# Bridge Pattern

> A design pattern that separates two independent axes of variation into two hierarchies joined by composition.

Record: `architecture:bridge-pattern`
Kind: pattern
Layer: [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md)
Severity: contextual
Scope: abstraction, implementation variation
Canonical: https://banes-lab.com/ontology#architecture-bridge-pattern

Listed in [Architecture principles](https://banes-lab.com/api/records/architecture.md), after [Proxy Pattern](https://banes-lab.com/records/architecture/proxy-pattern.md) and before [Decorator Pattern](https://banes-lab.com/records/architecture/decorator-pattern.md).

## Repair

- Refactored by: Introduce Bridge
- Detected by: parallel hierarchies / deep variant classes
- Violated by: subclass explosion for combinations
- Measured by: variant class count
- Enforced by: [design review](https://banes-lab.com/records/architecture/design-review.md)

## Requires

- [Independent Variation Axes](https://banes-lab.com/records/lexicon/independent-variation-axes.md)

## Reinforces

- [Composition Over Inheritance](https://banes-lab.com/records/architecture/composition-over-inheritance.md)

## Enables

- [Implementation Swap](https://banes-lab.com/records/lexicon/implementation-swap.md)

## Conflicts with

- [Cartesian Inheritance Explosion](https://banes-lab.com/records/lexicon/cartesian-inheritance-explosion.md)

## In tension with

- [Indirection](https://banes-lab.com/records/lexicon/indirection.md)

## Tensions

- [Bridge Pattern / Indirection](https://banes-lab.com/records/tension/bridge-pattern-indirection.md)

## Severity

- [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md)

## Category

- [Structural Patterns](https://banes-lab.com/records/architecture-category/structural-patterns.md)

## Linked from

- [Core Modular Design](https://banes-lab.com/ontology/principles/architecture-category-core-modular-design.md)
- [Structural Patterns](https://banes-lab.com/ontology/lexicon/lexicon-category-structural-patterns.md)
- [Severity levels](https://banes-lab.com/ontology/schema/the-vocabulary-severity.md)
- [The resolutions](https://banes-lab.com/ontology/schema/the-resolutions.md)