/*
 * DomNsNode.java
 * Copyright (C) 1999,2000,2001,2004 The Free Software Foundation
 * 
 * This file is part of GNU JAXP, a library.
 *
 * GNU JAXP is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * 
 * GNU JAXP is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Linking this library statically or dynamically with other modules is
 * making a combined work based on this library.  Thus, the terms and
 * conditions of the GNU General Public License cover the whole
 * combination.
 *
 * As a special exception, the copyright holders of this library give you
 * permission to link this library with independent modules to produce an
 * executable, regardless of the license terms of these independent
 * modules, and to copy and distribute the resulting executable under
 * terms of your choice, provided that you also meet, for each linked
 * independent module, the terms and conditions of the license of that
 * module.  An independent module is a module which is not derived from
 * or based on this library.  If you modify this library, you may extend
 * this exception to your version of the library, but you are not
 * obliged to do so.  If you do not wish to do so, delete this
 * exception statement from your version. 
 */

package gnu.xml.dom;

import javax.xml.XMLConstants;

/**
 * <p> Abstract implemention of namespace support.  This facilitates
 * sharing code for attribute and element nodes.
 *
 * @author David Brownell 
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 */
public abstract class DomNsNode
  extends DomNode
{
  
  private String name;
  private String namespace;
  private String prefix;
  private String localName;
  
  /**
   * Constructs a node associated with the specified document, and
   * with the specified namespace information.
   *
   * @param owner The document with which this entity is associated
   * @param namespaceURI Combined with the local part of the name,
   *	this identifies a type of element or attribute; may be null.
   *  If this is the empty string, it is reassigned as null so that
   *  applications only need to test that case.
   * @param name Name of this node, which may include a prefix
   */
  // package private
  DomNsNode(short nodeType, DomDocument owner, String namespaceURI, String name)
  {
    super(nodeType, owner);
    setNodeName(name);
    setNamespaceURI(namespaceURI);
  }

  /**
   * <b>DOM L1</b>
   * Returns the node's name, including any namespace prefix.
   */
  public final String getNodeName()
  {
    return name;
  }

  final void setNodeName(String name)
  {
    this.name = name.intern();
    int index = name.indexOf(':');
    if (index == -1)
      {
        prefix = null;
        localName = this.name;
      }
    else
      {
        prefix = name.substring(0, index).intern();
        localName = name.substring(index + 1).intern();
      }
  }
  
  /**
   * <b>DOM L2</b>
   * Returns the node's namespace URI
   * <em>or null</em> if the node name is not namespace scoped.
   */
  public final String getNamespaceURI()
  {
    return namespace;
  }

  final void setNamespaceURI(String namespaceURI)
  {
    if ("".equals(namespaceURI))
      {
        namespaceURI = null;
      }
    namespace = (namespaceURI == null) ? null : namespaceURI.intern();
  }
  
  /**
   * <b>DOM L2</b>
   * Returns any prefix part of the node's name (before any colon).
   */
  public final String getPrefix()
  {
    return prefix;
  }

  /**
   * <b>DOM L2</b>
   * Assigns the prefix part of the node's name (before any colon).
   */
  public final void setPrefix(String prefix)
  {
    if (readonly)
      {
        throw new DomEx(DomEx.NO_MODIFICATION_ALLOWED_ERR);
      }

    if (prefix == null)
      {
        name = localName;
        return;
      }
    else if (namespace == null)
      {
        throw new DomEx(DomEx.NAMESPACE_ERR,
                        "can't set prefix, node has no namespace URI",
                        this, 0);
      }

    DomDocument.checkName(prefix, "1.1".equals(owner.getXmlVersion()));
    if (prefix.indexOf (':') != -1)
      {
        throw new DomEx(DomEx.NAMESPACE_ERR,
                        "illegal prefix " + prefix, this, 0);
      }

    if (XMLConstants.XML_NS_PREFIX.equals(prefix)
        && !XMLConstants.XML_NS_URI.equals(namespace))
      {
        throw new DomEx(DomEx.NAMESPACE_ERR,
                        "xml namespace is always " +
                        XMLConstants.XML_NS_URI, this, 0);
      }

    if (XMLConstants.XMLNS_ATTRIBUTE.equals(prefix))
      {
        if (namespace != null || getNodeType() != ATTRIBUTE_NODE)
          {
            throw new DomEx(DomEx.NAMESPACE_ERR,
                            "xmlns attribute prefix is reserved", this, 0);
          }
      }
    else if (getNodeType () == ATTRIBUTE_NODE
             && (XMLConstants.XMLNS_ATTRIBUTE.equals(name) ||
                 name.startsWith("xmlns:")))
      {
        throw new DomEx(DomEx.NAMESPACE_ERR,
                        "namespace declarations can't change names", this, 0);
      }

    this.prefix = prefix.intern();
  }

  /**
   * <b>DOM L2</b>
   * Returns the local part of the node's name (after any colon).
   */
  public final String getLocalName()
  {
    return localName;
  }
  
}

