/**
    * Redistribution and use of this software and associated documentation
    * ("Software"), with or without modification, are permitted provided
    * that the following conditions are met:
    *
    * 1. Redistributions of source code must retain copyright
    *    statements and notices.  Redistributions must also contain a
    *    copy of this document.
    *
   * 2. Redistributions in binary form must reproduce the
   *    above copyright notice, this list of conditions and the
   *    following disclaimer in the documentation and/or other
   *    materials provided with the distribution.
   *
   * 3. The name "Exolab" must not be used to endorse or promote
   *    products derived from this Software without prior written
   *    permission of Intalio, Inc.  For written permission,
   *    please contact info@exolab.org.
   *
   * 4. Products derived from this Software may not be called "Exolab"
   *    nor may "Exolab" appear in their names without prior written
   *    permission of Intalio, Inc. Exolab is a registered
   *    trademark of Intalio, Inc.
   *
   * 5. Due credit should be given to the Exolab Project
   *    (http://www.exolab.org/).
   *
   * THIS SOFTWARE IS PROVIDED BY INTALIO, INC. AND CONTRIBUTORS
   * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
   * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
   * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
   * INTALIO, INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
   * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   * OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * Copyright 1999 (C) Intalio, Inc. All Rights Reserved.
   *
   * $Id$
   */
  
  
  package org.exolab.castor.dsml;
  
  
  import java.util.Enumeration;
  import org.xml.sax.DocumentHandler;
  import org.xml.sax.SAXException;
  import org.xml.sax.AttributeList;
  import org.xml.sax.Locator;
  import org.castor.core.util.Messages;
  
  
  /**
   *
   *
   * @author <a href="mailto:arkin@intalio.com">Assaf Arkin</a>
   * @version $Revision$ $Date: 2006-04-26 13:58:52 -0600 (Wed, 26 Apr 2006) $
   */
  public abstract class Consumer
      implements DocumentHandler
  {
  
  
      private boolean           _insideRoot;
  
  
      private DocumentHandler   _redirect;
  
  
      public Consumer()
      {
      }
  
  
      public abstract Enumeration getResults();
  
  
      protected abstract DocumentHandler getEntryConsumer();
  
  
      public void startElement( String tagName, AttributeList attr )
  	throws SAXException
      {
  	if ( _redirect != null ) {
  	    // When redirecting all element creations pass directly to
  	    // the other handler, we only look for closure.
  	    _redirect.startElement( tagName, attr );
  	} else if ( tagName.equals( XML.Namespace.ROOT ) ) {
  	    // Flag when entering (and leaving) the root element.
  	    if ( _insideRoot )
  		throw new SAXException( Messages.format( "dsml.elementNested",
  							 XML.Namespace.ROOT ) );
  	    _insideRoot = true;
  	} else {
 	    if ( ! _insideRoot )
 		throw new SAXException( Messages.format( "dsml.expectingOpeningTag",
 							 XML.Namespace.ROOT, tagName ) );
 	    if ( tagName.equals( XML.Schema.ELEMENT ) ||
 		 tagName.equals( XML.Entries.ELEMENT ) ) {
 		DocumentHandler entry;
 
 		entry = getEntryConsumer();
 		entry.startElement( tagName, attr );
 		_redirect = entry;
 	    } else {
 		throw new SAXException( Messages.format( "dsml.openingTagNotRecognized",
 							 tagName ) );
 	    }
 	}
     }
 
 
     public void endElement( String tagName )
 	throws SAXException
     {
 	if ( _redirect == null ) {
 	    // This is the only case where we expect the root element
 	    // to be closed.
 	    if ( tagName.equals( XML.Namespace.ROOT ) ) {
 		if ( _insideRoot == true )
 		    _insideRoot = false;
 		else
 		    throw new SAXException( Messages.format( "dsml.closingOutsideRoot",
 							     tagName ) );
 	    } else {
 		throw new SAXException( Messages.format( "dsml.expectingClosingTag",
 							 XML.Namespace.ROOT, tagName ) );
 	    }
 	} else {
 	    _redirect.endElement( tagName );
 	    
 	    if ( tagName.equals( XML.Schema.ELEMENT ) ||
 			tagName.equals( XML.Entries.ELEMENT ) ) {
 		// If we've reached this point we must be inside the
 		// entries/schema redirect.
 		_redirect = null;
 	    }
 	    // If we've reached this point we must be inside the
 	    // entries/schema redirect, we ignore all closing tags.
 	}
     }
 
 
     public void characters( char[] ch, int offset, int length )
 	throws SAXException
     {
 	if ( _redirect != null ) {
 	    _redirect.characters( ch, offset, length );
 	}
     }
 
 
     public void ignorableWhitespace( char[] ch, int offset, int length )
 	throws SAXException
     {
 	if ( _redirect != null ) {
 	    _redirect.ignorableWhitespace( ch, offset, length );
 	}
     }
 
 
     public void processingInstruction( String target, String instruction )
 	throws SAXException
     {
 	if ( _redirect != null ) {
 	    _redirect.processingInstruction( target, instruction );
 	}
     }
 
 
     public void startDocument()
 	throws SAXException
     {
     }
 
 
     public void endDocument()
 	throws SAXException
     {
 	if ( _insideRoot )
 	    throw new SAXException( Messages.message( "dsml.documentRootStillOpen" ) );
     }
 
 
     public void setDocumentLocator( Locator locator )
     {
     }
 
 
 }