if key is found.
    
    Throws:
    
    ConversionException - is thrown if the key maps to an object that is not a String/List of Strings.
    
    See Also:
    
    setListDelimiterHandler(ListDelimiterHandler)
  - getList
```
public List<Object> getList(String key)
```
    Get a List of the values associated with the given configuration key. This method is different from the generic getList() method in that it does not recursively obtain all values stored for the specified property key. Rather, only the first level of the hierarchy is processed. So the resulting list may contain complex objects like arrays or collections - depending on the storage structure used by a concrete subclass. If the key doesn't map to an existing object, an empty List is returned.
    
    Specified by:
    
    getList in interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    Returns:
    
    The associated List.
    
    See Also:
    
    getStringArray(String)
  - getList
```
public List<Object> getList(String key,
                            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 interface ImmutableConfiguration
    
    Parameters:
    
    key - The configuration key.
    
    defaultValue - The default value.
    
    Returns:
    
    The associated List of strings.
    
    See Also:
    
    ImmutableConfiguration.getList(Class, String, List)
  - get
```
public <T> T get(Class<T> cls,
                 String key)
```
    Description copied from interface: ImmutableConfiguration
    
    Get an object of the specified type associated with the given configuration key. If the key doesn't map to an existing object, the method returns null unless isThrowExceptionOnMissing() is set to true.
    
    Specified by:
    
    get in interface ImmutableConfiguration
    
    Type Parameters:
    
    T - the target type of the value
    
    Parameters:
    
    cls - the target class of the value
    
    key - the key of the value
    
    Returns:
    
    the value of the requested type for the key
  - get
```
public <T> T get(Class<T> cls,
                 String key,
                 T defaultValue)
```
    Get an object of the specified type associated with the given configuration key using a default value. If the key doesn't map to an existing object, the default value is returned. This implementation delegates to the ConversionHandler to perform the actual type conversion.
    
    Specified by:
    
    get in interface ImmutableConfiguration
    
    Type Parameters:
    
    T - the target type of the value
    
    Parameters:
    
    cls - the target class of the value
    
    key - the key of the value
    
    defaultValue - the default value
    
    Returns:
    
    the value of the requested type for the key
  - getArray
```
public Object getArray(Class<?> cls,
                       String key)
```
    Description copied from interface: ImmutableConfiguration
    
    Get an array of typed objects associated with the given configuration key. If the key doesn't map to an existing object, an empty list is returned.
    
    Specified by:
    
    getArray in interface ImmutableConfiguration
    
    Parameters:
    
    cls - the type expected for the elements of the array
    
    key - The configuration key.
    
    Returns:
    
    The associated array if the key is found, and the value compatible with the type specified.
  - getArray
```
public Object getArray(Class<?> cls,
                       String key,
                       Object defaultValue)
```
    Get an array of typed objects associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned. This implementation delegates to the ConversionHandler to perform the actual type conversion. If this results in a null result (because the property is undefined), the default value is returned. It is checked whether the default value is an array with the correct component type. If not, an exception is thrown.
    
    Specified by:
    
    getArray in interface ImmutableConfiguration
    
    Parameters:
    
    cls - the type expected for the elements of the array
    
    key - the configuration key.
    
    defaultValue - the default value
    
    Returns:
    
    The associated array if the key is found, and the value compatible with the type specified.
    
    Throws:
    
    IllegalArgumentException - if the default value is not a compatible array
  - getList
```
public <T> List<T> getList(Class<T> cls,
                           String key)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a list of typed objects associated with the given configuration key returning an empty list if the key doesn't map to an existing object.
    
    Specified by:
    
    getList in interface ImmutableConfiguration
    
    Type Parameters:
    
    T - the type expected for the elements of the list
    
    Parameters:
    
    cls - the class expected for the elements of the list
    
    key - The configuration key.
    
    Returns:
    
    The associated list if the key is found.
  - getList
```
public <T> List<T> getList(Class<T> cls,
                           String key,
                           List<T> defaultValue)
```
    Get a list of typed objects associated with the given configuration key returning the specified default value if the key doesn't map to an existing object. This method recursively retrieves all values stored for the passed in key, i.e. if one of these values is again a complex object like an array or a collection (which may be the case for some concrete subclasses), all values are extracted and added to the resulting list - performing a type conversion if necessary. This implementation delegates to the generic getCollection(). As target collection a newly created ArrayList is passed in.
    
    Specified by:
    
    getList in interface ImmutableConfiguration
    
    Type Parameters:
    
    T - the type expected for the elements of the list
    
    Parameters:
    
    cls - the class expected for the elements of the list
    
    key - the configuration key.
    
    defaultValue - the default value.
    
    Returns:
    
    The associated List.
  - getCollection
```
public <T> Collection<T> getCollection(Class<T> cls,
                                       String key,
                                       Collection<T> target)
```
    Description copied from interface: ImmutableConfiguration
    
    Get a collection of typed objects associated with the given configuration key. This method works like ImmutableConfiguration.getCollection(Class, String, Collection, Collection) passing in null as default value.
    
    Specified by:
    
    getCollection in interface ImmutableConfiguration
    
    Type Parameters:
    
    T - the element type of the result list
    
    Parameters:
    
    cls - the the element class of the result list
    
    key - the configuration key
    
    target - the target collection (may be null)
    
    Returns:
    
    the collection to which data was added
  - getCollection
```
public <T> Collection<T> getCollection(Class<T> cls,
                                       String key,
                                       Collection<T> target,
                                       Collection<T> defaultValue)
```
    Get a collection of typed objects associated with the given configuration key using the values in the specified default collection if the key does not map to an existing object. This method is similar to getList(), however, it allows specifying a target collection. Results are added to this collection. This is useful if the data retrieved should be added to a specific kind of collection, e.g. a set to remove duplicates. The return value is as follows:
    - If the key does not map to an existing object and the default value is null, the method returns null.
    - If the target collection is not null and data has been added (either from the resolved property value or from the default collection), the target collection is returned.
    - If the target collection is null and data has been added (either from the resolved property value or from the default collection), return value is the target collection created by this method.
    This implementation delegates to the ConversionHandler to perform the actual conversion. If no target collection is provided, an ArrayList is created.
    Specified by:
    
    getCollection in interface ImmutableConfiguration
    
    Type Parameters:
    
    T - the element type of the result list
    
    Parameters:
    
    cls - the the element class of the result list
    
    key - the configuration key
    
    target - the target collection (may be null)
    
    defaultValue - the default value (may be null)
    
    Returns:
    
    the collection to which data was added
  - isScalarValue
```
protected boolean isScalarValue(Object value)
```
    Checks whether the specified object is a scalar value. This method is called by getList() and getStringArray() if the property requested is not a string, a list, or an array. If it returns true, the calling method transforms the value to a string and returns a list or an array with this single element. This implementation returns true if the value is of a wrapper type for a primitive type.
    
    Parameters:
    
    value - the value to be checked
    
    Returns:
    
    a flag whether the value is a scalar
    
    Since:
    
    1.7
  - copy
```
public void copy(Configuration c)
```
    Copies the content of the specified configuration into this configuration. If the specified configuration contains a key that is also present in this configuration, the value of this key will be replaced by the new value. Note: This method won't work well when copying hierarchical configurations because it is not able to copy information about the properties' structure (i.e. the parent-child-relationships will get lost). So when dealing with hierarchical configuration objects their clone() methods should be used.
    
    Parameters:
    
    c - the configuration to copy (can be null, then this operation will have no effect)
    
    Since:
    
    1.5
  - append
```
public void append(Configuration c)
```
    Appends the content of the specified configuration to this configuration. The values of all properties contained in the specified configuration will be appended to this configuration. So if a property is already present in this configuration, its new value will be a union of the values in both configurations. Note: This method won't work well when appending hierarchical configurations because it is not able to copy information about the properties' structure (i.e. the parent-child-relationships will get lost). So when dealing with hierarchical configuration objects their clone() methods should be used.
    
    Parameters:
    
    c - the configuration to be appended (can be null, then this operation will have no effect)
    
    Since:
    
    1.5
  - interpolatedConfiguration
```
public Configuration interpolatedConfiguration()
```
    Returns a configuration with the same content as this configuration, but with all variables replaced by their actual values. This method tries to clone the configuration and then perform interpolation on all properties. So property values of the form ${var} will be resolved as far as possible (if a variable cannot be resolved, it remains unchanged). This operation is useful if the content of a configuration is to be exported or processed by an external component that does not support variable interpolation.
    
    Returns:
    
    a configuration with all variables interpolated
    
    Throws:
    
    ConfigurationRuntimeException - if this configuration cannot be cloned
    
    Since:
    
    1.5
  - initLogger
```
protected final void initLogger(ConfigurationLogger log)
```
    Initializes the logger. Supports null input. This method can be called by derived classes in order to enable logging.
    
    Parameters:
    
    log - the logger
    
    Since:
    
    2.0

Class AbstractConfiguration

Constructor Summary

Method Summary

Methods inherited from class org.apache.commons.configuration2.event.BaseEventSource

Methods inherited from class java.lang.Object

Constructor Detail

AbstractConfiguration

Method Detail

getListDelimiterHandler

setListDelimiterHandler

getConversionHandler

setConversionHandler

setThrowExceptionOnMissing

isThrowExceptionOnMissing

getInterpolator

setInterpolator

installInterpolator

setPrefixLookups

setDefaultLookups

setParentInterpolator

setConfigurationDecoder

getConfigurationDecoder

cloneInterpolator

getLogger

setLogger

addErrorLogListener

getSynchronizer

setSynchronizer

lock

unlock

beginRead

endRead

beginWrite

endWrite

addProperty

addPropertyInternal

addPropertyDirect

interpolate

interpolate

subset

immutableSubset

setProperty

setPropertyInternal

clearProperty

clearPropertyDirect

clear

clearInternal

getKeys

getKeys

getKeysInternal

getKeysInternal

getProperty

getPropertyInternal

isEmpty

isEmptyInternal

size

sizeInternal

containsKey

containsKeyInternal

getProperties

getProperties

getBoolean

getBoolean

getBoolean

getByte

getByte

getByte

getDouble

getDouble

getDouble

getFloat

getFloat

getFloat

getInt

getInt

getInteger

getLong

getLong

getLong

getShort