Liferay 启动过程分析12-处理全局启动事件

  在MainServlet中，当初始化扩展环境之后，就开始处理全局启动事件，对应代码是：

    if (_log.isDebugEnabled()) {
            _log.debug("Process global startup events");
        }

        try {
            processGlobalStartupEvents();
        }
..

 

它会去调用processGlobalStartupEvents()方法：

protected void processGlobalStartupEvents() throws Exception {
        EventsProcessorUtil.process(
            PropsKeys.GLOBAL_STARTUP_EVENTS, PropsValues.GLOBAL_STARTUP_EVENTS);
    }

 

我们看下系统是如何处理这些事件的，我们跟进到EventsProcessorUtil类的process方法，它实际传递了2个参数，第一个是字符串 "global.startup.events",第二个参数是字符串形式的事件类数组，它定义在portal.properties文件中：

#
   # Global startup event that runs once when the portal initializes.
   #
   global.startup.events=com.liferay.portal.events.GlobalStartupAction

 

而实际处理的process方法在EventsProcessUtil类中，代码如下：

public static void process(String key, String[] classes)
        throws ActionException {

        _instance.process(key, classes, null, null, null, null);
    }

 

最终消费它的方法是EventsProcessorUtil类的process()方法：

public void process(
            String key, String[] classes, String[] ids,
            HttpServletRequest request, HttpServletResponse response,
            HttpSession session)
        throws ActionException {

        for (String className : classes) {
            if (Validator.isNull(className)) {
                return;
            }

            if (_log.isDebugEnabled()) {
                _log.debug("Process event " + className);
            }

            Object event = InstancePool.get(className);

            processEvent(event, ids, request, response, session);
        }

        if (Validator.isNull(key)) {
            return;
        }

        List<Object> events = _getEvents(key);

        for (Object event : events) {
            processEvent(event, ids, request, response, session);
        }
    }

 

所以，从第16跟进到InstancePool的_get()方法可以看出，它会去调用参数传递过来的事件类对应的类加载器，让其创建事件类的实例:

private Object _get(String className, boolean logErrors) {
        className = className.trim();

        Object instance = _instances.get(className);

        if (instance == null) {
            ClassLoader portalClassLoader =
                PortalClassLoaderUtil.getClassLoader();

            try {
                Class<?> clazz = portalClassLoader.loadClass(className);

                instance = clazz.newInstance();

                _instances.put(className, instance);
            }
..

然后会吧这个事件类的实例传递进18行进行处理，我们继续跟进到EventProcessorImpl类的processEvent方法中：

public void processEvent(
            Object event, String[] ids, HttpServletRequest request,
            HttpServletResponse response, HttpSession session)
        throws ActionException {

        if (event instanceof Action) {
            Action action = (Action)event;

            try {
                action.run(request, response);
            }
           ..
        }
        else if (event instanceof SessionAction) {
            SessionAction sessionAction = (SessionAction)event;

            try {
                sessionAction.run(session);
            }
            ..
        }
        else if (event instanceof SimpleAction) {
            SimpleAction simpleAction = (SimpleAction)event;

            simpleAction.run(ids);
        }
    }

可以发现，它只是判断事件类型，然后运行这个Action.

 

联系到实际，因为在portal.properties中，我们的事件类型是GlobalStartupAction，它继承自SimpleAction,所以，它运行上述代码的第22-26行，我们跟进到GlobalStartupAction的run方法，发现它做了许多事情：

事情1：插件(layout templates,portlets,themes)的自动部署

事件2：插件的热部署

....

我们这里只对自动部署详细展开说明。

它的代码如下：

if (PrefsPropsUtil.getBoolean(
                    PropsKeys.AUTO_DEPLOY_ENABLED,
                    PropsValues.AUTO_DEPLOY_ENABLED)) {

                if (_log.isInfoEnabled()) {
                    _log.info("Registering auto deploy directories");
                }

                File deployDir = new File(
                    PrefsPropsUtil.getString(
                        PropsKeys.AUTO_DEPLOY_DEPLOY_DIR,
                        PropsValues.AUTO_DEPLOY_DEPLOY_DIR));
                File destDir = new File(DeployUtil.getAutoDeployDestDir());
                long interval = PrefsPropsUtil.getLong(
                    PropsKeys.AUTO_DEPLOY_INTERVAL,
                    PropsValues.AUTO_DEPLOY_INTERVAL);
                int blacklistThreshold = PrefsPropsUtil.getInteger(
                    PropsKeys.AUTO_DEPLOY_BLACKLIST_THRESHOLD,
                    PropsValues.AUTO_DEPLOY_BLACKLIST_THRESHOLD);

                List<AutoDeployListener> autoDeployListeners =
                    getAutoDeployListeners();

                AutoDeployDir autoDeployDir = new AutoDeployDir(
                    AutoDeployDir.DEFAULT_NAME, deployDir, destDir, interval,
                    blacklistThreshold, autoDeployListeners);

                AutoDeployUtil.registerDir(autoDeployDir);
            }
            else {
            ..

不难发现，01-03行，它先去查看系统是否开启了自动部署配置，这个配置在portal.properties中,默认是开启的：

#
   # Set this to true to enable auto deploy of layout templates, portlets, and
   # themes.
   #
   auto.deploy.enabled=true

然后它09-12行创建一个File对象指向自动部署目录，13行创建File对象指向部署的目标目录，14-16行获取自动部署的间隔时间，17-19行获取多少次失败就把被部署的插件拖到黑名单的临界值，这些值都可以从portal.properties中获取：

#
  # Set the directory to scan for layout templates, portlets, and themes to
  # auto deploy.
  #
  auto.deploy.deploy.dir=${liferay.home}/deploy

  #
  # Set the directory where auto deployed WARs are copied to. The application
  # server or servlet container must know to listen on that directory.
  # Different containers have different hot deploy paths. For example, Tomcat
  # listens on "${catalina.base}/webapps" whereas JBoss listens on
  # "${jboss.home.dir}/deploy". Set a blank directory to automatically use the
  # application server specific directory.
  #
  auto.deploy.dest.dir=
  auto.deploy.default.dest.dir=../webapps
  auto.deploy.geronimo.dest.dir=${org.apache.geronimo.home.dir}/deploy
  auto.deploy.glassfish.dest.dir=${com.sun.aas.instanceRoot}/autodeploy
  auto.deploy.jboss.dest.dir=${jboss.home.dir}/standalone/deployments
  auto.deploy.jetty.dest.dir=${jetty.home}/webapps
  auto.deploy.jonas.dest.dir=${jonas.base}/deploy
  auto.deploy.resin.dest.dir=${resin.home}/webapps
  auto.deploy.tomcat.dest.dir=${catalina.base}/webapps
  auto.deploy.weblogic.dest.dir=${env.DOMAIN_HOME}/autodeploy

  #
  # Set the interval in milliseconds on how often to scan the directory for
  # changes.
  #
  auto.deploy.interval=3000

  #
  # Set the number of attempts to deploy a file before blacklisting it.
  #
  auto.deploy.blacklist.threshold=10

所以自动部署目录为${liferay_home}/deploy,部署到的位置，如果是tomcat服务器，则是${catalina.base}/webapps，扫描自动部署目录的间隔是3秒，尝试失败直到拉入黑名单的临界次数是10次（第9次失败就拉黑了）

 

然后第21-22行，获取自动部署监听器列表，这些监听器类都配置在portal.properties文件中：

#
   # Input a list of comma delimited class names that implement
   # com.liferay.portal.kernel.deploy.auto.AutoDeployListener. These classes
   # are used to process the auto deployment of WARs.
   #
   auto.deploy.listeners=\
       com.liferay.portal.deploy.auto.OSGiAutoDeployListener,\
       com.liferay.portal.deploy.auto.ExtAutoDeployListener,\
       com.liferay.portal.deploy.auto.HookAutoDeployListener,\
       com.liferay.portal.deploy.auto.LayoutTemplateAutoDeployListener,\
       com.liferay.portal.deploy.auto.LiferayPackageAutoDeployListener,\
       com.liferay.portal.deploy.auto.PortletAutoDeployListener,\
       com.liferay.portal.deploy.auto.ThemeAutoDeployListener,\
       com.liferay.portal.deploy.auto.WebAutoDeployListener,\
       com.liferay.portal.deploy.auto.exploded.tomcat.HookExplodedTomcatListener,\
       com.liferay.portal.deploy.auto.exploded.tomcat.LayoutTemplateExplodedTomcatListener,\
       com.liferay.portal.deploy.auto.exploded.tomcat.PortletExplodedTomcatListener,\
      com.liferay.portal.license.deploy.auto.LicenseAutoDeployListener,com.liferay.portal.deploy.auto.exploded.tomcat.ThemeExplodedTomcatListener

 

然后第26-28行创建一个AutoDeployDir对象并吧所有的参数都填充进去，最后用工具类注册这个AutoDeployDir,注册的结果就是，用新的线程AutoDeployScanner去扫描自动部署目录，然后一旦发现部署目录有变化，则用相应的AutodeployListener来处理。