How to get PickList Values of a field in apex salesforce

Schema.DescribeFieldResult optyStages = Opportunity.stagename.getDescribe();
List<Schema.PicklistEntry> studentStatusValues = optyStages.getPicklistValues();
Map<string,integer> optystageOrderMap= new Map<string,integer>();
integer  i=0;
for(Schema.PicklistEntry item:studentStatusValues)
{
if(item.isActive())
optystageOrderMap.put(item.getLabel(),++i) ;
}