[ROOT] How to write lists of objects?

From: Thomas Bretz (tbretz@uni-sw.gwdg.de)
Date: Mon Nov 12 2001 - 12:45:43 MET 

Hello rooters,

I want to order some objects in a list, like:
    TList *list = new TList;
    TEllipse *ell = new TEllipse;
    TLine    *lin = new TLine;
    list->Add(ell);
    list->Add(lin);

Now I want to write this list of objects to a root file, like:
    TFile f1("test.root", "RECREATE");
    TTree *t = new TTree("List", "My List");
    t->Branch("TList", "TList", &list, 32000, 9);
    t->Fill();
    f1.Write();
    f1.Close();

And read the list again, like:
    TFile f2("test.root", "READ");
    t = (TTree*)f2.Get("List");
    t->GetBranch("TList")->SetAddress(&list);
    t->GetEntry(0);
    list->Print();

But this fails (as I understand, because of ClassDef(TSeqCollection,
0)). Is there a way to write such a list and get it back as one entry?

The idea is to have a list which stores several objects describing a
program setup (like the gui elements above, which are describing a
graphical setup). I want to be able to store and read this setup with a
single expression.

Thanks alot,
Thomas.

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