/*

  * Copyright 2007 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.kns.datadictionary;

 import java.io.File;

 import java.util.ArrayList;

 import java.util.List;

 import no.geosoft.cc.io.FileListener;

 import no.geosoft.cc.io.FileMonitor;

 import org.apache.commons.lang.StringUtils;

 import org.apache.commons.logging.Log;

 import org.apache.commons.logging.LogFactory;

 import org.kuali.rice.core.api.config.property.ConfigurationService;

 import org.kuali.rice.kns.service.KNSServiceLocator;

 import org.springframework.core.io.FileSystemResource;

 import org.springframework.core.io.Resource;

 /**

  * Extends the DataDictionary to add reloading of changed dictionary files

  * without a restart of the web container

  * 

  * <p>

  * To use modify the "dataDictionaryService" spring definition

  * (KNSSpringBeans.xml) and change the constructor arg bean class from

  * "org.kuali.rice.kns.datadictionary.DataDictionary" to

  * "org.kuali.rice.kns.datadictionary.ReloadingDataDictionary"

  * </p>

  * 

  * <p>

  * NOTE: For Development Purposes Only!

  * </p>

  * 

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

  */

 public class ReloadingDataDictionary extends DataDictionary implements FileListener {

         private static final Log LOG = LogFactory.getLog(DataDictionary.class);

         private static final String CLASS_DIR_CONFIG_PARM = "reload.data.dictionary.classes.dir";

         private static final String SOURCE_DIR_CONFIG_PARM = "reload.data.dictionary.source.dir";

         private static final String INTERVAL_CONFIG_PARM = "reload.data.dictionary.interval";

         public ReloadingDataDictionary() {

                 super();

         }

         /**

          * After dictionary has been loaded, determine the source files and add them

          * to the monitor

          * 

          * @see org.kuali.rice.kns.datadictionary.DataDictionary#parseDataDictionaryConfigurationFiles(boolean)

          */

         @Override

         public void parseDataDictionaryConfigurationFiles(boolean allowConcurrentValidation) {

                 ConfigurationService configurationService = KNSServiceLocator.getKualiConfigurationService();

                 // class directory part of the path that should be replaced

                 String classesDir = configurationService.getPropertyString(CLASS_DIR_CONFIG_PARM);

                 // source directory where dictionary files are found

                 String sourceDir = configurationService.getPropertyString(SOURCE_DIR_CONFIG_PARM);

                 // interval to poll for changes in milliseconds

                 int reloadInterval = Integer.parseInt(configurationService.getPropertyString(INTERVAL_CONFIG_PARM));

                 FileMonitor dictionaryFileMonitor = new FileMonitor(reloadInterval);

                 // need to copy the configFileLocations list here because it gets

                 // cleared out after processing by super

                 List<String> configLocations = new ArrayList<String>(configFileLocations);

                 super.parseDataDictionaryConfigurationFiles(allowConcurrentValidation);

                 for (String configLocation : configLocations) {

                         Resource classFileResource = getFileResource(configLocation);

                         try {

                                 String filePathClassesDir = classFileResource.getFile().getAbsolutePath();

                                 String sourceFilePath = StringUtils.replace(filePathClassesDir, classesDir, sourceDir);

                                 File dictionaryFile = new File(filePathClassesDir);

                                 if (dictionaryFile.exists()) {

                                         LOG.debug("Monitoring dictionary file: " + dictionaryFile.getName());

                                         dictionaryFileMonitor.addFile(dictionaryFile);

                                 }

                         }

                         catch (Exception e) {

                                 LOG.info("Exception in picking up dictionary file for monitoring:  " + e.getMessage(), e);

                         }

                 }

                 // add the dictionary as a listener for file changes

                 dictionaryFileMonitor.addListener(this);

         }

         /**

          * Call back when a dictionary file is changed. Calls the spring bean reader

          * to reload the file (which will override beans as necessary and destroy

          * singletons) and runs the indexer

          * 

          * @see no.geosoft.cc.io.FileListener#fileChanged(java.io.File)

          */

         @Override

         public void fileChanged(File file) {

                 LOG.info("reloading dictionary configuration for " + file.getName());

                 try {

                         Resource resource = new FileSystemResource(file);

                         xmlReader.loadBeanDefinitions(resource);

                         // re-index

                         ddIndex.run();

                 }

                 catch (Exception e) {

                         LOG.info("Exception in dictionary hot deploy: " + e.getMessage(), e);

                 }

         }

 }