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package javax.xml.xpath;

import java.util.List;


XPathFunction provides access to XPath functions.


Functions are identified by QName and arity in XPath.


Author: Norman Walsh,  Jeff Suttor
Since:1.5
/**
 * <p><code>XPathFunction</code> provides access to XPath functions.</p>
 *
 * <p>Functions are identified by QName and arity in XPath.</p>
 *
 * @author  <a href="mailto:Norman.Walsh@Sun.com">Norman Walsh</a>
 * @author  <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor</a>
 * @since 1.5
 */
public interface XPathFunction {
  
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.


Params:
  • args – The arguments, null is a valid value.
Throws:
Returns:The result of evaluating the XPath function as an Object.
/**
   * <p>Evaluate the function with the specified arguments.</p>
   *
   * <p>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.</p>
   *
   * @param args The arguments, <code>null</code> is a valid value.
   *
   * @return The result of evaluating the <code>XPath</code> function as an <code>Object</code>.
   *
   * @throws XPathFunctionException If <code>args</code> cannot be evaluated with this <code>XPath</code> function.
   */
  public Object evaluate(List args)
    throws XPathFunctionException;
}