/*

  * 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.kew.rule;

 import org.apache.log4j.Logger;

 import org.kuali.rice.kew.engine.RouteContext;

 import org.kuali.rice.kew.exception.WorkflowException;

 import javax.script.ScriptEngine;

 import javax.script.ScriptException;

 import java.util.ArrayList;

 import java.util.List;

 /**

  * An extension of BSFRuleExpression that makes it easier to accumulate a list of responsibilities

  * to emit. 

  * 

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

  */

 public class AccumulatingBSFRuleExpression extends BSFRuleExpression {

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

     @Override

     protected void declareBeans(ScriptEngine engine, Rule rule, RouteContext context) throws ScriptException {

         // define the standard beans

         super.declareBeans(engine, rule, context);

         // define our special rule helper class

         RuleHelper rh = new RuleHelper(rule, context);

         engine.put("metarule", rh); // backwards compatibility with existing KRAMetaRuleExpression usage

         engine.put("rulehelper", rh);

     }

     /**

      * Helper class that is exposed to groovy scripts

      */

     private static final class RuleHelper {

         private Rule rule;

         private WorkflowRuleAPI workflow;

         /**

          * Responsibilities accumulated during the evaluation

          */

         private List<RuleResponsibility> responsibilities = new ArrayList<RuleResponsibility>();

         private int responsibilityPriority = 0;

         private RuleHelper(Rule rule, RouteContext context) {

             this.workflow = new WorkflowRuleAPI(context);

             this.rule = rule;

         }

         /**

          * @return the accumulated responsibilities

          */

         public List<RuleResponsibility> getResponsibilities() {

             return responsibilities;

         }

         /**

          * @param success whether the result should be successful

          * @return the RuleExpressionResult with success flag and accumulated responsibilities

          */

         public RuleExpressionResult getResult(boolean success) {

             return new RuleExpressionResult(rule, success, responsibilities);

         }

         /**

          * Adds the responsibilities in the result to the list of accumulated responsibilities 

          * @param result a RuleExpressionResult whose responsibilities to accumulate

          */

         public void accumulate(RuleExpressionResult result) {

             if (result.getResponsibilities() == null || result.getResponsibilities().size() == 0) return;

             Integer curPriority = Integer.valueOf(responsibilityPriority);

             for (RuleResponsibility responsibility: result.getResponsibilities()) {

                 responsibility.setPriority(curPriority);

                 responsibilities.add(responsibility);

             }

             // increment responsibilityPriority for next rule expression result responsibilities

             responsibilityPriority++;

         }

         /**

          * Evaluates a named rule accumulating responsibilities regardless of rule success

          * @param ruleName the name of the rule to evaluate

          * @return whether the rule was successful

          */

         public boolean evalRule(String ruleName) throws WorkflowException {

             RuleExpressionResult result = workflow.invokeRule(ruleName);

             accumulate(result);

             return result.isSuccess();

         }

         /**

          * Evaluates a named rule and if it is successful accumulates the rule responsibilities

          * @param ruleName the name of the rule to evaluate

          * @param accumOnSuccess whether to accumulate the rules responsibilities on success (true), or on failure (false)

          * @return whether the rule was successful

          */

         public boolean evalRule(String ruleName, boolean accumOnSuccess) throws WorkflowException {

             RuleExpressionResult result = workflow.invokeRule(ruleName);

             if (accumOnSuccess == result.isSuccess()) {

                 accumulate(result);

             }

             return result.isSuccess();

         }

     }

 }