/*
 * 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;

import org.apache.axis.components.logger.LogFactory;
import org.apache.axis.handlers.BasicHandler;
import org.apache.axis.strategies.InvocationStrategy;
import org.apache.axis.strategies.WSDLGenStrategy;
import org.apache.axis.utils.Messages;
import org.apache.commons.logging.Log;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

import javax.xml.namespace.QName;
import java.util.Enumeration;
import java.util.Vector;

/**
 * A Simple Chain is a 'composite' Handler in that it aggregates a collection
 * of Handlers and also acts as a Handler which delegates its operations to
 * the collection.
 * <p/>
 * A Simple Chain initially has no Handlers. Handlers may be added until the
 * chain is invoke()d after which Handlers may not be added (and any attempt
 * to do so will throw an exception).
 *
 * @author Doug Davis (dug@us.ibm.com)
 * @author Glyn Normington (norm@uk.ibm.com)
 */
public class SimpleChain extends BasicHandler implements Chain
{
   private static Log log =
           LogFactory.getLog(SimpleChain.class.getName());

   protected Vector handlers = new Vector();
   protected boolean invoked = false;

   private String CAUGHTFAULT_PROPERTY =
           "org.apache.axis.SimpleChain.caughtFaultInResponse";

   public void init()
   {
      for (int i = 0; i < handlers.size(); i++)
         ((Handler)handlers.elementAt(i)).init();
   }

   public void cleanup()
   {
      for (int i = 0; i < handlers.size(); i++)
         ((Handler)handlers.elementAt(i)).cleanup();
   }

   private static final HandlerIterationStrategy iVisitor =
           new InvocationStrategy();

   private static final HandlerIterationStrategy wsdlVisitor =
           new WSDLGenStrategy();

   /**
    * Iterate over the chain invoking each handler.  If there's a fault
    * then call 'onFault' for each completed handler in reverse order, then
    * rethrow the exception.
    */
   public void invoke(MessageContext msgContext) throws AxisFault
   {
      if (log.isDebugEnabled())
      {
         log.debug("Enter: SimpleChain::invoke");
      }

      invoked = true;
      doVisiting(msgContext, iVisitor);

      if (log.isDebugEnabled())
      {
         log.debug("Exit: SimpleChain::invoke");
      }
   }

   /**
    * Iterate over the chain letting each handler have a crack at
    * contributing to a WSDL description.
    */
   public void generateWSDL(MessageContext msgContext) throws AxisFault
   {
      if (log.isDebugEnabled())
      {
         log.debug("Enter: SimpleChain::generateWSDL");
      }

      invoked = true;
      doVisiting(msgContext, wsdlVisitor);

      if (log.isDebugEnabled())
      {
         log.debug("Exit: SimpleChain::generateWSDL");
      }
   }

   private void doVisiting(MessageContext msgContext,
                           HandlerIterationStrategy visitor) throws AxisFault
   {
      int i = 0;
      try
      {
         Enumeration enum = handlers.elements();
         while (enum.hasMoreElements())
         {
            visitor.visit((Handler)enum.nextElement(), msgContext);
            i++;
         }
      }
      catch (AxisFault f)
      {
         // Something went wrong.  If we haven't already put this fault
         // into the MessageContext's response message, do so and make sure
         // we only do it once.  This allows onFault() methods to safely
         // set headers and such in the response message without them
         // getting stomped.
         if (!msgContext.isPropertyTrue(CAUGHTFAULT_PROPERTY))
         {
            // Attach the fault to the response message; enabling access to the
            // fault details while inside the handler onFault methods.
            Message respMsg = new Message(f);
            msgContext.setResponseMessage(respMsg);
            msgContext.setProperty(CAUGHTFAULT_PROPERTY, Boolean.TRUE);
         }
         while (--i >= 0)
            ((Handler)handlers.elementAt(i)).onFault(msgContext);
         throw f;
      }
   }

   /**
    * Notify the handlers in this chain because some handler
    * later on has faulted - in reverse order. If any handlers
    * have been added since we visited the chain, they will get
    * notified too!
    */
   public void onFault(MessageContext msgContext)
   {
      if (log.isDebugEnabled())
      {
         log.debug("Enter: SimpleChain::onFault");
      }

      for (int i = handlers.size() - 1; i >= 0; i--)
         ((Handler)handlers.elementAt(i)).onFault(msgContext);

      if (log.isDebugEnabled())
      {
         log.debug("Exit: SimpleChain::onFault");
      }
   }

   public boolean canHandleBlock(QName qname)
   {
      for (int i = 0; i < handlers.size(); i++)
         if (((Handler)handlers.elementAt(i)).canHandleBlock(qname))
            return (true);
      return (false);
   }

   public void addHandler(Handler handler)
   {
      if (handler == null)
         throw new InternalException(Messages.getMessage("nullHandler00",
                 "SimpleChain::addHandler"));

      if (invoked)
         throw new InternalException(Messages.getMessage("addAfterInvoke00",
                 "SimpleChain::addHandler"));

      handlers.add(handler);
   }

   public boolean contains(Handler handler)
   {
      return (handlers.contains(handler));
   }

   public Handler[] getHandlers()
   {
      if (handlers.size() == 0)
         return null;

      Handler[] ret = new Handler[handlers.size()];
      return ((Handler[])handlers.toArray(ret));
   }

   public Element getDeploymentData(Document doc)
   {
      if (log.isDebugEnabled())
      {
         log.debug(Messages.getMessage("enter00",
                 "SimpleChain::getDeploymentData"));
      }

      Element root = doc.createElementNS("", "chain");

      StringBuffer str = new StringBuffer();
      int i = 0;
      while (i < handlers.size())
      {
         if (i != 0) str.append(",");
         Handler h = (Handler)handlers.elementAt(i);
         str.append(h.getName());
         i++;
      }
      if (i > 0)
      {
         root.setAttribute("flow", str.toString());
      }

      if (options != null)
      {
         Enumeration e = options.keys();
         while (e.hasMoreElements())
         {
            String k = (String)e.nextElement();
            Object v = options.get(k);
            Element e1 = doc.createElementNS("", "option");
            e1.setAttribute("name", k);
            e1.setAttribute("value", v.toString());
            root.appendChild(e1);
         }
      }

      if (log.isDebugEnabled())
      {
         log.debug("Exit: SimpleChain::getDeploymentData");
      }

      return (root);
   }
}
