Validation Subsystem

Overview

The validation subsystem is responsible for ensuring that transition data context satisfies structural expectations before it is processed by transition handler.

Validation in BPUA is intentionally limited in scope:

• It verifies the shape of the transition context.
• It does not validate business rules.
• It operates before transition handler starts its execution.

Validation protects execution. It does not define business meaning.

Two Types of Validation

BPUA distinguishes between two different kinds of validation:

• Contract (structural) validation – ensures that the transition context contains expected tables and satisfies structural constraints.
• Data (value) validation – ensures that individual field values satisfy business or domain rules.

This page focuses on contract validation.

Transition Data Contract

The validation of the data context structure is driven by transition data contract, which is the declarative specification of expected tables and their properties:

• Table name
• Required flag
• Minimum row count
• Maximum row count

The contract describes what must exist. It does not perform validation itself.

Validation is performed by transition data contract validator, which:

• Iterates through table contracts
• Locates corresponding tables in the transition data context
• Validates presence and row count
• Produces a validation result

Validation Result

Validation produces a collection of issues consisting of:

• Error message
• Severity
• Optional context information

Validation does not throw exceptions. It returns a structured result.

Design Decisions

• Null data context is allowed – absence of data may be caused by infrastructure failures outside contract semantics.
• Extra tables are allowed – validation is selective and checks only relevant tables.
• No rule objects for table validation – simple constraints are expressed declaratively in the contract.

What Validation Does Not Do

• It does not validate business rules
• It does not interpret data meaning
• It does not enforce cross-transition logic

Business data validation belongs to business domain components.

Relation to Execution Pipeline

Validation is the first step in transition execution:

• Validation
• Handler execution
• Post-processing

Validation guards the pipeline before execution begins.

Table of Content BPUA Chapter Previous: Use Case Activator Next: Execution Lifecycle

 

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Business Process Programming in .Net
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