Mina2.0 framework source code analysis (5)

Previously, we introduced that iosessionrecycler is an interface used to recycle sessions that are no longer in use. expiringsessionrecycler is an implementation class used to recycle sessions with expired timeout.

Private expiringmap <object, iosession> sessionmap; // session set to be processed

Private expiringmap <object, iosession>. expirer mapexpirer; // recycles

The sessionmap key is composed of the local address and the remote address. The value is the session corresponding to the two addresses.

The expirer class implements the runnable interface. This thread monitors expiringmap and removes elements that exceed the threshold value in expiringmap from expiringmap. This thread calls setdaemon (true) and runs in the background as a daemon. The specific process is as follows:

Java code

1. Private
    
   Void
   Processexpires ()
   
2. {
3. Long
   Timenow = system. currenttimemillis ();
   // Current time
   
   
4. For
   (Expiringobject O: Delegate. Values ())
   
5. {
6. If
   (Timetolivemillis <=
   0
   )
   
7. {
8. Continue
   ;
   
9. }
10. Long
    Timeidle = timenow-o. getlastaccesstime ();
    // Time Difference
    
    
11. If
    (Timeidle> = timetolivemillis)
    
12. {// Timeout
    
    
13. Delegate. Remove (O. getkey ());
14. For
    (Expirationlistener <v> listener: expirationlisteners)
    
15. {// Call listener
    
    
16. Listener. Expired (O. getvalue ());
17. }
18. }
19. }
20. }

Private void processexpires () {long timenow = system. currenttimemillis (); // current time for (expiringobject O: Delegate. values () {If (timetolivemillis <= 0) {continue;} Long timeidle = timenow-o. getlastaccesstime (); // time difference if (timeidle> = timetolivemillis) {// time-out delegate. remove (O. getkey (); For (expirationlistener <v> listener: expirationlisteners) {// call listener. expired (O. getvalue ());}}}}

The lock mechanism is required to start/Close the timeout check thread. Here the read/write lock is used:

Java code

1. Private
    
   Final
   Readwritelock statelock =
   New
   Reentrantreadwritelock ();
   
3. Public
    
   Void
   Startexpiring ()
   
4. {
5. Statelock. writelock (). Lock ();
6. Try
   
   
7. {
8. If
   (! Running)
   
9. {
10. Running = true
    ;
    
11. Expirerthread. Start ();
12. }
13. }
14. Finally
    
    
15. {
16. Statelock. writelock (). Unlock ();
17. }
18. }
19. Public
     
    Void
    Stopexpiring ()
    
20. {
21. Statelock. writelock (). Lock ();
22. Try
    
    
23. {
24. If
    (Running)
    
25. {
26. Running = false
    ;
    
27. Expirerthread. Interrupt ();
28. }
29. }
30. Finally
    
    
31. {
32. Statelock. writelock (). Unlock ();
33. }
34. }

      private final ReadWriteLock stateLock = new ReentrantReadWriteLock();        public void startExpiring()         {            stateLock.writeLock().lock();            try             {                if (!running)                 {                    running = true;                    expirerThread.start();                }            }             finally             {                stateLock.writeLock().unlock();            }        }        public void stopExpiring()         {            stateLock.writeLock().lock();            try             {                if (running)                 {                    running = false;                    expirerThread.interrupt();                }            }             finally             {                stateLock.writeLock().unlock();            }        }

Session Timeout listener:

Java code

1. Private
    
   Class
   Defaultexpirationlistener
   Implements
   
   
2. Expirationlistener <iosession> {
3. Public
    
   Void
   Expired (iosession expiredsession ){
   
4. Expiredsession. Close (); // close the timeout session
   
   
5. }
6. }