Create a VO for the query which is given below through this you can get the current diagram url,
select WF_MONITOR.GetDiagramURL(WF_CORE.Translate('WF_WEB_AGENT'),NtfEO.MESSAGE_TYPE,NtfEO.ITEM_KEY,'NO') monitor_url from
(SELECT ITEM_KEY,MESSAGE_TYPE FROM WF_NOTIFICATIONS WHERE NOTIFICATION_ID = :1) NtfEO
Steps:
1.First find the button component of your page.
2.Call VO with the input parameters which will return the diagram url.
3.Put that url into the java script function.
4.Through the java script you can open a new popup window which will display the status monitor diagram
Sample Code:
OASubmitButtonBean reAssignBea1n = (OASubmitButtonBean) paramOAWebBean.findChildRecursive("WfMonDiagramCtrl");
Serializable[] parameters1 = { NotificationId };
Serializable aa1 = am.invokeMethod("getMonitorURL", parameters1);
if (aa1 != null && !aa1.toString().equals(""))
{
String url = "window.open('" + aa1.toString() + "')";
paramOAPageContext.putJavaScriptFunction("LaunchMonitor", url);
}
Source:http://anuj-oaframeworkblog.blogspot.in/2009/09/open-workflow-status-monitor-diagram.html