Glassfish example source code file (DynamicReloader.java)

This example Glassfish source code file (DynamicReloader.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Glassfish tags/keywords

application, application, applicationname, appreloadinfo, appreloadinfo, atomicboolean, file, io, list, log, logging, net, network, parametermap, reload_file_name, reloader, reloader, urisyntaxexception, urisyntaxexception, util

The Glassfish DynamicReloader.java source code

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright (c) 2008-2010 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
 * enclosed by brackets [] replaced by your own identifying information:
 * "Portions Copyright [year] [name of copyright owner]"
 *
 * Contributor(s):
 * If you wish your version of this file to be governed by only the CDDL or
 * only the GPL Version 2, indicate your decision by adding "[Contributor]
 * elects to include this software in this distribution under the [CDDL or GPL
 * Version 2] license."  If you don't indicate a single choice of license, a
 * recipient has the option to distribute your version of this file under
 * either the CDDL, the GPL Version 2 or to extend the choice of license to
 * its licensees as provided above.  However, if you add GPL Version 2 code
 * and therefore, elected the GPL Version 2 license, then the option applies
 * only if the new code is made subject to such option by the copyright
 * holder.
 */

package com.sun.enterprise.v3.server;

import com.sun.enterprise.config.serverbeans.Application;
import com.sun.enterprise.config.serverbeans.Applications;
import com.sun.enterprise.config.serverbeans.ServerTags;
import com.sun.enterprise.v3.admin.CommandRunnerImpl;
import com.sun.enterprise.v3.common.XMLActionReporter;
import java.io.File;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.Set;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.logging.Logger;
import org.glassfish.api.ActionReport;
import org.glassfish.api.admin.ParameterMap;
import org.glassfish.api.admin.config.ApplicationName;
import org.glassfish.deployment.common.DeploymentProperties;
import org.jvnet.hk2.component.Habitat;

/**
 * Triggers reloads of deployed applications depending on the presence of and
 * timestamp on a .reload file in the application's top-level directory.
 * 
 * An instance of this class can be reused, its run method invoked repeatedly
 * to check all known apps for their .reload files.  
 * 
 * @author tjquinn
 */
public class DynamicReloader implements Runnable {

    private static final String RELOAD_FILE_NAME = ".reload";
    
    private AtomicBoolean inProgress;
    
    /** Records info about apps being monitored */
    private Map<String,AppReloadInfo> appReloadInfo;
    
    private AtomicBoolean cancelRequested = new AtomicBoolean(false);
    
    private Applications applications;
    
    private Logger logger = Logger.getLogger(getClass().getName());
    
    private Habitat habitat;
    
    DynamicReloader(Applications applications, Habitat habitat) throws URISyntaxException {
        this.applications = applications;
        this.habitat = habitat;
        initAppReloadInfo(applications);
        inProgress = new AtomicBoolean(false);
    }
    
    /**
     * Records reload information about the currently-known applications.
     * 
     * @param applications
     */
    private void initAppReloadInfo(Applications applications) throws URISyntaxException {
         appReloadInfo = new HashMap<String,AppReloadInfo>();
         logger.fine("[Reloader] Preparing list of apps to monitor:");
         for (ApplicationName m : applications.getModules()) {
             if (m instanceof Application) {
                 Application app = (Application) m;
                 if (Boolean.valueOf(app.getDeployProperties().getProperty
                     (ServerTags.IS_LIFECYCLE))) {
                     // skip lifecycle modules
                     continue;
                 }
                 AppReloadInfo info = new AppReloadInfo(app);
                 appReloadInfo.put(app.getName(), info);
                 logger.fine("[Reloader] Monitoring " + app.getName() + " at " + app.getLocation());
             }
         }
    }
    
    public void run() {
        markInProgress();
        try {
            reloadApps();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            clearInProgress();
        }
    }

    void cancel() {
        cancelRequested.set(true);
    }
    
    private void reloadApps() throws URISyntaxException, IOException {
        List<AppReloadInfo> appsToReload = chooseAppsToReload();
        for (AppReloadInfo appInfo : appsToReload) {
            if (cancelRequested.get()) {
                break;
            }
            reloadApp(appInfo);
        }
        cancelRequested.set(false);
    }
    
    private synchronized List<AppReloadInfo> chooseAppsToReload() throws URISyntaxException {
        List<AppReloadInfo> result = new ArrayList();
        
        /*
         * The collectionof AppReloadInfo might not contain entries for all
         * current apps (for example, if an app has been deployed since the
         * previous run of the reloader).  Use the current list of all known
         * apps, and for each of those try to find an AppReloadInfo entry for
         * it.
         */
        Set<AppReloadInfo> possiblyUndeployedApps = new HashSet(appReloadInfo.values());
        
        for (ApplicationName m : applications.getModules()) {
            if (m instanceof Application) {
                Application app = (Application) m;
                if (Boolean.valueOf(app.getDeployProperties().getProperty
                    (ServerTags.IS_LIFECYCLE))) {
                    // skip lifecycle modules
                    continue;
                }
                AppReloadInfo reloadInfo = findOrCreateAppReloadInfo(app);
                if (reloadInfo.needsReload()) {
                    logger.fine("[Reloader] Selecting app " + reloadInfo.getApplication().getName() + " to reload");
                    result.add(reloadInfo);
                }
                possiblyUndeployedApps.remove(reloadInfo);
            }
        }
        
        /*
         * Remove any apps from the reload info that are no longer present.
         */
        for (AppReloadInfo info : possiblyUndeployedApps) {
            logger.fine("[Reloader] Removing undeployed app " + info.getApplication().getName() + " from reload info");
            appReloadInfo.remove(info.getApplication().getName());
        }
        

        return result;
    }

    private synchronized AppReloadInfo findOrCreateAppReloadInfo(Application app) throws URISyntaxException {
        AppReloadInfo result = appReloadInfo.get(app.getName());
        if (result == null) {
            logger.fine("[Reloader] Recording info for new app " + app.getName() + " at " + app.getLocation());
            result = new AppReloadInfo(app);
            appReloadInfo.put(app.getName(), result);
        }
        return result;
    }
    
    private void reloadApp(AppReloadInfo appInfo) throws IOException {
        logger.fine("[Reloader] Reloading " + appInfo.getApplication().getName());
        
        /*
         * Prepare a deploy command and invoke it, taking advantage of the
         * DeployCommand's logic to deal with redeploying an existing app.
         * 
         * Note that the redeployinplace internal option tells the undeploy
         * command (which is invoked by the deploy command) to preserve the
         * existing directory, even if the configuration does not indicate that
         * the app is directory-deployed.
         * 
         */
        CommandRunnerImpl commandRunner = habitat.getComponent(CommandRunnerImpl.class);

        ParameterMap deployParam = new ParameterMap();
        deployParam.set(DeploymentProperties.FORCE, Boolean.TRUE.toString());
        deployParam.set(DeploymentProperties.PATH, appInfo.getApplicationDirectory().getCanonicalPath());
        deployParam.set(DeploymentProperties.NAME, appInfo.getApplication().getName());
        deployParam.set(DeploymentProperties.KEEP_REPOSITORY_DIRECTORY, "true");
        commandRunner.getCommandInvocation("deploy", new XMLActionReporter()).parameters(deployParam).execute();
        
        
        appInfo.recordLoad();
    }
    
    private void markInProgress() {
        inProgress.set(true);
    }

    private void clearInProgress() {
        synchronized(inProgress) {
            inProgress.set(false);
            inProgress.notifyAll();
        }
    }
    
    public void waitUntilIdle() throws InterruptedException {
        synchronized(inProgress) {
            if (inProgress.get()) {
                inProgress.wait();
            }
        }
    }
    
    /**
     * Records information about every application, regardless of whether the
     * app has a .reload file or not.
     * 
     * The latestRecordedLoad time records either the object creation time (which should
     * be about the same as the initial load time of the app during a server 
     * restart or after a deployment) or the time at which an app was reloaded.
     * 
     * Note that this class uses the fact that lastModified of a non-existing
     * file is 0.
     */
    private final class AppReloadInfo {
        /** points to the .reload file, whether one exists for this app or not */
        private File reloadFile;
        
        private long latestRecordedLoad;
        
        /** application info */
        private Application app;
        
        private File appDir;
        
        private AppReloadInfo(Application app) throws URISyntaxException {
            this.app = app;
            appDir = new File(new URI(app.getLocation()));
            reloadFile = new File(appDir, RELOAD_FILE_NAME);
            recordLoad();
        }
        
        private Application getApplication() {
            return app;
        }
        
        private boolean needsReload() {
            boolean answer = reloadFile.lastModified() > latestRecordedLoad;
            return answer;
        }
        
        private void recordLoad() {
            latestRecordedLoad = System.currentTimeMillis();
        }
        
        private File getApplicationDirectory() {
            return appDir;
        }
    }

}