How to Add Listener to cell in GXT Editable Grid

Question

I am writing code for Editable Grid using GXT.I created one column with TextField as Editor like below:

column=new ColumnConfig();
    column.setId("checkinTime");
    column.setHeader("Check In Time");
    column.setWidth(80);
    column.setMenuDisabled(true);
    column.setSortable(false);
    final TextField<String> text = new TextField<String>();  
    column.setEditor(new CellEditor(text));
    configs.add(column);

Now I need to add Listener to the cell of this column to validate the value of the cell and need to reset the value if validations fails.Please suggest how to do this.

I am using Gxt 2.2.3.

UPDATE Below are the imports

import com.extjs.gxt.ui.client.widget.grid.ColumnConfig;
import com.extjs.gxt.ui.client.widget.grid.ColumnModel;
import com.extjs.gxt.ui.client.widget.grid.EditorGrid;
import com.extjs.gxt.ui.client.widget.form.TextField;
import com.extjs.gxt.ui.client.widget.grid.CellEditor;