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   * Copyright (c) 2000, 2006, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code 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
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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  // DefaultHandler.java - default implementation of the core handlers.
  // http://www.saxproject.org
  // Written by David Megginson
  // NO WARRANTY!  This class is in the public domain.
  // $Id: DefaultHandler.java,v 1.3 2006/04/13 02:06:32 jeffsuttor Exp $
  
  package org.xml.sax.helpers;
  
  import java.io.IOException;
  
  import org.xml.sax.InputSource;
  import org.xml.sax.Locator;
  import org.xml.sax.Attributes;
  import org.xml.sax.EntityResolver;
  import org.xml.sax.DTDHandler;
  import org.xml.sax.ContentHandler;
  import org.xml.sax.ErrorHandler;
  import org.xml.sax.SAXException;
  import org.xml.sax.SAXParseException;
  
  
  /**
   * Default base class for SAX2 event handlers.
   *
   * <blockquote>
   * <em>This module, both source code and documentation, is in the
   * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
   * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
   * for further information.
   * </blockquote>
   *
   * <p>This class is available as a convenience base class for SAX2
   * applications: it provides default implementations for all of the
   * callbacks in the four core SAX2 handler classes:</p>
   *
   * <ul>
   * <li>{@link org.xml.sax.EntityResolver EntityResolver}</li>
   * <li>{@link org.xml.sax.DTDHandler DTDHandler}</li>
   * <li>{@link org.xml.sax.ContentHandler ContentHandler}</li>
   * <li>{@link org.xml.sax.ErrorHandler ErrorHandler}</li>
   * </ul>
   *
   * <p>Application writers can extend this class when they need to
   * implement only part of an interface; parser writers can
   * instantiate this class to provide default handlers when the
   * application has not supplied its own.</p>
   *
   * <p>This class replaces the deprecated SAX1
   * {@link org.xml.sax.HandlerBase HandlerBase} class.</p>
   *
   * @since SAX 2.0
   * @author David Megginson,
   * @see org.xml.sax.EntityResolver
   * @see org.xml.sax.DTDHandler
   * @see org.xml.sax.ContentHandler
   * @see org.xml.sax.ErrorHandler
   */
  public class DefaultHandler
      implements EntityResolver, DTDHandler, ContentHandler, ErrorHandler
  {
  
  
      ////////////////////////////////////////////////////////////////////
      // Default implementation of the EntityResolver interface.
      ////////////////////////////////////////////////////////////////////
  
      /**
       * Resolve an external entity.
       *
       * <p>Always return null, so that the parser will use the system
       * identifier provided in the XML document.  This method implements
       * the SAX default behaviour: application writers can override it
       * in a subclass to do special translations such as catalog lookups
       * or URI redirection.</p>
       *
       * @param publicId The public identifier, or null if none is
       *                 available.
       * @param systemId The system identifier provided in the XML
       *                 document.
       * @return The new input source, or null to require the
       *         default behaviour.
       * @exception java.io.IOException If there is an error setting
       *            up the new input source.
       * @exception org.xml.sax.SAXException Any SAX exception, possibly
       *            wrapping another exception.
       * @see org.xml.sax.EntityResolver#resolveEntity
       */
      public InputSource resolveEntity (String publicId, String systemId)
          throws IOException, SAXException
      {
          return null;
      }
  
  
  
      ////////////////////////////////////////////////////////////////////
      // Default implementation of DTDHandler interface.
      ////////////////////////////////////////////////////////////////////
  
  
      /**
       * Receive notification of a notation declaration.
       *
       * <p>By default, do nothing.  Application writers may override this
       * method in a subclass if they wish to keep track of the notations
       * declared in a document.</p>
       *
       * @param name The notation name.
       * @param publicId The notation public identifier, or null if not
       *                 available.
       * @param systemId The notation system identifier.
       * @exception org.xml.sax.SAXException Any SAX exception, possibly
       *            wrapping another exception.
       * @see org.xml.sax.DTDHandler#notationDecl
       */
      public void notationDecl (String name, String publicId, String systemId)
          throws SAXException
      {
          // no op
      }
  
  
      /**
       * Receive notification of an unparsed entity declaration.
       *
       * <p>By default, do nothing.  Application writers may override this
       * method in a subclass to keep track of the unparsed entities
       * declared in a document.</p>
       *
       * @param name The entity name.
       * @param publicId The entity public identifier, or null if not
       *                 available.
       * @param systemId The entity system identifier.
       * @param notationName The name of the associated notation.
       * @exception org.xml.sax.SAXException Any SAX exception, possibly
       *            wrapping another exception.
       * @see org.xml.sax.DTDHandler#unparsedEntityDecl
       */
      public void unparsedEntityDecl (String name, String publicId,
                                      String systemId, String notationName)
          throws SAXException
      {
          // no op
      }
  
  
  
      ////////////////////////////////////////////////////////////////////
      // Default implementation of ContentHandler interface.
      ////////////////////////////////////////////////////////////////////
  
  
      /**
       * Receive a Locator object for document events.
       *
       * <p>By default, do nothing.  Application writers may override this
       * method in a subclass if they wish to store the locator for use
       * with other document events.</p>
       *
       * @param locator A locator for all SAX document events.
       * @see org.xml.sax.ContentHandler#setDocumentLocator
       * @see org.xml.sax.Locator
       */
      public void setDocumentLocator (Locator locator)
      {
          // no op
      }
  
  
      /**
       * Receive notification of the beginning of the document.
       *
       * <p>By default, do nothing.  Application writers may override this
       * method in a subclass to take specific actions at the beginning
       * of a document (such as allocating the root node of a tree or
       * creating an output file).</p>
       *
       * @exception org.xml.sax.SAXException Any SAX exception, possibly
       *            wrapping another exception.
       * @see org.xml.sax.ContentHandler#startDocument
       */
      public void startDocument ()
          throws SAXException
      {
          // no op
      }
  
  
      /**
       * Receive notification of the end of the document.
       *
       * <p>By default, do nothing.  Application writers may override this
       * method in a subclass to take specific actions at the end
       * of a document (such as finalising a tree or closing an output
       * file).</p>
       *
       * @exception org.xml.sax.SAXException Any SAX exception, possibly
       *            wrapping another exception.
       * @see org.xml.sax.ContentHandler#endDocument
       */
      public void endDocument ()
          throws SAXException
      {
          // no op
      }
  
  
      /**
       * Receive notification of the start of a Namespace mapping.
       *
       * <p>By default, do nothing.  Application writers may override this
       * method in a subclass to take specific actions at the start of
       * each Namespace prefix scope (such as storing the prefix mapping).</p>
       *
       * @param prefix The Namespace prefix being declared.
       * @param uri The Namespace URI mapped to the prefix.
       * @exception org.xml.sax.SAXException Any SAX exception, possibly
       *            wrapping another exception.
       * @see org.xml.sax.ContentHandler#startPrefixMapping
       */
      public void startPrefixMapping (String prefix, String uri)
          throws SAXException
      {
          // no op
      }
  
  
      /**
       * Receive notification of the end of a Namespace mapping.
       *
       * <p>By default, do nothing.  Application writers may override this
       * method in a subclass to take specific actions at the end of
       * each prefix mapping.</p>
       *
       * @param prefix The Namespace prefix being declared.
       * @exception org.xml.sax.SAXException Any SAX exception, possibly
       *            wrapping another exception.
       * @see org.xml.sax.ContentHandler#endPrefixMapping
       */
      public void endPrefixMapping (String prefix)
          throws SAXException
      {
          // no op
      }
  
  
      /**
       * Receive notification of the start of an element.
       *
       * <p>By default, do nothing.  Application writers may override this
       * method in a subclass to take specific actions at the start of
       * each element (such as allocating a new tree node or writing
       * output to a file).</p>
       *
       * @param uri The Namespace URI, or the empty string if the
       *        element has no Namespace URI or if Namespace
       *        processing is not being performed.
       * @param localName The local name (without prefix), or the
       *        empty string if Namespace processing is not being
       *        performed.
       * @param qName The qualified name (with prefix), or the
       *        empty string if qualified names are not available.
       * @param attributes The attributes attached to the element.  If
       *        there are no attributes, it shall be an empty
       *        Attributes object.
       * @exception org.xml.sax.SAXException Any SAX exception, possibly
       *            wrapping another exception.
       * @see org.xml.sax.ContentHandler#startElement
       */
      public void startElement (String uri, String localName,
                                String qName, Attributes attributes)
          throws SAXException
      {
          // no op
      }
  
  
      /**
       * Receive notification of the end of an element.
       *
       * <p>By default, do nothing.  Application writers may override this
       * method in a subclass to take specific actions at the end of
       * each element (such as finalising a tree node or writing
       * output to a file).</p>
       *
       * @param uri The Namespace URI, or the empty string if the
       *        element has no Namespace URI or if Namespace
       *        processing is not being performed.
       * @param localName The local name (without prefix), or the
       *        empty string if Namespace processing is not being
       *        performed.
       * @param qName The qualified name (with prefix), or the
       *        empty string if qualified names are not available.
       * @exception org.xml.sax.SAXException Any SAX exception, possibly
       *            wrapping another exception.
       * @see org.xml.sax.ContentHandler#endElement
       */
      public void endElement (String uri, String localName, String qName)
          throws SAXException
      {
          // no op
      }
  
  
      /**
       * Receive notification of character data inside an element.
       *
       * <p>By default, do nothing.  Application writers may override this
       * method to take specific actions for each chunk of character data
       * (such as adding the data to a node or buffer, or printing it to
       * a file).</p>
       *
       * @param ch The characters.
       * @param start The start position in the character array.
       * @param length The number of characters to use from the
       *               character array.
       * @exception org.xml.sax.SAXException Any SAX exception, possibly
       *            wrapping another exception.
       * @see org.xml.sax.ContentHandler#characters
       */
      public void characters (char ch[], int start, int length)
          throws SAXException
      {
          // no op
      }
  
  
      /**
       * Receive notification of ignorable whitespace in element content.
       *
       * <p>By default, do nothing.  Application writers may override this
       * method to take specific actions for each chunk of ignorable
       * whitespace (such as adding data to a node or buffer, or printing
       * it to a file).</p>
       *
       * @param ch The whitespace characters.
       * @param start The start position in the character array.
       * @param length The number of characters to use from the
       *               character array.
       * @exception org.xml.sax.SAXException Any SAX exception, possibly
       *            wrapping another exception.
       * @see org.xml.sax.ContentHandler#ignorableWhitespace
       */
      public void ignorableWhitespace (char ch[], int start, int length)
          throws SAXException
      {
          // no op
      }
  
  
      /**
       * Receive notification of a processing instruction.
       *
       * <p>By default, do nothing.  Application writers may override this
       * method in a subclass to take specific actions for each
       * processing instruction, such as setting status variables or
       * invoking other methods.</p>
       *
       * @param target The processing instruction target.
       * @param data The processing instruction data, or null if
       *             none is supplied.
       * @exception org.xml.sax.SAXException Any SAX exception, possibly
       *            wrapping another exception.
       * @see org.xml.sax.ContentHandler#processingInstruction
       */
      public void processingInstruction (String target, String data)
          throws SAXException
      {
          // no op
      }
  
  
      /**
       * Receive notification of a skipped entity.
       *
       * <p>By default, do nothing.  Application writers may override this
       * method in a subclass to take specific actions for each
       * processing instruction, such as setting status variables or
       * invoking other methods.</p>
       *
       * @param name The name of the skipped entity.
       * @exception org.xml.sax.SAXException Any SAX exception, possibly
       *            wrapping another exception.
       * @see org.xml.sax.ContentHandler#processingInstruction
       */
      public void skippedEntity (String name)
          throws SAXException
      {
          // no op
      }
  
  
  
      ////////////////////////////////////////////////////////////////////
      // Default implementation of the ErrorHandler interface.
      ////////////////////////////////////////////////////////////////////
  
  
      /**
       * Receive notification of a parser warning.
       *
       * <p>The default implementation does nothing.  Application writers
       * may override this method in a subclass to take specific actions
       * for each warning, such as inserting the message in a log file or
       * printing it to the console.</p>
       *
       * @param e The warning information encoded as an exception.
       * @exception org.xml.sax.SAXException Any SAX exception, possibly
       *            wrapping another exception.
       * @see org.xml.sax.ErrorHandler#warning
       * @see org.xml.sax.SAXParseException
       */
      public void warning (SAXParseException e)
          throws SAXException
      {
          // no op
      }
  
  
      /**
       * Receive notification of a recoverable parser error.
       *
       * <p>The default implementation does nothing.  Application writers
       * may override this method in a subclass to take specific actions
       * for each error, such as inserting the message in a log file or
       * printing it to the console.</p>
       *
       * @param e The error information encoded as an exception.
       * @exception org.xml.sax.SAXException Any SAX exception, possibly
       *            wrapping another exception.
       * @see org.xml.sax.ErrorHandler#warning
       * @see org.xml.sax.SAXParseException
       */
      public void error (SAXParseException e)
          throws SAXException
      {
          // no op
      }
  
  
      /**
       * Report a fatal XML parsing error.
       *
       * <p>The default implementation throws a SAXParseException.
       * Application writers may override this method in a subclass if
       * they need to take specific actions for each fatal error (such as
       * collecting all of the errors into a single report): in any case,
       * the application must stop all regular processing when this
       * method is invoked, since the document is no longer reliable, and
       * the parser may no longer report parsing events.</p>
       *
       * @param e The error information encoded as an exception.
       * @exception org.xml.sax.SAXException Any SAX exception, possibly
       *            wrapping another exception.
       * @see org.xml.sax.ErrorHandler#fatalError
       * @see org.xml.sax.SAXParseException
       */
      public void fatalError (SAXParseException e)
          throws SAXException
      {
          throw e;
      }
  
  }
  
  // end of DefaultHandler.java
  