/*
    * Copyright 2005-2007 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.engine.node;
  
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.Set;
  import java.util.StringTokenizer;
  
  import org.kuali.rice.kew.engine.RouteContext;
  import org.kuali.rice.kew.exception.WorkflowRuntimeException;
  import org.kuali.rice.kew.service.KEWServiceLocator;
  import org.kuali.rice.kew.util.Utilities;
  
  
  /**
   * A basic implementation of the JoinEngine which handles join setup and makes determinations
   * as to when a join condition has been satisfied.
   *
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class BasicJoinEngine implements JoinEngine {
  
      public static final String EXPECTED_JOINERS = "ExpectedJoiners";
      public static final String ACTUAL_JOINERS = "ActualJoiners";
      
      public void createExpectedJoinState(RouteContext context, RouteNodeInstance joinInstance, RouteNodeInstance previousNodeInstance) {
          RouteNodeInstance splitNode = previousNodeInstance.getBranch().getSplitNode();
          if (splitNode == null) {
              throw new WorkflowRuntimeException("The split node retrieved from node with name '" + previousNodeInstance.getName() + "' and branch with name '" + previousNodeInstance.getBranch().getName() + "' was null");
          }
          for (Iterator iter = splitNode.getNextNodeInstances().iterator(); iter.hasNext();) {
              RouteNodeInstance splitNodeNextNode = (RouteNodeInstance) iter.next();
              splitNodeNextNode.getBranch().setJoinNode(joinInstance);
              saveBranch(context, splitNodeNextNode.getBranch());
              addExpectedJoiner(joinInstance, splitNodeNextNode.getBranch());
          }
          joinInstance.setBranch(splitNode.getBranch());
          joinInstance.setProcess(splitNode.getProcess());
      }
      
      public void addExpectedJoiner(RouteNodeInstance nodeInstance, Branch branch) {
          addJoinState(nodeInstance, branch, EXPECTED_JOINERS);
      }
  
      public void addActualJoiner(RouteNodeInstance nodeInstance, Branch branch) {
          addJoinState(nodeInstance, branch, ACTUAL_JOINERS);
      }
      
      private void addJoinState(RouteNodeInstance nodeInstance, Branch branch, String key) {
          NodeState state = nodeInstance.getNodeState(key);
          if (state == null) {
              state = new NodeState();
              state.setKey(key);
              state.setValue("");
              state.setNodeInstance(nodeInstance);
              nodeInstance.addNodeState(state);
          }
          state.setValue(state.getValue()+branch.getBranchId()+",");
      }
  
      public boolean isJoined(RouteNodeInstance nodeInstance) {
          NodeState expectedState = nodeInstance.getNodeState(EXPECTED_JOINERS);
          if (expectedState == null || Utilities.isEmpty(expectedState.getValue())) {
              return true;
          }
          NodeState actualState = nodeInstance.getNodeState(ACTUAL_JOINERS);
          Set expectedSet = loadIntoSet(expectedState);
          Set actualSet = loadIntoSet(actualState);
          for (Iterator iterator = expectedSet.iterator(); iterator.hasNext();) {
              String value = (String) iterator.next();
              if (actualSet.contains(value)) {
                  iterator.remove();
              }            
          }
          return expectedSet.size() == 0;
      }
      
      private Set loadIntoSet(NodeState state) {
          Set set = new HashSet();
          StringTokenizer tokenizer = new StringTokenizer(state.getValue(), ",");
          while (tokenizer.hasMoreTokens()) {
              set.add(tokenizer.nextToken());
          }
          return set;
     }
     
     private void saveBranch(RouteContext context, Branch branch) {
         if (!context.isSimulation()) {
             KEWServiceLocator.getRouteNodeService().save(branch);
         }
     }
 
 }