/**
 * 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) {}


}

