001/**
002 * Copyright 2005-2017 The Kuali Foundation
003 *
004 * Licensed under the Educational Community License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.opensource.org/licenses/ecl2.php
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.kuali.rice.krms.impl.provider.repository;
017
018import org.kuali.rice.krms.api.engine.ExecutionEnvironment;
019import org.kuali.rice.krms.api.repository.agenda.AgendaDefinition;
020import org.kuali.rice.krms.framework.engine.AgendaTree;
021
022/**
023 * TODO... 
024 * 
025 * @author Kuali Rice Team (rice.collab@kuali.org)
026 *
027 */
028public final class LazyAgendaTree implements AgendaTree {
029
030        private final Object mutex = new Object();
031        private final AgendaDefinition agendaDefinition;
032        private final RepositoryToEngineTranslator translator;
033        
034        private AgendaTree agendaTree;
035        
036        public LazyAgendaTree(AgendaDefinition agendaDefinition, RepositoryToEngineTranslator translator) {
037                this.agendaDefinition = agendaDefinition;
038                this.translator = translator;
039        }
040
041        public void execute(ExecutionEnvironment environment) {
042                initialize();
043                agendaTree.execute(environment);
044        }
045        
046        public void initialize() {
047                // could use double-checked locking here for max efficiency
048                synchronized (mutex) {
049                        if (agendaTree == null) {
050                                agendaTree = translator.translateAgendaDefinitionToAgendaTree(agendaDefinition);
051                        }
052                }
053        }
054
055}