gomp-20050608-branch/libjava/classpath/gnu/xml/libxmlj/sax/Namespaces.java

   1 /* Namespaces.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.libxmlj.sax;
  39
  40 import java.util.ArrayList;
  41 import java.util.Collections;
  42 import java.util.HashMap;
  43 import java.util.Iterator;
  44
  45 /**
  46  * Helper class for managing namespaces.
  47  *
  48  * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
  49  */
  50 class Namespaces
  51 {
  52
  53   ArrayList stack = new ArrayList ();
  54
  55   /**
  56    * Increments the tree depth.
  57    * This allocates a new potential namespace entry.
  58    */
  59   void push ()
  60   {
  61     stack.add (null);
  62   }
  63
  64   /**
  65    * Decrements the tree depth.
  66    * This removes namespaces defined at the extremity.
  67    */
  68   void pop ()
  69   {
  70     stack.remove (stack.size() - 1);
  71   }
  72
  73   /**
  74    * Searches for the namespace URI corresponding to the specified prefix.
  75    */
  76   String getURI (String prefix)
  77   {
  78     for (int i = stack.size () - 1; i >= 0; i--)
  79     {
  80       HashMap ns = (HashMap) stack.get (i);
  81       if (ns != null && ns.containsKey (prefix))
  82       {
  83         String ret = (String) ns.get (prefix);
  84         return (ret == null) ? "" : ret;
  85       }
  86     }
  87     return "";
  88   }
  89
  90   /**
  91    * Defines the specified prefix-URI mapping at the current depth in the
  92    * tree.
  93    */
  94   void define (String prefix, String uri)
  95   {
  96     int index = stack.size () - 1;
  97     HashMap ns = (HashMap) stack.get (index);
  98     if (ns == null)
  99     {
 100       ns = new HashMap ();
 101       stack.set (index, ns);
 102     }
 103     ns.put (prefix, uri);
 104   }
 105
 106   /**
 107    * Returns an iterator over the prefixes defined at the current depth.
 108    */
 109   Iterator currentPrefixes ()
 110   {
 111     HashMap ns = (HashMap) stack.get (stack.size () - 1);
 112     if (ns == null)
 113       {
 114         return Collections.EMPTY_LIST.iterator ();
 115       }
 116     else
 117       {
 118         return ns.keySet ().iterator ();
 119       }
 120   }
 121
 122 }