1 /*
   2  * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package javax.xml.xpath;
  27 
  28 import java.util.List;
  29 
  30 /**
  31  * <p><code>XPathFunction</code> provides access to XPath functions.</p>
  32  *
  33  * <p>Functions are identified by QName and arity in XPath.</p>
  34  *
  35  * @author  <a href="mailto:Norman.Walsh@Sun.com">Norman Walsh</a>
  36  * @author  <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor</a>
  37  * @since 1.5
  38  */
  39 public interface XPathFunction {
  40   /**
  41    * <p>Evaluate the function with the specified arguments.</p>
  42    *
  43    * <p>To the greatest extent possible, side-effects should be avoided in the
  44    * definition of extension functions. The implementation evaluating an
  45    * XPath expression is under no obligation to call extension functions in
  46    * any particular order or any particular number of times.</p>
  47    *
  48    * @param args The arguments, <code>null</code> is a valid value.
  49    *
  50    * @return The result of evaluating the <code>XPath</code> function as an <code>Object</code>.
  51    *
  52    * @throws XPathFunctionException If <code>args</code> cannot be evaluated with this <code>XPath</code> function.
  53    */
  54   public Object evaluate(List<?> args)
  55     throws XPathFunctionException;
  56 }
--- EOF ---