/**
 * 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
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 * 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 2001-2002 (C) Intalio Inc. All Rights Reserved.
 *
 * $Id$
 */

package org.exolab.castor.xml.schema.reader;

// -- imported classes and packages
import org.exolab.castor.xml.AttributeSet;
import org.exolab.castor.xml.Namespaces;
import org.exolab.castor.xml.XMLException;
import org.exolab.castor.xml.schema.Annotated;
import org.exolab.castor.xml.schema.Annotation;
import org.exolab.castor.xml.schema.IdentityField;
import org.exolab.castor.xml.schema.IdentitySelector;
import org.exolab.castor.xml.schema.SchemaContext;
import org.exolab.castor.xml.schema.SchemaNames;

/**
 * A class for Unmarshalling Selector or Field elements for identity-constraints
 *
 * @author <a href="mailto:kvisco@intalio.com">Keith Visco</a>
 * @version $Revision$ $Date: 2003-03-03 00:05:44 -0700 (Mon, 03 Mar 2003) $
 **/
public class FieldOrSelectorUnmarshaller extends ComponentReader {

  // --------------------/
  // - Member Variables -/
  // --------------------/

  /**
   * The current ComponentReader
   **/
  private ComponentReader _unmarshaller;

  /**
   * The current branch depth
   **/
  private int _depth = 0;

  /**
   * The Field or Selector we are unmarshalling
   **/
  private Annotated _fieldOrSelector = null;

  private boolean _foundAnnotation = false;

  private String _elementName = null;

  // ----------------/
  // - Constructors -/
  // ----------------/

  /**
   * Creates a new FieldOrSelectorUnmarshaller.
   *
   * @param schemaContext the {@link SchemaContext} to get some configuration settings from
   * @param elementName the name of the element being unmarshalled.
   * @param atts the AttributeList.
   **/
  public FieldOrSelectorUnmarshaller(final SchemaContext schemaContext, final String elementName,
      final AttributeSet atts) throws XMLException {
    super(schemaContext);

    _elementName = elementName;

    String xpath = atts.getValue(SchemaNames.XPATH_ATTR);
    if (xpath == null) {
      error("The 'xpath' attribute for '" + _elementName + "' must exist.");
    }

    String id = atts.getValue(SchemaNames.ID_ATTR);

    // -- selector
    if (SchemaNames.SELECTOR.equals(elementName)) {
      _fieldOrSelector = new IdentitySelector(xpath);
      if (id != null) {
        ((IdentitySelector) _fieldOrSelector).setId(id);
      }
    }
    // -- field
    else {
      _fieldOrSelector = new IdentityField(xpath);
      if (id != null) {
        ((IdentityField) _fieldOrSelector).setId(id);
      }
    }

  } // -- FieldOrSelectorUnmarshaller

  // -----------/
  // - Methods -/
  // -----------/

  /**
   * Returns the name of the element that this ComponentReader handles
   * 
   * @return the name of the element that this ComponentReader handles
   **/
  public String elementName() {
    return _elementName;
  } // -- elementName

  /**
   * Returns the Object created by this ComponentReader
   *
   * @return the Object created by this ComponentReader
   **/
  public Object getObject() {
    return _fieldOrSelector;
  } // -- getObject

  public void finish() throws XMLException {
    // -- do nothing
  } // -- finish

  /**
   * Signals the start of an element with the given name.
   *
   * @param name the NCName of the element. It is an error if the name is a QName (ie. contains a
   *        prefix).
   * @param namespace the namespace of the element. This may be null. Note: A null namespace is not
   *        the same as the default namespace unless the default namespace is also null.
   * @param atts the AttributeSet containing the attributes associated with the element.
   * @param nsDecls the namespace declarations being declared for this element. This may be null.
   **/
  public void startElement(String name, String namespace, AttributeSet atts, Namespaces nsDecls)
      throws XMLException {
    // -- Do delagation if necessary
    if (_unmarshaller != null) {
      _unmarshaller.startElement(name, namespace, atts, nsDecls);
      ++_depth;
      return;
    }

    if (SchemaNames.ANNOTATION.equals(name)) {

      if (_foundAnnotation)
        error("Only one (1) annotation may appear as a child of '" + _elementName + "'.");
      _foundAnnotation = true;
      _unmarshaller = new AnnotationUnmarshaller(getSchemaContext(), atts);
    } else
      illegalElement(name);

  } // -- startElement

  /**
   * Signals to end of the element with the given name.
   *
   * @param name the NCName of the element. It is an error if the name is a QName (ie. contains a
   *        prefix).
   * @param namespace the namespace of the element.
   **/
  public void endElement(String name, String namespace) throws XMLException {

    // -- Do delagation if necessary
    if ((_unmarshaller != null) && (_depth > 0)) {
      _unmarshaller.endElement(name, namespace);
      --_depth;
      return;
    }

    // -- have unmarshaller perform any necessary clean up
    _unmarshaller.finish();

    if (SchemaNames.ANNOTATION.equals(name)) {
      Annotation annotation = (Annotation) _unmarshaller.getObject();
      _fieldOrSelector.addAnnotation(annotation);
    }

    _unmarshaller = null;
  } // -- endElement

  public void characters(char[] ch, int start, int length) throws XMLException {
    // -- Do delagation if necessary
    if (_unmarshaller != null) {
      _unmarshaller.characters(ch, start, length);
    }
  } // -- characters

} // -- FieldOrSelectorUnmarshaller
