data not coming to web client

**rd2008** · February 5th, 2009, 12:11 PM

I'm going to go from the basics...

I created a simple web client that uses a nonvisual table.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html>

<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Lightstreamer :: Basic Stock-List Demo</title>
<link rel="stylesheet" type="text/css" href="css/table.css" />


<script src="ls/lscommons.js" type="text/javascript"></script>
<script src="ls/lspushpage.js" type="text/javascript"></script>
</head>

<body>
<table width="766" border="0">
<tr>
<td><a href="http://www.lightstreamer.com" target="_blank">
<img src="images/logo.gif" alt="LIGHTSTREAMER" hspace="0" border="0" /></a></td>
<td class="demoTitle">demo basic</td>
</tr>
</table>

<br />

<div id="test2">This is a test</div>
<div id="testnon">--</div>
<script type="text/javascript">

//////////////// Master Push-Page Configuration

var pushPage = new PushPage();
pushPage.context.setDebugAlertsOnClientError(true) ; // (set false in production)
pushPage.context.setDomain()// (set the domain when deploying on web server)

pushPage.onEngineCreation = function(lsEngine) {
lsEngine.context.setDebugAlertsOnClientError(true) ; // (set false in production)
lsEngine.connection.setLSHost(null); // (set the hostname when deploying on web server)
lsEngine.connection.setLSPort(null); // (set the port when deploying on web server)
lsEngine.connection.setAdapterName("MY_REAL_TIME") ;
//lsEngine.policy.setMaxBandwidth(40); // ignored in Moderato and Allegro editions
lsEngine.changeStatus("STREAMING");
};

pushPage.bind();
pushPage.createEngine("MyCommonEngine", "ls/", "SHARE_SESSION", true);
// both group and schema need to be defined by the backend
var nvTable = new NonVisualTable("a","b","MERGE");
nvTable.setSnapshotRequired(true);
nvTable.setRequestedMaxFrequency(1.0);
nvTable.setDataAdapter("DEMO");
pushPage.addTable(nvTable , "nlist");
nvTable.onItemUpdate = function(itemIndex,update,itemName) {
document.getElementById("testnon").innerHTML =update.getNewValue("last_price");

}
</script></body></html>

My Meta adapter needs to determine both group and schema.

package stocklist_demo.adapters;

import com.lightstreamer.interfaces.metadata.*;

/**
* Created by IntelliJ IDEA.
* User: admin
* Date: Feb 5, 2009
* Time: 5:25:10 PM
* To change this template use File | Settings | File Templates.
*/
public class MyMetaAdapter extends MetadataProviderAdapter {

public String[] getItems(String user, String session, String id) throws ItemsException {
//TODO return items depending on id
return new String[] {"item1","item2","item3"};
}

public String[] getSchema(String user, String session, String groupId, String schema) throws ItemsException, SchemaException {
//TODO return customized schema
return new String[] {"last_price", "ref_price", "open_price"};
}

public void notifyUser(String user, String password,java.util.Map httpHeaders) throws AccessException, CreditsException {
if (!authenticate(user, password)) {
throw new AccessException("Unauthorized user");
}

}

private boolean authenticate(String userName, String password){

//do authentication here
return true;
}

}

I use the StockListDemo_DataAdapter as it is.

My log looks like this.

**rd2008** · February 5th, 2009, 12:15 PM

i've attached the log file

Thanks

**rd2008** · February 6th, 2009, 05:47 AM

It works fine if I set the schema in the web client. But in my case I'm aiming to determine the schema in the meta adapter depending on the groupid and schema id.

**Mone** · February 6th, 2009, 09:10 AM

Hi,

the problem here is that your client doesn't know the names of your fields because you're creating your table with a schema name (string) instead of using a field list (array of strings)

this way you can't access the fields by name as the library doesn't know at all how the schema was expanded by your metadata adapter, but you should access them by index

let me know if you need further help.