XPathVariableResolver

  • XPathVariableResolver allows access and management of user-defined variables within XPath expressions.

  • While variables can be changed between XPath expression evaluations, their values must remain constant during a single expression's evaluation.

  • The resolveVariable method retrieves a variable's value by its QName, returning null if not found and throwing an exception if the QName is null.
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 be immutable.

Public Method Summary

abstract Object
resolveVariable(QName variableName)

Find a variable in the set of available variables.

Public Methods

public abstract 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.