Identify when the selected row in the table is already selected - jsf-2

Question

I have a p:datatable in primefaces and i have different listeners for differents ways to select row event in datatable.
I need identify when the selected row in the table is already selected, how can i do that?
I need this because i dont wonna that p:blockUI runs when i select row in the table that is already selected.
There is my page code:
...
<pe:blockUI autoShow="true"
source="itemsDT"
event="rowSelect"
target=":processTab">
<au:loading />
</pe:blockUI>
<p:dataTable widgetVar="processesTable"
id="itemsDT"
var="item"
value="
{tasksbacking2.availableProcesses}"
selection="#{tasksbacking2.selectedProcess}"
rowKey="#{item.id}"
tableStyleClass="table
table-condensed table-bordered"
resizableColumns="true">
<p:ajax event="rowSelect"
listener="#{tasksbacking2.onClickFillDetails}"
update="#this,:processTab,:menuForm:menuBar" />
...
</p:dataTable>
...
On managed bean i have this listener:
...
public void onClickFillDetails(SelectEvent event) {
AnoProcess clickedProcess = (AnoProcess) event.getObject();
setSelectedProcess(clickedProcess);
Movement currentMovement = this.getProcessesLastMovement().get(clickedProcess);
if (currentMovement != null && !currentMovement.isViewed()) {
markAsRead(processes);
}
...
}

Answer 1

Here is the script to check for duplicate click on same row.
Put this script below your p:dataTable code.
<script type="text/javascript">
var prevRow ;
function checkDupRowClick(){
var currRow = $('tr.ui-widget-content.ui-datatable-selectable[aria-selected="true"]');
if($(currRow).is($(prevRow))){
//selected or clicked same row so return FALSE to prevent p:ajax from executing
return false;
}else{
//selected or clicked different row so return TRUE to allow p:ajax to execute
prevRow = currRow;
return true;
}
}
</script>
AND use function as a return parameter for p:ajax
<p:ajax event="rowSelect" onstart="return checkDupRowClick();" />
Post comment if you require more explanation.

Answer 2

I think that you need is some function in js and apply this in onstart.
like that
<p:ajax event="rowSelect" onstart="???" />