## org.apache.commons.configuration
Class AbstractConfiguration

    java.lang.Object
      org.apache.commons.configuration.event.EventSource
          org.apache.commons.configuration.AbstractConfiguration

All Implemented Interfaces:
  Configuration

Direct Known Subclasses:
  AppletConfiguration, BaseConfiguration, CompositeConfiguration, DatabaseConfiguration, DataConfiguration, HierarchicalConfiguration, JNDIConfiguration, MapConfiguration, ServletConfiguration, ServletContextConfiguration, ServletFilterConfiguration, ServletRequestConfiguration, SubsetConfiguration

    public abstract class AbstractConfiguration

extends EventSource
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.
- 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. (With the `setListDelimiter()` method the delimiter character can be specified; per default a comma is used. The `setDelimiterParsingDisabled()` method can be used to disable list splitting completely.)
- Allows to specify 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.

Version:
  $Id: AbstractConfiguration.java 1234985 2012-01-23 21:09:09Z oheger $
Author:
  Konstantin Shaposhnikov , Henning P. Schmiedehausen

Field Summary
`protected static String` `END_TOKEN` end token
`static int` `EVENT_ADD_PROPERTY` Constant for the add property event type.
`static int` `EVENT_CLEAR` Constant for the clear configuration event type.
`static int` `EVENT_CLEAR_PROPERTY` Constant for the clear property event type.
`static int` `EVENT_READ_PROPERTY` Constant for the get property event type.
`static int` `EVENT_SET_PROPERTY` Constant for the set property event type.
`protected static String` `START_TOKEN` start token

Constructor Summary
`AbstractConfiguration()` Creates a new instance of `AbstractConfiguration`.

Method Summary
`void` `addErrorLogListener()` Adds a special `ConfigurationErrorListener` 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.
`void` `append(Configuration c)` Appends the content of the specified configuration to this configuration.
`void` `clear()` Remove all properties from the configuration.
`void` `clearProperty(String key)` Removes the specified property from this configuration.
`protected void` `clearPropertyDirect(String key)` Removes the specified property from this configuration.
`void` `copy(Configuration c)` Copies the content of the specified configuration into this configuration.
`protected ConfigurationInterpolator` `createInterpolator()` Creates the interpolator object that is responsible for variable interpolation.
`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.
`static char` `getDefaultListDelimiter()` Retrieve the current delimiter.
`static char` `getDelimiter()` Deprecated. Use AbstractConfiguration.getDefaultListDelimiter() instead
`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.
`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(String prefix)` Get the list of the keys contained in the configuration that match the specified prefix.
`List<Object>` `getList(String key)` Get a List of strings associated with the given configuration key.
`List<Object>` `getList(String key, List<Object> defaultValue)` Get a List of strings associated with the given configuration key.
`char` `getListDelimiter()` Retrieve the delimiter for this configuration.
`org.apache.commons.logging.Log` `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.
`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.
`org.apache.commons.lang.text.StrSubstitutor` `getSubstitutor()` Returns the object that is responsible for variable interpolation.
`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.
`protected String` `interpolateHelper(String base, List<?> priorVariables)` Deprecated. Interpolation is now handled by `PropertyConverter`; this method will no longer be called
`boolean` `isDelimiterParsingDisabled()` Determine if this configuration is using delimiters when parsing property values to convert them to lists of values.
`protected boolean` `isScalarValue(Object value)` Checks whether the specified object is a scalar value.
`boolean` `isThrowExceptionOnMissing()` Returns true if missing values throw Exceptions.
`protected Object` `resolveContainerStore(String key)` Returns an object from the store described by the key.
`static void` `setDefaultListDelimiter(char delimiter)` For configurations extending AbstractConfiguration, allow them to change the listDelimiter from the default comma (",").
`static void` `setDelimiter(char delimiter)` Deprecated. Use AbstractConfiguration.setDefaultListDelimiter(char) instead
`void` `setDelimiterParsingDisabled(boolean delimiterParsingDisabled)` Set whether this configuration should use delimiters when parsing property values to convert them to lists of values.
`void` `setListDelimiter(char listDelimiter)` Change the list delimiter for this configuration.
`void` `setLogger(org.apache.commons.logging.Log log)` Allows to set the logger to be used by this configuration object.
`void` `setProperty(String key, Object value)` Set a property, this will replace any previously set values.
`void` `setThrowExceptionOnMissing(boolean throwExceptionOnMissing)` Allows to set the `throwExceptionOnMissing` flag.
`Configuration` `subset(String prefix)` Return a decorator Configuration containing every key from the current Configuration that starts with the specified prefix.

Methods inherited from class org.apache.commons.configuration.event.EventSource
`addConfigurationListener, addErrorListener, clearConfigurationListeners, clearErrorListeners, clone, createErrorEvent, createEvent, fireError, fireEvent, getConfigurationListeners, getErrorListeners, isDetailEvents, removeConfigurationListener, removeErrorListener, setDetailEvents`

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

Methods inherited from interface org.apache.commons.configuration.Configuration
`containsKey, getKeys, getProperty, isEmpty`

Field Detail

### EVENT_ADD_PROPERTY

    public static final int EVENT_ADD_PROPERTY

  Constant for the add property event type.

  Since:
    1.3
  See Also:
    Constant Field Values

### EVENT_CLEAR_PROPERTY

    public static final int EVENT_CLEAR_PROPERTY

  Constant for the clear property event type.

  Since:
    1.3
  See Also:
    Constant Field Values

### EVENT_SET_PROPERTY

    public static final int EVENT_SET_PROPERTY

  Constant for the set property event type.

  Since:
    1.3
  See Also:
    Constant Field Values

### EVENT_CLEAR

    public static final int EVENT_CLEAR

  Constant for the clear configuration event type.

  Since:
    1.3
  See Also:
    Constant Field Values

### EVENT_READ_PROPERTY

    public static final int EVENT_READ_PROPERTY

  Constant for the get property event type. This event type is used for error events.

  Since:
    1.4
  See Also:
    Constant Field Values

### START_TOKEN

    protected static final String START_TOKEN

  start token

  See Also:
    Constant Field Values

### END_TOKEN

    protected static final String END_TOKEN

  end token

  See Also:
    Constant Field Values

Constructor Detail

### AbstractConfiguration

    public AbstractConfiguration()

  Creates a new instance of `AbstractConfiguration`.

Method Detail

### setDefaultListDelimiter

    public static void setDefaultListDelimiter(char delimiter)

  For configurations extending AbstractConfiguration, allow them to change the listDelimiter from the default comma (","). This value will be used only when creating new configurations. Those already created will not be affected by this change

  Parameters:
    `delimiter` - The new listDelimiter

### setDelimiter

    @Deprecated
    public static void setDelimiter(char delimiter)

  Deprecated. Use AbstractConfiguration.setDefaultListDelimiter(char) instead

  Sets the default list delimiter.

  Parameters:
    `delimiter` - the delimiter character

### getDefaultListDelimiter

    public static char getDefaultListDelimiter()

  Retrieve the current delimiter. By default this is a comma (",").

  Returns:
    The delimiter in use

### getDelimiter

    @Deprecated
    public static char getDelimiter()

  Deprecated. Use AbstractConfiguration.getDefaultListDelimiter() instead

  Returns the default list delimiter.

  Returns:
    the default list delimiter

### setListDelimiter

    public void setListDelimiter(char listDelimiter)

  Change the list delimiter for this configuration. Note: this change will only be effective for new parsings. If you want it to take effect for all loaded properties use the no arg constructor and call this method before setting the source.

  Parameters:
    `listDelimiter` - The new listDelimiter

### getListDelimiter

    public char getListDelimiter()

  Retrieve the delimiter for this configuration. The default is the value of defaultListDelimiter.

  Returns:
    The listDelimiter in use

### isDelimiterParsingDisabled

    public boolean isDelimiterParsingDisabled()

  Determine if this configuration is using delimiters when parsing property values to convert them to lists of values. Defaults to false

  Returns:
    true if delimiters are not being used

### setDelimiterParsingDisabled

    public void setDelimiterParsingDisabled(boolean delimiterParsingDisabled)

  Set whether this configuration should use delimiters when parsing property values to convert them to lists of values. By default delimiter parsing is enabled Note: this change will only be effective for new parsings. If you want it to take effect for all loaded properties use the no arg constructor and call this method before setting source.

  Parameters:
    `delimiterParsingDisabled` - a flag whether delimiter parsing should be disabled

### 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

### getSubstitutor

    public org.apache.commons.lang.text.StrSubstitutor getSubstitutor()

  Returns the object that is responsible for variable interpolation.

  Returns:
    the object responsible for variable interpolation
  Since:
    1.4

### getInterpolator

    public ConfigurationInterpolator getInterpolator()

  Returns the `ConfigurationInterpolator` object that manages the lookup objects for resolving variables. Note: If this object is manipulated (e.g. new lookup objects added), synchronization has to be manually ensured. Because `ConfigurationInterpolator` is not thread-safe concurrent access to properties of this configuration instance (which causes the interpolator to be invoked) may cause race conditions.

  Returns:
    the `ConfigurationInterpolator` associated with this configuration
  Since:
    1.4

### createInterpolator

    protected ConfigurationInterpolator createInterpolator()

  Creates the interpolator object that is responsible for variable interpolation. This method is invoked on first access of the interpolation features. It creates a new instance of `ConfigurationInterpolator` and sets the default lookup object to an implementation that queries this configuration.

  Returns:
    the newly created interpolator object
  Since:
    1.4

### getLogger

    public org.apache.commons.logging.Log getLogger()

  Returns the logger used by this configuration object.

  Returns:
    the logger
  Since:
    1.4

### setLogger

    public void setLogger(org.apache.commons.logging.Log log)

  Allows to set 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.

  Parameters:
    `log` - the new logger
  Since:
    1.4

### addErrorLogListener

    public void addErrorLogListener()

  Adds a special `ConfigurationErrorListener` 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

### addProperty

    public 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.

### 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. Non String values are returned without change.

  Parameters:
    `value` - the value to interpolate
  Returns:
    returns the value with variables substituted

### interpolateHelper

    @Deprecated
    protected String interpolateHelper(String base,
                                                  List<?> priorVariables)

  Deprecated. Interpolation is now handled by `PropertyConverter`; this method will no longer be called

  Recursive handler for multple levels of interpolation. When called the first time, priorVariables should be null.

  Parameters:
    `base` - string with the ${key} variables
    `priorVariables` - serves two purposes: to allow checking for loops, and creating a meaningful exception message should a loop occur. It's 0'th element will be set to the value of base from the first call. All subsequent interpolated variables are added afterward.
  Returns:
    the string with the interpolation taken care of

### 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`

### setProperty

    public 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

### clearProperty

    public 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 void clearPropertyDirect(String key)

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

  Parameters:
    `key` - the key to be removed

### clear

    public void clear()

  Description copied from interface: `Configuration`
  Remove all properties from the configuration.

  Specified by:
    `clear` in interface `Configuration`

### getKeys

    public 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 `Configuration`
  Parameters:
    `prefix` - The prefix to test against.
  Returns:
    An Iterator of keys that match the prefix.
  See Also:
    `Configuration.getKeys()`

### getProperties

    public Properties getProperties(String key)

  Description copied from interface: `Configuration`
  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 {code 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 `Configuration`
  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)

  Get a boolean associated with the given configuration key.

  Specified by:
    `getBoolean` in interface `Configuration`
  Parameters:
    `key` - The configuration key.
  Returns:
    The associated boolean.
  See Also:
    `PropertyConverter.toBoolean(Object)`

### getBoolean

    public boolean getBoolean(String key,
                              boolean defaultValue)

  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 `Configuration`
  Parameters:
    `key` - The configuration key.
    `defaultValue` - The default value.
  Returns:
    The associated boolean.
  See Also:
    `PropertyConverter.toBoolean(Object)`

### 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 `Configuration`
  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`
  See Also:
    `PropertyConverter.toBoolean(Object)`

### getByte

    public byte getByte(String key)

  Description copied from interface: `Configuration`
  Get a byte associated with the given configuration key.

  Specified by:
    `getByte` in interface `Configuration`
  Parameters:
    `key` - The configuration key.
  Returns:
    The associated byte.

### getByte

    public byte getByte(String key,
                        byte defaultValue)

  Description copied from interface: `Configuration`
  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 `Configuration`
  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: `Configuration`
  Get a `Byte` associated with the given configuration key.

  Specified by:
    `getByte` in interface `Configuration`
  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: `Configuration`
  Get a double associated with the given configuration key.

  Specified by:
    `getDouble` in interface `Configuration`
  Parameters:
    `key` - The configuration key.
  Returns:
    The associated double.

### getDouble

    public double getDouble(String key,
                            double defaultValue)

  Description copied from interface: `Configuration`
  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 `Configuration`
  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: `Configuration`
  Get a `Double` associated with the given configuration key.

  Specified by:
    `getDouble` in interface `Configuration`
  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: `Configuration`
  Get a float associated with the given configuration key.

  Specified by:
    `getFloat` in interface `Configuration`
  Parameters:
    `key` - The configuration key.
  Returns:
    The associated float.

### getFloat

    public float getFloat(String key,
                          float defaultValue)

  Description copied from interface: `Configuration`
  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 `Configuration`
  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: `Configuration`
  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 `Configuration`
  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: `Configuration`
  Get a int associated with the given configuration key.

  Specified by:
    `getInt` in interface `Configuration`
  Parameters:
    `key` - The configuration key.
  Returns:
    The associated int.

### getInt

    public int getInt(String key,
                      int defaultValue)

  Description copied from interface: `Configuration`
  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 `Configuration`
  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: `Configuration`
  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 `Configuration`
  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: `Configuration`
  Get a long associated with the given configuration key.

  Specified by:
    `getLong` in interface `Configuration`
  Parameters:
    `key` - The configuration key.
  Returns:
    The associated long.

### getLong

    public long getLong(String key,
                        long defaultValue)

  Description copied from interface: `Configuration`
  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 `Configuration`
  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: `Configuration`
  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 `Configuration`
  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: `Configuration`
  Get a short associated with the given configuration key.

  Specified by:
    `getShort` in interface `Configuration`
  Parameters:
    `key` - The configuration key.
  Returns:
    The associated short.

### getShort

    public short getShort(String key,
                          short defaultValue)

  Description copied from interface: `Configuration`
  Get a short associated with the given configuration key.

  Specified by:
    `getShort` in interface `Configuration`
  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: `Configuration`
  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 `Configuration`
  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 `Configuration`
  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: `Configuration`
  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 `Configuration`
  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 `Configuration`
  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: `Configuration`
  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 `Configuration`
  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 `Configuration`
  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: `Configuration`
  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 `Configuration`
  Parameters:
    `key` - The configuration key.
    `defaultValue` - The default value.
  Returns:
    The associated string if key is found and has valid format, default value otherwise.

### 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. If a property is added to a configuration, it is checked whether it contains multiple values. This is obvious if the added object is a list or an array. For strings it is checked whether the string contains the list delimiter character that can be specified using the `setListDelimiter()` method. If this is the case, the string is split at these positions resulting in a property with multiple values.

  Specified by:
    `getStringArray` in interface `Configuration`
  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:
    `setListDelimiter(char)`, `setDelimiterParsingDisabled(boolean)`

### getList

    public List<Object> getList(String key)

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

  Specified by:
    `getList` in interface `Configuration`
  Parameters:
    `key` - The configuration key.
  Returns:
    The associated List.
  See Also:
    `getStringArray(String)`

### getList

    public List<Object> getList(String key,
                                List<Object> defaultValue)

  Description copied from interface: `Configuration`
  Get a List of strings associated with the given configuration key. If the key doesn't map to an existing object, the default value is returned.

  Specified by:
    `getList` in interface `Configuration`
  Parameters:
    `key` - The configuration key.
    `defaultValue` - The default value.
  Returns:
    The associated List of strings.

### resolveContainerStore

    protected Object resolveContainerStore(String key)

  Returns an object from the store described by the key. If the value is a Collection object, replace it with the first object in the collection.

  Parameters:
    `key` - The property key.
  Returns:
    value Value, transparently resolving a possible collection dependency.

### 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

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