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

   1 /* DomEntityReference.java --
   2    Copyright (C) 1999,2000,2001,2004 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 org.w3c.dom.DocumentType;
  41 import org.w3c.dom.Entity;
  42 import org.w3c.dom.EntityReference;
  43
  44 /**
  45  * <p> "EntityReference" implementation (reference to parsed entity).
  46  * This is a non-core DOM class, supporting the "XML" feature.
  47  * It does not represent builtin entities (such as "&amp;amp;")
  48  * or character references, which are always directly expanded in
  49  * DOM trees.</p>
  50  *
  51  * <p> Note that while the DOM specification permits these nodes to have
  52  * a readonly set of children, this is not required.  Similarly, it does
  53  * not require a DOM to couple EntityReference nodes with any Entity nodes
  54  * that have the same entity name (and equivalent children).  It also
  55  * effectively guarantees that references created directly or indirectly
  56  * through the <em>Document.ImportNode</em> method will not have children.
  57  * The level of functionality you may get is extremely variable.
  58  *
  59  * <p> Also significant is that even at their most functional level, the fact
  60  * that EntityReference children must be readonly has caused significant
  61  * problems when modifying work products held in DOM trees.  Other problems
  62  * include issues related to undeclared namespace prefixes (and references
  63  * to the current default namespace) that may be found in the text of such
  64  * parsed entities nodes.  These must be contextually bound as part of DOM
  65  * tree construction.  When such nodes are moved, the namespace associated
  66  * with a given prefix (or default) may change to be in conflict with the
  67  * namespace bound to the node at creation time.
  68  *
  69  * <p> In short, <em>avoid using this DOM functionality</em>.
  70  *
  71  * @see DomDoctype
  72  * @see DomEntity
  73  *
  74  * @author David Brownell
  75  * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
  76  */
  77 public class DomEntityReference
  78   extends DomNode
  79   implements EntityReference
  80 {
  81
  82   private String name;
  83
  84   /**
  85    * Constructs an EntityReference node associated with the specified
  86    * document.  The creator should populate this with whatever contents
  87    * are appropriate, and then mark it as readonly.
  88    *
  89    * <p>This constructor should only be invoked by a Document as part of
  90    * its createEntityReference functionality, or through a subclass which
  91    * is similarly used in a "Sub-DOM" style layer.
  92    *
  93    * @see DomNode#makeReadonly
  94    */
  95   protected DomEntityReference(DomDocument owner, String name)
  96   {
  97     super(ENTITY_REFERENCE_NODE, owner);
  98     this.name = name;
  99   }
 100
 101   /**
 102    * Returns the name of the referenced entity.
 103    * @since DOM Level 1 Core
 104    */
 105   public final String getNodeName()
 106   {
 107     return name;
 108   }
 109
 110   /**
 111    * The base URI of an entity reference is the base URI where the entity
 112    * declaration occurs.
 113    * @since DOM Level 3 Core
 114    */
 115   public final String getBaseURI()
 116   {
 117     DocumentType doctype = owner.getDoctype();
 118     if (doctype == null)
 119       {
 120         return null;
 121       }
 122     Entity entity = (Entity) doctype.getEntities().getNamedItem(name);
 123     if (entity == null)
 124       {
 125         return null;
 126       }
 127     return entity.getBaseURI();
 128   }
 129
 130 }