I have a scenario where a scheduled job being run by Quartz will update an arraylist of objects every hour.<\/p>\n
But I need this arraylist of objects to be visible to all sessions created by Tomcat. So what I’m thinking is that I write this object somewhere every hour from the Quartz job that runs so that each session can access it.<\/p>\n
Store the list in the ServletContext as an application-scoped attribute. Pulling the data from a database instead is probably less efficient, since you’re only updating the list every hour. Creating a ServletContextListener might be necessary in order to give the Quartz task a reference to the ServletContext object. The ServletContext can only be retrieved from JavaEE-related classes like Servlets and Listeners.In the ServletContextListener, when you create the job, you can pass the list into the job by adding it to a JobDataMap.<\/p>\n
\r\npublic class MyServletContextListener implements ServletContextListener{\r\n public void contextInitialized(ServletContextEvent event){\r\n ArrayList list = new ArrayList();\r\n\r\n \/\/add to ServletContext\r\n event.getServletContext().setAttribute("list", list);\r\n\r\n JobDataMap map = new JobDataMap();\r\n map.put("list", list);\r\n JobDetail job = new JobDetail(..., MyJob.class);\r\n job.setJobDataMap(map);\r\n \/\/execute job\r\n }\r\n\r\n public void contextDestroyed(ServletContextEvent event){}\r\n}\r\n\r\n\/\/Quartz job\r\npublic class MyJob implements Job{\r\n public void execute(JobExecutionContext context){\r\n ArrayList list = (ArrayList)context.getMergedJobDataMap().get("list");\r\n \/\/...\r\n }\r\n}\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"I have a scenario where a scheduled job being run by Quartz will update an arraylist of objects every hour. But I need this arraylist of objects to be visible to all sessions created by Tomcat. So what I’m thinking is that I write this object somewhere every hour from the Quartz job that runs… Continue reading