Athena Developer Guide

Athena
Chapter 8 StoreGate - the event data access model Version/Issue: 2.0.0
Typically MyDataObj will be a collection containing several objects. You may iterate over these
Contained Objects using the code shown in Listing 8.10:
Listing 8.10 Iterate over Contained Objects
MyDataObj::iterator first = dhandle->begin();
MyDataObj::iterator last = dhandle->end();
for (; first != last; ++first)
{
(*first)->use_me();
}
where (*first) is the pointer to the Contained Object; use_me() is a method in this Contained Object
and ++first iterates over the Contained Objects.
8.6.2 Retrieving a keyed DataObject
In the WriteData example, three MyDataObj were recorded in the TDS, but only one with a key. The
key was a string key containing “MyDataObjName”. Here we will show how to retrieve that
DataObject. Note that since no other MyDataObj can be registered with a key “MyDataObjName”, you
will retrieve at most one object. Note further that this is not necessarily the last DataObject of this type
recorded in the TDS.
Listing 8.11 Retrieve a keyed DataObject
std::string keystring = "MyDataObjName";
DataHandle dhandle; //non-const access required. May fail!!!
StatusCode sc = storeGateSvc()->retrieve(dhandle,keystring);
if (sc.isFailure())
{
log