/**

  * Copyright 2005-2011 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.kew.actionlist.dao.impl;

 import java.util.Comparator;

 import org.kuali.rice.kew.actionitem.ActionItem;

 import org.kuali.rice.kew.actionitem.ActionItemComparator;

 /**

  * Compares an action item to another action item and determines if one

  * item has a higher priority than the other.

  * Therefore, calling code needs to ensure that the document and user on the item

  * are the same.  If action items for different documents are passed in, then the 

  * compare method should always return 0.

  * 

  * If the response returned from compare is less than 0, it means the first argument is

  * lower priority than the second.  If a value greater than 0 is returned it means the

  * first argument has a higher priority then the second.  If the result returned is 0, then

  * the two action items have the same priority.

  * 

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

  */

 public class ActionListPriorityComparator implements Comparator {

         private ActionItemComparator itemComparator = new ActionItemComparator();

         public int compare(Object object1, Object object2) throws ClassCastException {

                 ActionItem actionItem1 = (ActionItem)object1;

                 ActionItem actionItem2 = (ActionItem)object2;

                 if (requiresComparison(actionItem1, actionItem2)) {

                         return itemComparator.compare(object1, object2);

                 }

                 return 0;

         }

         /**

          * Returns whether or not the two action items require comparison.  The Action List only operates 

          * on Action Items for a single user and we only care about comparing the action items if they are

          * on the same document and for the same user.

          */

         protected boolean requiresComparison(ActionItem actionItem1, ActionItem actionItem2) {

                 return actionItem1.getDocumentId().equals(actionItem2.getDocumentId()) &&

                         actionItem1.getPrincipalId().equals(actionItem2.getPrincipalId());

         }

 }