Bug 3770 - HttpSessionListener.sessionCreated() called twice for each session
HttpSessionListener.sessionCreated() called twice for each session
Status: RESOLVED FIXED
Product: Tomcat 4
Classification: Unclassified
Component: Catalina
4.0 Final
All All
: P3 major (vote)
: ---
Assigned To: Tomcat Developers Mailing List
:
Depends on:
Blocks:
  Show dependency tree
 
Reported: 2001-09-21 11:26 UTC by Hans Bergsten
Modified: 2004-11-16 19:05 UTC (History)
0 users



Attachments

Note You need to log in before you can comment on or make changes to this bug.
Description Hans Bergsten 2001-09-21 11:26:19 UTC
The sessionCreated() method is called twice for each new session.

Test code:

public class MyListener implements HttpSessionListener {
    public void sessionCreated(HttpSessionEvent hse) {
	HttpSession session = hse.getSession();
	System.out.println("Created called: " + session.getId());
	System.out.println("isNew(): " + session.isNew());
    }
}

Result:
  Created called: F054C065430771A554A54117C113D446
  isNew(): true
  Created called: F054C065430771A554A54117C113D446
  isNew(): true
Comment 1 Hans Bergsten 2001-09-25 11:48:20 UTC
On further experimentation, I noticed that this error only occurs when I define 
the tag library that contains the listener in the web.xml file with a taglib 
element. If I rely on auto-discovery of tag libraries, everything works fine.

Most likely, the listener is registered once when the container processes the 
TLD it finds through auto-discovery, and then again when it finds the TLD 
through the web.xml definition. Checking whether a TLD has already been 
processed before registering listeners should fix the problem.
Comment 2 Remy Maucherat 2001-10-12 19:31:22 UTC
This problem will be addressed later.

It only affects people which:
* Explicitly have a <taglib> element in your web.xml file
* This <taglib> element refers to a JAR file, not a TLD file
* There is a TLD inside this JAR file that defines a listener.
Comment 3 Remy Maucherat 2002-02-14 19:52:31 UTC
Reopen.
Comment 4 Remy Maucherat 2002-02-14 20:03:24 UTC
I've added a chack which should prevent registering the same listener twice.
Comment 5 Brian Ortner 2003-03-04 00:13:21 UTC
I am seeing symptoms of this bug in tomcat 4.1.12 and 4.1.18 on Linux 7.2

I use the following code for the HttpSessionListener.sessionCreated() method:

  public void sessionCreated(HttpSessionEvent event) {
    try {
      Object sessionId = event.getSession().getId();
      System.out.println("SessionCounter.sessionCreated called for 
id: "+sessionId);
      System.out.println("SessionCounter.sessionCreated isNew="+event.getSession
().isNew());
      if(! (sessionList.contains(sessionId)) ){
        sessionList.add(sessionId);
        totalSessionCount++;
        currentSessionCount++;
        if (currentSessionCount > maxSessionCount) {
          maxSessionCount = currentSessionCount;
        }
        if (context == null) {
          storeInServletContext(event);
        }
      }
    }
    catch(Exception e) {
      e.printStackTrace();
    }
  }


Please note: I'm using the vector to hold the sessionId so that I can avoid the 
double counting. However, the problem occurs without the added code.

The web.xml is as follows:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 
2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>
  <filter>
    <filter-name>RedirectFilter</filter-name>
    <filter-class>com.checkpoint.webapp.filter.RedirectFilter</filter-class>
    <init-param>
      <param-name>maxActiveSessions</param-name>
      <param-value>4</param-value>
    </init-param>
    <init-param>
      <param-name>redirectURL</param-name>
      <param-value>https://usercenter.checkpoint.com/</param-value>
    </init-param>
  </filter>
  <filter-mapping>
    <filter-name>RedirectFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
  <listener>
    <listener-class>com.checkpoint.webapp.listener.SessionCounter</listener-
class>
  </listener>
  <session-config>
    <session-timeout>2</session-timeout>
  </session-config>
</web-app>


the output is:

SessionCounter.sessionCreated called for id: 
632E263A1EDE464BBD19BB1D5D4C7EDD.tomcat1
SessionCounter.sessionCreated isNew=true
SessionCounter.sessionCreated called for id: 
632E263A1EDE464BBD19BB1D5D4C7EDD.tomcat1
SessionCounter.sessionCreated isNew=true


there are no other contexts (no ROOT or others) and no taglibs





Comment 6 Remy Maucherat 2003-04-15 15:45:07 UTC
JFC's session manager refactoring should fix it in 4.1.24 (as well as other 
cleanups and fixes).