# SOLID / Object-Oriented Design > Every principle in this category is listed as a record. Page: Ontology · Principles Canonical: https://banes-lab.com/ontology#architecture-category-solid-object-oriented-design Listed in [Ontology · Principles](https://banes-lab.com/api/pages/ontology/principles.md), after [Core Modular Design](https://banes-lab.com/ontology/principles/architecture-category-core-modular-design.md) and before [Event / Messaging / Asynchronous Architecture](https://banes-lab.com/ontology/principles/architecture-category-event-messaging-asynchronous-architecture.md). Every principle in this category is listed as a record. Each record carries its kind, its severity, the scopes it applies at and the layer it lives in, then the edge relations that join it to other records, the records that point back at it, the contracts that answer to it and the tensions it takes part in. The descriptors say how it is violated, detected, measured, repaired and enforced. Where the record carries one, an exemplar shows the shape before and after the principle is applied. Relations diagram The relations inside this category. ```mermaid flowchart LR n_interface_segregation["Interface Segregation Principle (ISP)"] n_dependency_inversion["Dependency Inversion Principle (DIP)"] n_open_closed["Open/Closed Principle (OCP)"] n_liskov_substitution["Liskov Substitution Principle (LSP)"] n_polymorphism["Polymorphism"] n_liskov_substitution --> n_polymorphism n_polymorphism --> n_open_closed ``` ### Interface Segregation Principle (ISP) - Kind: [principle](https://banes-lab.com/records/kind/principle.md) - Category: [SOLID / Object-Oriented Design](https://banes-lab.com/ontology/principles/architecture-category-solid-object-oriented-design.md) - Severity: [mandatory](https://banes-lab.com/records/vocabulary/severity-mandatory.md) - Scope: interface, service, module - Layer: [Structural Core](https://banes-lab.com/records/layer/structural-core.md) Details Definition A design rule that a client depends on an interface holding only the methods it uses. Requires [Role-Specific Interfaces](https://banes-lab.com/records/lexicon/role-specific-interfaces.md) Reinforces [Single Responsibility Principle (SRP)](https://banes-lab.com/records/architecture/single-responsibility.md), [Low Coupling](https://banes-lab.com/records/architecture/low-coupling.md) Enables [Consumer-Specific Contracts](https://banes-lab.com/records/lexicon/consumer-specific-contracts.md) In tension with [Interface Proliferation](https://banes-lab.com/records/lexicon/interface-proliferation.md) Conflicts with [Fat Interface](https://banes-lab.com/records/lexicon/fat-interface.md), [Repository Dump](https://banes-lab.com/records/architecture/repository-dump.md) Tensions [Interface Segregation Principle (ISP) / Interface Proliferation](https://banes-lab.com/records/tension/interface-proliferation-interface-segregation-principle-isp.md) Violated by clients depending on unused methods Detected by unused interface method implementations Measured by interface method usage ratio Refactored by Split Interface, Extract Role Interface Enforced by interface usage analysis, lint rules Before ```typescript interface FooWorker { load(id: FooId): Foo; save(foo: Foo): void; delete(id: FooId): void; export(): string; } class FooReader implements FooWorker {} ``` After ```typescript interface FooReader { load(id: FooId): Foo; } interface FooWriter { save(foo: Foo): void; } interface FooRemover { delete(id: FooId): void; } class CachedFooReader implements FooReader { load(id: FooId) { return fooCache.get(id)!; } } ``` How it is checked Checked by interface usage analysis, lint rules Population Every interface, class hierarchy and dependency edge in the object model Freshness A verdict stands until an interface, an override or a dependency changes Refusal The dependency rule or the contract test fails a change that breaks substitution, segregation or dependency direction Observation Interface usage, override contracts and dependency direction, read from source and contract tests Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The interface contract, which every implementation and override conforms to Depends on [Role-Specific Interfaces](https://banes-lab.com/records/lexicon/role-specific-interfaces.md), [Single Responsibility Principle (SRP)](https://banes-lab.com/records/architecture/single-responsibility.md), [Low Coupling](https://banes-lab.com/records/architecture/low-coupling.md), [Consumer-Specific Contracts](https://banes-lab.com/records/lexicon/consumer-specific-contracts.md) Shape it refuses [Fat Interface](https://banes-lab.com/records/lexicon/fat-interface.md), [Repository Dump](https://banes-lab.com/records/architecture/repository-dump.md) ### Dependency Inversion Principle (DIP) - Kind: [principle](https://banes-lab.com/records/kind/principle.md) - Category: [SOLID / Object-Oriented Design](https://banes-lab.com/ontology/principles/architecture-category-solid-object-oriented-design.md) - Severity: [mandatory](https://banes-lab.com/records/vocabulary/severity-mandatory.md) - Scope: module, component, layer - Aliases: DIP - Layer: [Structural Core](https://banes-lab.com/records/layer/structural-core.md) Details Definition A design rule that high-level policy and low-level detail both depend on an abstraction owned by the policy. Requires [Abstraction](https://banes-lab.com/records/architecture/abstraction.md), [Stable Interfaces](https://banes-lab.com/records/architecture/stable-interfaces.md) Reinforces [Low Coupling](https://banes-lab.com/records/architecture/low-coupling.md), [Clean Architecture](https://banes-lab.com/records/architecture/clean-architecture.md) Enables [Dependency Injection](https://banes-lab.com/records/architecture/dependency-injection.md), [Ports and Adapters](https://banes-lab.com/records/lexicon/ports-and-adapters.md) In tension with [Runtime Indirection](https://banes-lab.com/records/lexicon/runtime-indirection.md) Conflicts with [Concrete Dependency](https://banes-lab.com/records/lexicon/concrete-dependency.md) Referenced by [Interface-Based Design](https://banes-lab.com/records/architecture/interface-based-design.md), [Testability](https://banes-lab.com/records/architecture/testability.md), [Abstraction](https://banes-lab.com/records/architecture/abstraction.md), [Replaceability](https://banes-lab.com/records/architecture/replaceability.md), [Inversion of Control (IoC)](https://banes-lab.com/records/architecture/inversion-of-control.md), [Dependency Injection](https://banes-lab.com/records/architecture/dependency-injection.md), [Service Locator Pattern](https://banes-lab.com/records/architecture/service-locator-pattern.md), [Ports and Adapters Architecture](https://banes-lab.com/records/architecture/ports-and-adapters-architecture.md), [Clean Architecture](https://banes-lab.com/records/architecture/clean-architecture.md) Tensions [Dependency Inversion Principle (DIP) / Runtime Indirection](https://banes-lab.com/records/tension/dependency-inversion-principle-dip-runtime-indirection.md) Distinct from [Inversion of Control (IoC)](https://banes-lab.com/records/architecture/inversion-of-control.md): Dependency inversion fixes which side owns the abstraction, while inversion of control moves object creation and control flow to a framework or composition root. Violated by domain importing infrastructure Detected by dependency direction violations Measured by inward dependency ratio Refactored by Extract Interface, Introduce Port, Inject Dependency Enforced by dependency graph rules, architecture tests Before ```typescript class FooService { private readonly store = new SqlFooStore(); save(foo: Foo) { return this.store.save(foo); } } ``` After ```typescript interface FooStore { save(foo: Foo): Promise; } class FooService { constructor(private readonly store: FooStore) {} save(foo: Foo) { return this.store.save(foo); } } ``` How it is checked Checked by dependency graph rules, architecture tests Population Every interface, class hierarchy and dependency edge in the object model Freshness A verdict stands until an interface, an override or a dependency changes Refusal The dependency rule or the contract test fails a change that breaks substitution, segregation or dependency direction Observation Interface usage, override contracts and dependency direction, read from source and contract tests Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The interface contract, which every implementation and override conforms to Depends on [Abstraction](https://banes-lab.com/records/architecture/abstraction.md), [Stable Interfaces](https://banes-lab.com/records/architecture/stable-interfaces.md), [Low Coupling](https://banes-lab.com/records/architecture/low-coupling.md), [Clean Architecture](https://banes-lab.com/records/architecture/clean-architecture.md), [Dependency Injection](https://banes-lab.com/records/architecture/dependency-injection.md), [Ports and Adapters](https://banes-lab.com/records/lexicon/ports-and-adapters.md) Shape it refuses [Concrete Dependency](https://banes-lab.com/records/lexicon/concrete-dependency.md) ### Open/Closed Principle (OCP) - Kind: [principle](https://banes-lab.com/records/kind/principle.md) - Category: [SOLID / Object-Oriented Design](https://banes-lab.com/ontology/principles/architecture-category-solid-object-oriented-design.md) - Severity: [recommended](https://banes-lab.com/records/vocabulary/severity-recommended.md) - Scope: class, module, component - Aliases: OCP - Layer: [Structural Core](https://banes-lab.com/records/layer/structural-core.md) Details Definition A design rule that a module gains new behavior by adding code at an extension point, leaving its existing code unchanged. Requires [Abstraction](https://banes-lab.com/records/architecture/abstraction.md), [Extension Points](https://banes-lab.com/records/architecture/extension-points.md) Reinforces [Plugin Architecture](https://banes-lab.com/records/architecture/plugin-architecture.md), [Strategy Pattern](https://banes-lab.com/records/architecture/strategy-pattern.md) Enables [Feature Extension without Modification](https://banes-lab.com/records/lexicon/feature-extension-without-modification.md) In tension with [Simplicity](https://banes-lab.com/records/lexicon/simplicity.md) Conflicts with [Switch-Based Extension](https://banes-lab.com/records/lexicon/switch-based-extension.md) Referenced by [Dynamic Dispatch](https://banes-lab.com/records/architecture/dynamic-dispatch.md), [Runtime Extensibility](https://banes-lab.com/records/architecture/runtime-extensibility.md), [Polymorphism](https://banes-lab.com/records/architecture/polymorphism.md), [Strategy Pattern](https://banes-lab.com/records/architecture/strategy-pattern.md), [Command Pattern](https://banes-lab.com/records/architecture/command-pattern.md), [State Pattern](https://banes-lab.com/records/architecture/state-pattern.md), [Chain of Responsibility Pattern](https://banes-lab.com/records/architecture/chain-of-responsibility-pattern.md), [Visitor Pattern](https://banes-lab.com/records/architecture/visitor-pattern.md), [Factory Pattern](https://banes-lab.com/records/architecture/factory-pattern.md), [Factory Method Pattern](https://banes-lab.com/records/architecture/factory-method-pattern.md), [Decorator Pattern](https://banes-lab.com/records/architecture/decorator-pattern.md), [Composite Pattern](https://banes-lab.com/records/architecture/composite-pattern.md), [Plugin Architecture](https://banes-lab.com/records/architecture/plugin-architecture.md), [Extension Points](https://banes-lab.com/records/architecture/extension-points.md) Contracts [Extensibility Core](https://banes-lab.com/records/algorithms/extensibility-core.md) Tensions [Open/Closed Principle (OCP) / Simplicity](https://banes-lab.com/records/tension/open-closed-principle-ocp-simplicity.md) Distinct from [Composability](https://banes-lab.com/records/architecture/composability.md): The open/closed principle adds behavior without editing existing code, while composability combines parts through compatible interfaces. Violated by repeated modification of stable core for variants Detected by growing conditionals, repeated edits to central classes Measured by modification frequency of core modules Refactored by Extract Strategy, Add Extension Point, Introduce Plugin Enforced by extension policies, change analysis Refused by rules open-closed Before ```typescript function priceFoo(kind: string, value: number) { if (kind === "foo") return value; if (kind === "bar") return value * 2; throw new Error("unknown kind"); } ``` After ```typescript interface FooPricing { price(value: number): number; } const registry = new Map(); export function registerPricing(kind: string, pricing: FooPricing) { registry.set(kind, pricing); } export function priceFoo(kind: string, value: number) { const pricing = registry.get(kind); if (!pricing) throw new Error(`unknown kind ${kind}`); return pricing.price(value); } registerPricing("bar", { price: value => value * 2 }); ``` How it is checked Checked by extension policies, change analysis Population Every interface, class hierarchy and dependency edge in the object model Freshness A verdict stands until an interface, an override or a dependency changes Refusal The dependency rule or the contract test fails a change that breaks substitution, segregation or dependency direction Observation Interface usage, override contracts and dependency direction, read from source and contract tests Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The interface contract, which every implementation and override conforms to Depends on [Abstraction](https://banes-lab.com/records/architecture/abstraction.md), [Extension Points](https://banes-lab.com/records/architecture/extension-points.md), [Plugin Architecture](https://banes-lab.com/records/architecture/plugin-architecture.md), [Strategy Pattern](https://banes-lab.com/records/architecture/strategy-pattern.md), [Feature Extension without Modification](https://banes-lab.com/records/lexicon/feature-extension-without-modification.md) Shape it refuses [Switch-Based Extension](https://banes-lab.com/records/lexicon/switch-based-extension.md) ### Liskov Substitution Principle (LSP) - Kind: [principle](https://banes-lab.com/records/kind/principle.md) - Category: [SOLID / Object-Oriented Design](https://banes-lab.com/ontology/principles/architecture-category-solid-object-oriented-design.md) - Severity: [mandatory](https://banes-lab.com/records/vocabulary/severity-mandatory.md) - Scope: class, interface, type hierarchy - Aliases: LSP - Layer: [Structural Core](https://banes-lab.com/records/layer/structural-core.md) Details Definition A design rule that a subtype can replace its base type anywhere, because it keeps the base type's preconditions, postconditions and invariants. Requires [Contract Preservation](https://banes-lab.com/records/lexicon/contract-preservation.md), [Preconditions](https://banes-lab.com/records/architecture/preconditions.md), [Postconditions](https://banes-lab.com/records/architecture/postconditions.md), [Invariant](https://banes-lab.com/records/architecture/invariant.md) Reinforces [Polymorphism](https://banes-lab.com/records/architecture/polymorphism.md), [Type Safety](https://banes-lab.com/records/architecture/type-safety.md) Enables [Safe Substitution](https://banes-lab.com/records/lexicon/safe-substitution.md), [Substitutability](https://banes-lab.com/records/lexicon/substitutability.md) In tension with [Narrow Specialized Behavior](https://banes-lab.com/records/lexicon/narrow-specialized-behavior.md) Conflicts with [Broken Inheritance](https://banes-lab.com/records/lexicon/broken-inheritance.md), [Broken Inheritance](https://banes-lab.com/records/lexicon/broken-inheritance.md) Referenced by [Design by Contract](https://banes-lab.com/records/architecture/design-by-contract.md) Tensions [Liskov Substitution Principle (LSP) / Narrow Specialized Behavior](https://banes-lab.com/records/tension/liskov-substitution-principle-lsp-narrow-specialized-behavior.md) Violated by subclass weakening postconditions or strengthening preconditions Detected by overridden method contract divergence Measured by contract test pass rate across subtypes Refactored by Replace Inheritance, Extract Interface, Split Hierarchy Enforced by contract tests, type tests Before ```typescript class FooStore { save(foo: Foo): Promise { return persist(foo); } } class ReadOnlyFooStore extends FooStore { save(): Promise { throw new Error("not supported"); } } ``` After ```typescript class FooStore { save(foo: Foo): Promise { return persist(foo); } } class AuditedFooStore extends FooStore { async save(foo: Foo): Promise { const receipt = await super.save(foo); audit.record(receipt); return receipt; } } ``` How it is checked Checked by contract tests, type tests Population Every interface, class hierarchy and dependency edge in the object model Freshness A verdict stands until an interface, an override or a dependency changes Refusal The dependency rule or the contract test fails a change that breaks substitution, segregation or dependency direction Observation Interface usage, override contracts and dependency direction, read from source and contract tests Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The interface contract, which every implementation and override conforms to Depends on [Contract Preservation](https://banes-lab.com/records/lexicon/contract-preservation.md), [Preconditions](https://banes-lab.com/records/architecture/preconditions.md), [Postconditions](https://banes-lab.com/records/architecture/postconditions.md), [Invariant](https://banes-lab.com/records/architecture/invariant.md), [Polymorphism](https://banes-lab.com/records/architecture/polymorphism.md), [Type Safety](https://banes-lab.com/records/architecture/type-safety.md), [Safe Substitution](https://banes-lab.com/records/lexicon/safe-substitution.md), [Substitutability](https://banes-lab.com/records/lexicon/substitutability.md) Shape it refuses [Broken Inheritance](https://banes-lab.com/records/lexicon/broken-inheritance.md), [Broken Inheritance](https://banes-lab.com/records/lexicon/broken-inheritance.md) ### Polymorphism - Kind: [mechanism](https://banes-lab.com/records/kind/mechanism.md) - Category: [SOLID / Object-Oriented Design](https://banes-lab.com/ontology/principles/architecture-category-solid-object-oriented-design.md) - Severity: [recommended](https://banes-lab.com/records/vocabulary/severity-recommended.md) - Scope: class, interface, runtime - Layer: [Structural Core](https://banes-lab.com/records/layer/structural-core.md) Details Definition A mechanism that lets one interface have several implementations, with the implementation chosen by the object that receives the call. Requires [Abstraction](https://banes-lab.com/records/architecture/abstraction.md), [Substitutability](https://banes-lab.com/records/lexicon/substitutability.md) Reinforces [Open/Closed Principle (OCP)](https://banes-lab.com/records/architecture/open-closed.md), [Strategy Pattern](https://banes-lab.com/records/architecture/strategy-pattern.md) Enables [Dynamic Dispatch](https://banes-lab.com/records/architecture/dynamic-dispatch.md), [Interchangeability](https://banes-lab.com/records/architecture/interchangeability.md) In tension with [Traceability](https://banes-lab.com/records/architecture/traceability.md) Conflicts with [Type Switching](https://banes-lab.com/records/lexicon/type-switching.md) Referenced by [Dynamic Binding](https://banes-lab.com/records/architecture/dynamic-binding.md), [Dynamic Dispatch](https://banes-lab.com/records/architecture/dynamic-dispatch.md), [Abstraction](https://banes-lab.com/records/architecture/abstraction.md), [Interchangeability](https://banes-lab.com/records/architecture/interchangeability.md), [Liskov Substitution Principle (LSP)](https://banes-lab.com/records/architecture/liskov-substitution.md), [Strategy Pattern](https://banes-lab.com/records/architecture/strategy-pattern.md), [State Pattern](https://banes-lab.com/records/architecture/state-pattern.md), [Null Object Pattern](https://banes-lab.com/records/architecture/null-object-pattern.md) Tensions [Polymorphism / Traceability](https://banes-lab.com/records/tension/polymorphism-traceability.md) Distinct from [Dynamic Dispatch](https://banes-lab.com/records/architecture/dynamic-dispatch.md): Polymorphism is one interface with several implementations, while dynamic dispatch is the runtime selection of which one runs, from the receiver or a keyed table. Distinct from [Type Safety](https://banes-lab.com/records/architecture/type-safety.md): Polymorphism varies the implementation behind a type, while type safety rejects operations on the wrong type. Violated by instanceof/switch dispatch over types Detected by conditional type checks, duplicated branching Measured by polymorphic dispatch ratio Refactored by [Replace Conditional with Polymorphism](https://banes-lab.com/records/lexicon/replace-conditional-with-polymorphism.md) Enforced by [code review](https://banes-lab.com/records/architecture/code-review.md), static analysis rules Before ```typescript function renderFoo(kind: string, foo: Foo) { if (kind === "text") return foo.name; if (kind === "json") return JSON.stringify(foo); throw new Error("unknown renderer"); } ``` After ```typescript interface FooRenderer { render(foo: Foo): string; } class TextFooRenderer implements FooRenderer { render(foo: Foo) { return foo.name; } } class JsonFooRenderer implements FooRenderer { render(foo: Foo) { return JSON.stringify(foo); } } function renderFoo(renderer: FooRenderer, foo: Foo) { return renderer.render(foo); } ``` How it is checked Checked by code review, static analysis rules Population Every interface, class hierarchy and dependency edge in the object model Freshness A verdict stands until an interface, an override or a dependency changes Refusal The dependency rule or the contract test fails a change that breaks substitution, segregation or dependency direction Observation Interface usage, override contracts and dependency direction, read from source and contract tests Evidence None, because the catalog states this check as a class, so a watched run belongs to each system that adopts it Authoritative side The interface contract, which every implementation and override conforms to Depends on [Abstraction](https://banes-lab.com/records/architecture/abstraction.md), [Substitutability](https://banes-lab.com/records/lexicon/substitutability.md), [Open/Closed Principle (OCP)](https://banes-lab.com/records/architecture/open-closed.md), [Strategy Pattern](https://banes-lab.com/records/architecture/strategy-pattern.md), [Dynamic Dispatch](https://banes-lab.com/records/architecture/dynamic-dispatch.md), [Interchangeability](https://banes-lab.com/records/architecture/interchangeability.md) Shape it refuses [Type Switching](https://banes-lab.com/records/lexicon/type-switching.md) ## Links to - [principle](https://banes-lab.com/records/kind/principle.md) - [mandatory](https://banes-lab.com/records/vocabulary/severity-mandatory.md) - [Structural Core](https://banes-lab.com/records/layer/structural-core.md) - [Role-Specific Interfaces](https://banes-lab.com/records/lexicon/role-specific-interfaces.md) - [Single Responsibility Principle](https://banes-lab.com/records/architecture/single-responsibility.md) - [Low Coupling](https://banes-lab.com/records/architecture/low-coupling.md) - [Consumer-Specific Contracts](https://banes-lab.com/records/lexicon/consumer-specific-contracts.md) - [Interface Proliferation](https://banes-lab.com/records/lexicon/interface-proliferation.md) - [Fat Interface](https://banes-lab.com/records/lexicon/fat-interface.md) - [Repository Dump](https://banes-lab.com/records/architecture/repository-dump.md) - [Interface Segregation Principle (ISP) / Interface Proliferation](https://banes-lab.com/records/tension/interface-proliferation-interface-segregation-principle-isp.md) - [Abstraction](https://banes-lab.com/records/architecture/abstraction.md) - [Stable Interfaces](https://banes-lab.com/records/architecture/stable-interfaces.md) - [Clean Architecture](https://banes-lab.com/records/architecture/clean-architecture.md) - [Dependency Injection](https://banes-lab.com/records/architecture/dependency-injection.md) - [Ports and Adapters](https://banes-lab.com/records/lexicon/ports-and-adapters.md) - [Runtime Indirection](https://banes-lab.com/records/lexicon/runtime-indirection.md) - [Concrete Dependency](https://banes-lab.com/records/lexicon/concrete-dependency.md) - [Interface-Based Design](https://banes-lab.com/records/architecture/interface-based-design.md) - [Testability](https://banes-lab.com/records/architecture/testability.md) - [Replaceability](https://banes-lab.com/records/architecture/replaceability.md) - [Inversion of Control](https://banes-lab.com/records/architecture/inversion-of-control.md) - [Service Locator Pattern](https://banes-lab.com/records/architecture/service-locator-pattern.md) - [Ports and Adapters Architecture](https://banes-lab.com/records/architecture/ports-and-adapters-architecture.md) - [Dependency Inversion Principle (DIP) / Runtime Indirection](https://banes-lab.com/records/tension/dependency-inversion-principle-dip-runtime-indirection.md) - [recommended](https://banes-lab.com/records/vocabulary/severity-recommended.md) - [Extension Points](https://banes-lab.com/records/architecture/extension-points.md) - [Plugin Architecture](https://banes-lab.com/records/architecture/plugin-architecture.md) - [Strategy Pattern](https://banes-lab.com/records/architecture/strategy-pattern.md) - [Feature Extension without Modification](https://banes-lab.com/records/lexicon/feature-extension-without-modification.md) - [Simplicity](https://banes-lab.com/records/lexicon/simplicity.md) - [Switch-Based Extension](https://banes-lab.com/records/lexicon/switch-based-extension.md) - [Dynamic Dispatch](https://banes-lab.com/records/architecture/dynamic-dispatch.md) - [Runtime Extensibility](https://banes-lab.com/records/architecture/runtime-extensibility.md) - [Polymorphism](https://banes-lab.com/records/architecture/polymorphism.md) - [Command Pattern](https://banes-lab.com/records/architecture/command-pattern.md) - [State Pattern](https://banes-lab.com/records/architecture/state-pattern.md) - [Chain of Responsibility Pattern](https://banes-lab.com/records/architecture/chain-of-responsibility-pattern.md) - [Visitor Pattern](https://banes-lab.com/records/architecture/visitor-pattern.md) - [Factory Pattern](https://banes-lab.com/records/architecture/factory-pattern.md) - [Factory Method Pattern](https://banes-lab.com/records/architecture/factory-method-pattern.md) - [Decorator Pattern](https://banes-lab.com/records/architecture/decorator-pattern.md) - [Composite Pattern](https://banes-lab.com/records/architecture/composite-pattern.md) - [Extensibility Core](https://banes-lab.com/records/algorithms/extensibility-core.md) - [Open/Closed Principle (OCP) / Simplicity](https://banes-lab.com/records/tension/open-closed-principle-ocp-simplicity.md) - [Composability](https://banes-lab.com/records/architecture/composability.md) - [Contract Preservation](https://banes-lab.com/records/lexicon/contract-preservation.md) - [Preconditions](https://banes-lab.com/records/architecture/preconditions.md) - [Postconditions](https://banes-lab.com/records/architecture/postconditions.md) - [Invariant](https://banes-lab.com/records/architecture/invariant.md) - [Type Safety](https://banes-lab.com/records/architecture/type-safety.md) - [Safe Substitution](https://banes-lab.com/records/lexicon/safe-substitution.md) - [Substitutability](https://banes-lab.com/records/lexicon/substitutability.md) - [Narrow Specialized Behavior](https://banes-lab.com/records/lexicon/narrow-specialized-behavior.md) - [Broken Inheritance](https://banes-lab.com/records/lexicon/broken-inheritance.md) - [Design by Contract](https://banes-lab.com/records/architecture/design-by-contract.md) - [Liskov Substitution Principle (LSP) / Narrow Specialized Behavior](https://banes-lab.com/records/tension/liskov-substitution-principle-lsp-narrow-specialized-behavior.md) - [mechanism](https://banes-lab.com/records/kind/mechanism.md) - [Open/Closed Principle](https://banes-lab.com/records/architecture/open-closed.md) - [Interchangeability](https://banes-lab.com/records/architecture/interchangeability.md) - [Traceability](https://banes-lab.com/records/architecture/traceability.md) - [Type Switching](https://banes-lab.com/records/lexicon/type-switching.md) - [Dynamic Binding](https://banes-lab.com/records/architecture/dynamic-binding.md) - [Liskov Substitution Principle](https://banes-lab.com/records/architecture/liskov-substitution.md) - [Null Object Pattern](https://banes-lab.com/records/architecture/null-object-pattern.md) - [Polymorphism / Traceability](https://banes-lab.com/records/tension/polymorphism-traceability.md) - [Replace Conditional with Polymorphism](https://banes-lab.com/records/lexicon/replace-conditional-with-polymorphism.md) - [Code Review](https://banes-lab.com/records/architecture/code-review.md) ## Linked from - [The layer topology](https://banes-lab.com/ontology/schema/the-layer-topology.md) - [The membership](https://banes-lab.com/ontology/schema/the-membership.md)