/*

  * Copyright 2011 The Kuali Foundation

  *

  * Licensed under the Educational Community License, Version 1.0 (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/ecl1.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.krms.impl.provider.repository;

 import org.kuali.rice.krms.api.engine.ExecutionEnvironment;

 import org.kuali.rice.krms.api.repository.agenda.AgendaDefinition;

 import org.kuali.rice.krms.framework.engine.AgendaTree;

 /**

  * TODO... 

  * 

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

  *

  */

 final class LazyAgendaTree implements AgendaTree {

         private final Object mutex = new Object();

         private final AgendaDefinition agendaDefinition;

         private final RepositoryToEngineTranslator translator;

         private AgendaTree agendaTree;

         public LazyAgendaTree(AgendaDefinition agendaDefinition, RepositoryToEngineTranslator translator) {

                 this.agendaDefinition = agendaDefinition;

                 this.translator = translator;

         }

         public void execute(ExecutionEnvironment environment) {

                 initialize();

                 agendaTree.execute(environment);

         }

         public void initialize() {

                 // could use double-checked locking here for max efficiency

                 synchronized (mutex) {

                         if (agendaTree == null) {

                                 agendaTree = translator.translateAgendaDefinitionToAgendaTree(agendaDefinition);

                         }

                 }

         }

 }