## org.apache.commons.configuration
Class EnvironmentConfiguration

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

All Implemented Interfaces:
  Cloneable, Configuration

    public class EnvironmentConfiguration

extends MapConfiguration

A Configuration implementation that reads the platform specific environment variables using the map returned by `System.getenv()`.

This configuration implementation is read-only. It allows read access to the defined OS environment variables, but their values cannot be changed. Any attempts to add or remove a property will throw an `UnsupportedOperationException`

Usage of this class is easy: After an instance has been created the get methods provided by the `Configuration` interface can be used for querying environment variables, e.g.:

     Configuration envConfig = new EnvironmentConfiguration();
     System.out.println("JAVA_HOME=" + envConfig.getString("JAVA_HOME");

Since:
  1.5
Version:
  $Id: EnvironmentConfiguration.java 1210171 2011-12-04 18:32:07Z oheger $
Author:
  Nicolas De Loof

Field Summary

Fields inherited from class org.apache.commons.configuration.MapConfiguration
`map`

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
`EnvironmentConfiguration()` Create a Configuration based on the environment variables.

Method Summary
`protected void` `addPropertyDirect(String key, Object value)` Adds a property to this configuration.
`void` `clear()` Removes all properties from this configuration.
`void` `clearProperty(String key)` Removes a property from this configuration.

Methods inherited from class org.apache.commons.configuration.MapConfiguration
`clearPropertyDirect, clone, containsKey, getKeys, getMap, getProperty, isEmpty, isTrimmingDisabled, setTrimmingDisabled`

Methods inherited from class org.apache.commons.configuration.AbstractConfiguration

`addErrorLogListener, addProperty, append, 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`

Constructor Detail

### EnvironmentConfiguration

    public EnvironmentConfiguration()

  Create a Configuration based on the environment variables.

  See Also:
    `System.getenv()`

Method Detail

### addPropertyDirect

    protected void addPropertyDirect(String key,
                                     Object value)

  Adds a property to this configuration. Because this configuration is read-only, this operation is not allowed and will cause an exception.

  Overrides:
    `addPropertyDirect` in class `MapConfiguration`
  Parameters:
    `key` - the key of the property to be added
    `value` - the property value

### clearProperty

    public void clearProperty(String key)

  Removes a property from this configuration. Because this configuration is read-only, this operation is not allowed and will cause an exception.

  Specified by:
    `clearProperty` in interface `Configuration`
  Overrides:
    `clearProperty` in class `AbstractConfiguration`
  Parameters:
    `key` - the key of the property to be removed

### clear

    public void clear()

  Removes all properties from this configuration. Because this configuration is read-only, this operation is not allowed and will cause an exception.

  Specified by:
    `clear` in interface `Configuration`
  Overrides:
    `clear` in class `AbstractConfiguration`

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