HibernateFilterLong


1   package org.hibernate.ce.auction.persistence;
2   
3   import org.hibernate.Session;
4   import org.apache.commons.logging.*;
5   
6   import javax.servlet.*;
7   import javax.servlet.http.*;
8   import java.io.IOException  ;
9   
10  /**
11   * A servlet filter that disconnects and reconnects a Hibernate Session for each request.
12   * <p>
13   * Use this filter for the <b>session-per-application-transaction</b> pattern
14   * with a <i>Long Session</i>. Don't forget to demarcate application transactions
15   * in your code, as described in Hibernate in Action.
16   *
17   * @see HibernateUtil
18   * @author Christian Bauer <christian@hibernate.org>
19   */
20  public class HibernateFilterLong
21          implements Filter {
22  
23      private static final String   HTTPSESSIONKEY = "HibernateSession";
24      private static Log log = LogFactory.getLog(HibernateFilterLong.class);
25  
26      public void init(FilterConfig filterConfig) throws ServletException {
27          log.info("Servlet filter init, now disconnecting/reconnecting a Session for each request.");
28      }
29  
30      public void doFilter(ServletRequest request,
31                           ServletResponse response,
32                           FilterChain chain)
33              throws IOException  , ServletException {
34  
35          // Try to get a Hibernate Session from the HttpSession
36          HttpSession userSession =
37                  ((HttpServletRequest) request).getSession();
38          Session hibernateSession =
39                  (Session) userSession.getAttribute(HTTPSESSIONKEY);
40  
41          if (hibernateSession != null)
42              HibernateUtil.reconnect(hibernateSession);
43  
44          // If there is no Session, the first call to
45          // HibernateUtil.beginTransaction in application code will open
46          // a new Session for this thread.
47          try {
48              chain.doFilter(request, response);
49  
50              // Commit any pending database transaction.
51              HibernateUtil.commitTransaction();
52  
53          } finally {
54              // TODO: The Session should be closed if a fatal exceptions occurs
55  
56              // No matter what happens, disconnect the Session.
57              hibernateSession = HibernateUtil.disconnectSession();
58              // and store it in the users HttpSession
59              userSession.setAttribute(HTTPSESSIONKEY, hibernateSession);
60          }
61      }
62  
63      public void destroy() {}
64  
65  }
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