DynaScrollTable

betasec

Hi
is there a class DynaScrollTable or something like that
on new version Lightstreamer JavaScript Client 6.0 b4 API !!??

Thanks

Giuseppe Corti

Hi,

the functionalities that you could find in DynaScrollTable in the new JavaScript Client API have been divided, for a better logical model, into two separate classes: Subscriptionand DynaGrid .

With Subscription object you can specify what information you need and how to obtain them from the Lightstreamer server. DynaGrid can be used to display the values from the internal model in a dynamically created grid.

Please refer to JavaScript Client API Reference for fully description of the new classes and to the source code of Basic Chat Demo that replaced a DynaSrollTable with a Subscription and a DynaGrid while updating to the new version of the Lightstreamer JavaScript Client 6.0 API.

betasec

Hi ,
i did it with DynaGrid and looks working, but there is a problem with the update , no all subscribe items working,
the same subscribes works fine on a html table but on scroll many items don't
ETE and PPC are working fine in both the "IX129775350","EI09CAC","EI09CCMP","EI09FTSEMIB" are not working with Scroll table

var stocksSchema = ["o_Sym","o_ddeItem","o_Last","o_Bid","o_Ask"];
var page2Group = ["ETE","PPC","IX129775350","EI09CAC","EI09CCMP","EI09FTSEMIB"];

var scrollSubscription = new Subscription("DISTINCT",page2Group,stocksSchema);
scrollSubscription.setDataAdapter(myDataAdapter);
scrollSubscription.setRequestedSnapshot("no");
scrollSubscription.setRequestedBufferSize("unlimited");

scrollSubscription.addListener(scrollGrid);
sharingClient.subscribe(scrollSubscription);

Thanks

Mone

Hi Betasec,

What do you mean with "works fine on a html table"?
We need to understand where the problem lies;
Do you see any error on the server log?
Is it possible that the same items are subscribed somewhere else in MERGE mode?

try to log all the data received by the Subscription. Is data already missing there?
(you may use a piece of code like this to log updates on the browser console)
[SYNTAX=JS] scrollSubscription.addListener({
onItemUpdate: function(obj) {
console.log("Update " + obj.getItemName());
obj.forEachField(function(fName,fPos,val) {
console.log(fName+"|"+val);
});
}

});[/SYNTAX]

betasec

Hi
actually the problem is that the same items are subscribed in more pages with MERGE and DISTINCT mode
what i am doing is to have tables with stocks and a scroll table where scrolling all the updates for all items
so if an item is subscribed in MERGE table is not available in DISTINCT table and the opposite.
Is this normal !!?? because with the previous versions I didn't have a problem.
Thanks

Giuseppe Corti

Hi betasec,

I think you have just to change the subscription mode from DISTINCT to MERGE in this statement:

var scrollSubscription = new Subscription("DISTGINCT",page2Group,stocksSchema);

Please note that DISTINCT and MERGE are subscription modes not compatible between them, so you can not subscribe the same item both in MERGE and DISTINCT mode. I confirm you that this was not changed from previous Lightstreamer version.
For this reason it is good practice to implement the method modeMayBeAllowed of MetadataProvider to define
precisely subscription mode allowed for each item according to the nature of the data.

betasec

Hi , you have right
with previous version i use [MERGE] with the scroll table

var scrollTable = new DynaScrollTable(page1Group, stocksSchema,"MERGE");

when i use

var scrollSubscription = new Subscription("MERGE",page1Group,stocksSchema);

<table class="scrollContainer" id="scrollTable1" data-source="lightstreamer" border="1">
<tr>
<td>

</td>
<td>

</td>
<td>

</td>
<td>

</td>
<td>

</td>
</tr>
</table>

then in a scroll table i get the items but when i get update in a item its not scrolling but is update it in the all ready inserted row
how i can make the new value to scroll on the table and not to update the cell !!??

Mone

Well, that was unexpected.

Because of the nature of DISTINCT and MERGE subscriptions we decided to force the "scroll behavior" on the grid for DISTINCT subscription and the "table behavior" for MERGE subscriptions:
a DISTINCT item ideally is used to represent a list of things while a MERGE item represents something whose status changes. See section 3.1 of http://www.lightstreamer.com/distros/Lightstreamer_Allegro-Presto-Vivace_5_0_b1_Colosseo_20120629/Lightstreamer/DOCS-SDKs/General%20Concepts.pdf for details.

In any case, if you can describe us your use case, why you want to use a MERGE subscription to feed a scrolling grid, we may re-evaluate our initial decision (well that's what the beta is for) or show you how to obtain the same effect without modifying the library on our side.

betasec

Mone

Thank you for the explanation.

We decided to add a new method to StaticGrid and DynaGrid that can be used to force the behavior of the grid (overwrite vs scroll) regardless of the Subscription mode of the associated Subscription.
I will let you know as soon as you can use it.

In the meanwhile, assuming you're using build 1561 of the client you can force the scroll behavior with the following code

[SYNTAX=JS]
myGrid = new Dynagrid(...);
myGrid.TJY = true;
myGrid.NI = "UPDATE_IS_KEY";
[/SYNTAX]

The code is build-dependant, let me know if you're using a different build. You can check the build you're using by opening the lightstreamer.js file and watching its "header".
If you're using an older build you can download the latest one here: http://www.lightstreamer.com/distros/Lightstreamer_Moderato_5_0_b1_Colosseo_20120629/Lightstreamer/DOCS-SDKs/sdk_client_javascript/lib/lightstreamer.js

HTH

betasec

Hi ,
first off all thanks it will be very helpful to add the method , the code is not working even with the latest build 1561,
in the meanwhile i am ok because i use the old client on the pages i want to scroll table
I expecting news
Thanks

Mone

Hi,
I just deployed the rc version of the JS library including the promised method on our website.
You can download the lib from here http://www.lightstreamer.com/demo/commons/lightstreamer.js or just wait a week or so for the final official release.

You can use the method like this:

[SYNTAX=JS]yourGrid.forceSubscriptionInterpretation("UPDATE_IS_KEY");[/SYNTAX]

(call it before setting the grid as listener for a Subscription as for the method call to be accepted you need to have an empty grid)

betasec

Hi , i will wait for the final release , as i work some pages i need with previews versions

Thanks

Mone

Just to inform you that the final release is now online: http://blog.lightstreamer.com/2012/08/lightstreamer-50-colosseo-is-now_3.html

betasec

Hi I am trying to setup with the latest version the grid-table and the scroll-list for same items subscriptions
bat i don't think that i have see any change

page1
var stocksGrid = new StaticGrid(tableName,true);
stocksGrid.forceSubscriptionInterpretation();
........
var stockSubscription = new Subscription("MERGE",stocksGrid.extractItemList(),stocksGrid.extractFieldList());
stockSubscription.addListener(stocksGrid);

page2
var scrollGrid = new DynaGrid("scrollTable1",true);
scrollGrid.forceSubscriptionInterpretation();
..........
var scrollSubscription = new Subscription("DISTINCT",page1Group,stocksSchema);

thanks

Giuseppe Corti

Hi Betasec,
with the latest version you can not yet subscribe the same item both in MERGE and DISTINCT mode, but you can change the behavior of visual objects by the forceSubscriptionInterpretation(interpretation) method.

So, please, try this pieces of code:

page1:
[SYNTAX=JS]var stocksGrid = new StaticGrid(tableName,true);
........
var stockSubscription = new Subscription("MERGE",stocksGrid.extractItemList(), stocksGrid.extractFieldList());
stockSubscription.addListener(stocksGrid);[/SYNTAX]

page2:
[SYNTAX=JS]var scrollGrid = new DynaGrid("scrollTable1",true);
var u = "UPDATE_IS_KEY";
scrollGrid.forceSubscriptionInterpretation(u);
..........
var scrollSubscription = new Subscription("MERGE",page1Group,stocksSchema);
scrollSubscription.addListener(scrollGrid);[/SYNTAX]