Source for gnu.xml.xpath.Root

   1: /* Root.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.xpath;
  39: 
  40: import java.util.Collection;
  41: import java.util.Collections;
  42: import java.util.Set;
  43: 
  44: import javax.xml.namespace.QName;
  45: import org.w3c.dom.Document;
  46: import org.w3c.dom.Node;
  47: 
  48: /**
  49:  * Expression that evaluates to the document root.
  50:  *
  51:  * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
  52:  */
  53: public final class Root
  54:   extends Path
  55: {
  56: 
  57:   public boolean matches(Node node)
  58:   {
  59:     return (node.getNodeType() == Node.DOCUMENT_NODE);
  60:   }
  61: 
  62:   public Object evaluate(Node context, int pos, int len)
  63:   {
  64:     Set<Node> emptySet = Collections.emptySet();
  65:     return evaluate(context, emptySet);
  66:   }
  67: 
  68:   @Override
  69:   Collection<Node> evaluate(Node context, Collection<Node> ns)
  70:   {
  71:     Node doc = (context instanceof Document) ? context :
  72:       context.getOwnerDocument();
  73:     return Collections.singleton(doc);
  74:   }
  75: 
  76:   public Expr clone(Object context)
  77:   {
  78:     return new Root();
  79:   }
  80: 
  81:   public boolean references(QName var)
  82:   {
  83:     return false;
  84:   }
  85: 
  86:   public String toString()
  87:   {
  88:     return "/";
  89:   }
  90: 
  91: }