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    1   /*
    2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/ext/EvaluateFunction.java,v 1.9 2005/06/28 13:44:45 elharo Exp $
    3    * $Revision: 1.9 $
    4    * $Date: 2005/06/28 13:44:45 $
    5    *
    6    * ====================================================================
    7    *
    8    * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
    9    * All rights reserved.
    10   *
    11   * Redistribution and use in source and binary forms, with or without
    12   * modification, are permitted provided that the following conditions
    13   * are met:
    14   *
    15   * 1. Redistributions of source code must retain the above copyright
    16   *    notice, this list of conditions, and the following disclaimer.
    17   *
    18   * 2. Redistributions in binary form must reproduce the above copyright
    19   *    notice, this list of conditions, and the disclaimer that follows
    20   *    these conditions in the documentation and/or other materials
    21   *    provided with the distribution.
    22   *
    23   * 3. The name "Jaxen" must not be used to endorse or promote products
    24   *    derived from this software without prior written permission.  For
    25   *    written permission, please contact license@jaxen.org.
    26   *
    27   * 4. Products derived from this software may not be called "Jaxen", nor
    28   *    may "Jaxen" appear in their name, without prior written permission
    29   *    from the Jaxen Project Management (pm@jaxen.org).
    30   *
    31   * In addition, we request (but do not require) that you include in the
    32   * end-user documentation provided with the redistribution and/or in the
    33   * software itself an acknowledgement equivalent to the following:
    34   *     "This product includes software developed by the
    35   *      Jaxen Project <http://www.jaxen.org/>."
    36   * Alternatively, the acknowledgment may be graphical using the logos
    37   * available at http://www.jaxen.org/
    38   *
    39   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
    40   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
    41   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    42   * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
    43   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    44   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    45   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
    46   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
    47   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
    48   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
    49   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
    50   * SUCH DAMAGE.
    51   *
    52   * ====================================================================
    53   * This software consists of voluntary contributions made by many
    54   * individuals on behalf of the Jaxen Project and was originally
    55   * created by bob mcwhirter <bob@werken.com> and
    56   * James Strachan <jstrachan@apache.org>.  For more information on the
    57   * Jaxen Project, please see <http://www.jaxen.org/>.
    58   *
    59   * $Id: EvaluateFunction.java,v 1.9 2005/06/28 13:44:45 elharo Exp $
    60   */
    61
    62  package org.jaxen.function.ext;
    63
    64  import java.util.Collections;
    65  import java.util.List;
    66
    67  import org.jaxen.Context;
    68  import org.jaxen.ContextSupport;
    69  import org.jaxen.Function;
    70  import org.jaxen.FunctionCallException;
    71  import org.jaxen.Navigator;
    72  import org.jaxen.XPath;
    73  import org.jaxen.function.StringFunction;
    74
    75  /***
    76   * <code><i>node-set</i> evaluate(<i>string</i>)</code>
    77   *
    78   * @author Erwin Bolwidt (ejb @ klomp.org)
    79   */
    80  public class EvaluateFunction implements Function
    81  {
    82      public Object call( Context context, List args )
    83          throws FunctionCallException
    84      {
    85          if ( args.size() == 1 ) {
    86              return evaluate( context, args.get(0));
    87          }
    88
    89          throw new FunctionCallException( "evaluate() requires one argument" );
    90      }
    91
    92      public static List evaluate (Context context, Object arg)
    93          throws FunctionCallException
    94      {
    95          List contextNodes = context.getNodeSet();
    96
    97          if (contextNodes.size() == 0)
    98              return Collections.EMPTY_LIST;
    99
    100         Navigator nav = context.getNavigator();
    101
    102         String xpathString;
    103         if ( arg instanceof String )
    104             xpathString = (String)arg;
    105         else
    106             xpathString = StringFunction.evaluate(arg, nav);
    107
    108         try {
    109             XPath xpath = nav.parseXPath(xpathString);
    110             ContextSupport support = context.getContextSupport();
    111             xpath.setVariableContext( support.getVariableContext() );
    112             xpath.setFunctionContext( support.getFunctionContext() );
    113             xpath.setNamespaceContext( support.getNamespaceContext() );
    114             return xpath.selectNodes( context.duplicate() );
    115         }
    116         catch ( org.jaxen.saxpath.SAXPathException e ) {
    117             throw new FunctionCallException(e.toString());
    118         }
    119     }
    120 }
    121