Module java.xml
Package javax.xml.xpath

# Interface XPathVariableResolver

public interface XPathVariableResolver

`XPathVariableResolver` provides access to the set of user defined XPath variables.

The `XPathVariableResolver` and the XPath evaluator must adhere to a contract that cannot be directly enforced by the API. Although variables may be mutable, that is, an application may wish to evaluate the same XPath expression more than once with different variable values, in the course of evaluating any single XPath expression, a variable's value must not change.

Since:
  1.5

- ## Method Summary

  Modifier and Type
  Method
  Description
  `Object`
  `resolveVariable(QName variableName)`
  Find a variable in the set of available variables.

- ## Method Details

  - ### resolveVariable

    Object resolveVariable(QName variableName)

    Find a variable in the set of available variables.

    If `variableName` is `null`, then a `NullPointerException` is thrown.

    Parameters:
      `variableName` - The `QName` of the variable name.
    Returns:
      The variables value, or `null` if no variable named `variableName` exists. The value returned must be of a type appropriate for the underlying object model.
    Throws:
      `NullPointerException` - If `variableName` is `null`.