Maarten,
In you example. Every time messageReceived is called for a IoSession,
you make a new connection. The cost for the connection will be high,
particular for a database connection.
But Suppose the example is change to use a Connection Pool. In that way
every time a new client is connected to the server, a new connection is
added to the db connection pool, or reuse a connection that is not
associated to a IOSession.
How this can me implemented in mina.?
Angel Figueroa
Maarten Bosteels wrote:
>
> On 11/2/07, Angel.Figueroa <[EMAIL PROTECTED]> wrote:
>>
>>
>> Maarten,
>>
>> I understand that the messageReceived will never be called
>> simultaneously
>> for the same session. But it can be called concurrently for different
>> IoSession's.
>>
>> Let put a real example. A Server Application that received SQL Query
>> from
>> different client connected to it.
>> Each client sent a SQL query to the Server. The Server has 10
>> connections
>> to the database.
>>
>> How the messageReceived can process each client request (SQL Query)
>> simultaneously, using the 10 connections ?
>
>
>
> The fact that messageReceived can be called simultaneously (by multiple
> threads)
> just means that you have to be careful with using shared resources, but
> other than that, you don't need to worry.
>
> Since it's reasonable that any DataSource implementation is thread-safe,
> you
> could implement your example like this:
>
> public class QuickMina extends IoHandlerAdapter {
>
> DataSource dataSource;
>
> public void setDataSource(DataSource dataSource) {
> this.dataSource = dataSource;
> }
>
> public void messageReceived(IoSession session, Object message) throws
> Exception {
> // a TextLineDecoder will ensure that passed in message is a string
> String sql = (String) message;
> Connection connection = dataSource.getConnection();
> try {
> Statement stmt = connection.createStatement();
> try {
> int rowsUpdated = stmt.executeUpdate(sql);
> session.write("rows updated: " + rowsUpdated);
> } catch(SQLException e) {
> session.write("failed: " + e.getMessage());
> } finally {
> stmt.close();
> }
> } finally {
> connection.close();
> }
>
> }
> }
>
> Disclaimer:
> I haven't tested this code, it's just an example. I wouldn't advise you to
> allow clients to send db updates this way :-)
>
> Maarten
>
>
>
>>
>>
>>
>> Maarten Bosteels wrote:
>> >
>> > Angel,
>> >
>> > Your question is not really clear to me.
>> > What exactly are you worried about ?
>> > Note that, by default, messageReceived will never be called
>> simultaneously
>> > for the same session.
>> > But it can be called concurrently for different IoSession's, this does
>> not
>> > pose a problem by itself.
>> > You just have to make sure your implementation is thread-safe: don't
>> store
>> > conversattional state in instance fields of your IoHandler and properly
>> > synchronize access to shared data.
>> > This is all very analogous to servlet programming.
>> >
>> > Maarten
>> >
>> > On 11/1/07, Angel.Figueroa <[EMAIL PROTECTED]> wrote:
>> >>
>> >>
>> >> If more that one message is received at the same time. How to control
>> the
>> >> execution of the business logic method.
>> >>
>> >> public void messageReceived(IoSession session, Object message)
>> throws
>> >> Exception
>> >> {
>> >>
>> >>
>> >>
>> //----------------------------------------------------------------------
>> >> // received the Request Transaction
>> >>
>> >>
>> //----------------------------------------------------------------------
>> >> String theMessage = ( String ) message;
>> >>
>> >>
>> //--------------------------------------------------------------
>> >> // Process Transaction Code business logic method
>> >>
>> //--------------------------------------------------------------
>> >> theMessage = transaction.ProcessTransaction
>> (theMessage,arclient);
>> >>
>> >>
>> >>
>> //----------------------------------------------------------------------
>> >> // send the response Transaction Back
>> >>
>> >>
>> //----------------------------------------------------------------------
>> >> session.write(theMessage);
>> >> }
>> >>
>> >> --
>> >> View this message in context:
>> >>
>> http://www.nabble.com/messageReceived-and-bussiness-logic-tf4729241s16868.html#a13522950
>> >> Sent from the Apache MINA Support Forum mailing list archive at
>> >> Nabble.com
>> >> .
>> >>
>> >>
>> >
>> >
>>
>> --
>> View this message in context:
>> http://www.nabble.com/messageReceived-and-bussiness-logic-tf4729241s16868.html#a13541041
>> Sent from the Apache MINA Support Forum mailing list archive at
>> Nabble.com
>> .
>>
>>
>
>
--
View this message in context:
http://www.nabble.com/messageReceived-and-bussiness-logic-tf4729241s16868.html#a13546644
Sent from the Apache MINA Support Forum mailing list archive at Nabble.com.
