Java tutorial
/* This file is part of Cyclos (www.cyclos.org). A project of the Social Trade Organisation (www.socialtrade.org). Cyclos is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. Cyclos is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with Cyclos; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package nl.strohalm.cyclos.http; import java.util.Collection; import java.util.concurrent.Callable; import javax.servlet.ServletContext; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; import javax.servlet.http.HttpSession; import javax.servlet.http.HttpSessionEvent; import javax.servlet.http.HttpSessionListener; import nl.strohalm.cyclos.annotations.Inject; import nl.strohalm.cyclos.entities.settings.LocalSettings; import nl.strohalm.cyclos.initializations.LocalWebInitialization; import nl.strohalm.cyclos.services.access.AccessService; import nl.strohalm.cyclos.services.access.exceptions.NotConnectedException; import nl.strohalm.cyclos.services.application.ApplicationService; import nl.strohalm.cyclos.services.settings.SettingsService; import nl.strohalm.cyclos.utils.SpringHelper; import nl.strohalm.cyclos.utils.TransactionHelper; import nl.strohalm.cyclos.utils.access.LoggedUser; import nl.strohalm.cyclos.utils.transaction.CurrentTransactionData; import nl.strohalm.cyclos.utils.transaction.TransactionEndListener; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.transaction.TransactionStatus; import org.springframework.transaction.support.TransactionCallbackWithoutResult; import org.springframework.web.context.WebApplicationContext; import org.springframework.web.context.support.WebApplicationContextUtils; /** * Listener for context events * @author luis */ public class LifecycleListener implements ServletContextListener, HttpSessionListener { private static final Log LOG = LogFactory.getLog(LifecycleListener.class); private AccessService accessService; private TransactionHelper transactionHelper; private SettingsService settingsService; private ApplicationService applicationService; /** * @see javax.servlet.ServletContextListener#contextDestroyed(javax.servlet.ServletContextEvent) */ @Override public void contextDestroyed(final ServletContextEvent event) { LoggedUser.runAsSystem(new Callable<Void>() { @Override public Void call() throws Exception { try { final ServletContext context = event.getServletContext(); final LocalSettings settings = settingsService == null ? null : settingsService.getLocalSettings(); // Shutdown the application service if (applicationService != null) { applicationService.shutdown(); } final String applicationName = settings == null ? null : settings.getApplicationName(); context.log(applicationName == null ? "Cyclos" : applicationName + " destroyed"); // Suggest a GC as probably there were several released resources System.gc(); } catch (final Throwable e) { LOG.error("Error on LifecycleListener.contextDestroyed()", e); throw new RuntimeException(e); } return null; // required by compiler } }); } /** * @see javax.servlet.ServletContextListener#contextInitialized(javax.servlet.ServletContextEvent) */ @Override public void contextInitialized(final ServletContextEvent event) { LoggedUser.runAsSystem(new Callable<Void>() { @Override public Void call() { try { final ServletContext context = event.getServletContext(); final WebApplicationContext applicationContext = WebApplicationContextUtils .getWebApplicationContext(context); SpringHelper.injectBeans(applicationContext, LifecycleListener.this); applicationService.initialize(); context.setAttribute("systemOnline", applicationService.isOnline()); context.setAttribute("cyclosVersion", applicationService.getCyclosVersion()); // Run web initializations final Collection<LocalWebInitialization> initializations = applicationContext .getBeansOfType(LocalWebInitialization.class).values(); runAll(initializations); final LocalSettings settings = settingsService.getLocalSettings(); context.log(settings.getApplicationName() + " initialized"); // Suggest a GC in order to keep the heap low right after a startup System.gc(); } catch (final Throwable e) { LOG.error("Error on LifecycleListener.contextInitialized()", e); throw new RuntimeException(e); } return null; // required by compiler } }); } /** * @see javax.servlet.http.HttpSessionListener#sessionCreated(javax.servlet.http.HttpSessionEvent) */ @Override public void sessionCreated(final HttpSessionEvent event) { // Nothing to do } /** * @see javax.servlet.http.HttpSessionListener#sessionDestroyed(javax.servlet.http.HttpSessionEvent) */ @Override public void sessionDestroyed(final HttpSessionEvent event) { final HttpSession session = event.getSession(); final String sessionId = session == null ? null : session.getId(); if (sessionId == null) { return; } // If there is an active transaction, use an transaction end listener to actually logout if (transactionHelper.hasActiveTransaction()) { CurrentTransactionData.addTransactionEndListener(new TransactionEndListener() { @Override protected void onTransactionEnd(final boolean commit) { doLogout(sessionId); } }); } else { // Logout directly (this is in another TX) doLogout(sessionId); } } @Inject public void setAccessService(final AccessService accessService) { this.accessService = accessService; } @Inject public void setApplicationService(final ApplicationService applicationService) { this.applicationService = applicationService; } @Inject public void setSettingsService(final SettingsService settingsService) { this.settingsService = settingsService; } @Inject public void setTransactionHelper(final TransactionHelper transactionHelper) { this.transactionHelper = transactionHelper; } private void doLogout(final String sessionId) { transactionHelper.runInNewTransaction(new TransactionCallbackWithoutResult() { @Override protected void doInTransactionWithoutResult(final TransactionStatus status) { try { accessService.logout(sessionId); } catch (final NotConnectedException e) { // Ok, just ignore } catch (final RuntimeException e) { LOG.warn("Error logging out member on session destroy", e); status.setRollbackOnly(); } } }); } /** * Run a single initialization inside a transaction if it is required */ private void run(final LocalWebInitialization initialization) { LOG.debug(String.format("Running web initialization (%s)...", initialization.getName())); transactionHelper.runInCurrentThread(new TransactionCallbackWithoutResult() { @Override protected void doInTransactionWithoutResult(final TransactionStatus status) { try { initialization.initialize(); } catch (final RuntimeException e) { LOG.error(String.format("Error running web initialization: %s", initialization.getName()), e); throw e; } } }); } /** * Run all given initializations / finalizations */ private void runAll(final Collection<LocalWebInitialization> initializations) { try { for (final LocalWebInitialization initialization : initializations) { run(initialization); } } finally { CurrentTransactionData.cleanup(); } } }