Source for gnu.xml.dom.DomEntityReference

   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: }