Yes, I'm using DWR.
The way I do it, is, I have an interface which provides all the data that ColumnModels and DataModels need.
public interface ListProvider
{
public String getId();
public void close();
public ListColumn[] getColumnModel();
public long getRowCount();
public boolean setPosition(int row);
public boolean hasMore();
public Object[] getNext();
public Object[] get(int rowIndex);
public Object[] getBlock(int startRow, int blockSize);
public Object[] refresh(int startRow, int blockSize);
public Object[] refresh(String paramString, int startRow, int blockSize);
public Object[] orderBy(int columnIndex, String order, int startRow, int blockSize);
public void moveColumn(int from, int to);
public void hideColumn(int col);
public void setColumnWidth(int col, int width);
}
As you can see, everything needed by the Model objects is provided there.
I have a ListHelper class which is exported to DWR which provides a createListProvider call taking a class name as a parameter, and a uurlencoded string of parameters which is passed to the constructor. We're using Hibernate here, so the implementation of ListProvider is quite easy - just cobble up a bunch of HQL.
The ListHelper class exports all the methods of ListProvider taking the created ListProvider's ID as the 1st parameter.
ListHelper:
public class ListHelper
{
public static String create(String className, String id, String uurlEncodedParams) throws Exception
{
WebContext w = WebContextFactory.get();
HttpServletRequest request = w.getHttpServletRequest();
HttpSession session = w.getSession();
Locale locale = request.getLocale();
Principal principal = request.getUserPrincipal();
Class c = Class.forName(className);
Constructor con = c.getConstructor(String.class, String.class, Locale.class, Principal.class, HttpSession.class);
String result = null;
try
{
// Create an instance of the requested ListProvider implementation. This stores itself in the HttpSession
// under the passed ID (Same as the ID of the yui-ext Grid). All calls to it are routed through the methods below.
result = ((ListProvider)con.newInstance(id, uurlEncodedParams, locale, principal, session)).getId();
}
catch (InvocationTargetException e)
{
throw (Exception)e.getCause();
}
// Return the ID
return result;
}
// All the methods of ListProvider, taking the ID of the Provider as the 1st param:
public static ListColumn[] getColumnModel(String ListProviderId) throws Exception....
public static long getRowCount(String ListProviderId) throws Exception....
The Column Model is returned as an array of ListColumn objects which exactly match the object array which initializes DefaultColumnModel, so that gets passed right in.
The ListProvider implementation is stashed in the session under the passed ID (which is this id of the grid, so that everything matches up and debugging is easier), and DWR calls are routed through the ListHelper class which exports all the ListProvider methods pefixed by an ID, so that you can have mulitple grid, and communicate with the ListProvider that;s appropriate.
dwr.xml:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE dwr PUBLIC "-//GetAhead Limited//DTD Direct Web Remoting 2.0//EN" "http://www.getahead.ltd.uk/dwr/dwr20.dtd">
<dwr>
<allow>
<create creator="new" javascript="ListHelper">
<param name="class" value="com.aspicio.util.ListHelper"/>
</create>
<convert converter="bean" match="com.aspicio.util.SearchResult"/>
<convert converter="bean" match="com.aspicio.util.ListColumn">
<param name="exclude" value="type"/>
</convert>
</allow>
</dwr>
[ListColumn]
package com.aspicio.util;
import javax.persistence.Entity;
import com.aspicio.beanInfo.Property;
public class ListColumn
{
private String header;
private int width;
private boolean hidden;
private int dataIndex;
private int visibleIndex;
private Property type;
public void setHeader(String header)
{
this.header = header;
}
public String getHeader()
{
return header;
}
public void setWidth(int width)
{
this.width = width;
}
public int getWidth()
{
return width;
}
public void setHidden(boolean hidden)
{
this.hidden = hidden;
}
public boolean isHidden()
{
return hidden;
}
public void setDataIndex(int dataIndex)
{
this.dataIndex = dataIndex;
}
public int getDataIndex()
{
return dataIndex;
}
public void setVisibleIndex(int visibleIndex)
{
this.visibleIndex = visibleIndex;
}
public int getVisibleIndex()
{
return visibleIndex;
}
public void setType(Property type)
{
this.type = type;
}
public Property getType()
{
return type;
}
public String getName()
{
return type.getFieldName();
}
public String getEntityName()
{
Class<?> c = type.getType();
return c.isAnnotationPresent(Entity.class) ? c.getSimpleName() : "";
}
public int getInputType()
{
return type.getInputType();
}
public String[] getSelectValues()
{
return type.getSelectValues();
}
}[/code]
It's so easy to pull data in with DWR, in my DataModel, loadPage is just a couple of statements:
YAHOO.ext.grid.AspicioDataModel.prototype.loadPage = function(pageNum, callback, keepExisting)
{
this.fireEvent('beforeload');
ListHelper.getBlock(this.listerId, (pageNum - 1) * this.pageSize, this.pageSize,
this.loadData.createDelegate(this, [pageNum, callback, keepExisting], 1));
};
and loadData is simple (apart from my grid has to have the ability to have checkboxes on each row to allow multiple entity operations):
YAHOO.ext.grid.AspicioDataModel.prototype.loadData = function(rowData, pageNum, callback, keepExisting)
{
var doCallback = (typeof callback == "function");
try
{
if (keepExisting !== true)
{
this.removeAll();
}
// Add "Selected" column
if (this.checkboxes)
{
for (var i = 0; i < rowData.length; i++)
rowData[i].unshift(false);
}
this.addRows(rowData);
this.loadedPage = pageNum;
}
catch (e)
{
YAHOO.widget.Logger.log(e.description + " at line " + e.lineNumber + " in " + e.fileName);
this.fireLoadException(e, null);
if(doCallback)
{
callback(this, false);
}
return;
}
// Call external code outside our try/catch. IT should handle its errors, not us.
this.fireLoadEvent();
if (doCallback)
{
callback(this, true);
}
};