SchedulerServlet


1   package org.jbpm.scheduler.impl;
2   
3   import java.io.IOException  ;
4   import java.io.PrintWriter  ;
5   
6   import javax.servlet.ServletException  ;
7   import javax.servlet.http.HttpServlet  ;
8   import javax.servlet.http.HttpServletRequest  ;
9   import javax.servlet.http.HttpServletResponse  ;
10  
11  /**
12   * the jBPM timer execution servlet.
13   * <p>Config parameters : 
14   * <ul>
15   *   <li><b>interval</b>: maximum time in milliseconds between 2 calls to {@link org.jbpm.scheduler.spi.TimerExecutor#executeTimers()}. defaults to 5000.</li>
16   *   <li><b>historyMaxSize</b>: maximum number of logs to be kept for display on the page. defaults to 50.</li>
17   * </ul>
18   * </p>
19   * 
20   * <p>Configuration example with:
21   * <pre>
22   * &lt;web-app&gt;
23   *   ...
24   *   &lt;servlet &gt;
25   *     &lt;servlet-name>SchedulerServlet&lt;/servlet-name>
26   *     &lt;servlet-class>org.jbpm.scheduler.impl.SchedulerServlet&lt;/servlet-class>
27   *     &lt;init-param&gt;
28   *       &lt;param-name&gt;interval&lt;/param-name&gt;
29   *       &lt;param-value&gt;5000&lt;/param-value&gt;
30   *     &lt;/init-param&gt;
31   *     &lt;init-param&gt;
32   *       &lt;param-name&gt;historyMaxSize&lt;/param-name&gt;
33   *       &lt;param-value&gt;50&lt;/param-value&gt;
34   *     &lt;/init-param&gt;
35   *     &lt;load-on-startup&gt;1&lt;/load-on-startup&gt;
36   *   &lt;/servlet&gt;
37   *   &lt;servlet-mapping &gt;
38   *     &lt;servlet-name&gt;SchedulerServlet&lt;/servlet-name&gt;
39   *     &lt;url-pattern&gt;/jbpmscheduler&lt;/url-pattern&gt;
40   *   &lt;/servlet-mapping&gt;
41   *   ...
42   * &lt;/web-app&gt;
43   * </pre>
44   * </p>
45   */
46  public class SchedulerServlet extends HttpServlet   {
47  
48    private static final long serialVersionUID = 1L;
49    
50    Scheduler scheduler = null;
51  
52    public void init() throws ServletException   {
53      // create a new scheduler
54      scheduler = new Scheduler();
55      
56      // initialize it with the servlet init parameters 
57      int interval = Integer.parseInt(getInitParameter("interval", "5000"));
58      scheduler.setInterval(interval);
59      int historyMaxSize = Integer.parseInt(getInitParameter("historyMaxSize", "50"));
60      scheduler.setHistoryMaxSize(historyMaxSize);
61      
62      // put the scheduler in the web app context
63      getServletContext().setAttribute("scheduler", scheduler);
64      
65      // start the scheduler
66      scheduler.start();
67    }
68    
69    public void destroy() {
70      scheduler.stop();
71    }
72  
73    protected void doGet(HttpServletRequest   request, HttpServletResponse   response) throws ServletException  , IOException   {
74      PrintWriter   out = response.getWriter();
75      out.println("<html>");
76      out.println("<body>");
77      out.println("<h2>JBoss jBPM Scheduler Servlet</h2><hr />");
78      out.println("</body>");
79      out.println("</html>");
80    }
81  
82    private String   getInitParameter(String   name, String   defaultValue) {
83      String   value = getInitParameter(name);
84      if (value!=null) {
85        return value;
86      }
87      return defaultValue;
88    }
89  }
90
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