How to fetch the latest events on lead records without using query?

Question

I have a Map where key is event id and value is the event, Map. These events are created on Lead object. And this Map may contain more than one event created on Lead records. My requirement is to create a new Map that includes only the most recent event per Lead without using any query.

Answer 1

Map<Id,Event> ObjYourMAp  = new Map<Id,Event>();
// add some values in Map 
Map <Id,Event> MapLeadEvent = new Map <Id,Event>();
for(Event objEvt : ObjYourMAp.Values())
{
    //-----------------getObjectName
    String sObjName = (objEvt.WhoId).getSObjectType().getDescribe().getName();
    if(sObjName == 'Lead')
    {
        if(MapLeadEvent != null && MapLeadEvent.containsKey(objEvt.Id) )
        {
            if(MapLeadEvent.get(objEvt.Id).CreatedDate < objEvt.CreatedDate)    
                MapLeadEvent.put(objEvt.WhoId,objEvt);
        }
        else
        {
            MapLeadEvent.put(objEvt.WhoId,objEvt);
        }
    }
}