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## org.apache.commons.configuration
Class MapConfiguration

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

All Implemented Interfaces:
  Cloneable, Configuration

Direct Known Subclasses:
  EnvironmentConfiguration, SystemConfiguration

    public class MapConfiguration

extends AbstractConfiguration
implements Cloneable

A Map based Configuration.

This implementation of the `Configuration` interface is initialized with a `java.util.Map`. The methods of the `Configuration` interface are implemented on top of the content of this map. The following storage scheme is used:

Property keys are directly mapped to map keys, i.e. the `getProperty()` method directly performs a `get()` on the map. Analogously, `setProperty()` or `addProperty()` operations write new data into the map. If a value is added to an existing property, a `java.util.List` is created, which stores the values of this property.

An important use case of this class is to treat a map as a `Configuration` allowing access to its data through the richer interface. This can be a bit problematic in some cases because the map may contain values that need not adhere to the default storage scheme used by typical configuration implementations, e.g. regarding lists. In such cases care must be taken when manipulating the data through the `Configuration` interface, e.g. by calling `addProperty()`; results may be different than expected.

An important point is the handling of list delimiters: If delimiter parsing is enabled (which it is per default), `getProperty()` checks whether the value of a property is a string and whether it contains the list delimiter character. If this is the case, the value is split at the delimiter resulting in a list. This split operation typically also involves trimming the single values as the list delimiter character may be surrounded by whitespace. Trimming can be disabled with the `setTrimmingDisabled(boolean)` method. The whole list splitting behavior can be disabled using the `AbstractConfiguration.setDelimiterParsingDisabled(boolean)` method.

Notice that list splitting is only performed for single string values. If a property has multiple values, the single values are not split even if they contain the list delimiter character.

As the underlying `Map` is directly used as store of the property values, the thread-safety of this `Configuration` implementation depends on the map passed to the constructor.

Notes about type safety: For properties with multiple values this implementation creates lists of type `Object` and stores them. If a property is assigned another value, the value is added to the list. This can cause problems if the map passed to the constructor already contains lists of other types. This should be avoided, otherwise it cannot be guaranteed that the application might throw `ClassCastException` exceptions later.

Since:
  1.1
Version:
  $Id: MapConfiguration.java 1210171 2011-12-04 18:32:07Z oheger $
Author:
  Emmanuel Bourg

Field Summary
`protected Map<String,Object>` | `map` The Map decorated by this configuration.

Fields inherited from class org.apache.commons.configuration.AbstractConfiguration
`END_TOKEN, EVENT_ADD_PROPERTY, EVENT_CLEAR, EVENT_CLEAR_PROPERTY, EVENT_READ_PROPERTY, EVENT_SET_PROPERTY, START_TOKEN`

Constructor Summary
`MapConfiguration(Map<String,Object> map)` Create a Configuration decorator around the specified Map.
`MapConfiguration(Properties props)` Creates a new instance of `MapConfiguration` and initializes its content from the specified `Properties` object.

Method Summary
`protected void` | `addPropertyDirect(String key, Object value)` Adds a key/value pair to the Configuration.
`protected void` | `clearPropertyDirect(String key)` Removes the specified property from this configuration.
`Object` | `clone()` Returns a copy of this object.
`boolean` | `containsKey(String key)` Check if the configuration contains the specified key.
`Iterator<String>` | `getKeys()` Get the list of the keys contained in the configuration.
`Map<String,Object>` | `getMap()` Return the Map decorated by this configuration.
`Object` | `getProperty(String key)` Gets a property from the configuration.
`boolean` | `isEmpty()` Check if the configuration is empty.
`boolean` | `isTrimmingDisabled()` Returns the flag whether trimming of property values is disabled.
`void` | `setTrimmingDisabled(boolean trimmingDisabled)` Sets a flag whether trimming of property values is disabled.

Methods inherited from class org.apache.commons.configuration.AbstractConfiguration
`addErrorLogListener, addProperty, append, clear, clearProperty, copy, createInterpolator, getBigDecimal, getBigDecimal, getBigInteger, getBigInteger, getBoolean, getBoolean, getBoolean, getByte, getByte, getByte, getDefaultListDelimiter, getDelimiter, getDouble, getDouble, getDouble, getFloat, getFloat, getFloat, getInt, getInt, getInteger, getInterpolator, getKeys, getList, getList, getListDelimiter, getLogger, getLong, getLong, getLong, getProperties, getProperties, getShort, getShort, getShort, getString, getString, getStringArray, getSubstitutor, interpolate, interpolate, interpolatedConfiguration, interpolateHelper, isDelimiterParsingDisabled, isScalarValue, isThrowExceptionOnMissing, resolveContainerStore, setDefaultListDelimiter, setDelimiter, setDelimiterParsingDisabled, setListDelimiter, setLogger, setProperty, setThrowExceptionOnMissing, subset`

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

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

Field Detail

### map

    protected Map<String,Object> map

  The Map decorated by this configuration.

Constructor Detail

### MapConfiguration

    public MapConfiguration(Map<String,Object> map)

  Create a Configuration decorator around the specified Map. The map is used to store the configuration properties, any change will also affect the Map.

  Parameters:
    `map` - the map

### MapConfiguration

    public MapConfiguration(Properties props)

  Creates a new instance of `MapConfiguration` and initializes its content from the specified `Properties` object. The resulting configuration is not connected to the `Properties` object, but all keys which are strings are copied (keys of other types are ignored).

  Parameters:
    `props` - the `Properties` object defining the content of this configuration
  Throws:
    `NullPointerException` - if the `Properties` object is null
  Since:
    1.8

Method Detail

### getMap

    public Map<String,Object> getMap()

  Return the Map decorated by this configuration.

  Returns:
    the map this configuration is based onto

### isTrimmingDisabled

    public boolean isTrimmingDisabled()

  Returns the flag whether trimming of property values is disabled.

  Returns:
    true if trimming of property values is disabled; false otherwise
  Since:
    1.7

### setTrimmingDisabled

    public void setTrimmingDisabled(boolean trimmingDisabled)

  Sets a flag whether trimming of property values is disabled. This flag is only evaluated if list splitting is enabled. Refer to the header comment for more information about list splitting and trimming.

  Parameters:
    `trimmingDisabled` - a flag whether trimming of property values should be disabled
  Since:
    1.7

### getProperty

    public Object getProperty(String key)

  Description copied from interface: `Configuration`
  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).

  Specified by:
    `getProperty` in interface `Configuration`
  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.

### addPropertyDirect

    protected void addPropertyDirect(String key,
                                     Object value)

  Description copied from class: `AbstractConfiguration`
  Adds a key/value pair to the Configuration. Override this method to provide write access to underlying Configuration store.

  Specified by:
    `addPropertyDirect` in class `AbstractConfiguration`
  Parameters:
    `key` - key to use for mapping
    `value` - object to store

### isEmpty

    public boolean isEmpty()

  Description copied from interface: `Configuration`
  Check if the configuration is empty.

  Specified by:
    `isEmpty` in interface `Configuration`
  Returns:
    `true` if the configuration contains no property, `false` otherwise.

### containsKey

    public boolean containsKey(String key)

  Description copied from interface: `Configuration`
  Check if the configuration contains the specified key.

  Specified by:
    `containsKey` in interface `Configuration`
  Parameters:
    `key` - the key whose presence in this configuration is to be tested
  Returns:
    `true` if the configuration contains a value for this key, `false` otherwise

### clearPropertyDirect

    protected void clearPropertyDirect(String key)

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

  Overrides:
    `clearPropertyDirect` in class `AbstractConfiguration`
  Parameters:
    `key` - the key to be removed

### getKeys

    public Iterator<String> getKeys()

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

  Specified by:
    `getKeys` in interface `Configuration`
  Returns:
    An Iterator.

### clone

    public Object clone()

  Returns a copy of this object. The returned configuration will contain the same properties as the original. Event listeners are not cloned.

  Overrides:
    `clone` in class `EventSource`
  Returns:
    the copy
  Since:
    1.3

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