ApplicationContext class abstract

The central interface for a JetLeaf application context.

An ApplicationContext is the core container that provides:

• Dependency Injection: Access to managed pods (beans) via ListablePodFactory and HierarchicalPodFactory
• Environment Management: Configuration and profile handling via EnvironmentCapable
• Internationalization: Message resolution and localization via MessageSource
• Event System: Application-wide event publication through publishEvent
• Lifecycle Management: Context state tracking and lifecycle operations

This interface serves as the primary entry point for configuring, bootstrapping, and interacting with a JetLeaf application at runtime.

Core Responsibilities:

• Container Management: Hosts and manages the complete dependency injection container
• Configuration Centralization: Provides unified access to application configuration
• Lifecycle Coordination: Manages context lifecycle from startup to shutdown
• Event Distribution: Facilitates loose coupling through event-driven architecture
• Resource Access: Provides access to framework and application resources

Basic Usage Example:

void main() async {
  // Create and configure application context
  final context = MyApplicationContext();
  
  // Initialize the context (loads pods, processes configurations)
  await context.refresh();

  // Publish application startup event
  context.publishEvent(ApplicationStartedEvent(context));

  // Access context information
  print("Application '${context.getApplicationName()}' started at: ${context.getStartTime()}");
  print("Context ID: ${context.getId()}");
  
  // Use the context throughout application lifetime
  final userService = context.getPod<UserService>();
  await userService.initialize();
  
  // Properly close context on shutdown
  await context.close();
}

Context Hierarchy:

Application contexts can form parent-child relationships where child contexts inherit configuration and can delegate pod lookups to their parents. This enables:

• Modular Applications: Separate contexts for different application modules
• Testing Scenarios: Isolated test contexts with shared parent services
• Multi-tenant Systems: Tenant-specific contexts with common infrastructure

Thread Safety:

Implementations should be thread-safe for concurrent access, particularly for read operations like pod retrieval and configuration access. Lifecycle operations (refresh, start, stop, close) should be properly synchronized.

See also:

• ConfigurableApplicationContext for lifecycle management and configuration
• Environment for environment and property management
• MessageSource for internationalization support
• ApplicationEvent for event system integration