bc-code-intelligence-mcp/embedded-knowledge/domains/sam-coder/manual-binding-conditional-subscribers.md

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---
title: "Manual Binding for Conditional Event Subscribers"
domain: "sam-coder"
difficulty: "advanced"
bc_versions: "16+"
tags: ["events", "binding", "conditional", "runtime"]
prerequisites: ["event-subscriber-basics", "binding-patterns"]
samples: "samples/manual-binding.md"
---
# Manual Binding for Conditional Event Subscribers

## Overview

Manual binding enables runtime control over event subscriber activation, allowing conditional subscriber registration based on business logic, configuration, or environmental factors. This pattern provides architectural flexibility beyond static EventSubscriber attribute declarations.

Manual binding requires explicit subscriber registration and deregistration through the BC event management framework. This approach trades development simplicity for runtime control and dynamic event handling capabilities.

The pattern is essential for scenarios requiring conditional event processing, multi-tenant customizations, or feature-flag-controlled functionality where static binding creates unnecessary overhead or conflicts.

## Architectural Benefits

Manual binding enables conditional event processing based on runtime criteria such as user permissions, feature flags, or business configuration. Subscribers only activate when actually needed, reducing unnecessary event processing overhead.

Dynamic binding supports multi-tenant scenarios where different tenants require different event handling logic. The same codebase can provide tenant-specific event processing without static coupling to all possible variations.

Feature toggles and A/B testing scenarios benefit from manual binding's ability to enable or disable event handlers without code deployment. Business logic changes can control event processing behavior dynamically.

## Implementation Patterns

Manual binding requires implementing custom registration logic typically executed during application startup or feature activation. The registration code must handle both binding and unbinding scenarios appropriately.

Conditional binding logic should evaluate business rules, configuration settings, or environmental factors to determine when subscribers should be active. The evaluation timing and frequency impact system performance and behavior consistency.

Error handling becomes critical in manual binding scenarios since registration failures can silently disable expected functionality. Robust error handling and logging ensure binding issues are detected and resolved promptly.

## Lifecycle Management

Manual binding requires explicit lifecycle management for subscriber registration and deregistration. Unlike static subscribers, manually bound subscribers need active management throughout their operational lifetime.

Registration timing affects when events begin processing through manual subscribers. Early registration ensures events are captured from system startup, while delayed registration may miss early system events.

Deregistration becomes necessary when conditional criteria change or features deactivate. Failed deregistration can lead to unexpected event processing and potential system conflicts.

## Configuration Integration

Manual binding integrates naturally with configuration management systems, allowing business users to control event processing behavior without technical intervention. Configuration changes can enable or disable event handlers dynamically.

Configuration-driven binding requires robust validation to ensure only valid subscribers are registered and conflicting configurations are detected early. Invalid configurations should fail safely without disrupting other system functions.

Runtime configuration changes need careful handling to avoid inconsistent states where some events are processed by newly configured handlers while others use previous configurations.

## Performance Considerations

Manual binding introduces registration overhead during application startup or feature activation. The registration cost must be balanced against the flexibility benefits, particularly in high-frequency event scenarios.

Conditional evaluation logic adds processing overhead to determine when subscribers should be active. Efficient evaluation algorithms minimize performance impact while providing necessary flexibility.

Dynamic binding and unbinding during system operation can create temporary inconsistencies where some events are processed differently than others. Timing considerations ensure consistent event processing behavior.

## Testing Strategies

Manual binding requires comprehensive testing of both bound and unbound states to ensure correct behavior under all configuration scenarios. Test suites must validate conditional binding logic and edge cases.

Integration testing becomes more complex with manual binding since the same codebase behaves differently based on binding configuration. Test environments must exercise all possible binding combinations.

Performance testing must account for binding overhead and conditional evaluation impact on overall system performance, particularly during startup and configuration change scenarios.