org.apache.commons.configuration.interpol

Class EnvironmentLookup

java.lang.Object

org.apache.commons.lang.text.StrLookup

org.apache.commons.configuration.interpol.EnvironmentLookup

public class EnvironmentLookup
extends org.apache.commons.lang.text.StrLookup

A specialized lookup implementation that allows access to environment variables.

This implementation relies on EnvironmentConfiguration to resolve environment variables. It can be used for referencing environment variables in configuration files in an easy way, for instance:

 java.home = ${env:JAVA_HOME}
 

EnvironmentLookup is one of the standard lookups that is registered per default for each configuration.

Since:

1.7

Version:

$Id: EnvironmentLookup.java 1210620 2011-12-05 20:57:31Z oheger $

Author:

Commons Configuration team

Constructor Summary

Constructors

Constructor and Description
EnvironmentLookup()

Method Summary

Modifier and Type	Method and Description
String	lookup(String key) Performs a lookup for the specified variable.

Methods inherited from class org.apache.commons.lang.text.StrLookup

mapLookup, noneLookup, systemPropertiesLookup

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

EnvironmentLookup

public EnvironmentLookup()

Method Detail

lookup

public String lookup(String key)

Performs a lookup for the specified variable. This implementation directly delegates to a EnvironmentConfiguration.

Specified by:

lookup in class org.apache.commons.lang.text.StrLookup

Parameters:

key - the key to lookup

Returns:

the value of this key or null if it cannot be resolved