Hello,
I want to display a grid that is updated say each 5s on on user action with data that comes from a servlet. The servlet answers a JSON array that I get thru a dataSource. The JSON array contains messages that are added slowly.
I want my grid to be updated according to the content of the json. I have filters in my page to drive the access to the servlet.
example: I want all the messages of this kind of today. The filtering is performed in the serverside.
The url to acces is like “my-servlet?fromDate=20101021&kind=WARN” according to the filter.
What is the best practice to do that? below, I have put the piece of code I tried (method query is called). My grid does not change. The callback returns a com.google.gwt.core.client.JavaScriptObject, I don’t know what to do with it.
Thank’s for helping me start with smartGWT
package com.airbus.mcctls.client;
import java.util.HashMap;
import java.util.Map;
import org.apache.tools.ant.types.CommandlineJava.SysProperties;
import com.smartgwt.client.data.DSCallback;
import com.smartgwt.client.data.DSRequest;
import com.smartgwt.client.data.DSResponse;
import com.smartgwt.client.data.DataSource;
import com.smartgwt.client.data.DataSourceField;
import com.smartgwt.client.data.fields.DataSourceDateTimeField;
import com.smartgwt.client.data.fields.DataSourceTextField;
import com.smartgwt.client.types.Alignment;
import com.smartgwt.client.types.DSDataFormat;
import com.smartgwt.client.types.ListGridFieldType;
import com.smartgwt.client.widgets.grid.ListGrid;
import com.smartgwt.client.widgets.grid.ListGridField;
public class MessageGrid extends ListGrid{
private DataSource dataSource = null;
public MessageGrid() {
dataSource = new DataSource();
dataSource.setDataFormat(DSDataFormat.JSON);
dataSource.setDataURL("my-servlet?fromDate=20101021");
DataSourceTextField msnSrc = new DataSourceTextField(
"EXT_AIRCRAFT_MSN", "MSN");
DataSourceTextField airlineSrc = new DataSourceTextField(
"EXT_AIRLINE_IDENTIFIER", "Airline");
DataSourceTextField acTypeSrc = new DataSourceTextField(
"EXT_AIRCRAFT_FAMILY", "AcType");
DataSourceTextField msgTypeSrc = new DataSourceTextField(
"TYPE_IDENTIFIER", "Type");
DataSourceTextField tailNumberSrc = new DataSourceTextField(
"MSG_AIRCRAFT_TAILNUMBER", "Id");
DataSourceDateTimeField timeSrc = new DataSourceDateTimeField(
"MSG_UTC_TRANSMISSION_DATE_TIME", "time");
dataSource .setFields(timeSrc, airlineSrc, tailNumberSrc, msnSrc,
acTypeSrc, msgTypeSrc);
//airline column
ListGridField airlineField = defaultField(airlineSrc);
airlineField.setAlign(Alignment.CENTER);
airlineField.setWidth(40);
airlineField.setType(ListGridFieldType.IMAGE);
airlineField.setImageURLPrefix("airline/icon/");
airlineField.setImageURLSuffix(".gif");
ListGridField timeField = defaultField (timeSrc);
timeField.setWidth(125);
timeField.setAlign(Alignment.CENTER);
ListGridField acTypeField = defaultField(acTypeSrc);
acTypeField.setWidth(50);
ListGridField msnField = defaultField(msnSrc);
msnField.setWidth(50);
ListGridField tailNumberField = defaultField(tailNumberSrc);
tailNumberField.setWidth(50);
ListGridField msgTypeField = defaultField(msgTypeSrc);
msgTypeField.setWidth(50);
setFields(timeField, airlineField, tailNumberField, msnField, acTypeField, msgTypeField);
setDataSource(dataSource );
setAutoFetchData(true);
}
private ListGridField defaultField(DataSourceField src) {
return new ListGridField(src.getName(), src.getTitle());
}
public void query() {
DSCallback callback = new DSCallback() {
@Override
public void execute(DSResponse response, Object rawData, DSRequest request) {
System.out.println(rawData);
//what have I to do?
}
};
DSRequest request = new DSRequest();
Map<String, String> params = new HashMap<String, String>();
params.put("kind",//getTheKind);
params.put("fromDate",//getTheFromDate);
request.setParams(params);
dataSource.fetchData(null, callback, request);
}
}
version:
SmartGWT 2.2 / Firefox 3.6