GroupListDescriptor Item names cannot be empty

vaduganathan

I am create creating an engine, to connect my LS server using the following code.

public native static void init(String username, String password)
	/*-{
		$wnd.user_name = username;		
		var divTag = document.createElement("div");
		divTag.id = "list";

		divTag.setAttribute("class","ClassName");
		divTag.setAttribute("source","lightstreamer");
		divTag.setAttribute("table","TableName");
		divTag.setAttribute("item",username+"#TableName");
		divTag.setAttribute("field","FieldName");
		divTag.style.display = 'none'; 
		document.body.appendChild(divTag);

		$wnd.page = new $wnd.PushPage();
		$wnd.page.context.setDomain("chellasoftapp.com"); 
		$wnd.page.onEngineCreation = function(engine) {
			$wnd.lsEngine = engine;

			engine.connection.setLSHost("domainName.com"); 
			engine.connection.setLSPort("port"); 
			
			engine.connection.setAdapterName("AdapterName");						

			engine.connection.setUserName(username);
			engine.connection.setPassword(password);

			engine.changeStatus("STREAMING");
		}

		$wnd.page.bind();		
		$wnd.page.createEngine("AdapterName", "LS", "SHARE_SESSION", true);

		var itemName = username+"#iTableName";
		$wnd.pushtable = new $wnd.NonVisualTable(itemName, new Array("TableName"), "DISTINCT");
		$wnd.chellaSoft = this;
		$wnd.pushtable.onItemUpdate = function (item, updateInfo) {
			$wnd.jsonUpdatedStaticJS(updateInfo.getNewValue("FieldName"));
		}

		$wnd.page.addTable($wnd.pushtable, "TableName");
	}-*/;

While I am login it throws an error message states that "ER GroupListDescriptor Item names cannot be empty"

What do i need to do, for this exception, And where do i need make the changes either client side or Server side?

Thank you in advance

Dario Crivelli

I can't replicate the issue, though I can't replicate your case exactly.
Which version of the client library are you using?
The message is issued when a null or empty string is supplied within an Array of field names to a Table constructor;
however, you don't supply an Array to your NonVisualTable, but just a group id;
which is the final value of your itemName variable?
Are there any other Lightstreamer-related pieces of code in the page?

I see that you dynamically create a push cell in your divTag, but then you define a NonVisualTable, which doesn't use push cells. Do you still use that element?
Are there any other push cells defined in the page?

By the way, it seems to me that the field name you specify in the $wnd.pushtableconstructor (namely "TableName") is a typo, as later you issue getNewValue("FieldName") .

vaduganathan

Hi,

Thank you for showing interest on this DarioCrivelli.
Here are your questions and my responses for the corresponding, I hope this will help you track the problem.

Which version of the client library are you using? - 3.5

which is the final value of your itemName variable? - Yes

Are there any other Lightstreamer-related pieces of code in the page? - No

I see that you dynamically create a push cell in your divTag, but then you define a NonVisualTable, which doesn't use push cells. Do you still use that element? - No

Are there any other push cells defined in the page? = No

By the way, it seems to me that the field name you specify in the $wnd.pushtable constructor (namely "TableName") is a typo, as later you issue getNewValue("FieldName"). - Yes this is a type.

Thank you...

Dario Crivelli

We can't find any explaination for that error message.
Do you still get it upon page startup?
May you please log the value of the "itemName" variable just before calling the constructor of NonVisualTable?
Also, try commenting out the code that invokes the constructor of the NonVisualTable (and the subsequent code that depends on that object) and let's see if the exception happens again.