/*

  * Copyright 2007-2008 The Kuali Foundation

  *

  * Licensed under the Educational Community License, Version 2.0 (the "License");

  * you may not use this file except in compliance with the License.

  * You may obtain a copy of the License at

  *

  * http://www.opensource.org/licenses/ecl2.php

  *

  * Unless required by applicable law or agreed to in writing, software

  * distributed under the License is distributed on an "AS IS" BASIS,

  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

  * See the License for the specific language governing permissions and

  * limitations under the License.

  */

 package org.kuali.rice.kcb.service.impl;

 import java.sql.Timestamp;

 import java.util.ArrayList;

 import java.util.Collection;

 import java.util.HashMap;

 import java.util.Map;

 import org.apache.log4j.Logger;

 import org.apache.ojb.broker.query.Criteria;

 import org.kuali.rice.core.util.RiceConstants;

 import org.kuali.rice.kcb.bo.Message;

 import org.kuali.rice.kcb.bo.MessageDelivery;

 import org.kuali.rice.kcb.bo.MessageDeliveryStatus;

 import org.kuali.rice.kcb.service.MessageDeliveryService;

 /**

  * MessageDeliveryService implementation 

  * 

  * @author Kuali Rice Team (rice.collab@kuali.org)

  */

 public class MessageDeliveryServiceImpl extends BusinessObjectServiceImpl implements MessageDeliveryService {

     private static final Logger LOG = Logger.getLogger(MessageDeliveryServiceImpl.class);

     /**

      * Number of processing attempts to make.  {@link MessageDelivery}s with this number or more of attempts

      * will not be selected for further processing.

      */

     private int maxProcessAttempts;

     /**

      * Sets the max processing attempts

      * @param maxProcessAttempts the max delivery attempts

      */

     public void setMaxProcessAttempts(int maxProcessAttempts) {

         this.maxProcessAttempts = maxProcessAttempts;

     }

     /**

      * @see org.kuali.rice.kcb.service.MessageDeliveryService#saveMessageDelivery(org.kuali.rice.kcb.bo.MessageDelivery)

      */

     public void saveMessageDelivery(MessageDelivery delivery) {

         dao.save(delivery);

     }

     /**

      * @see org.kuali.rice.kcb.service.MessageDeliveryService#deleteMessageDelivery(java.lang.Long)

      */

     public void deleteMessageDelivery(MessageDelivery messageDelivery) {

         dao.delete(messageDelivery);

     }

     /**

      * @see org.kuali.rice.kcb.service.MessageDeliveryService#getMessageDeliveries()

      */

     public Collection<MessageDelivery> getAllMessageDeliveries() {

         return dao.findAll(MessageDelivery.class);

     }

     /**

      * @see org.kuali.rice.kcb.service.MessageDeliveryService#getMessageDelivery(java.lang.Long)

      */

     public MessageDelivery getMessageDelivery(Long id) {

         Map<String, Object> fields = new HashMap<String, Object>(1);

         fields.put(MessageDelivery.ID_FIELD, id);

         return (MessageDelivery) dao.findByPrimaryKey(MessageDelivery.class, fields);

     }

     /**

      * @see org.kuali.rice.kcb.service.MessageDeliveryService#getMessageDeliveryByDelivererSystemId(java.lang.Long)

      */

     public MessageDelivery getMessageDeliveryByDelivererSystemId(Long id) {

         Criteria criteria = new Criteria();

         criteria.addEqualTo(MessageDelivery.SYSTEMID_FIELD, id);

         Collection<MessageDelivery> results = dao.findMatching(MessageDelivery.class, criteria);

         if (results == null || results.size() == 0) return null;

         if (results.size() > 1) {

             throw new RuntimeException("More than one message delivery found with the following delivery system id: " + id);

         }

         return results.iterator().next();

     }

     /**

      * @see org.kuali.rice.kcb.service.MessageDeliveryService#getMessageDeliveries(org.kuali.rice.kcb.bo.Message)

      */

     public Collection<MessageDelivery> getMessageDeliveries(Message message) {

         Criteria criteria = new Criteria();

         criteria.addEqualTo(MessageDelivery.MESSAGEID_FIELD, message.getId());

         return dao.findMatching(MessageDelivery.class, criteria);

     }

     /* This method is responsible for atomically finding messagedeliveries, marking them as taken

      * and returning them to the caller for processing.

      * NOTE: it is important that this method execute in a SEPARATE dedicated transaction; either the caller should

      * NOT be wrapped by Spring declarative transaction and this service should be wrapped (which is the case), or

      * the caller should arrange to invoke this from within a newly created transaction).

      */

     public Collection<MessageDelivery> lockAndTakeMessageDeliveries(MessageDeliveryStatus[] statuses) {

         return lockAndTakeMessageDeliveries(null, statuses);

     }

     public Collection<MessageDelivery> lockAndTakeMessageDeliveries(Long messageId, MessageDeliveryStatus[] statuses) {

         LOG.debug("========>> ENTERING LockAndTakeMessageDeliveries: " + Thread.currentThread());

         // DO WITHIN TRANSACTION: get all untaken messagedeliveries, and mark as "taken" so no other thread/job takes them

         // need to think about durability of work list

         // get all undelivered message deliveries

         Criteria criteria = new Criteria();

         criteria.addIsNull(MessageDelivery.LOCKED_DATE);

         if (messageId != null) {

             criteria.addEqualTo(MessageDelivery.MESSAGEID_FIELD, messageId);

         }

         criteria.addLessThan(MessageDelivery.PROCESS_COUNT, maxProcessAttempts);

         Collection<String> statusCollection = new ArrayList<String>(statuses.length);

         for (MessageDeliveryStatus status: statuses) {

             statusCollection.add(status.name());

         }

         criteria.addIn(MessageDelivery.DELIVERY_STATUS, statusCollection);

         // implement our select for update hack

         Collection<MessageDelivery> messageDeliveries = dao.findMatching(MessageDelivery.class, criteria, true, RiceConstants.NO_WAIT);

         //LOG.debug("Retrieved " + messageDeliveries.size() + " available message deliveries: " + System.currentTimeMillis());

         // mark messageDeliveries as taken

         for (MessageDelivery delivery: messageDeliveries) {

             LOG.debug("Took: " + delivery);

             delivery.setLockedDate(new Timestamp(System.currentTimeMillis()));

             dao.save(delivery);

         }

         LOG.debug("<<=======  LEAVING LockAndTakeMessageDeliveries: " + Thread.currentThread());

         return messageDeliveries;

     }

 }