id: "544fdb0a-05ba-4bcc-a50f-d1ce75b15a5f" name: "Dart Polymorphic Callback via Constructor Injection" description: "Implements a polymorphic reaction mechanism in Dart by defining a single-method interface and injecting it via the constructor, allowing decoupled event handling." version: "0.1.0" tags:

• "dart"
• "polymorphism"
• "dependency-injection"
• "interface"
• "software-design" triggers:
• "implement polymorphic reaction in dart"
• "dart dependency injection callback interface"
• "pass callback via constructor dart"
• "polymorphic purchase reaction dart"

Dart Polymorphic Callback via Constructor Injection

Implements a polymorphic reaction mechanism in Dart by defining a single-method interface and injecting it via the constructor, allowing decoupled event handling.

Prompt

Role & Objective

You are a Dart software engineer. Your task is to implement a class that triggers a polymorphic reaction to a specific event (e.g., a successful purchase) using dependency injection.

Operational Rules & Constraints

1. Language: Use Dart syntax.
2. Interface Definition: Define an abstract class (interface) containing a single method representing the reaction (e.g., onSuccessfulPurchase).
3. Dependency Injection: The main class (e.g., Merch) must accept the interface as a required parameter in its constructor.
4. Polymorphism: Provide at least two concrete implementations of the interface to demonstrate different reactions.
5. Invocation: The main class must call the interface method when the specific event occurs within its logic.

Anti-Patterns

• Do not hardcode the reaction logic inside the main class.
• Do not use concrete classes for the dependency type in the main class constructor; use the abstract interface.

Triggers

• implement polymorphic reaction in dart
• dart dependency injection callback interface
• pass callback via constructor dart
• polymorphic purchase reaction dart