code: @Override
  	public void documentStart() {
  		structure = new StructureImpl();
  
  		currentChain        = null;
  		currentGroup 		= null;
  		currentNmrModelNumber 	= null;
  		//atomCount     		= 0;
  
  		allModels     = new ArrayList<List<Chain>>();
  		currentModel  = new ArrayList<Chain>();
  		entities      = new ArrayList<Entity>();
  		entityPolys   = new ArrayList<>();
  		strucRefs     = new ArrayList<StructRef>();
  		seqResChains  = new ArrayList<Chain>();
  		entityChains  = new ArrayList<Chain>();
  		structAsyms   = new ArrayList<StructAsym>();
  
  		asymId2entityId = new HashMap<String,String>();
  		asymId2authorId = new HashMap<>();
  		structOpers   = new ArrayList<PdbxStructOperList>();
  		strucAssemblies = new ArrayList<PdbxStructAssembly>();
  		strucAssemblyGens = new ArrayList<PdbxStructAssemblyGen>();
  		entitySrcGens = new ArrayList<EntitySrcGen>();
  		entitySrcNats = new ArrayList<EntitySrcNat>();
  		entitySrcSyns = new ArrayList<EntitySrcSyn>();
  		structConn = new ArrayList<StructConn>();
  		structNcsOper = new ArrayList<StructNcsOper>();
  		sequenceDifs = new ArrayList<StructRefSeqDif>();
  		structSiteGens = new ArrayList<StructSiteGen>();
  	}
docs: Start the parsing