public ExprNode CompileValidate(
            string expression,
            EventType[] eventTypes,
            string[] streamNames)
        {
            var services = new StatementCompileTimeServices(0, moduleServices);

            ExprNode node;
            try {
                node = services.CompilerServices.CompileExpression(expression, services);
            }
            catch (ExprValidationException e) {
                throw new EPCompileException(
                    "Failed to compile expression '" + expression + "': " + e.Message,
                    e,
                    new EmptyList<EPCompileExceptionItem>());
            }

            try {
                ExprNodeUtilityValidate.ValidatePlainExpression(ExprNodeOrigin.API, node);

                StreamTypeService streamTypeService;

                if (eventTypes == null || eventTypes.Length == 0) {
                    streamTypeService = new StreamTypeServiceImpl(true);
                }
                else {
                    var istreamOnly = new bool[eventTypes.Length];
                    istreamOnly.Fill(true);
                    streamTypeService = new StreamTypeServiceImpl(eventTypes, streamNames, istreamOnly, true, false);
                }
                
                var statementRawInfo = new StatementRawInfo(
                    0,
                    "API-provided",
                    null,
                    StatementType.INTERNAL_USE_API_COMPILE_EXPR,
                    null,
                    null,
                    new CompilableEPL(expression),
                    "API-provided");
                var validationContext = new ExprValidationContextBuilder(streamTypeService, statementRawInfo, services).Build();
                node = ExprNodeUtilityValidate.GetValidatedSubtree(ExprNodeOrigin.API, node, validationContext);
            }
            catch (ExprValidationException e) {
                throw new EPCompileException(
                    "Failed to validate expression '" + expression + "': " + e.Message,
                    e,
                    new EmptyList<EPCompileExceptionItem>());
            }

            return node;
        }
Beispiel #2
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        private static EventAdvancedIndexProvisionCompileTime ValidateAdvanced(
            string indexName,
            string indexType,
            CreateIndexItem columnDesc,
            EventType eventType,
            StatementRawInfo statementRawInfo,
            StatementCompileTimeServices services)
        {
            // validate index expressions: valid and plain expressions
            StreamTypeService streamTypeService = new StreamTypeServiceImpl(eventType, null, false);
            var validationContextColumns =
                new ExprValidationContextBuilder(streamTypeService, statementRawInfo, services)
                    .WithDisablePropertyExpressionEventCollCache(true)
                    .Build();
            var columns = columnDesc.Expressions.ToArray();
            ExprNodeUtilityValidate.GetValidatedSubtree(
                ExprNodeOrigin.CREATEINDEXCOLUMN,
                columns,
                validationContextColumns);
            ExprNodeUtilityValidate.ValidatePlainExpression(ExprNodeOrigin.CREATEINDEXCOLUMN, columns);

            // validate parameters, may not depend on props
            ExprNode[] parameters = null;
            if (columnDesc.Parameters != null && !columnDesc.Parameters.IsEmpty()) {
                parameters = columnDesc.Parameters.ToArray();
                ExprNodeUtilityValidate.GetValidatedSubtree(
                    ExprNodeOrigin.CREATEINDEXPARAMETER,
                    parameters,
                    validationContextColumns);
                ExprNodeUtilityValidate.ValidatePlainExpression(ExprNodeOrigin.CREATEINDEXPARAMETER, parameters);

                // validate no stream dependency of parameters
                var visitor = new ExprNodeIdentifierAndStreamRefVisitor(false);
                foreach (var param in columnDesc.Parameters) {
                    param.Accept(visitor);
                    if (!visitor.Refs.IsEmpty()) {
                        throw new ExprValidationException("Index parameters may not refer to event properties");
                    }
                }
            }

            // obtain provider
            AdvancedIndexFactoryProvider provider;
            try {
                provider = services.ImportServiceCompileTime.ResolveAdvancedIndexProvider(indexType);
            }
            catch (ImportException ex) {
                throw new ExprValidationException(ex.Message, ex);
            }

            return provider.ValidateEventIndex(indexName, indexType, columns, parameters);
        }
        private static void ValidateExpression(ExprNode repeat)
        {
            ExprNodeUtilityValidate.ValidatePlainExpression(ExprNodeOrigin.MATCHRECOGPATTERN, repeat);

            if (!(repeat is ExprConstantNode)) {
                throw new ExprValidationException(
                    GetPatternQuantifierExpressionText(repeat) + " must return a constant value");
            }

            if (repeat.Forge.EvaluationType.GetBoxedType() != typeof(int?)) {
                throw new ExprValidationException(
                    GetPatternQuantifierExpressionText(repeat) + " must return an integer-type value");
            }
        }
Beispiel #4
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        public static ExprNode ValidateSimpleGetSubtree(
            ExprNodeOrigin origin,
            ExprNode expression,
            EventType optionalEventType,
            bool allowBindingConsumption,
            StatementRawInfo statementRawInfo,
            StatementCompileTimeServices services)
        {
            ExprNodeUtilityValidate.ValidatePlainExpression(origin, expression);

            StreamTypeServiceImpl streamTypes;
            if (optionalEventType != null) {
                streamTypes = new StreamTypeServiceImpl(optionalEventType, null, true);
            }
            else {
                streamTypes = new StreamTypeServiceImpl(false);
            }

            var validationContext = new ExprValidationContextBuilder(streamTypes, statementRawInfo, services)
                .WithAllowBindingConsumption(allowBindingConsumption)
                .Build();
            return ExprNodeUtilityValidate.GetValidatedSubtree(origin, expression, validationContext);
        }
Beispiel #5
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        private IList<StmtClassForgeableFactory> ValidateContextDetail(
            ContextSpec contextSpec,
            int nestingLevel,
            CreateContextValidationEnv validationEnv)
        {
            ISet<string> eventTypesReferenced = new HashSet<string>();
            IList<StmtClassForgeableFactory> additionalForgeables = new List<StmtClassForgeableFactory>();
            
            if (contextSpec is ContextSpecKeyed) {
                var segmented = (ContextSpecKeyed) contextSpec;
                IDictionary<string, EventType> asNames = new Dictionary<string, EventType>();
                var partitionHasNameAssignment = false;
                Type[] getterTypes = null;
                foreach (var partition in segmented.Items) {
                    Pair<FilterSpecCompiled, IList<StmtClassForgeableFactory>> pair = CompilePartitionedFilterSpec(
                        partition.FilterSpecRaw, eventTypesReferenced, validationEnv);
                    FilterSpecCompiled filterSpecCompiled = pair.First;
                    additionalForgeables.AddAll(pair.Second);
                   
                    partition.FilterSpecCompiled = filterSpecCompiled;

                    var getters = new EventPropertyGetterSPI[partition.PropertyNames.Count];
                    var serdes = new DataInputOutputSerdeForge[partition.PropertyNames.Count];
                    var eventType = (EventTypeSPI) filterSpecCompiled.FilterForEventType;
                    getterTypes = new Type[partition.PropertyNames.Count];
                    
                    for (var i = 0; i < partition.PropertyNames.Count; i++) {
                        var propertyName = partition.PropertyNames[i];
                        var getter = eventType.GetGetterSPI(propertyName);
                        if (getter == null) {
                            throw new ExprValidationException(
                                "For context '" + validationEnv.ContextName + "' property name '" + propertyName + "' not found on type " + eventType.Name);
                        }
                        getters[i] = getter;
                        getterTypes[i] = eventType.GetPropertyType(propertyName);
                        serdes[i] = validationEnv.Services.SerdeResolver.SerdeForFilter(
                            getterTypes[i], validationEnv.StatementRawInfo);
                    }

                    partition.Getters = getters;
                    partition.LookupableSerdes = serdes;

                    if (partition.AliasName != null) {
                        partitionHasNameAssignment = true;
                        ValidateAsName(asNames, partition.AliasName, filterSpecCompiled.FilterForEventType);
                    }
                }

                // plan multi-key, make sure we use the same multikey for all items
                MultiKeyPlan multiKeyPlan = MultiKeyPlanner.PlanMultiKey(
                    getterTypes, false, @base.StatementRawInfo, validationEnv.Services.SerdeResolver);
                additionalForgeables.AddAll(multiKeyPlan.MultiKeyForgeables);
                foreach (ContextSpecKeyedItem partition in segmented.Items) {
                    partition.KeyMultiKey = multiKeyPlan.ClassRef;
                }
                segmented.MultiKeyClassRef = multiKeyPlan.ClassRef;
                
                if (segmented.OptionalInit != null) {
                    asNames.Clear();
                    foreach (var initCondition in segmented.OptionalInit) {
                        ContextDetailMatchPair pair = ValidateRewriteContextCondition(
                            true,
                            nestingLevel,
                            initCondition,
                            eventTypesReferenced,
                            new MatchEventSpec(),
                            new EmptySet<string>(),
                            validationEnv);
                        additionalForgeables.AddAll(pair.AdditionalForgeables);

                        var filterForType = initCondition.FilterSpecCompiled.FilterForEventType;
                        var found = false;
                        foreach (var partition in segmented.Items) {
                            if (partition.FilterSpecCompiled.FilterForEventType == filterForType) {
                                found = true;
                                break;
                            }
                        }

                        if (!found) {
                            throw new ExprValidationException(
                                "Segmented context '" +
                                validationEnv.ContextName +
                                "' requires that all of the event types that are listed in the initialized-by also appear in the partition-by, type '" +
                                filterForType.Name +
                                "' is not one of the types listed in partition-by");
                        }

                        if (initCondition.OptionalFilterAsName != null) {
                            if (partitionHasNameAssignment) {
                                throw new ExprValidationException(
                                    "Segmented context '" +
                                    validationEnv.ContextName +
                                    "' requires that either partition-by or initialized-by assign stream names, but not both");
                            }

                            ValidateAsName(asNames, initCondition.OptionalFilterAsName, filterForType);
                        }
                    }
                }

                if (segmented.OptionalTermination != null) {
                    var matchEventSpec = new MatchEventSpec();
                    var allTags = new LinkedHashSet<string>();
                    foreach (var partition in segmented.Items) {
                        if (partition.AliasName != null) {
                            allTags.Add(partition.AliasName);
                            var eventType = partition.FilterSpecCompiled.FilterForEventType;
                            matchEventSpec.TaggedEventTypes[partition.AliasName] = new Pair<EventType,string>(
                                eventType, partition.FilterSpecRaw.EventTypeName);
                            var serdeForgeables = SerdeEventTypeUtility.Plan(
                                eventType,
                                validationEnv.StatementRawInfo,
                                validationEnv.Services.SerdeEventTypeRegistry,
                                validationEnv.Services.SerdeResolver);
                            additionalForgeables.AddAll(serdeForgeables);
                        }
                    }

                    if (segmented.OptionalInit != null) {
                        foreach (var initCondition in segmented.OptionalInit) {
                            if (initCondition.OptionalFilterAsName != null) {
                                allTags.Add(initCondition.OptionalFilterAsName);
                                matchEventSpec.TaggedEventTypes.Put(
                                    initCondition.OptionalFilterAsName,
                                    new Pair<EventType, string>(
                                        initCondition.FilterSpecCompiled.FilterForEventType,
                                        initCondition.FilterSpecRaw.EventTypeName));
                            }
                        }
                    }

                    var endCondition = ValidateRewriteContextCondition(
                        false,
                        nestingLevel,
                        segmented.OptionalTermination,
                        eventTypesReferenced,
                        matchEventSpec,
                        allTags,
                        validationEnv);
                    additionalForgeables.AddAll(endCondition.AdditionalForgeables);

                    segmented.OptionalTermination = endCondition.Condition;
                }
            }
            else if (contextSpec is ContextSpecCategory) {
                // compile filter
                var category = (ContextSpecCategory) contextSpec;
                ValidateNotTable(category.FilterSpecRaw.EventTypeName, validationEnv.Services);
                var raw = new FilterStreamSpecRaw(
                    category.FilterSpecRaw,
                    ViewSpec.EMPTY_VIEWSPEC_ARRAY,
                    null,
                    StreamSpecOptions.DEFAULT);

                var compiledDesc = StreamSpecCompiler.CompileFilter(
                    raw,
                    false,
                    false,
                    true,
                    false,
                    null,
                    validationEnv.StatementRawInfo,
                    validationEnv.Services);
                var result = (FilterStreamSpecCompiled) compiledDesc.StreamSpecCompiled;
                additionalForgeables.AddAll(compiledDesc.AdditionalForgeables);
                
                category.FilterSpecCompiled = result.FilterSpecCompiled;
                validationEnv.FilterSpecCompileds.Add(result.FilterSpecCompiled);

                // compile expressions
                foreach (var item in category.Items) {
                    ValidateNotTable(category.FilterSpecRaw.EventTypeName, validationEnv.Services);
                    var filterSpecRaw = new FilterSpecRaw(
                        category.FilterSpecRaw.EventTypeName,
                        Collections.SingletonList(item.Expression),
                        null);
                    var rawExpr = new FilterStreamSpecRaw(
                        filterSpecRaw,
                        ViewSpec.EMPTY_VIEWSPEC_ARRAY,
                        null,
                        StreamSpecOptions.DEFAULT);
                    var compiledDescItems = StreamSpecCompiler.CompileFilter(
                        rawExpr,
                        false,
                        false,
                        true,
                        false,
                        null,
                        validationEnv.StatementRawInfo,
                        validationEnv.Services);
                    var compiled = (FilterStreamSpecCompiled) compiledDescItems.StreamSpecCompiled;
                    additionalForgeables.AddAll(compiledDescItems.AdditionalForgeables);
                    compiled.FilterSpecCompiled.TraverseFilterBooleanExpr(
                        node => validationEnv.FilterBooleanExpressions.Add(node));
                    item.FilterPlan = compiled.FilterSpecCompiled.Parameters;
                }
            }
            else if (contextSpec is ContextSpecHash) {
                var hashed = (ContextSpecHash) contextSpec;
                foreach (var hashItem in hashed.Items) {
                    var raw = new FilterStreamSpecRaw(
                        hashItem.FilterSpecRaw,
                        ViewSpec.EMPTY_VIEWSPEC_ARRAY,
                        null,
                        StreamSpecOptions.DEFAULT);
                    ValidateNotTable(hashItem.FilterSpecRaw.EventTypeName, validationEnv.Services);

                    var compiledDesc = StreamSpecCompiler.Compile(
                        raw,
                        eventTypesReferenced,
                        false,
                        false,
                        true,
                        false,
                        null,
                        0,
                        validationEnv.StatementRawInfo,
                        validationEnv.Services);
                    additionalForgeables.AddAll(compiledDesc.AdditionalForgeables);
                    var result = (FilterStreamSpecCompiled)  compiledDesc.StreamSpecCompiled;

                    validationEnv.FilterSpecCompileds.Add(result.FilterSpecCompiled);
                    hashItem.FilterSpecCompiled = result.FilterSpecCompiled;

                    // validate parameters
                    var streamTypes = new StreamTypeServiceImpl(
                        result.FilterSpecCompiled.FilterForEventType,
                        null,
                        true);
                    var validationContext =
                        new ExprValidationContextBuilder(
                                streamTypes,
                                validationEnv.StatementRawInfo,
                                validationEnv.Services)
                            .WithIsFilterExpression(true)
                            .Build();
                    ExprNodeUtilityValidate.Validate(
                        ExprNodeOrigin.CONTEXT,
                        Collections.SingletonList(hashItem.Function),
                        validationContext);
                }
            }
            else if (contextSpec is ContextSpecInitiatedTerminated) {
                var def = (ContextSpecInitiatedTerminated) contextSpec;
                var startCondition = ValidateRewriteContextCondition(
                    true,
                    nestingLevel,
                    def.StartCondition,
                    eventTypesReferenced,
                    new MatchEventSpec(),
                    new LinkedHashSet<string>(),
                    validationEnv);
                additionalForgeables.AddAll(startCondition.AdditionalForgeables);

                var endCondition = ValidateRewriteContextCondition(
                    false,
                    nestingLevel,
                    def.EndCondition,
                    eventTypesReferenced,
                    startCondition.Matches,
                    startCondition.AllTags,
                    validationEnv);
                additionalForgeables.AddAll(endCondition.AdditionalForgeables);
                
                def.StartCondition = startCondition.Condition;
                def.EndCondition = endCondition.Condition;

                if (def.DistinctExpressions != null) {
                    if (!(startCondition.Condition is ContextSpecConditionFilter)) {
                        throw new ExprValidationException(
                            "Distinct-expressions require a stream as the initiated-by condition");
                    }

                    var distinctExpressions = def.DistinctExpressions;
                    if (distinctExpressions.Length == 0) {
                        throw new ExprValidationException("Distinct-expressions have not been provided");
                    }

                    var filter = (ContextSpecConditionFilter) startCondition.Condition;
                    if (filter.OptionalFilterAsName == null) {
                        throw new ExprValidationException(
                            "Distinct-expressions require that a stream name is assigned to the stream using 'as'");
                    }

                    var types = new StreamTypeServiceImpl(
                        filter.FilterSpecCompiled.FilterForEventType,
                        filter.OptionalFilterAsName,
                        true);
                    var validationContext =
                        new ExprValidationContextBuilder(types, validationEnv.StatementRawInfo, validationEnv.Services)
                            .WithAllowBindingConsumption(true)
                            .Build();
                    for (var i = 0; i < distinctExpressions.Length; i++) {
                        ExprNodeUtilityValidate.ValidatePlainExpression(
                            ExprNodeOrigin.CONTEXTDISTINCT,
                            distinctExpressions[i]);
                        distinctExpressions[i] = ExprNodeUtilityValidate.GetValidatedSubtree(
                            ExprNodeOrigin.CONTEXTDISTINCT,
                            distinctExpressions[i],
                            validationContext);
                    }

                    var multiKeyPlan = MultiKeyPlanner.PlanMultiKey(
                        distinctExpressions,
                        false,
                        @base.StatementRawInfo,
                        validationEnv.Services.SerdeResolver);
                    def.DistinctMultiKey = multiKeyPlan.ClassRef;
                    additionalForgeables.AddAll(multiKeyPlan.MultiKeyForgeables);
                }
            }
            else if (contextSpec is ContextNested) {
                var nested = (ContextNested) contextSpec;
                var level = 0;
                ISet<string> namesUsed = new HashSet<string>();
                namesUsed.Add(validationEnv.ContextName);
                foreach (var nestedContext in nested.Contexts) {
                    if (namesUsed.Contains(nestedContext.ContextName)) {
                        throw new ExprValidationException(
                            "Context by name '" +
                            nestedContext.ContextName +
                            "' has already been declared within nested context '" +
                            validationEnv.ContextName +
                            "'");
                    }

                    namesUsed.Add(nestedContext.ContextName);

                    var forgeables = ValidateContextDetail(nestedContext.ContextDetail, level, validationEnv);
                    additionalForgeables.AddAll(forgeables);
                    level++;
                }
            }
            else {
                throw new IllegalStateException("Unrecognized context detail " + contextSpec);
            }

            return additionalForgeables;
        }
        public static PropertyEvaluatorForge MakeEvaluator(
            PropertyEvalSpec spec,
            EventType sourceEventType,
            string optionalSourceStreamName,
            StatementRawInfo rawInfo,
            StatementCompileTimeServices services)
        {
            var length = spec.Atoms.Count;
            var containedEventForges = new ContainedEventEvalForge[length];
            var fragmentEventTypes = new FragmentEventType[length];
            var currentEventType = sourceEventType;
            var whereClauses = new ExprForge[length];

            IList<EventType> streamEventTypes = new List<EventType>();
            IList<string> streamNames = new List<string>();
            IDictionary<string, int> streamNameAndNumber = new Dictionary<string, int>().WithNullKeySupport();
            IList<string> expressionTexts = new List<string>();

            streamEventTypes.Add(sourceEventType);
            streamNames.Add(optionalSourceStreamName);
            streamNameAndNumber.Put(optionalSourceStreamName, 0);
            expressionTexts.Add(sourceEventType.Name);

            IList<SelectClauseElementCompiled> cumulativeSelectClause = new List<SelectClauseElementCompiled>();
            for (var i = 0; i < length; i++) {
                var atom = spec.Atoms[i];
                ContainedEventEvalForge containedEventEval = null;
                string expressionText = null;
                EventType streamEventType = null;
                FragmentEventType fragmentEventType = null;

                // Resolve directly as fragment event type if possible
                if (atom.SplitterExpression is ExprIdentNode) {
                    var propertyName = ((ExprIdentNode) atom.SplitterExpression).FullUnresolvedName;
                    fragmentEventType = currentEventType.GetFragmentType(propertyName);
                    if (fragmentEventType != null) {
                        var getter = ((EventTypeSPI) currentEventType).GetGetterSPI(propertyName);
                        if (getter != null) {
                            containedEventEval = new ContainedEventEvalGetterForge(getter);
                            expressionText = propertyName;
                            streamEventType = fragmentEventType.FragmentType;
                        }
                    }
                }

                // evaluate splitter expression
                if (containedEventEval == null) {
                    ExprNodeUtilityValidate.ValidatePlainExpression(
                        ExprNodeOrigin.CONTAINEDEVENT,
                        atom.SplitterExpression);

                    var availableTypes = streamEventTypes.ToArray();
                    var availableStreamNames = streamNames.ToArray();
                    var isIStreamOnly = new bool[streamNames.Count];
                    isIStreamOnly.Fill(true);
                    StreamTypeService streamTypeService = new StreamTypeServiceImpl(
                        availableTypes,
                        availableStreamNames,
                        isIStreamOnly,
                        false,
                        false);
                    var validationContext = new ExprValidationContextBuilder(streamTypeService, rawInfo, services)
                        .WithAllowBindingConsumption(true)
                        .Build();
                    var validatedExprNode = ExprNodeUtilityValidate.GetValidatedSubtree(
                        ExprNodeOrigin.CONTAINEDEVENT,
                        atom.SplitterExpression,
                        validationContext);

                    // determine result type
                    if (atom.OptionalResultEventType == null) {
                        throw new ExprValidationException(
                            "Missing @type(name) declaration providing the event type name of the return type for expression '" +
                            ExprNodeUtilityPrint.ToExpressionStringMinPrecedenceSafe(atom.SplitterExpression) +
                            "'");
                    }

                    streamEventType = services.EventTypeCompileTimeResolver.GetTypeByName(atom.OptionalResultEventType);
                    if (streamEventType == null) {
                        throw new ExprValidationException(
                            "Event type by name '" + atom.OptionalResultEventType + "' could not be found");
                    }

                    var returnType = validatedExprNode.Forge.EvaluationType;

                    // when the expression returns an array, allow array values to become the column of the single-column event type
                    if (returnType.IsArray &&
                        streamEventType.PropertyNames.Length == 1 &&
                        !(streamEventType is JsonEventType) && // since json string-array should not become itself the property
                        TypeHelper.IsSubclassOrImplementsInterface(
                            returnType.GetElementType().GetBoxedType(),
                            streamEventType.GetPropertyType(streamEventType.PropertyNames[0]).GetBoxedType())) {
                        var writables = EventTypeUtility.GetWriteableProperties(streamEventType, false, false);
                        if (writables != null && !writables.IsEmpty()) {
                            try {
                                var manufacturer = EventTypeUtility.GetManufacturer(
                                    streamEventType,
                                    new[] {writables.First()},
                                    services.ImportServiceCompileTime,
                                    false,
                                    services.EventTypeAvroHandler);
                                containedEventEval = new ContainedEventEvalArrayToEventForge(
                                    validatedExprNode.Forge,
                                    manufacturer);
                            }
                            catch (EventBeanManufactureException e) {
                                throw new ExprValidationException(
                                    "Event type '" + streamEventType.Name + "' cannot be populated: " + e.Message,
                                    e);
                            }
                        }
                        else {
                            throw new ExprValidationException(
                                "Event type '" + streamEventType.Name + "' cannot be written to");
                        }
                    }
                    else if (returnType.IsArray &&
                             returnType.GetElementType() == typeof(EventBean)) {
                        containedEventEval = new ContainedEventEvalEventBeanArrayForge(validatedExprNode.Forge);
                    }
                    else {
                        // check expression result type against eventtype expected underlying type
                        if (returnType.IsArray) {
                            if (!(streamEventType is JsonEventType)) {
                                if (!TypeHelper.IsSubclassOrImplementsInterface(
                                    returnType.GetElementType(),
                                    streamEventType.UnderlyingType)) {
                                    throw new ExprValidationException(
                                        "Event type '" +
                                        streamEventType.Name +
                                        "' underlying type " +
                                        streamEventType.UnderlyingType.CleanName() +
                                        " cannot be assigned a value of type " +
                                        returnType.CleanName());
                                }
                            }
                            else {
                                if (returnType.GetElementType() != typeof(string)) {
                                    throw new ExprValidationException(
                                        "Event type '" +
                                        streamEventType.Name +
                                        "' requires string-type array and cannot be assigned from value of type " +
                                        returnType.CleanName());
                                }
                            }
                        }
                        else if (GenericExtensions.IsGenericEnumerable(returnType) || 
                                 TypeHelper.IsImplementsInterface<System.Collections.IEnumerable>(returnType)) {
                            // fine, assumed to return the right type
                        }
                        else {
                            throw new ExprValidationException(
                                "Return type of expression '" +
                                ExprNodeUtilityPrint.ToExpressionStringMinPrecedenceSafe(atom.SplitterExpression) +
                                "' is '" +
                                returnType.Name +
                                "', expected an Iterable or array result");
                        }

                        containedEventEval = new ContainedEventEvalExprNodeForge(
                            validatedExprNode.Forge,
                            streamEventType);
                    }

                    expressionText = ExprNodeUtilityPrint.ToExpressionStringMinPrecedenceSafe(validatedExprNode);
                    fragmentEventType = new FragmentEventType(streamEventType, true, false);
                }

                // validate where clause, if any
                streamEventTypes.Add(streamEventType);
                streamNames.Add(atom.OptionalAsName);
                streamNameAndNumber.Put(atom.OptionalAsName, i + 1);
                expressionTexts.Add(expressionText);

                if (atom.OptionalWhereClause != null) {
                    var whereTypes = streamEventTypes.ToArray();
                    var whereStreamNames = streamNames.ToArray();
                    var isIStreamOnly = new bool[streamNames.Count];
                    isIStreamOnly.Fill(true);
                    StreamTypeService streamTypeService = new StreamTypeServiceImpl(
                        whereTypes,
                        whereStreamNames,
                        isIStreamOnly,
                        false,
                        false);
                    var validationContext = new ExprValidationContextBuilder(streamTypeService, rawInfo, services)
                        .WithAllowBindingConsumption(true)
                        .Build();
                    var whereClause = ExprNodeUtilityValidate.GetValidatedSubtree(
                        ExprNodeOrigin.CONTAINEDEVENT,
                        atom.OptionalWhereClause,
                        validationContext);
                    whereClauses[i] = whereClause.Forge;
                }

                // validate select clause
                if (atom.OptionalSelectClause != null && !atom.OptionalSelectClause.SelectExprList.IsEmpty()) {
                    var whereTypes = streamEventTypes.ToArray();
                    var whereStreamNames = streamNames.ToArray();
                    var isIStreamOnly = new bool[streamNames.Count];
                    isIStreamOnly.Fill(true);
                    StreamTypeService streamTypeService = new StreamTypeServiceImpl(
                        whereTypes,
                        whereStreamNames,
                        isIStreamOnly,
                        false,
                        false);
                    var validationContext = new ExprValidationContextBuilder(streamTypeService, rawInfo, services)
                        .WithAllowBindingConsumption(true)
                        .Build();

                    foreach (var raw in atom.OptionalSelectClause.SelectExprList) {
                        if (raw is SelectClauseStreamRawSpec) {
                            var rawStreamSpec = (SelectClauseStreamRawSpec) raw;
                            if (!streamNames.Contains(rawStreamSpec.StreamName)) {
                                throw new ExprValidationException(
                                    "Property rename '" + rawStreamSpec.StreamName + "' not found in path");
                            }

                            var streamSpec = new SelectClauseStreamCompiledSpec(
                                rawStreamSpec.StreamName,
                                rawStreamSpec.OptionalAsName);
                            var streamNumber = streamNameAndNumber.Get(rawStreamSpec.StreamName);
                            streamSpec.StreamNumber = streamNumber;
                            cumulativeSelectClause.Add(streamSpec);
                        }
                        else if (raw is SelectClauseExprRawSpec) {
                            var exprSpec = (SelectClauseExprRawSpec) raw;
                            var exprCompiled = ExprNodeUtilityValidate.GetValidatedSubtree(
                                ExprNodeOrigin.CONTAINEDEVENT,
                                exprSpec.SelectExpression,
                                validationContext);
                            var resultName = exprSpec.OptionalAsName;
                            if (resultName == null) {
                                resultName = ExprNodeUtilityPrint.ToExpressionStringMinPrecedenceSafe(exprCompiled);
                            }

                            cumulativeSelectClause.Add(
                                new SelectClauseExprCompiledSpec(
                                    exprCompiled,
                                    resultName,
                                    exprSpec.OptionalAsName,
                                    exprSpec.IsEvents));

                            var isMinimal = ExprNodeUtilityValidate.IsMinimalExpression(exprCompiled);
                            if (isMinimal != null) {
                                throw new ExprValidationException(
                                    "Expression in a property-selection may not utilize " + isMinimal);
                            }
                        }
                        else if (raw is SelectClauseElementWildcard) {
                            // wildcards are stream selects: we assign a stream name (any) and add a stream wildcard select
                            var streamNameAtom = atom.OptionalAsName;
                            if (streamNameAtom == null) {
                                streamNameAtom = UuidGenerator.Generate();
                            }

                            var streamSpec = new SelectClauseStreamCompiledSpec(streamNameAtom, atom.OptionalAsName);
                            var streamNumber = i + 1;
                            streamSpec.StreamNumber = streamNumber;
                            cumulativeSelectClause.Add(streamSpec);
                        }
                        else {
                            throw new IllegalStateException("Unknown select clause item:" + raw);
                        }
                    }
                }

                currentEventType = fragmentEventType.FragmentType;
                fragmentEventTypes[i] = fragmentEventType;
                containedEventForges[i] = containedEventEval;
            }

            if (cumulativeSelectClause.IsEmpty()) {
                if (length == 1) {
                    return new PropertyEvaluatorSimpleForge(
                        containedEventForges[0],
                        fragmentEventTypes[0],
                        whereClauses[0],
                        expressionTexts[0]);
                }

                return new PropertyEvaluatorNestedForge(
                    containedEventForges,
                    fragmentEventTypes,
                    whereClauses,
                    expressionTexts.ToArray());
            }

            {
                var fragmentEventTypeIsIndexed = new bool[fragmentEventTypes.Length];
                for (var i = 0; i < fragmentEventTypes.Length; i++) {
                    fragmentEventTypeIsIndexed[i] = fragmentEventTypes[i].IsIndexed;
                }

                var accumulative = new PropertyEvaluatorAccumulativeForge(
                    containedEventForges,
                    fragmentEventTypeIsIndexed,
                    whereClauses,
                    expressionTexts);

                var whereTypes = streamEventTypes.ToArray();
                var whereStreamNames = streamNames.ToArray();
                var isIStreamOnly = new bool[streamNames.Count];
                isIStreamOnly.Fill(true);
                StreamTypeService streamTypeService = new StreamTypeServiceImpl(
                    whereTypes,
                    whereStreamNames,
                    isIStreamOnly,
                    false,
                    false);

                var cumulativeSelectArr = cumulativeSelectClause.ToArray();
                var args = new SelectProcessorArgs(
                    cumulativeSelectArr,
                    null,
                    false,
                    null,
                    null,
                    streamTypeService,
                    null,
                    false,
                    rawInfo.Annotations,
                    rawInfo,
                    services);
                var selectExprDesc = SelectExprProcessorFactory.GetProcessor(args, null, false);

                return new PropertyEvaluatorSelectForge(selectExprDesc, accumulative);
            }
        }