Module java.xml
Package javax.xml.xpath

## Interface XPathFunction

-     public interface XPathFunction

  `XPathFunction` provides access to XPath functions.

  Functions are identified by QName and arity in XPath.

  Since:
    1.5

- - ### Method Summary

    Modifier and Type | Method | Description
    --- | --- | ---
    `Object` | `evaluate​(List<?> args)` | Evaluate the function with the specified arguments.

- - ### Method Detail

    - #### evaluate

          Object evaluate​(List<?> args)
                   throws XPathFunctionException

      Evaluate the function with the specified arguments.

      To the greatest extent possible, side-effects should be avoided in the definition of extension functions. The implementation evaluating an XPath expression is under no obligation to call extension functions in any particular order or any particular number of times.

      Parameters:
        `args` - The arguments, `null` is a valid value.
      Returns:
        The result of evaluating the `XPath` function as an `Object`.
      Throws:
        `XPathFunctionException` - If `args` cannot be evaluated with this `XPath` function.