/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 2001-2003 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 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 end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Axis" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``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 THE APACHE SOFTWARE FOUNDATION 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package org.apache.axis.encoding.ser;

import org.apache.axis.Constants;
import org.apache.axis.encoding.Serializer;
import org.apache.axis.encoding.SerializerFactory;
import org.apache.axis.utils.Messages;

import javax.xml.namespace.QName;
import javax.xml.rpc.JAXRPCException;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Iterator;
import java.util.Vector;

/**
 * Base class for Axis Serialization Factory classes for code reuse
 *
 * @author Rich Scheuerle <scheu@us.ibm.com>
 */
public abstract class BaseSerializerFactory extends BaseFactory
        implements SerializerFactory
{

   transient static Vector mechanisms = null;

   protected Class serClass = null;
   protected QName xmlType = null;
   protected Class javaType = null;

   transient protected Serializer ser = null;
   transient protected Constructor serClassConstructor = null;
   transient protected Method getSerializer = null;

   /**
    * Constructor
    *
    * @param serClass is the class of the Serializer
    *                 Sharing is only valid for xml primitives.
    */
   public BaseSerializerFactory(Class serClass)
   {
      this.serClass = serClass;
   }

   public BaseSerializerFactory(Class serClass,
                                QName xmlType, Class javaType)
   {
      this(serClass);
      this.xmlType = xmlType;
      this.javaType = javaType;
   }

   public javax.xml.rpc.encoding.Serializer
           getSerializerAs(String mechanismType)
           throws JAXRPCException
   {
      synchronized (this)
      {
         if (ser == null)
         {
            ser = getSerializerAsInternal(mechanismType);
         }
         return ser;
      }
   }

   protected Serializer getSerializerAsInternal(String mechanismType)
           throws JAXRPCException
   {
      // Try getting a specialized Serializer
      Serializer serializer = getSpecialized(mechanismType);

      // Try getting a general purpose Serializer via constructor
      // invocation
      if (serializer == null)
      {
         serializer = getGeneralPurpose(mechanismType);
      }

      try
      {
         // If not successfull, try newInstance
         if (serializer == null)
         {
            serializer = (Serializer)serClass.newInstance();
         }
      }
      catch (Exception e)
      {
         throw new JAXRPCException(Messages.getMessage("CantGetSerializer",
                 serClass.getName()),
                 e);
      }
      return serializer;
   }

   /**
    * Obtains a serializer by invoking <constructor>(javaType, xmlType)
    * on the serClass.
    */
   protected Serializer getGeneralPurpose(String mechanismType)
   {
      if (javaType != null && xmlType != null)
      {
         Constructor serClassConstructor = getSerClassConstructor();
         if (serClassConstructor != null)
         {
            try
            {
               return (Serializer)
                       serClassConstructor.newInstance(new Object[]{javaType, xmlType});
            }
            catch (InstantiationException e)
            {
            }
            catch (IllegalAccessException e)
            {
            }
            catch (InvocationTargetException e)
            {
            }
         }
      }
      return null;
   }

   /**
    * return constructor for class if any
    */
   private Constructor getConstructor(Class clazz)
   {
      try
      {
         return clazz.getConstructor(new Class[]{Class.class, QName.class});
      }
      catch (NoSuchMethodException e)
      {
      }
      return null;
   }

   /**
    * Obtains a serializer by invoking getSerializer method in the
    * javaType class or its Helper class.
    */
   protected Serializer getSpecialized(String mechanismType)
   {
      if (javaType != null && xmlType != null)
      {
         if (getSerializer != null)
         {
            try
            {
               return (Serializer)
                       getSerializer.invoke(null,
                               new Object[]{mechanismType,
                                            javaType,
                                            xmlType});
            }
            catch (IllegalAccessException e)
            {
            }
            catch (InvocationTargetException e)
            {
            }
         }
      }
      return null;
   }

   /**
    * Returns a list of all XML processing mechanism types supported
    * by this SerializerFactory.
    *
    * @return List of unique identifiers for the supported XML
    *         processing mechanism types
    */
   public Iterator getSupportedMechanismTypes()
   {
      if (mechanisms == null)
      {
         mechanisms = new Vector();
         mechanisms.add(Constants.AXIS_SAX);
      }
      return mechanisms.iterator();
   }

   /**
    * get xmlType
    *
    * @return xmlType QName for this factory
    */
   public QName getXMLType()
   {
      return xmlType;
   }

   /**
    * get javaType
    *
    * @return javaType Class for this factory
    */
   public Class getJavaType()
   {
      return javaType;
   }

   /**
    * Utility method that intospects on a factory class to decide how to
    * create the factory.  Tries in the following order:
    * public static create(Class javaType, QName xmlType)
    * public <constructor>(Class javaType, QName xmlType)
    * public <constructor>()
    *
    * @param factory  class
    * @param xmlType
    * @param javaType
    */
   public static SerializerFactory createFactory(Class factory,
                                                 Class javaType,
                                                 QName xmlType)
   {

      SerializerFactory sf = null;
      try
      {
         Method method =
                 factory.getMethod("create",
                         new Class[]{Class.class, QName.class});
         sf = (SerializerFactory)
                 method.invoke(null,
                         new Object[]{javaType, xmlType});
      }
      catch (NoSuchMethodException e)
      {
      }
      catch (IllegalAccessException e)
      {
      }
      catch (InvocationTargetException e)
      {
      }

      if (sf == null)
      {
         try
         {
            Constructor constructor =
                    factory.getConstructor(new Class[]{Class.class, QName.class});
            sf = (SerializerFactory)
                    constructor.newInstance(new Object[]{javaType, xmlType});
         }
         catch (NoSuchMethodException e)
         {
         }
         catch (InstantiationException e)
         {
         }
         catch (IllegalAccessException e)
         {
         }
         catch (InvocationTargetException e)
         {
         }
      }

      if (sf == null)
      {
         try
         {
            sf = (SerializerFactory)factory.newInstance();
         }
         catch (InstantiationException e)
         {
         }
         catch (IllegalAccessException e)
         {
         }
      }
      return sf;
   }

   /**
    * Returns the getSerializer.
    *
    * @return Method
    */
   protected Method getGetSerializer()
   {
      if (getSerializer == null)
      {
         getSerializer = getMethod(javaType, "getSerializer");
      }
      return getSerializer;
   }

   /**
    * Returns the serClassConstructor.
    *
    * @return Constructor
    */
   protected Constructor getSerClassConstructor()
   {
      if (serClassConstructor == null)
      {
         serClassConstructor = getConstructor(serClass);
      }
      return serClassConstructor;
   }

}
