protected ParameterRepresentation(IOidStrategy oidStrategy, HttpRequestMessage req, IObjectFacade objectFacade, IActionParameterFacade parameter, RestControlFlags flags)
     : base(oidStrategy, flags) {
     SetName(parameter);
     SetExtensions(req, objectFacade, parameter, flags);
     SetLinks(req, objectFacade, parameter);
     SetHeader(objectFacade);
 }

        private LinkRepresentation CreatePromptLink(HttpRequestMessage req, IObjectFacade objectFacade, IActionParameterFacade parameter) {
            var opts = new List<OptionalProperty>();

            var parameterContext = new ParameterContextFacade {
                Action = parameter.Action,
                Target = objectFacade,
                Parameter = parameter
            };

            if (parameter.IsAutoCompleteEnabled) {
                var arguments = new OptionalProperty(JsonPropertyNames.Arguments, MapRepresentation.Create(new OptionalProperty(JsonPropertyNames.XRoSearchTerm, MapRepresentation.Create(new OptionalProperty(JsonPropertyNames.Value, null, typeof (object))))));
                var extensions = new OptionalProperty(JsonPropertyNames.Extensions, MapRepresentation.Create(new OptionalProperty(JsonPropertyNames.MinLength, parameter.AutoCompleteMinLength)));

                opts.Add(arguments);
                opts.Add(extensions);
            }
            else {
                Tuple<string, ITypeFacade>[] parms = parameter.GetChoicesParameters();
                OptionalProperty[] args = parms.Select(tuple => RestUtils.CreateArgumentProperty(OidStrategy ,req, tuple, Flags)).ToArray();
                var arguments = new OptionalProperty(JsonPropertyNames.Arguments, MapRepresentation.Create(args));
                opts.Add(arguments);
            }

            return LinkRepresentation.Create(OidStrategy ,new PromptRelType(new UriMtHelper(OidStrategy ,req, parameterContext)), Flags, opts.ToArray());
        }

 public UriMtHelper(IOidStrategy oidStrategy, HttpRequestMessage req, IObjectFacade objectFacade) : this(oidStrategy ,req) {
     this.objectFacade = objectFacade;
     spec = objectFacade.Specification;
     IOidTranslation oid = oidStrategy.FrameworkFacade.OidTranslator.GetOidTranslation(objectFacade);
     cachedId = oid.InstanceId;
     CachedType = oid.DomainType;
 }

 public static string GetMaskedValue(this ISpecification spec, IObjectFacade objectFacade, INakedObjectManager nakedObjectManager) {
     if (objectFacade == null) {
         return null;
     }
     var mask = spec.GetFacet<IMaskFacet>();
     var no = ((ObjectFacade) objectFacade).WrappedNakedObject;
     return mask != null ? no.Spec.GetFacet<ITitleFacet>().GetTitleWithMask(mask.Value, no, nakedObjectManager) : no.TitleString();
 }

        protected ListRepresentation(IOidStrategy oidStrategy, IObjectFacade list, HttpRequestMessage req, RestControlFlags flags, ActionContextFacade actionContext)
            : base(oidStrategy, flags) {
            Value = list.ToEnumerable().Select(no => CreateObjectLink(oidStrategy, req, no, actionContext)).ToArray();

            SetLinks(req, actionContext);
            SetExtensions(oidStrategy, actionContext);
            SetHeader(false);
        }

        public string GetOidAsString(IObjectFacade nakedObject) {
            // don't know if services need to be handled differently 

            //if (nakedObject.Specification.IsService) {
            //    return nakedObject.Specification.FullName; 
            //}
            return nakedObject.Oid.ToString();
        }

        private void SetLinks(HttpRequestMessage req, IObjectFacade objectFacade, FieldFacadeAdapter parameter) {
            var tempLinks = new List<LinkRepresentation>();

            if (parameter.IsAutoCompleteEnabled || parameter.GetChoicesParameters().Any()) {
                tempLinks.Add(CreatePromptLink(req, objectFacade, parameter));
            }

            Links = tempLinks.ToArray();
        }

        public IOidTranslation GetOidTranslation(IObjectFacade objectFacade) {
            if (objectFacade.IsViewModel) {
                var vm = ((ObjectFacade) objectFacade).WrappedNakedObject;
                framework.LifecycleManager.PopulateViewModelKeys(vm);
            }

            Tuple<string, string> codeAndKey = GetCodeAndKeyAsTuple(objectFacade);
            return new OidTranslationSlashSeparatedTypeAndIds(codeAndKey.Item1, codeAndKey.Item2);
        }

 public UriMtHelper(IOidStrategy oidStrategy, HttpRequestMessage req, IObjectFacade objectFacade, string instanceId) : this(oidStrategy, req) {
     this.objectFacade = objectFacade;
     spec = objectFacade.Specification;
     if (objectFacade.Specification.IsParseable) {
         throw new ArgumentException($"Cannot build URI  for parseable specification : {objectFacade.Specification.FullName}");
     }
     IOidTranslation oid = oidStrategy.FrameworkFacade.OidTranslator.GetOidTranslation(objectFacade);
     cachedId = instanceId;
     CachedType = oid.DomainType;
 }

        public IOidTranslation GetOidTranslation(IObjectFacade objectFacade) {
            if (objectFacade.IsViewModel) {
                var vm = ((ObjectFacade) objectFacade).WrappedNakedObject;
                lifecycleManager.PopulateViewModelKeys(vm);
            }

            var oid = objectFacade.Oid;
            var id = GetObjectId(oid);
            return GetOidTranslation(id);
        }

        public UriMtHelper GetHelper(IOidStrategy oidStrategy, HttpRequestMessage req, IObjectFacade objectFacade) {
            if (parameter != null) {
                var parameterContext = new ParameterContextFacade {
                    Action = parameter.Action,
                    Target = objectFacade,
                    Parameter = parameter
                };
                return new UriMtHelper(oidStrategy, req, parameterContext);
            }

            return new UriMtHelper(oidStrategy, req, association);
        }

        public string GetObjectId(IObjectFacade objectFacade) {
            INakedObjectAdapter owner = objectFacade.WrappedAdapter();
            string postFix = "";

            if (owner.Spec.IsCollection) {
                var elementFacet = owner.Spec.GetFacet<ITypeOfFacet>();
                var elementType = elementFacet.GetValue(owner);

                postFix = Sep + elementType.Name;
            }

            return owner.Spec.ShortName + postFix;
        }

        protected string GetKeyValues(IObjectFacade nakedObjectForKey) {
            string[] keys;
            INakedObjectAdapter wrappedNakedObject = ((ObjectFacade) nakedObjectForKey).WrappedNakedObject;

            if (wrappedNakedObject.Spec.IsViewModel) {
                keys = wrappedNakedObject.Spec.GetFacet<IViewModelFacet>().Derive(wrappedNakedObject, framework.NakedObjectManager, framework.DomainObjectInjector);
            }
            else {
                PropertyInfo[] keyPropertyInfo = nakedObjectForKey.GetKeys();
                keys = keyPropertyInfo.Select(pi => KeyRepresentation(pi.GetValue(nakedObjectForKey.Object, null))).ToArray();
            }

            return GetKeyCodeMapper().CodeFromKey(keys, nakedObjectForKey.Object.GetType());
        }

        private void SetExtensions(HttpRequestMessage req, IObjectFacade objectFacade, FieldFacadeAdapter parameter, RestControlFlags flags) {
            IDictionary<string, object> custom = null;

            if (IsUnconditionalChoices(parameter)) {
                custom = new Dictionary<string, object>();

                Tuple<IObjectFacade, string>[] choices = parameter.GetChoicesAndTitles(objectFacade, null);
                Tuple<object, string>[] choicesArray = choices.Select(tuple => new Tuple<object, string>(parameter.GetChoiceValue(OidStrategy, req, tuple.Item1, flags), tuple.Item2)).ToArray();

                OptionalProperty[] op = choicesArray.Select(tuple => new OptionalProperty(tuple.Item2, tuple.Item1)).ToArray();
                MapRepresentation map = MapRepresentation.Create(op);
                custom[JsonPropertyNames.CustomChoices] = map;
            }

            string mask = parameter.Mask;

            if (!string.IsNullOrWhiteSpace(mask)) {
                custom = custom ?? new Dictionary<string, object>();
                custom[JsonPropertyNames.CustomMask] = mask;
            }

            var multipleLines = parameter.NumberOfLines;

            if (multipleLines > 1) {
                custom = custom ?? new Dictionary<string, object>();
                custom[JsonPropertyNames.CustomMultipleLines] = multipleLines;
            }

            custom = RestUtils.AddRangeExtension(parameter.AsField, custom);

            Extensions = RestUtils.GetExtensions(friendlyname: parameter.Name,
                                                  description: parameter.Description,
                                                  pluralName: null,
                                                  domainType: null,
                                                  isService: null,
                                                  hasParams: null,
                                                  optional: !parameter.IsMandatory,
                                                  maxLength: parameter.MaxLength,
                                                  pattern: parameter.Pattern,
                                                  memberOrder: null,
                                                  dataType: parameter.DataType,
                                                  presentationHint: parameter.PresentationHint,
                                                  customExtensions: custom,
                                                  returnType: parameter.Specification,
                                                  elementType: parameter.ElementType,
                                                  oidStrategy: OidStrategy,
                                                  useDateOverDateTime: true);
        }

        // custom extension for pagination 
        private void SetPagination(IObjectFacade list, RestControlFlags flags) {
            Pagination = new MapRepresentation();

            var totalCount = list.Count();
            var pageSize = flags.PageSize ;
            var page = flags.Page;
            var numPages = (int)Math.Round(totalCount / (decimal)pageSize + 0.5m);
            numPages = numPages == 0 ? 1 : numPages;

            var exts = new Dictionary<string, object> {
                {"page", page},
                {"pageSize", pageSize},
                {"numPages", numPages},
                {"totalCount", totalCount}
            };

            Pagination = RestUtils.CreateMap(exts);
        }

        // custom extension for pagination 
        private void SetPagination(IObjectFacade list, RestControlFlags flags, ActionContextFacade actionContext) {
            Pagination = new MapRepresentation();

            var totalCount = list.Count();
            var pageSize = PageSize(flags, actionContext);
            var page = flags.Page;
            var numPages = (int) Math.Round(totalCount/(decimal) pageSize + 0.5m);
            numPages = numPages == 0 ? 1 : numPages;

            var exts = new Dictionary<string, object> {
                {JsonPropertyNames.Page, page},
                {JsonPropertyNames.PageSize, pageSize},
                {JsonPropertyNames.NumPages, numPages},
                {JsonPropertyNames.TotalCount, totalCount}
            };

            Pagination = RestUtils.CreateMap(exts);
        }

        private void SetLinks(HttpRequestMessage req, IObjectFacade objectFacade, IActionParameterFacade parameter) {
            var tempLinks = new List<LinkRepresentation>();


            if (Flags.FormalDomainModel) {
                var parameterTypeContext = new ParameterTypeContextFacade {
                    Action = parameter.Action,
                    OwningSpecification = objectFacade.Specification,
                    Parameter = parameter
                };
                LinkRepresentation describedBy = LinkRepresentation.Create(OidStrategy ,new ParamTypeRelType(RelValues.DescribedBy, new UriMtHelper(OidStrategy, req, parameterTypeContext)), Flags);
                tempLinks.Add(describedBy);
            }

            if (parameter.IsAutoCompleteEnabled || parameter.GetChoicesParameters().Any()) {
                tempLinks.Add(CreatePromptLink(req, objectFacade, parameter));
            }

            Links = tempLinks.ToArray();
        }

        public string GetActionId(string propertyName, IActionFacade actionContextActionFacade, IObjectFacade actionObjectFacade, IObjectFacade targetObjectFacade, IActionFacade targetActionFacade) {
            IActionSpec actionContextAction = actionContextActionFacade == null ? null :  actionContextActionFacade.WrappedSpec();
            INakedObjectAdapter actionContextTarget = actionObjectFacade == null ? null : actionObjectFacade.WrappedAdapter();
            IActionSpec targetActionContextAction = targetActionFacade == null ? null : targetActionFacade.WrappedSpec();
            INakedObjectAdapter targetActionContextTarget = targetObjectFacade == null ? null : targetObjectFacade.WrappedAdapter();

            string contextActionName = actionContextAction == null ? "" : actionContextAction.Id + Sep;
            string contextNakedObjectId = actionContextTarget == null || actionContextTarget == targetActionContextTarget ? "" : GetObjectId(actionObjectFacade) + Sep;
            string propertyId = string.IsNullOrEmpty(propertyName) ? "" : NameUtils.CapitalizeName(propertyName) + Sep;
            return contextNakedObjectId + contextActionName + propertyId + GetObjectId(targetObjectFacade) + Sep + targetActionContextAction.Id;
        }

 public string GetConcurrencyActionInputId(IObjectFacade owner, IActionFacade action, IAssociationFacade assocFacade) {
     IAssociationSpec assoc =  assocFacade.WrappedSpec();
     return GetActionId(owner, action) + Sep + assoc.Id + Sep + ConcurrencyName;
 }

 public string GetInlineConcurrencyFieldInputId(IAssociationFacade parent, IObjectFacade owner, IAssociationFacade assoc) {
     return GetInlineFieldId(parent, owner, assoc) + Sep + ConcurrencyName;
 }