1 /*

     2  * Copyright (c) 2003, 2005, 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 }