How to use the queue.alertThresholdMessageSize function in queue

thisObj.updateHeader();


                       // update alerting info
                       var alertRepeatGap = formatter.formatTime( thisObj.vhostData["queue.alertRepeatGap"] );

                       thisObj.alertRepeatGap.innerHTML = alertRepeatGap.value;
                       thisObj.alertRepeatGapUnits.innerHTML = alertRepeatGap.units;


                       var alertMsgAge = formatter.formatTime( thisObj.vhostData["queue.alertThresholdMessageAge"] );

                       thisObj.alertThresholdMessageAge.innerHTML = alertMsgAge.value;
                       thisObj.alertThresholdMessageAgeUnits.innerHTML = alertMsgAge.units;

                       var alertMsgSize = formatter.formatBytes( thisObj.vhostData["queue.alertThresholdMessageSize"] );

                       thisObj.alertThresholdMessageSize.innerHTML = alertMsgSize.value;
                       thisObj.alertThresholdMessageSizeUnits.innerHTML = alertMsgSize.units;

                       var alertQueueDepth = formatter.formatBytes( thisObj.vhostData["queue.alertThresholdQueueDepthBytes"] );

                       thisObj.alertThresholdQueueDepthBytes.innerHTML = alertQueueDepth.value;
                       thisObj.alertThresholdQueueDepthBytesUnits.innerHTML = alertQueueDepth.units;

                       thisObj.alertThresholdQueueDepthMessages.innerHTML = entities.encode(String(thisObj.vhostData["queue.alertThresholdQueueDepthMessages"]));

                       var stats = thisObj.vhostData[ "statistics" ];

                       var sampleTime = new Date();
                       var messageIn = stats["messagesIn"];
                       var bytesIn = stats["bytesIn"];