Package org.apache.commons.configuration2.interpol

# Class SystemPropertiesLookup

java.lang.Object
org.apache.commons.configuration2.interpol.SystemPropertiesLookup

All Implemented Interfaces:
  `Lookup`

@Deprecated public class SystemPropertiesLookup extends Object implements Lookup
Deprecated.
Use `DefaultLookups.SYSTEM_PROPERTIES`.

A specialized implementation of the `Lookup` interface that allows access to system properties.

This implementation relies on `StrLookup.systemPropertiesLookup()` from the Commons Lang project to resolve system properties. It can be used for referencing system properties in configuration files in an easy way, for instance:

     current.user = ${sys:user.name}

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

Since:
  2.0

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `SystemPropertiesLookup()`
  Deprecated.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `Object`
  `lookup(String variable)`
  Deprecated.
  Looks up the value of the specified variable.

  ### Methods inherited from class java.lang.Object

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

- ## Constructor Details

  - ### SystemPropertiesLookup

    public SystemPropertiesLookup()
    Deprecated.

- ## Method Details

  - ### lookup

    public Object lookup(String variable)
    Deprecated.
    Description copied from interface: `Lookup`
    Looks up the value of the specified variable. This method is called by `ConfigurationInterpolator` with the variable name extracted from the expression to interpolate (i.e. the prefix name has already been removed). A concrete implementation has to return the value of this variable or null if the variable name is unknown.
    Specified by:
      `lookup` in interface `Lookup`
    Parameters:
      `variable` - the name of the variable to be resolved
    Returns:
      the value of this variable or null