Object representation of the node element.
   Object fields are:
    Scalar:     metadataIdRef, 
    Scalar:     id, 
    Object reference:   name => type HASH,
    Object reference:   hostName => type HASH,
    Object reference:   description => type HASH,
    Object reference:   location => type HASH,
    Object reference:   contact => type HASH,
    Object reference:   parameters => type HASH,
    Object reference:   port => type HASH,

   The constructor accepts only single parameter, it could be a hashref to parameters hash  or DOM with  'node' element 

    

              use perfSONAR_PS::Datatypes::v2_0::pingertopo::Topology::Domain::Node;

          my $el =  perfSONAR_PS::Datatypes::v2_0::pingertopo::Topology::Domain::Node->new($DOM_Obj);

      creates   object, accepts DOM with  element tree or hashref to the list of
      keyd parameters
         metadataIdRef   => undef, 
         id   => undef, 
         name => HASH,
         hostName => HASH,
         description => HASH,
         location => HASH,
         contact => HASH,
         parameters => HASH,
         port => HASH,

       accept parent DOM
       return node object DOM, generated from object contents 

      depending on config  it will return some hash ref  to the initialized fields
    for example querySQL ()
    accepts one optional prameter - query hashref
    will return:
    { ip_name_src =>  'hepnrc1.hep.net' },}

      merge with another node ( append + overwrite if exists )
      we can do it differently
      method #1:
         convert to dom both objects and then get resulted object from combined dom 
      method #2 default:
         through the introspection of the object

    if any of subelements has id then get a map of it in form of
    hashref to { element}{id} = index in array and store in the idmap field

   will parse all subelements and register all namepspaces within the node namespace

   Maxim Grigoriev (FNAL)  2007-2008, maxim@fnal.gov