Re: [xmlblaster] connecting

[Kai <yavin at gmx.com>]

Thanks for explaination. Replies inline.

Michele Laghi wrote:
> Hi Kai,
> I think there is a missunderstanding:
> 
> When you try to connect in failsafe mode (failsafe: register a
> I_ConnectionStateListener + retries=-1) you don't get an exception even
> if the server is not available.

I read that retries=-1 is default, isn't it? And I registered a
ConnectionStateListener. The code I provided is a bit simplified, but I
got an exception. Maybe my configuration is something missing for
failsafe mode!?

I tried the following:
ConnectQos qos = new ConnectQos(glob);
Address addressProp = new Address(glob);
addressProp.setDelay(4000L); // retry connecting every 4 sec
addressProp.setRetries(-1); // -1 == forever
addressProp.setPingInterval(0L); // switched off
qos.setAddress(addressProp);
ConnectReturnQos result = access.connect(qos, new CallBackListener());

But I got an exception!

> What happens is that the connection request is queued on the client side
> and the XmlBlasterAccess object creates a fake return qos for you. So
> under a client point of view you are connected (even if the physical low
> level connection is not established).
>
> So isConnected returns true because the connect message was (at least)
> safely queued on the client side and you are allowed to publish
> subscribe and so on (as you would be physically connected). The only
> feature you are not able to do is GET (see the table in the failsafe
> requirement).
> 
> Once you connect you are connected. The Connection has several states:
> 
> POLLING
> ALIVE
> DEAD
> 
> so in your case isConnected() gives true, isPolling() gives also true
> and isAlive() gives false.

Sorry maybe I'm to stupid but in my case all of this functions return
false because the field XmlBlasterAccess.connectReturnQos is null!

> So try the following:
> 
> make a connect (no need to loop in the catch)
> => you connection msg is queued
> start the xmlBlaster
> => your method reachedAlive(..) is invoked
> stop the xmlBlaster
> => your method reachedPolling() is invoked
> 
> So if you really need the server for your work (in many use cases you
> don't need it) you would block in the thread making the connect and you
> would release that thread in your reachedAlive() method.
> 
> Also see the second example in the requirement for more details.

Okay attached you will find my simple test program. I hope I got it
right. I use the client jar build with "build dist-client" and the
standalone server with default config.

import org.xmlBlaster.client.I_Callback;
import org.xmlBlaster.client.I_ConnectionStateListener;
import org.xmlBlaster.client.I_XmlBlasterAccess;
import org.xmlBlaster.client.key.UpdateKey;
import org.xmlBlaster.client.qos.ConnectQos;
import org.xmlBlaster.client.qos.ConnectReturnQos;
import org.xmlBlaster.client.qos.UpdateQos;
import org.xmlBlaster.util.EmbeddedXmlBlaster;
import org.xmlBlaster.util.Global;
import org.xmlBlaster.util.XmlBlasterException;
import org.xmlBlaster.util.dispatch.ConnectionStateEnum;
import org.xmlBlaster.util.qos.address.Address;

public class XmlBlasterAccessTest
{
    class CallBackListener implements I_Callback
    {

        /*
         * (non-Javadoc)
         * 
         *  at see org.xmlBlaster.client.I_Callback#update(java.lang.String,
         *      org.xmlBlaster.client.key.UpdateKey, byte[],
         *      org.xmlBlaster.client.qos.UpdateQos)
         */
        public String update(String cbSessionId, UpdateKey updateKey, byte[] content, UpdateQos updateQos) throws XmlBlasterException
        {
            // TODO update implementation
            return null;
        }

    }

    class ConnectionListener implements I_ConnectionStateListener
    {

        /*
         * (non-Javadoc)
         * 
         *  at see org.xmlBlaster.client.I_ConnectionStateListener#reachedAlive(org.xmlBlaster.util.dispatch.ConnectionStateEnum,
         *      org.xmlBlaster.client.I_XmlBlasterAccess)
         */
        public void reachedAlive(ConnectionStateEnum oldState, I_XmlBlasterAccess connection)
        {
            // TODO reachedAlive implementation
            System.out.println("reachedAlive");
            synchronized (XmlBlasterAccessTest.this)
            {
                XmlBlasterAccessTest.this.notify();
            }
        }

        /*
         * (non-Javadoc)
         * 
         *  at see org.xmlBlaster.client.I_ConnectionStateListener#reachedDead(org.xmlBlaster.util.dispatch.ConnectionStateEnum,
         *      org.xmlBlaster.client.I_XmlBlasterAccess)
         */
        public void reachedDead(ConnectionStateEnum oldState, I_XmlBlasterAccess connection)
        {
            // TODO reachedDead implementation
            System.out.println("reachedDead");
        }

        /*
         * (non-Javadoc)
         * 
         *  at see org.xmlBlaster.client.I_ConnectionStateListener#reachedPolling(org.xmlBlaster.util.dispatch.ConnectionStateEnum,
         *      org.xmlBlaster.client.I_XmlBlasterAccess)
         */
        public void reachedPolling(ConnectionStateEnum oldState, I_XmlBlasterAccess connection)
        {
            // TODO reachedPolling implementation
            System.out.println("reachedPolling");
        }

    }

    public static void main(String[] args)
    {
        XmlBlasterAccessTest test = new XmlBlasterAccessTest();
        test.test();
    }
    I_XmlBlasterAccess access;
    Global glob;

    EmbeddedXmlBlaster server;

    public void test()
    {
        glob = new Global();
        access = glob.getXmlBlasterAccess();
        access.registerConnectionListener(new ConnectionListener());

        try
        {
            ConnectQos qos = new ConnectQos(glob);
            Address addressProp = new Address(glob);
            addressProp.setDelay(4000L); // retry connecting every 4 sec
            addressProp.setRetries(-1); // -1 == forever
            addressProp.setPingInterval(0L); // switched off
            qos.setAddress(addressProp);
            ConnectReturnQos result = access.connect(qos, new CallBackListener());

        } catch (XmlBlasterException e)
        {
            e.printStackTrace();
        }

        boolean alive = access.isAlive();
        boolean connected = access.isConnected();
        boolean polling = access.isPolling();
        if (!alive && connected && polling)
        {
            try
            {
                synchronized (this)
                {
                    this.wait();
                }
            } catch (InterruptedException e)
            {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        access.disconnect(null);
        System.out.println("exit");
    }
}