gomp-20050608-branch/libjava/classpath/gnu/xml/transform/KeyFunction.java

   1 /* KeyFunction.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.transform;
  39
  40 import java.util.ArrayList;
  41 import java.util.Collection;
  42 import java.util.Collections;
  43 import java.util.Iterator;
  44 import java.util.LinkedHashSet;
  45 import java.util.LinkedList;
  46 import java.util.List;
  47 import javax.xml.namespace.QName;
  48 import javax.xml.xpath.XPathFunction;
  49 import javax.xml.xpath.XPathFunctionException;
  50 import org.w3c.dom.Document;
  51 import org.w3c.dom.Node;
  52 import gnu.xml.xpath.Expr;
  53 import gnu.xml.xpath.Function;
  54 import gnu.xml.xpath.Pattern;
  55
  56 /**
  57  * The XSLT <code>key()</code>function.
  58  *
  59  * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
  60  */
  61 final class KeyFunction
  62   extends Pattern
  63   implements XPathFunction, Function
  64 {
  65
  66   final Stylesheet stylesheet;
  67   List args;
  68
  69   KeyFunction(Stylesheet stylesheet)
  70   {
  71     this.stylesheet = stylesheet;
  72   }
  73
  74   public Object evaluate(List args)
  75     throws XPathFunctionException
  76   {
  77     // Useless...
  78     return Collections.EMPTY_SET;
  79   }
  80
  81   public void setArguments(List args)
  82   {
  83     this.args = args;
  84   }
  85
  86   public boolean matches(Node context)
  87   {
  88     Object ret = evaluate(context, 1, 1);
  89     return !((Collection) ret).isEmpty();
  90   }
  91
  92   public Object evaluate(Node context, int pos, int len)
  93   {
  94     // Evaluate arguments
  95     int arity = args.size();
  96     List values = new ArrayList(arity);
  97     for (int i = 0; i < arity; i++)
  98       {
  99         Expr arg = (Expr) args.get(i);
 100         values.add(arg.evaluate(context, pos, len));
 101       }
 102     // Get key name
 103     QName keyName = QName.valueOf(_string(context, values.get(0)));
 104     // Expand qualified name
 105     String uri = keyName.getNamespaceURI();
 106     String prefix = keyName.getPrefix();
 107     if ((uri == null || uri.length() == 0) &&
 108         (prefix != null && prefix.length() > 0))
 109       {
 110         uri = stylesheet.getNamespaceURI(prefix);
 111         if (uri != null && uri.length() > 0)
 112           {
 113             String localName = keyName.getLocalPart();
 114             keyName = new QName(uri, localName, prefix);
 115           }
 116       }
 117     // Compute matching key set
 118     Collection keySet = new LinkedList();
 119     for (Iterator i = stylesheet.keys.iterator(); i.hasNext(); )
 120       {
 121         Key key = (Key) i.next();
 122         if (key.name.equals(keyName))
 123           {
 124             keySet.add(key);
 125           }
 126       }
 127     // Get target
 128     Object target = values.get(1);
 129     Collection acc = new LinkedHashSet();
 130     Document doc = (context instanceof Document) ? (Document) context :
 131       context.getOwnerDocument();
 132     if (target instanceof Collection)
 133       {
 134         for (Iterator i = ((Collection) target).iterator(); i.hasNext(); )
 135           {
 136             String val = Expr.stringValue((Node) i.next());
 137             addKeyNodes(doc, keySet, val, acc);
 138           }
 139       }
 140     else
 141       {
 142         String val = Expr._string(context, target);
 143         addKeyNodes(doc, keySet, val, acc);
 144       }
 145     List ret = new ArrayList(acc);
 146     Collections.sort(ret, documentOrderComparator);
 147     return ret;
 148   }
 149
 150   final void addKeyNodes(Node node, Collection keySet,
 151                          String value, Collection acc)
 152   {
 153     addKeyNodeIfMatch(node, keySet, value, acc);
 154     // Apply children
 155     for (Node ctx = node.getFirstChild(); ctx != null;
 156          ctx = ctx.getNextSibling())
 157       {
 158         addKeyNodes(ctx, keySet, value, acc);
 159       }
 160   }
 161
 162   final void addKeyNodeIfMatch(Node node, Collection keySet,
 163                                String value, Collection acc)
 164   {
 165     for (Iterator i = keySet.iterator(); i.hasNext(); )
 166       {
 167         Key key = (Key) i.next();
 168         if (key.match.matches(node))
 169           {
 170             Object eval = key.use.evaluate(node, 1, 1);
 171             if (eval instanceof Collection)
 172               {
 173                 for (Iterator j = ((Collection) eval).iterator();
 174                      j.hasNext(); )
 175                   {
 176                     String keyValue = Expr.stringValue((Node) j.next());
 177                     if (value.equals(keyValue))
 178                       {
 179                         acc.add(node);
 180                         return;
 181                       }
 182                   }
 183               }
 184             else
 185               {
 186                 String keyValue = Expr._string(node, eval);
 187                 if (value.equals(keyValue))
 188                   {
 189                     acc.add(node);
 190                     return;
 191                   }
 192               }
 193           }
 194       }
 195   }
 196
 197   public Expr clone(Object context)
 198   {
 199     Stylesheet s = stylesheet;
 200     if (context instanceof Stylesheet)
 201       {
 202         s = (Stylesheet) context;
 203       }
 204     KeyFunction f = new KeyFunction(s);
 205     int len = args.size();
 206     List args2 = new ArrayList(len);
 207     for (int i = 0; i < len; i++)
 208       {
 209         args2.add(((Expr) args.get(i)).clone(context));
 210       }
 211     f.setArguments(args2);
 212     return f;
 213   }
 214
 215   public boolean references(QName var)
 216   {
 217     for (Iterator i = args.iterator(); i.hasNext(); )
 218       {
 219         if (((Expr) i.next()).references(var))
 220           {
 221             return true;
 222           }
 223       }
 224     return false;
 225   }
 226
 227 }
 228