Apache Mina Learning Notes (4)-session

The session is the core of Apache, and whenever a client connection arrives, a new session is created until the connection is closed. The session is used to save the connection, as well as various information.

The session has the following States:

Connected:the session has been created and was availableidle:the session hasn ' t processed any request for at least a PE Riod of time (this period was configurable) Idle for Read:no read have actually been made for a period of timeidle for writ E:no write have actually been made for a period of timeidle for Both:no read nor write for a period of timeclosing:th  E session is being closed (the remaining messages was being flushed, cleaning up isn't terminated) Closed:the session is Now closed, nothing else can is done to revive it.

Represents the state transition relationship for a session:

Several parameters can be used to configure the session

Receive Buffer size
Sending buffer size
Idle time
Write TimeOut

Manage user-defined properties:

For example, if you want to track how many requests a user has sent since the session was established, it can easily be stored in such a mapping: simply create a key to associate to value on the line.

...  int countervalue = Session.getattribute ("counter");  Session.setattribute ("Counter", Countervalue + 1);  ...

We use Key/value to store properties in the session, and this key/value can be read, added, or deleted by the container through the session.

Define Container

As we said, this container is a key/value container, which is a mapping by default, and of course can be defined as other data structures. When the session is created, we can implement an interface and a factory to create the container. The following code snippet is an example of how to create a container when the session is initialized (I don't understand, what does this mean?). ）

Protected final void Initsession (iosession session,          iofuture future, Iosessioninitializer Sessioninitializer) {      ...      try {          (abstractiosession) session. Setattributemap (Session.getservice ()                  . getsessiondatastructurefactory (). Getattributemap (session));      } catch (Iosessioninitializationexception e) {          throw e;      } catch (Exception e) {          throw new Iosessioninitializationexception (                  "Failed to initialize an attributemap.", E);      }

And here are the factory interface we can implement if we want to define another kind of container:

Public interface Iosessiondatastructurefactory {      /**      * Returns a {@link iosessionattributemap} which is going to Be associated      * with the specified <tt>session</tt>.  Please note that the returned      * implementation must is Thread-safe.      *       /Iosessionattributemap Getattributemap (iosession session) throws Exception;   }

Filter Chain

Each session is associated with a filter chain to handle incoming requests or data that goes out. Each session will specify a separate filter chain, and in most cases we will use many of the same filter chains in the session.

Statistics

Each session also keep a track of records about what have been done for the session:number of bytes Received/sentnumber of Messages Received/sentidle Statusthroughputand Many other useful informations. Handler

Finally, it is also important that a handler be attached to a session that is used to process the message of the program. This handler also sends a packet as a response, as long as it simply calls the Write method:

...  Session.write (<your message>);  ...

The above is the Apache Mina study Note (4)-session content, more relevant content please pay attention to topic.alibabacloud.com (www.php.cn)!

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