Application service
An application service is a software component that provides or coordinates application-level functionality for callers, typically by coordinating operations and interactions with other components.
Unit Testing Principles, Practices, and Patterns
An application service is a service that coordinates application operations and connects a functional core with external clients and side-effecting infrastructure.
- How it is used
- Coordinates business use cases between domain logic, external clients, persistence, and side-effecting infrastructure.
- How deep it goes
- Explains layering, dependency direction, orchestration boundaries, refactoring, and output-based testing, stopping short of implementation-specific infrastructure design.
- Examples
- Uses user renaming, customer purchasing, and filesystem-based audit recording to demonstrate orchestration and testing trade-offs.
- What you can do after
- Build it from scratch as a thin use-case entry point that coordinates domain operations, persistence, and justified external effects.
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Simple Object-Oriented Design: Create clean, maintainable applications
An application service coordinates application tasks and interactions between components without containing the domain's business rules.
- How it is used
- Coordinates request flow among repositories, validators, and domain objects while preventing invalid operations.
- How deep it goes
- Works through concrete enrollment and cancellation flows, contrasting orchestration with validation rules and aggregate-invariant control.
- Examples
- Uses adding an employee to a training offering and cancelling an enrollment, including service, validator, and repository-query listings.
- What you can do after
- Evaluate/understand when a service is coordinating work versus taking over business rules or weakening aggregate invariants.
Related concepts
- repositoryuses · A software repository is an organized storage location or collection of project files and related artifacts, often managed with version history and change tracking.
- portimplements · A port is a defined interface or endpoint through which a system communicates with another component, service, or external capability.
- waitforconfigured by · WaitFor is a .NET Aspire app-model API method that declares a startup dependency on another resource being ready.
- hexagonal architecturepart of · Hexagonal architecture is a software architecture pattern that isolates an application’s core logic from external systems through ports and adapters.
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