# Uses of Interface
org.apache.commons.configuration2.tree.ExpressionEngine

Packages that use ExpressionEngine
Package
Description
org.apache.commons.configuration2
The Configuration main package.
org.apache.commons.configuration2.builder
This package contains the implementations of configuration builder classes used to create new `Configuration` objects.
org.apache.commons.configuration2.tree
A package with helper and utility classes used by hierarchical configurations.
org.apache.commons.configuration2.tree.xpath
This package contains the `XPathExpressionEngine` class which enables XPATH support for querying configuration properties.

- ## Uses of ExpressionEngine in org.apache.commons.configuration2

  Methods in org.apache.commons.configuration2 that return ExpressionEngine
  Modifier and Type
  Method
  Description
  `ExpressionEngine`
  CombinedConfiguration.`getConversionExpressionEngine()`
  Gets the `ExpressionEngine` for converting flat child configurations to hierarchical ones.
  `ExpressionEngine`
  AbstractHierarchicalConfiguration.`getExpressionEngine()`
  Gets the expression engine used by this configuration.
  `ExpressionEngine`
  ImmutableHierarchicalConfiguration.`getExpressionEngine()`
  Gets the expression engine used by this configuration.
  `ExpressionEngine`
  PatternSubtreeConfigurationWrapper.`getExpressionEngine()`
  Methods in org.apache.commons.configuration2 with parameters of type ExpressionEngine
  Modifier and Type
  Method
  Description
  `static HierarchicalConfiguration<?>`
  ConfigurationUtils.`convertToHierarchical(Configuration conf, ExpressionEngine engine)`
  Converts the passed in `Configuration` object to a hierarchical one using the specified `ExpressionEngine`.
  `void`
  CombinedConfiguration.`setConversionExpressionEngine(ExpressionEngine conversionExpressionEngine)`
  Sets the `ExpressionEngine` for converting flat child configurations to hierarchical ones.
  `void`
  AbstractHierarchicalConfiguration.`setExpressionEngine(ExpressionEngine expressionEngine)`
  Sets the expression engine to be used by this configuration.
  `void`
  HierarchicalConfiguration.`setExpressionEngine(ExpressionEngine expressionEngine)`
  Sets the expression engine to be used by this configuration.
  `void`
  PatternSubtreeConfigurationWrapper.`setExpressionEngine(ExpressionEngine expressionEngine)`

- ## Uses of ExpressionEngine in org.apache.commons.configuration2.builder

  Methods in org.apache.commons.configuration2.builder with parameters of type ExpressionEngine
  Modifier and Type
  Method
  Description
  `HierarchicalBuilderParametersImpl`
  HierarchicalBuilderParametersImpl.`setExpressionEngine(ExpressionEngine engine)`
  Sets the `ExpressionEngine` to be used when querying the configuration.
  `T`
  HierarchicalBuilderProperties.`setExpressionEngine(ExpressionEngine engine)`
  Sets the `ExpressionEngine` to be used when querying the configuration.

- ## Uses of ExpressionEngine in org.apache.commons.configuration2.tree

  Classes in org.apache.commons.configuration2.tree that implement ExpressionEngine
  Modifier and Type
  Class
  Description
  `class`
  `DefaultExpressionEngine`
  A default implementation of the `ExpressionEngine` interface providing the "native" expression language for hierarchical configurations.

- ## Uses of ExpressionEngine in org.apache.commons.configuration2.tree.xpath

  Classes in org.apache.commons.configuration2.tree.xpath that implement ExpressionEngine
  Modifier and Type
  Class
  Description
  `class`
  `XPathExpressionEngine`
  A specialized implementation of the `ExpressionEngine` interface that is able to evaluate XPATH expressions.