question: static OptimizedClassDescriptor classDescriptor ( ConcurrentMap < Class , OptimizedClassDescriptor > clsMap , Class cls , MarshallerContext ctx , OptimizedMarshallerIdMapper mapper ) throws IOException { OptimizedClassDescriptor desc = clsMap . get ( cls ) ; if ( desc == null ) { int typeId = resolveTypeId ( cls . getName ( ) , mapper ) ; boolean registered ; try { registered = ctx . registerClass ( typeId , cls ) ; } catch ( IgniteCheckedException e ) { throw new IOException ( "Failed to register class: " + cls . getName ( ) , e ) ; } desc = new OptimizedClassDescriptor ( cls , registered ? typeId : 0 , clsMap , ctx , mapper ) ; if ( registered ) { OptimizedClassDescriptor old = clsMap . putIfAbsent ( cls , desc ) ; if ( old != null ) desc = old ; } } return desc ; }
target:  Gets descriptor for provided class.