gomp-20050608-branch/libjava/classpath/gnu/xml/dom/DomXPathExpression.java

   1 /* DomXPathExpression.java --
   2    Copyright (C) 2004 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38 package gnu.xml.dom;
  39
  40 import java.util.ArrayList;
  41 import java.util.Collection;
  42 import java.util.Collections;
  43 import java.util.List;
  44 import javax.xml.namespace.QName;
  45 import javax.xml.xpath.XPath;
  46 import javax.xml.xpath.XPathConstants;
  47 import javax.xml.xpath.XPathExpression;
  48 import javax.xml.xpath.XPathExpressionException;
  49 import javax.xml.xpath.XPathFactory;
  50 import org.w3c.dom.DOMException;
  51 import org.w3c.dom.Node;
  52 import org.w3c.dom.xpath.XPathException;
  53 import org.w3c.dom.xpath.XPathNSResolver;
  54 import org.w3c.dom.xpath.XPathResult;
  55 import gnu.xml.xpath.DocumentOrderComparator;
  56
  57 /**
  58  * An XPath expression.
  59  *
  60  * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
  61  */
  62 class DomXPathExpression
  63 implements org.w3c.dom.xpath.XPathExpression
  64 {
  65
  66   final DomDocument doc;
  67   final XPathExpression expression;
  68   final XPathNSResolver resolver;
  69
  70   DomXPathExpression(DomDocument doc, String expression,
  71                      XPathNSResolver resolver)
  72     throws XPathException
  73   {
  74     this.doc = doc;
  75     this.resolver = resolver;
  76
  77                 XPathFactory factory = XPathFactory.newInstance();
  78                 XPath xpath = factory.newXPath();
  79                 if (resolver != null)
  80                   {
  81                                 xpath.setNamespaceContext(new DomNSResolverContext(resolver));
  82                   }
  83     try
  84       {
  85         this.expression = xpath.compile(expression);
  86       }
  87     catch (XPathExpressionException e)
  88       {
  89         throw new XPathException(XPathException.INVALID_EXPRESSION_ERR,
  90                                                                      e.getMessage ());
  91       }
  92   }
  93
  94   public Object evaluate(Node contextNode, short type, Object result)
  95     throws XPathException, DOMException
  96   {
  97                 try
  98                   {
  99                                 QName typeName = null;
 100                                 switch (type)
 101                                   {
 102                                                 case XPathResult.BOOLEAN_TYPE:
 103                                                         typeName = XPathConstants.BOOLEAN;
 104                                                         break;
 105                                                 case XPathResult.NUMBER_TYPE:
 106                                                         typeName = XPathConstants.NUMBER;
 107                                                         break;
 108                                                 case XPathResult.STRING_TYPE:
 109                                                         typeName = XPathConstants.STRING;
 110                                                         break;
 111                                                 case XPathResult.ANY_UNORDERED_NODE_TYPE:
 112                                                 case XPathResult.FIRST_ORDERED_NODE_TYPE:
 113                                                         typeName = XPathConstants.NODE;
 114                                                         break;
 115                                                 case XPathResult.UNORDERED_NODE_ITERATOR_TYPE:
 116                                                 case XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE:
 117                                                 case XPathResult.ORDERED_NODE_ITERATOR_TYPE:
 118                                                 case XPathResult.ORDERED_NODE_SNAPSHOT_TYPE:
 119                                                         typeName = XPathConstants.NODESET;
 120                                                         break;
 121                                                 default:
 122                                                         throw new XPathException(XPathException.TYPE_ERR, null);
 123                                         }
 124                                 Object val = expression.evaluate(contextNode, typeName);
 125                                 switch (type)
 126                                   {
 127                                                 case XPathResult.ORDERED_NODE_ITERATOR_TYPE:
 128                                                 case XPathResult.ORDERED_NODE_SNAPSHOT_TYPE:
 129                                                         // Sort the nodes
 130                                                         List ns = new ArrayList((Collection) val);
 131                                                         Collections.sort(ns, new DocumentOrderComparator());
 132                                                         val = ns;
 133                                         }
 134                                 return new DomXPathResult(val, type);
 135                         }
 136                 catch (javax.xml.xpath.XPathException e)
 137                   {
 138                                 throw new XPathException(XPathException.TYPE_ERR, e.getMessage());
 139                         }
 140   }
 141
 142   public String toString ()
 143   {
 144     return getClass ().getName () + "[expression=" + expression + "]";
 145   }
 146
 147 }