/**
 * 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
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 * 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 1999-2002 (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.Annotation;
import org.exolab.castor.xml.schema.ElementDecl;
import org.exolab.castor.xml.schema.Group;
import org.exolab.castor.xml.schema.ModelGroup;
import org.exolab.castor.xml.schema.Order;
import org.exolab.castor.xml.schema.Schema;
import org.exolab.castor.xml.schema.SchemaContext;
import org.exolab.castor.xml.schema.SchemaException;
import org.exolab.castor.xml.schema.SchemaNames;
import org.exolab.castor.xml.schema.Wildcard;

/**
 * A class for Unmarshalling ModelGroups
 * 
 * @author <a href="mailto:kvisco@intalio.com">Keith Visco</a>
 * @version $Revision$ $Date: 2005-12-13 14:58:48 -0700 (Tue, 13 Dec 2005) $
 **/
public class GroupUnmarshaller extends ComponentReader {

  // --------------------------/
  // - Static Class Variables -/
  // --------------------------/

  /**
   * The value of the maximum occurance wild card
   */
  private static final String MAX_OCCURS_WILDCARD = "unbounded";

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

  /**
   * The current ComponentReader
   **/
  private ComponentReader unmarshaller;

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

  /**
   * The ModelGroup reference for the ModelGroup we are constructing
   **/
  private Group _group = null;

  /**
   * The Schema being "unmarshalled"
   **/
  private Schema _schema = null;

  /**
   * The element name of the Group to be unmarshalled.
   **/
  private String _element = SchemaNames.SEQUENCE;

  private boolean foundAll = false;
  private boolean foundElement = false;
  private boolean foundGroup = false;
  private boolean foundModelGroup = false;
  private boolean foundAnnotation = false;

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

  /**
   * Creates a new GroupUnmarshaller.
   * 
   * @param schemaContext the {@link SchemaContext} to get some configuration settings from
   * @param schema the Schema to which the Group belongs
   * @param element the element name for this type of group
   * @param atts the AttributeList
   **/
  public GroupUnmarshaller(final SchemaContext schemaContext, final Schema schema,
      final String element, final AttributeSet atts) {
    super(schemaContext);

    this._schema = schema;

    _group = new Group();
    // -- handle attributes
    String attValue = null;


    if (SchemaNames.SEQUENCE.equals(element)) {
      _group.setOrder(Order.sequence);
    } else if (SchemaNames.CHOICE.equals(element)) {
      _group.setOrder(Order.choice);
    } else if (SchemaNames.ALL.equals(element)) {
      foundAll = true;
      _group.setOrder(Order.all);
    } else {
      String err = "Invalid group element name: '" + element + "'";
      throw new IllegalArgumentException(err);
    }


    _element = element;

    // -- set name
    attValue = atts.getValue(SchemaNames.NAME_ATTR);
    if (attValue != null) {
      _group.setName(attValue);
    }

    /*
     * @maxOccurs If maxOccurs is present, the value is either unbounded or the int value of the
     * attribute, otherwise maxOccurs equals the minOccurs value.
     */
    attValue = atts.getValue(SchemaNames.MAX_OCCURS_ATTR);

    if (attValue != null) {
      if (MAX_OCCURS_WILDCARD.equals(attValue))
        _group.setMaxOccurs(-1);
      else
        _group.setMaxOccurs(toInt(attValue));
    }
    // -- minOccurs
    attValue = atts.getValue("minOccurs");
    if (attValue != null)
      _group.setMinOccurs(toInt(attValue));

    if (_group.getOrder() == Order.all) {
      if (_group.getMaxOccurs() != 1) {
        String err = "Wrong maxOccurs value for a <all>:" + _group.getMaxOccurs();
        err += "\n1 is the only possible value.";
        throw new IllegalArgumentException(err);
      }
      if (_group.getMinOccurs() > 1) {
        String err = "Wrong minOccurs value for a <all>:" + _group.getMinOccurs();
        err += "\n0 or 1 are the only possible values.";
        throw new IllegalArgumentException(err);
      }
    }
    // -- id
    _group.setId(atts.getValue("id"));

  } // -- GroupUnmarshaller

  // -----------/
  // - 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 _element;
  } // -- elementName


  /**
   * Returns the Group that was unmarshalled by this Unmarshaller. This method should only be called
   * after unmarshalling has been completed.
   *
   * @return the unmarshalled Group
   **/
  public Group getGroup() {
    return _group;
  } // -- getGroup

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

  /**
   * 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 (foundElement || foundGroup || foundModelGroup)
        error("An annotation may only appear as the first child " + "of an element definition.");


      if (foundAnnotation)
        error("Only one (1) 'annotation' is allowed as a child of " + "element definitions.");

      foundAnnotation = true;
      unmarshaller = new AnnotationUnmarshaller(getSchemaContext(), atts);
    } else if (SchemaNames.ELEMENT.equals(name)) {
      foundElement = true;
      unmarshaller = new ElementUnmarshaller(getSchemaContext(), _schema, atts);
    }
    // --group
    else if (name.equals(SchemaNames.GROUP)) {
      foundModelGroup = true;
      unmarshaller = new ModelGroupUnmarshaller(getSchemaContext(), _schema, atts);
    }

    // --all, sequence, choice
    else if ((SchemaNames.isGroupName(name)) && (name != SchemaNames.GROUP)) {
      foundGroup = true;
      if (SchemaNames.ALL.equals(name))
        foundAll = true;
      unmarshaller = new GroupUnmarshaller(getSchemaContext(), _schema, name, atts);
    }
    // --any
    else if (SchemaNames.ANY.equals(name)) {
      if (foundAll)
        error("<any> can not appear as a child of a <all> element");
      unmarshaller = new WildcardUnmarshaller(getSchemaContext(), _group, _schema, name, atts);
    }

    else {
      StringBuffer err = new StringBuffer("illegal element <");
      err.append(name);
      err.append("> found in <group>.");
      throw new SchemaException(err.toString());
    }

  } // -- 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;
    }
    // -- check for name mismatches
    if (unmarshaller != null) {
      if (!name.equals(unmarshaller.elementName())) {
        String err = "missing end element for ";
        err += unmarshaller.elementName();
        throw new SchemaException(err);
      }
    }

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

    // -- <any>
    if (SchemaNames.ANY.equals(name)) {
      Wildcard wildcard = ((WildcardUnmarshaller) unmarshaller).getWildcard();
      try {
        _group.addWildcard(wildcard);
      } catch (SchemaException e) {
        throw new IllegalArgumentException(e.getMessage());
      }
    }
    if (SchemaNames.ANNOTATION.equals(name)) {
      Annotation ann = (Annotation) unmarshaller.getObject();
      _group.addAnnotation(ann);
    } else if (SchemaNames.ELEMENT.equals(name)) {
      ElementDecl element = (ElementDecl) unmarshaller.getObject();
      _group.addElementDecl(element);
    } else if (name.equals(SchemaNames.GROUP)) {
      ModelGroup group = (ModelGroup) unmarshaller.getObject();
      _group.addGroup(group);
    } else if ((SchemaNames.isGroupName(name)) && (name != SchemaNames.GROUP)) {
      Group group = ((GroupUnmarshaller) unmarshaller).getGroup();
      _group.addGroup(group);
    }

    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

} // -- GroupUnmarshaller
