/*
    * 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);
  			}
  		}
  	}
  
  }