/* DomNotation.java -- 
   Copyright (C) 1999,2000,2001,2004 Free Software Foundation, Inc.

This file is part of GNU Classpath.

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package gnu.xml.dom;

import org.w3c.dom.Notation;

/**
 * <p> "Notation" implementation.  This is a non-core DOM class, supporting
 * the "XML" feature. </p>
 *
 * <p> Although unparsed entities using this notation can be detected using
 * DOM, neither NOTATIONS nor ENTITY/ENTITIES attributes can be so detected.
 * More, there is no portable way to construct a Notation node, so there's
 * no way that vendor-neutral DOM construction APIs could even report a
 * NOTATION used to identify the intended meaning of a ProcessingInstruction.
 * </p>
 *
 * <p> In short, <em>avoid using this DOM functionality</em>.
 *
 * @see DomDoctype
 * @see DomEntity
 * @see DomPI
 *
 * @author David Brownell 
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 */
public class DomNotation
  extends DomExtern
  implements Notation
{
    
  /**
   * Constructs a Notation node associated with the specified document,
   * with the specified descriptive data.  Note that at least one of
   * the PUBLIC and SYSTEM identifiers must be provided; unlike other
   * external objects in XML, notations may have only a PUBLIC identifier.
   *
   * <p>This constructor should only be invoked by a DomDoctype object
   * as part of its declareNotation functionality, or through a subclass
   * which is similarly used in a "Sub-DOM" style layer. 
   *
   * @param owner The document with which this notation is associated
   * @param name Name of this notation
   * @param publicId If non-null, provides the notation's PUBLIC identifier
   * @param systemId If non-null, rovides the notation's SYSTEM identifier
   */
  protected DomNotation(DomDocument owner,
                        String name,
                        String publicId,
                        String systemId)
  {
    super(NOTATION_NODE, owner, name, publicId, systemId);
    makeReadonly();
  }
  
  /**
   * The base URI of an external entity is its system ID.
   * The base URI of an internal entity is the parent document's base URI.
   * @since DOM Level 3 Core
   */
  public String getBaseURI()
  {
    String systemId = getSystemId();
    return (systemId == null) ? owner.getBaseURI() : systemId;
  }
  
}