Java Development

[Iyenemi_Tyger]

hello and good day ,

Please what is the most efficient way to manage http connections in a case where for example i need to load people data and display like this :

picture              name

--------------    --------------------------

picture              name

---------------  ----------------------------

now i will need to display @ least 200 + of this , so i first of all downloaded all the names , and then created a threadpool to manage the download of images , i have an exception when downloading more than 20 images when making a httpconnection is there a way to pool the httpconnection knowing that the url of the image is different for each row , i really need to know , thanks .

[simon_hain]

the OS cannot manage more than a few connections at a time anyhow, so using more than these few makes no sense.
ensure that you close a connection properly and you should be able to open a new one after that.

[Iyenemi_Tyger]

Thanks simon , that's the problem my connections are properly closed after each image is fetched and that is when the error pops up , what I am asking is how do I optimize the connection process so it won't try to create a new connection for each row of photo is there any pattern or technic ? , I am testing using one global connection object for the class and once the screen is closed I terminate the connection but its danm slow to fetch images

[peter_strange]

There are a number of Threads on the forum that discuss this.  This is not too bad:

http://supportforums.blackberry.com/t5/Java-Development/Getting-Too-many-Threads-problem-while-dowlo...

but I think there are a number of others.  Have a search round. 

A single queue and a single Thread downloading is a simple solution to implement usually.  but Mutliple Threads will probably see better performance, the debate is how many, and I think that depends on the OS and the connection method. 

[simon_hain · Accepted solution]

we use three threads in a command queue where we just throw runnables in (with a callback for the result).
we modified the number a few times, but 3 seemed the best (without any real analysis, as this was not that important)

[Iyenemi_Tyger]

Thanks everyone , Please can anyone lead me to a proper sample thread pool implementation for blackberry , thanks.

[simon_hain]

i am not aware of any.
our approach uses a notify object (notify/wait) and a queue, with three worker threads that sleep unless notified.

[Iyenemi_Tyger]

Thanks simon please can i see your sample code so i can understand how to implement mine i am talking of a system wide threadpool impementation that will enable tasks to be accomplished in a queue if there are no tasks they all sleep.