Package 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:

java.lang.Cloneable, Configuration

Direct Known Subclasses:

EnvironmentConfiguration, SystemConfiguration

public class MapConfiguration
extends AbstractConfiguration
implements java.lang.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 1534429 2013-10-22 00:45:36Z henning $

Author:

Emmanuel Bourg

Field Summary

Fields

Modifier and Type	Field	Description
protected java.util.Map<java.lang.String,java.lang.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

Constructors

Constructor	Description
MapConfiguration(java.util.Map<java.lang.String,?> map)	Create a Configuration decorator around the specified Map.
MapConfiguration(java.util.Properties props)	Creates a new instance of MapConfiguration and initializes its content from the specified Properties object.

Method Summary

Modifier and Type	Method	Description
protected void	addPropertyDirect(java.lang.String key, java.lang.Object value)	Adds a key/value pair to the Configuration.
protected void	clearPropertyDirect(java.lang.String key)	Removes the specified property from this configuration.
java.lang.Object	clone()	Returns a copy of this object.
boolean	containsKey(java.lang.String key)	Check if the configuration contains the specified key.
java.util.Iterator<java.lang.String>	getKeys()	Get the list of the keys contained in the configuration.
java.util.Map<java.lang.String,java.lang.Object>	getMap()	Return the Map decorated by this configuration.
java.lang.Object	getProperty(java.lang.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 java.util.Map<java.lang.String,java.lang.Object> map

The Map decorated by this configuration.

Constructor Detail

MapConfiguration

public MapConfiguration(java.util.Map<java.lang.String,?> 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(java.util.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:

java.lang.NullPointerException - if the Properties object is null

Since:

1.8

Method Detail

getMap

public java.util.Map<java.lang.String,java.lang.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 java.lang.Object getProperty(java.lang.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(java.lang.String key,
                                 java.lang.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(java.lang.String key)

Description copied from interface: Configuration

Check if the configuration contains the specified key.

Specified by:

containsKey in interface Configuration

Parameters:

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

Returns:

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

clearPropertyDirect

protected void clearPropertyDirect(java.lang.String key)

Description copied from class: AbstractConfiguration

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

Overrides:

clearPropertyDirect in class AbstractConfiguration

Parameters:

key - the key to be removed

getKeys

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

Description copied from interface: Configuration

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

Specified by:

getKeys in interface Configuration

Returns:

An Iterator.

clone

public java.lang.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