LogicBuilder.Structures 8.0.0

LogicBuilder.Structures

A comprehensive metadata library for building dynamic LINQ expressions through descriptors. This library provides a rich set of classes that represent expression components, enabling the construction of complex LINQ queries from serializable metadata structures.

Purpose

LogicBuilder.Structures serves as the metadata foundation for the LogicBuilder.Expressions framework. Instead of writing LINQ expressions directly in code, developers can:

1. Define expressions as metadata using descriptor classes
2. Serialize and store query definitions independent of code
3. Dynamically build LINQ Expression Trees at runtime
4. Support data-driven query scenarios where query logic comes from configuration or user input

Key Features

Expression Building Blocks

• Binary Operations: EqualsBinaryDescriptor, GreaterThanBinaryDescriptor, LessThanBinaryDescriptor, etc.
• Logical Operations: AndBinaryDescriptor, OrBinaryDescriptor, NotDescriptor
• Arithmetic Operations: AddBinaryDescriptor, SubtractBinaryDescriptor, MultiplyBinaryDescriptor, DivideBinaryDescriptor, ModuloBinaryDescriptor

Queryable Operations

• Filtering: WhereDescriptor, AnyDescriptor, AllDescriptor
• Projection: SelectDescriptor, SelectManyDescriptor
• Ordering: OrderByDescriptor, ThenByDescriptor
• Aggregation: CountDescriptor, SumDescriptor, AverageDescriptor, MinDescriptor, MaxDescriptor
• Paging: SkipDescriptor, TakeDescriptor
• Grouping: GroupByDescriptor
• Element Access: FirstDescriptor, LastDescriptor, SingleDescriptor, and their OrDefault variants

Collection Operations

• Set Operations: UnionDescriptor, ConcatDescriptor, ExceptDescriptor
• Collection Tests: AnyDescriptor, AllDescriptor, ContainsDescriptor

String Functions

• SubstringDescriptor, ContainsDescriptor, StartsWithDescriptor, EndsWithDescriptor
• ToUpperDescriptor, ToLowerDescriptor, TrimDescriptor
• LengthDescriptor, IndexOfDescriptor, ConcatDescriptor

Date/Time Functions

• Component extraction: YearDescriptor, MonthDescriptor, DayDescriptor, HourDescriptor, MinuteDescriptor, SecondDescriptor
• Conversions: ConvertToNumericDateDescriptor, ConvertToNumericTimeDescriptor
• Fractional seconds: FractionalSecondsDescriptor

Math Functions

• FloorDescriptor, CeilingDescriptor, RoundDescriptor

Type Operations

• Casting: CastDescriptor, ConvertDescriptor, CollectionCastDescriptor, CollectionOfTypeDescriptor
• Type Checking: IsOfDescriptor
• Conversions: ConvertToStringDescriptor, ConvertToEnumDescriptor, ConvertToNullableUnderlyingValueDescriptor

Member Access

• MemberSelectorDescriptor - Access properties and fields
• ParameterDescriptor - Define lambda parameters
• ConstantDescriptor - Represent constant values
• CollectionConstantDescriptor - Represent collection constants

Custom Operations

• CustomMethodDescriptor - Call custom methods on types
• MemberInitDescriptor - Initialize anonymous types or objects

Integration

Works seamlessly with LogicBuilder.Expressions.Utils to:

• Map descriptors to LINQ Expression Trees via AutoMapper
• Execute dynamic queries against Entity Framework, LINQ to Objects, and other LINQ providers
• Build complex filtering, sorting, paging, and aggregation logic from configuration

Supported Scenarios

• OData-style filtering with complex predicates
• Dynamic reporting queries with runtime-defined aggregations
• Configurable business rules expressed as queryable filters
• User-defined search criteria converted to type-safe LINQ expressions
• Multi-tenant filtering applied dynamically based on context

Benefits

1. Serializable: All descriptors are POCOs that can be JSON/XML serialized
2. Type-safe: Generates strongly-typed LINQ expressions at runtime
3. Testable: Expression logic can be unit tested through descriptors
4. Maintainable: Query logic separated from code into data structures
5. Extensible: Custom descriptors can be added for domain-specific needs

Related Libraries

• LogicBuilder.Expressions.Utils: Descriptors can be converted to their corresponding operators which generate executable LINQ expressions
• LogicBuilder.EntityFrameworkCore.SqlServer: Entity Framework integration and testing