Java tutorial
/* * #! * Ontopia DB2TM * #- * Copyright (C) 2001 - 2013 The Ontopia Project * #- * Licensed under the Apache 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.apache.org/licenses/LICENSE-2.0 * * 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 net.ontopia.topicmaps.db2tm; import java.text.DateFormat; import java.text.SimpleDateFormat; import java.util.Arrays; import java.util.Calendar; import java.util.Collection; import java.util.Date; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import net.ontopia.topicmaps.entry.TopicMapReferenceIF; import net.ontopia.topicmaps.entry.TopicMapRepositoryIF; import net.ontopia.topicmaps.nav2.utils.NavigatorUtils; import net.ontopia.utils.OntopiaRuntimeException; import org.apache.commons.lang3.StringUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * PUBLIC: Servlet that sets up and schedules DB2TM synchronization * at regular intervals. Parameters: start-time, delay, interval, mapping, * relations and topicmap. * * Example web.xml configuation: * * <pre> * <servlet> * <servlet-name>MySynchronizationServlet</servlet-name> * <description> * DB2TM synchronization * </description> * <servlet-class> * net.ontopia.topicmaps.db2tm.SynchronizationServlet * </servlet-class> * <init-param> * <param-name>start-time</param-name> * <param-value>09:50</param-value> * </init-param> * <init-param> * <param-name>interval</param-name> * <param-value>86400000</param-value> * </init-param> * <init-param> * <param-name>mapping</param-name> * <param-value>bk.db2tm.xml</param-value> * </init-param> * <init-param> * <param-name>topicmap</param-name> * <param-value>result.xtm</param-value> * </init-param> * <load-on-startup>1</load-on-startup> * </servlet> * </pre> * * This configuration will make the DB2TM synchronization run at every * day at 09:50 in the morning. The mapping file must either be * adressed directly on the file system or it will be loaded by name * from the CLASSPATH. * * @since 3.3.0 */ public class SynchronizationServlet extends HttpServlet { private static Logger log = LoggerFactory.getLogger(SynchronizationServlet.class); private static DateFormat df = new SimpleDateFormat("HH:mm"); protected SynchronizationTask task; @Override public void init(ServletConfig config) throws ServletException { super.init(config); log.info("Initializing synchronization servlet."); try { // no default starttime Date time = null; long delay = 180 * 1000; String timeval = config.getInitParameter("start-time"); if (timeval != null) { Date d = df.parse(timeval); Calendar c0 = Calendar.getInstance(); Calendar c = Calendar.getInstance(); c.set(Calendar.HOUR_OF_DAY, 1); c.set(Calendar.MINUTE, 0); c.add(Calendar.MILLISECOND, (int) d.getTime()); if (c.before(c0)) c.add(Calendar.HOUR_OF_DAY, 24); time = c.getTime(); log.info("Setting synchronization start time to {} ms.", time); } else { // default delay is 180 sec. delay = getLongProperty(config, "delay", delay); log.info("Setting synchronization delay to {} ms.", delay); } // default interval is 24 hours. long interval = getLongProperty(config, "interval", 1000 * 60 * 60 * 24); log.info("Setting synchronization interval to {} ms.", interval); // load relation mapping file String mapping = config.getInitParameter("mapping"); if (mapping == null) throw new OntopiaRuntimeException("Servlet init-param 'mapping' must be specified."); // get relation names (comma separated) Collection<String> relnames = null; String relations = config.getInitParameter("relations"); if (relations != null) relnames = Arrays.asList(StringUtils.split(relations, ",")); // get hold of the topic map String tmid = config.getInitParameter("topicmap"); if (tmid == null) throw new OntopiaRuntimeException("Servlet init-param 'topicmap' must be specified."); TopicMapRepositoryIF rep = NavigatorUtils.getTopicMapRepository(config.getServletContext()); TopicMapReferenceIF ref = rep.getReferenceByKey(tmid); // make sure delay is at least 10 seconds to make sure that it doesn't // start too early if (time == null) task = new SynchronizationTask(config.getServletName(), (delay < 10000 ? 10000 : delay), interval); else task = new SynchronizationTask(config.getServletName(), time, interval); task.setRelationMappingFile(mapping); task.setRelationNames(relnames); task.setTopicMapReference(ref); task.setBaseLocator(null); } catch (Exception e) { throw new ServletException(e); } } private long getLongProperty(ServletConfig config, String propname, long defval) { String propval = config.getInitParameter(propname); if (propval != null) { try { return Long.parseLong(propval); } catch (NumberFormatException e) { log.warn("Invalid long in servlet parameter '{}': {}", propname, propval); } } return defval; } @Override public void destroy() { log.info("Destructing synchronization servlet."); if (task != null) { task.stop(); task = null; } } }