class TXMLPlayer: public TObject

 Class for xml code generation
 It should be used for generation of xml steramers, which could be used outside root
 environment. This means, that with help of such streamers user can read and write
 objects from/to xml file, which later can be accepted by ROOT.

 At the moment supported only classes, which are not inherited from TObject
 and which not contains any TObject members.

 To generate xml code:

 1. ROOT library with required classes should be created.
    In general, without such library non of user objects can be stored and
    retrived from any ROOT file

 2. Generate xml streamers by root script like:

    void generate() {
      gSystem->Load("libRXML.so");   // load ROOT xml library
      gSystem->Load("libuser.so");   // load user ROOT library

      TList lst;
      lst.Add(TClass::GetClass("TUserClass1"));
      lst.Add(TClass::GetClass("TUserClass2"));

      TXMLPlayer player;
      player.ProduceCode(&lst, "streamers");    // create xml streamers
    }

  3. Copy "streamers.h", "streamers.cxx", "TXmlFile.h", "TXmlFile.cxx" files
     to user project and compile them. TXmlFile class implementation can be taken
     from http://www-linux.gsi.de/~linev/xmlfile.tar.gz

 TXMLPlayer class generates one function per class, which called class streamer.
 Name of such function for class TExample will be TExample_streamer.

 Following data members for streamed classes are supported:
  - simple data types (int, double, float)
  - array of simple types (int[5], double[5][6])
  - dynamic array of simple types (int* with comment field // [fSize])
  - const char*
  - object of any nonROOT class
  - pointer on object
  - array of objects
  - array of pointers on objects
  - stl string
  - stl vector, list, deque, set, multiset, map, multimap
  - allowed arguments for stl containers are: simple data types, string, object, pointer on object
  Any other data member can not be (yet) read from xml file and write to xml file.

 If data member of class is private or protected, it can not be accessed via
 member name. Two alternative way is supported. First, if for class member fValue
 exists function GetValue(), it will be used to get value from the class, and if
 exists SetValue(), it will be used to set apropriate data member. Names of setter
 and getter methods can be specified in comments filed like:

     int  fValue;   // *OPTION={GetMethod="GetV";SetMethod="SetV"}

 If getter or setter methods does not available, address to data member will be
 calculated as predefined offeset to object start address. In that case generated code
 should be used only on the same platform (OS + compiler), where it was generated.

 Generated streamers resolve inheritance tree for given class. This allows to have
 array (or vector) of object pointers on some basic class, while objects of derived
 class(es) are used.

 To access data from xml files, user should use TXmlFile class, which is different from
 ROOT TXMLFile, but provides very similar functionality. For example, to read
 object from xml file:

        TXmlFile file("test.xml");             // open xml file
        file.ls();                             // show list of keys in file
        TExample* ex1 = (TExample*) file.Get("ex1", TExample_streamer); // get object
        file.Close();

 To write object to file:

        TXmlFile outfile("test2.xml", "recreate");    // create xml file
        TExample* ex1 = new TExample;
        outfile.Write(ex1, "ex1", TExample_streamer);   // write object to file
        outfile.Close();

 Complete example for generating and using of external xml streamers can be taken from
 http://www-linux.gsi.de/~linev/xmlreader.tar.gz

 Any bug reports and requests for additional functionality are welcome.

 Sergey Linev, S.Linev@gsi.de