# Package org.apache.commons.configuration2.interpol

package org.apache.commons.configuration2.interpol

A package with helper classes used for interpolation (variable substitution).

- Related Packages
  Package
  Description
  org.apache.commons.configuration2
  The Configuration main package.
- Class
  Description
  ConfigurationInterpolator
  A class that handles interpolation (variable substitution) for configuration objects.
  ConstantLookup
  Looks up constant fields in classes.
  DefaultLookups
  An enumeration class defining constants for built-in `Lookup` objects available for `Configuration` instances.
  DummyLookup
  A simple dummy `Lookup` implementation.
  EnvironmentLookup
  Deprecated.
  Use `DefaultLookups.ENVIRONMENT`.
  ExprLookup
  Lookup that allows expressions to be evaluated.
  ExprLookup.Variable
  The key and corresponding object that will be made available to the JexlContext for use in expressions.
  ExprLookup.Variables
  List wrapper used to allow the Variables list to be created as beans in DefaultConfigurationBuilder.
  InterpolatorSpecification
  A simple value class defining a `ConfigurationInterpolator`.
  InterpolatorSpecification.Builder
  A builder class for creating instances of `InterpolatorSpecification`.
  Lookup
  Definition of an interface for looking up variables during interpolation.
  SystemPropertiesLookup
  Deprecated.
  Use `DefaultLookups.SYSTEM_PROPERTIES`.