/**
 * 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 2000 (C) Intalio, Inc. All Rights Reserved.
 *
 * $Id$
 */


package org.exolab.castor.xml.schema;

import java.util.Enumeration;

/**
 * An XML Schema Attribute Group Definition
 * 
 * @author <a href="mailto:kvisco@intalio.com">Keith Visco</a>
 * @version $Revision$ $Date: 2006-04-14 04:14:43 -0600 (Fri, 14 Apr 2006) $
 **/
public final class AttributeGroupReference extends AttributeGroup {
  /** SerialVersionUID */
  private static final long serialVersionUID = -6283626049554689747L;

  /**
   * Error message for a null argument
   **/
  private static String NULL_ARGUMENT =
      "A null argument was passed to the constructor of " + "AttributeGroupReference";

  /**
   * The Schema to which this AttributeDecl belongs
   **/
  private Schema _schema = null;

  private String _reference = null;

  /**
   * Creates a new AttributeGroup definition
   * 
   * @param schema the Schema that this AttributeGroup belongs to.
   **/
  public AttributeGroupReference(Schema schema, String reference) {
    if (schema == null) {
      String err = NULL_ARGUMENT + "; 'schema' must not be null.";
      throw new IllegalArgumentException(err);
    }
    if (reference == null) {
      String err = NULL_ARGUMENT + "; 'reference' must not be null.";
      throw new IllegalArgumentException(err);
    }
    _schema = schema;
    _reference = reference;
  } // -- AttributeGroup

  /**
   * Returns the anyAttribute set in this attribute group if any.
   * 
   * @return the anyAttribute set in this attribute group if any.
   */
  public Wildcard getAnyAttribute() {
    return resolveReference().getAnyAttribute();
  }


  /**
   * Gets the name of the attribute group this class refers to.
   */
  public String getReference() {
    return _reference;
  }

  /**
   * Resolves the attribute group reference
   * 
   * @return the attribute group defined at the schema level that is refered to by this class.
   */
  public AttributeGroup resolveReference() {
    AttributeGroup attrGroup = null;
    // --check if there is no definition in the
    // --master schema
    if (_schema.getMasterSchema() != null) {
      attrGroup = _schema.getMasterSchema().getAttributeGroup(_reference);
    }

    if (attrGroup == null)
      attrGroup = _schema.getAttributeGroup(_reference);

    if (attrGroup == null) {
      throw new IllegalStateException("Invalid AttributeGroupReference");
    }
    return attrGroup;
  }

  /**
   * Returns the AttributeDecl associated with the given name
   * 
   * @return the AttributeDecl associated with the given name, or null if no AttributeDecl with the
   *         given name was found.
   **/
  public AttributeDecl getAttribute(String name) {
    return resolveReference().getAttribute(name);

  } // -- getAttribute


  /**
   * Returns an enumeration of the AttributeDecls and AttributeGroups of this AttributeGroup
   *
   * @return an Enumeration of the AttributeDecls and AttributeGroups of this AttributeGroup
   **/
  public Enumeration<AttributeDecl> getAttributes() {
    return resolveReference().getAttributes();
  } // -- getAttributes

  /**
   * Returns true if this AttributeGroup does not contain any AttributeDecls or any non-empty
   * AttributeGroups
   *
   * @return true if this AttributeGroup does not contain any AttributeDecls or any non-empty
   *         AttributeGroups
   **/
  public boolean isEmpty() {
    return resolveReference().isEmpty();

  } // -- isEmpty

} // -- AttributeGroupReference
