Iterating in Discrete Event System

Hi,

can somone show me how I can iterate over a FIFO storage and forward the entiyty which entered first. I´m iterating over a storage using function [entity, event, next] = entityIterate how can I tell the allgorithm to forward the entity with a specific attribute which has the longest waiting time to a specific output. I´ve coded it like this but the problem is that it´s forwards the first entity it found (the one which entered last) but I need it to forward the one who entered first:

function [entity, event, next] = entityIterate(obj,~,entity,~,~)

event=obj.initEventArray;

if entity.data.Attribute==1

event=obj.eventForward('output',3,0);

next=false;

else

next=true;

end