/*
    * 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 2000-2004 (C) Intalio, Inc. All Rights Reserved.
   *
   * $Id$
   */
  package org.exolab.castor.xml.descriptors;
  
  import java.util.Enumeration;
  import java.util.Locale;
  import java.util.Vector;
  
  import org.exolab.castor.xml.XMLClassDescriptor;
  
  /**
   * The default set of built-in ClassDescriptors. A static utility class.
   *
   * @author <a href="mailto:kvisco-at-intalio.com">Keith Visco</a>
   * @version $Revision$ $Date: 2004-11-04 15:55:27 -0700 (Thu, 04 Nov 2004) $
   */
  public final class CoreDescriptors {
  
    /** Fully-qualified name of the List class from Java 1.2. */
    private static final String LIST_CLASS_NAME = "java.util.List";
    /** Fully-qualified name of our List Class Descriptor. */
    private static final String LIST_DESCRIPTOR_NAME =
        "org.exolab.castor.xml.descriptors.ListClassDescriptor";
    /** If not null, the Java 1.2 or later list class. */
    private static final Class LIST_CLASS = getListClass();
  
    /** The Date ClassDescriptor. */
    private static final XMLClassDescriptor DATE_DESCRIPTOR = new DateClassDescriptor();
    /**
     * The java.util.Enumeration ClassDescriptor, really only useful for marshaling since Enumerations
     * are read-only.
     */
    private static final XMLClassDescriptor ENUMERATION_DESCRIPTOR = new EnumerationDescriptor();
    /** The List ClassDescriptor (only loaded for JDK 1.2+). */
    private static final XMLClassDescriptor LIST_DESCRIPTOR = getListClassDescriptor();
    /** The java.util.Locale ClassDescriptor. */
    private static final XMLClassDescriptor LOCALE_DESCRIPTOR = new LocaleDescriptor();
    /** The java.sql.Date ClassDescriptor. */
    private static final XMLClassDescriptor SQL_DATE_DESCRIPTOR = new SQLDateClassDescriptor();
    /** The java.sql.Time ClassDescriptor. */
    private static final XMLClassDescriptor SQL_TIME_DESCRIPTOR = new SQLTimeClassDescriptor();
    /** The java.sql.Timestamp ClassDescriptor. */
    private static final XMLClassDescriptor SQL_TIMESTAMP_DESCRIPTOR =
        new SQLTimestampClassDescriptor();
    /** The String ClassDescriptor. */
    private static final XMLClassDescriptor STRING_DESCRIPTOR = new StringClassDescriptor();
    /** The Vector ClassDescriptor. */
    private static final XMLClassDescriptor VECTOR_DESCRIPTOR = new VectorClassDescriptor();
  
    /**
     * Default constructor. Intentionally private.
     */
    private CoreDescriptors() {
      super();
    } // -- CoreDescriptors
  
    /**
     * Returns the XMLClassDescriptor for the given Class. This method will return null if there is no
     * built-in XMLClassDescriptor.
     *
     * @param clazz the Class to return the XMLClassDescriptor for.
     * @return the XMLClassDescriptor for the given class, or null.
     */
    public static XMLClassDescriptor getDescriptor(final Class clazz) {
      if (clazz == null) {
        return null;
      }
 
     if (clazz == String.class) {
       return STRING_DESCRIPTOR;
     }
 
     if (clazz == java.util.Date.class) {
       return DATE_DESCRIPTOR;
     }
 
     if (Enumeration.class.isAssignableFrom(clazz)) {
       return ENUMERATION_DESCRIPTOR;
     }
 
     if (clazz == Vector.class || Vector.class.isAssignableFrom(clazz)) {
       return VECTOR_DESCRIPTOR;
     }
 
     // -- JDK 1.2
     if (LIST_DESCRIPTOR != null && (LIST_CLASS == clazz || LIST_CLASS.isAssignableFrom(clazz))) {
       return LIST_DESCRIPTOR;
     }
 
     if (clazz == Locale.class) {
       return LOCALE_DESCRIPTOR;
     }
 
     // -- java.sql Date/Time classes
     if (clazz == java.sql.Date.class) {
       return SQL_DATE_DESCRIPTOR;
     }
 
     if (clazz == java.sql.Time.class) {
       return SQL_TIME_DESCRIPTOR;
     }
 
     if (clazz == java.sql.Timestamp.class) {
       return SQL_TIMESTAMP_DESCRIPTOR;
     }
 
     return null;
   } // -- getDescriptor
 
   /**
    * Loads and returns the list class class descriptor. Used during static initialization.
    *
    * @return the list class class descriptor.
    */
   private static XMLClassDescriptor getListClassDescriptor() {
     // If null, then not JDK 1.2 or greater
     if (LIST_CLASS == null) {
       return null;
     }
 
     ClassLoader loader = CoreDescriptors.class.getClassLoader();
     Class descriptorClass = null;
     try {
       if (loader == null) {
         descriptorClass = Class.forName(LIST_DESCRIPTOR_NAME);
       } else {
         descriptorClass = loader.loadClass(LIST_DESCRIPTOR_NAME);
       }
     } catch (ClassNotFoundException cnfe) {
       // -- do nothing...handled below
     }
 
     XMLClassDescriptor listDescriptor = null;
     if (descriptorClass != null) {
       try {
         listDescriptor = (XMLClassDescriptor) descriptorClass.newInstance();
       } catch (InstantiationException ie) {
         // -- just ignore
       } catch (IllegalAccessException iae) {
         // -- just ignore
       }
     } else {
       listDescriptor = null;
     }
     return listDescriptor;
   }
 
   /**
    * Looks for the JDK 1.2 List class Class object and return it. Used during static initialization.
    *
    * @return the Class object for the JDK 1.2 List class.
    */
   private static Class getListClass() {
     Class listClass = null;
 
     // Look for JDK 1.2 Collections
     ClassLoader loader = null;
     try {
       loader = java.util.Vector.class.getClassLoader();
       if (loader == null) {
         // probably JDK 1.1 if loader is null, but we can double-check anyway
         listClass = Class.forName(LIST_CLASS_NAME);
       } else {
         listClass = loader.loadClass(LIST_CLASS_NAME);
       }
     } catch (ClassNotFoundException cnfe) {
       // -- do nothing...handled below
     }
 
     return listClass;
   }
 
 } // -- CoreDescriptors