# Creational Patterns > Every principle in this category is listed as a record. Page: Ontology · Principles Canonical: https://banes-lab.com/ontology#architecture-category-creational-patterns Listed in [Ontology · Principles](https://banes-lab.com/api/pages/ontology/principles.md), after [Behavioral Patterns](https://banes-lab.com/ontology/principles/architecture-category-behavioral-patterns.md) and before [Structural Patterns](https://banes-lab.com/ontology/principles/architecture-category-structural-patterns.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_factory_pattern["Factory Pattern"] n_factory_method_pattern["Factory Method Pattern"] n_abstract_factory_pattern["Abstract Factory Pattern"] n_builder_pattern["Builder Pattern"] n_prototype_pattern["Prototype Pattern"] n_singleton_pattern["Singleton Pattern"] ``` ### Factory Pattern - Kind: [pattern](https://banes-lab.com/records/kind/pattern.md) - Category: [Creational Patterns](https://banes-lab.com/ontology/principles/architecture-category-creational-patterns.md) - Severity: [recommended](https://banes-lab.com/records/vocabulary/severity-recommended.md) - Scope: [object_creation](https://banes-lab.com/records/force/object-creation.md), module - Layer: [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md) Details Definition A design pattern that moves the construction of an object and its defaults into one function or object. Requires [Creation Variation](https://banes-lab.com/records/lexicon/creation-variation.md) Reinforces [Open/Closed Principle (OCP)](https://banes-lab.com/records/architecture/open-closed.md), [Encapsulation](https://banes-lab.com/records/architecture/encapsulation.md) Enables [Polymorphic Construction](https://banes-lab.com/records/lexicon/polymorphic-construction.md) In tension with [Simplicity](https://banes-lab.com/records/lexicon/simplicity.md) Conflicts with [Scattered Construction Logic](https://banes-lab.com/records/lexicon/scattered-construction-logic.md) Referenced by [Registry Pattern](https://banes-lab.com/records/architecture/registry-pattern.md) Tensions [Factory Pattern / Simplicity](https://banes-lab.com/records/tension/factory-pattern-simplicity.md) Violated by duplicated conditional construction Detected by repeated constructors/switches Measured by construction duplication count Refactored by Extract Factory Enforced by creation policy review Before ```typescript const foo = new Foo("foo", 0, [], new Date(), "draft"); ``` After ```typescript function makeFoo(name: string): Foo { return new Foo(fooId(), name, 0, [], clock.now(), "draft"); } ``` How it is checked Checked by creation policy review Population Every construction site of the types the pattern governs Freshness A verdict stands until a constructor, a variant or the composition root changes Refusal The review or the construction test rejects a construction that bypasses the creational owner Observation Constructor call sites and their argument counts, read from source 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 creational owner, which every construction site goes through Depends on [Creation Variation](https://banes-lab.com/records/lexicon/creation-variation.md), [Open/Closed Principle (OCP)](https://banes-lab.com/records/architecture/open-closed.md), [Encapsulation](https://banes-lab.com/records/architecture/encapsulation.md), [Polymorphic Construction](https://banes-lab.com/records/lexicon/polymorphic-construction.md) Shape it refuses [Scattered Construction Logic](https://banes-lab.com/records/lexicon/scattered-construction-logic.md) ### Factory Method Pattern - Kind: [pattern](https://banes-lab.com/records/kind/pattern.md) - Category: [Creational Patterns](https://banes-lab.com/ontology/principles/architecture-category-creational-patterns.md) - Severity: [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md) - Scope: class hierarchy, framework - Layer: [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md) Details Definition A design pattern in which a base class calls an overridable method to create the objects its workflow uses. Requires [Subclass-Controlled Creation](https://banes-lab.com/records/lexicon/subclass-controlled-creation.md) Reinforces [Open/Closed Principle (OCP)](https://banes-lab.com/records/architecture/open-closed.md) Enables [Deferred Instantiation](https://banes-lab.com/records/lexicon/deferred-instantiation.md) In tension with [Inheritance Complexity](https://banes-lab.com/records/lexicon/inheritance-complexity.md) Conflicts with [Concrete Constructor Coupling](https://banes-lab.com/records/lexicon/concrete-constructor-coupling.md) Tensions [Factory Method Pattern / Inheritance Complexity](https://banes-lab.com/records/tension/factory-method-pattern-inheritance-complexity.md) Violated by fixed construction in base workflow Detected by base class directly instantiates variant Measured by variant construction duplication Refactored by Introduce Factory Method Enforced by [design review](https://banes-lab.com/records/architecture/design-review.md) Before ```typescript class FooImporter { import(raw: string) { return new JsonFooParser().parse(raw); } } ``` After ```typescript abstract class FooImporter { protected abstract parser(): FooParser; import(raw: string) { return this.parser().parse(raw); } } class JsonFooImporter extends FooImporter { protected parser() { return new JsonFooParser(); } } ``` How it is checked Checked by design review Population Every construction site of the types the pattern governs Freshness A verdict stands until a constructor, a variant or the composition root changes Refusal The review or the construction test rejects a construction that bypasses the creational owner Observation Constructor call sites and their argument counts, read from source 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 creational owner, which every construction site goes through Depends on [Subclass-Controlled Creation](https://banes-lab.com/records/lexicon/subclass-controlled-creation.md), [Open/Closed Principle (OCP)](https://banes-lab.com/records/architecture/open-closed.md), [Deferred Instantiation](https://banes-lab.com/records/lexicon/deferred-instantiation.md) Shape it refuses [Concrete Constructor Coupling](https://banes-lab.com/records/lexicon/concrete-constructor-coupling.md) ### Abstract Factory Pattern - Kind: [pattern](https://banes-lab.com/records/kind/pattern.md) - Category: [Creational Patterns](https://banes-lab.com/ontology/principles/architecture-category-creational-patterns.md) - Severity: [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md) - Scope: product family, component - Layer: [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md) Details Definition A design pattern that creates a whole family of related objects through one interface, so the members always match. Requires [Related Product Variants](https://banes-lab.com/records/lexicon/related-product-variants.md) Reinforces [Interchangeability](https://banes-lab.com/records/architecture/interchangeability.md) Enables [Family-Level Replacement](https://banes-lab.com/records/lexicon/family-level-replacement.md) In tension with [Boilerplate](https://banes-lab.com/records/lexicon/boilerplate.md) Conflicts with [Mixed Product Families](https://banes-lab.com/records/lexicon/mixed-product-families.md) Tensions [Abstract Factory Pattern / Boilerplate](https://banes-lab.com/records/tension/abstract-factory-pattern-boilerplate.md) Violated by incompatible product combinations Detected by manual selection of related product classes Measured by family mismatch defects Refactored by Introduce Abstract Factory Enforced by factory conformance tests Before ```typescript const store = env === "test" ? new MemoryFooStore() : new SqlFooStore(); const bus = env === "test" ? new MemoryFooBus() : new KafkaFooBus(); ``` After ```typescript interface FooPlatformFactory { store(): FooStore; bus(): FooBus; } class TestFooPlatformFactory implements FooPlatformFactory { store() { return new MemoryFooStore(); } bus() { return new MemoryFooBus(); } } ``` How it is checked Checked by factory conformance tests Population Every construction site of the types the pattern governs Freshness A verdict stands until a constructor, a variant or the composition root changes Refusal The review or the construction test rejects a construction that bypasses the creational owner Observation Constructor call sites and their argument counts, read from source 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 creational owner, which every construction site goes through Depends on [Related Product Variants](https://banes-lab.com/records/lexicon/related-product-variants.md), [Interchangeability](https://banes-lab.com/records/architecture/interchangeability.md), [Family-Level Replacement](https://banes-lab.com/records/lexicon/family-level-replacement.md) Shape it refuses [Mixed Product Families](https://banes-lab.com/records/lexicon/mixed-product-families.md) ### Builder Pattern - Kind: [pattern](https://banes-lab.com/records/kind/pattern.md) - Category: [Creational Patterns](https://banes-lab.com/ontology/principles/architecture-category-creational-patterns.md) - Severity: [recommended](https://banes-lab.com/records/vocabulary/severity-recommended.md) - Scope: object construction, API - Layer: [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md) Details Definition A design pattern that assembles a complex object step by step through named calls and validates it when it is built. Requires [Complex Construction](https://banes-lab.com/records/lexicon/complex-construction.md) Reinforces [Intent-Revealing Interface](https://banes-lab.com/records/architecture/intent-revealing-interface.md) Enables [Valid Object Creation](https://banes-lab.com/records/lexicon/valid-object-creation.md) In tension with [Boilerplate](https://banes-lab.com/records/lexicon/boilerplate.md) Conflicts with [Telescoping Constructor](https://banes-lab.com/records/lexicon/telescoping-constructor.md) Tensions [Builder Pattern / Boilerplate](https://banes-lab.com/records/tension/boilerplate-builder-pattern.md) Violated by constructors with many optional params Detected by high-arity constructors Measured by constructor parameter count Refactored by Introduce Builder Enforced by API review Before ```typescript const foo = new Foo("foo_1", "Foo", [], 0, false, undefined, "draft"); ``` After ```typescript const foo = new FooBuilder() .withId("foo_1") .withName("Foo") .withStatus("draft") .build(); ``` How it is checked Checked by API review Population Every construction site of the types the pattern governs Freshness A verdict stands until a constructor, a variant or the composition root changes Refusal The review or the construction test rejects a construction that bypasses the creational owner Observation Constructor call sites and their argument counts, read from source 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 creational owner, which every construction site goes through Depends on [Complex Construction](https://banes-lab.com/records/lexicon/complex-construction.md), [Intent-Revealing Interface](https://banes-lab.com/records/architecture/intent-revealing-interface.md), [Valid Object Creation](https://banes-lab.com/records/lexicon/valid-object-creation.md) Shape it refuses [Telescoping Constructor](https://banes-lab.com/records/lexicon/telescoping-constructor.md) ### Prototype Pattern - Kind: [pattern](https://banes-lab.com/records/kind/pattern.md) - Category: [Creational Patterns](https://banes-lab.com/ontology/principles/architecture-category-creational-patterns.md) - Severity: [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md) - Scope: [object_creation](https://banes-lab.com/records/force/object-creation.md), runtime - Layer: [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md) Details Definition A design pattern that creates new objects by cloning a prepared template and applying overrides. Requires [Cloneable Template Object](https://banes-lab.com/records/lexicon/cloneable-template-object.md) Reinforces [Runtime Extensibility](https://banes-lab.com/records/architecture/runtime-extensibility.md) Enables [Dynamic Object Creation](https://banes-lab.com/records/lexicon/dynamic-object-creation.md) In tension with [Copy Semantics](https://banes-lab.com/records/lexicon/copy-semantics.md) Conflicts with [Complex Factory Hierarchies](https://banes-lab.com/records/lexicon/complex-factory-hierarchies.md) Tensions [Prototype Pattern / Copy Semantics](https://banes-lab.com/records/tension/copy-semantics-prototype-pattern.md) Violated by expensive repeated setup Detected by duplicate initialization flows Measured by initialization duplication/cost Refactored by Introduce Prototype, Add Clone Semantics Enforced by clone tests Before ```typescript function copyFoo(foo: Foo) { return new Foo(foo.id, foo.name, [...foo.tags], foo.settings.theme, foo.settings.mode); } ``` After ```typescript class FooPrototype { constructor(private readonly base: Foo) {} clone(overrides: Partial = {}): Foo { return structuredClone({ ...this.base, ...overrides }); } } const template = new FooPrototype(await buildExpensiveFoo()); const draft = template.clone({ name: "quick" }); ``` How it is checked Checked by clone tests Population Every construction site of the types the pattern governs Freshness A verdict stands until a constructor, a variant or the composition root changes Refusal The review or the construction test rejects a construction that bypasses the creational owner Observation Constructor call sites and their argument counts, read from source 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 creational owner, which every construction site goes through Depends on [Cloneable Template Object](https://banes-lab.com/records/lexicon/cloneable-template-object.md), [Runtime Extensibility](https://banes-lab.com/records/architecture/runtime-extensibility.md), [Dynamic Object Creation](https://banes-lab.com/records/lexicon/dynamic-object-creation.md) Shape it refuses [Complex Factory Hierarchies](https://banes-lab.com/records/lexicon/complex-factory-hierarchies.md) ### Singleton Pattern - Kind: [pattern](https://banes-lab.com/records/kind/pattern.md) - Category: [Creational Patterns](https://banes-lab.com/ontology/principles/architecture-category-creational-patterns.md) - Severity: [discouraged](https://banes-lab.com/records/vocabulary/severity-discouraged.md) - Scope: [object_creation](https://banes-lab.com/records/force/object-creation.md), lifetime, composition root - Layer: [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md) Details Definition A design pattern that restricts a class to one instance, reached through a global access point. Requires [Single-Instance Need](https://banes-lab.com/records/lexicon/single-instance-need.md) Reinforces [Controlled Instantiation](https://banes-lab.com/records/lexicon/controlled-instantiation.md) Enables [Shared Resource Access](https://banes-lab.com/records/lexicon/shared-resource-access.md) In tension with [Testability](https://banes-lab.com/records/architecture/testability.md), [Dependency Injection](https://banes-lab.com/records/architecture/dependency-injection.md) Conflicts with [Global Mutable State](https://banes-lab.com/records/lexicon/global-mutable-state.md) Tensions [Singleton Pattern / Testability](https://banes-lab.com/records/tension/singleton-pattern-testability.md), [Singleton Pattern / Dependency Injection](https://banes-lab.com/records/tension/dependency-injection-singleton-pattern.md) Violated by a global mutable instance reached from anywhere Detected by static global access to a shared service Measured by global-instance reach-in count Refactored by Compose Single Instance at the Root, Inject It Enforced by composition-root review Before ```typescript let instance: FooService | undefined; function getFooService() { return instance ??= new FooService(); } ``` After ```typescript class FooService {} export function composeApp() { const fooService = new FooService(); return { fooService, fooController: new FooController(fooService) }; } ``` How it is checked Checked by composition-root review Population Every construction site of the types the pattern governs Freshness A verdict stands until a constructor, a variant or the composition root changes Refusal The review or the construction test rejects a construction that bypasses the creational owner Observation Constructor call sites and their argument counts, read from source 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 creational owner, which every construction site goes through Depends on [Single-Instance Need](https://banes-lab.com/records/lexicon/single-instance-need.md), [Controlled Instantiation](https://banes-lab.com/records/lexicon/controlled-instantiation.md), [Shared Resource Access](https://banes-lab.com/records/lexicon/shared-resource-access.md) Shape it refuses [Global Mutable State](https://banes-lab.com/records/lexicon/global-mutable-state.md) ## Links to - [pattern](https://banes-lab.com/records/kind/pattern.md) - [recommended](https://banes-lab.com/records/vocabulary/severity-recommended.md) - [Object creation](https://banes-lab.com/records/force/object-creation.md) - [Design Patterns Core](https://banes-lab.com/records/layer/design-patterns-core.md) - [Creation Variation](https://banes-lab.com/records/lexicon/creation-variation.md) - [Open/Closed Principle](https://banes-lab.com/records/architecture/open-closed.md) - [Encapsulation](https://banes-lab.com/records/architecture/encapsulation.md) - [Polymorphic Construction](https://banes-lab.com/records/lexicon/polymorphic-construction.md) - [Simplicity](https://banes-lab.com/records/lexicon/simplicity.md) - [Scattered Construction Logic](https://banes-lab.com/records/lexicon/scattered-construction-logic.md) - [Registry Pattern](https://banes-lab.com/records/architecture/registry-pattern.md) - [Factory Pattern / Simplicity](https://banes-lab.com/records/tension/factory-pattern-simplicity.md) - [contextual](https://banes-lab.com/records/vocabulary/severity-contextual.md) - [Subclass-Controlled Creation](https://banes-lab.com/records/lexicon/subclass-controlled-creation.md) - [Deferred Instantiation](https://banes-lab.com/records/lexicon/deferred-instantiation.md) - [Inheritance Complexity](https://banes-lab.com/records/lexicon/inheritance-complexity.md) - [Concrete Constructor Coupling](https://banes-lab.com/records/lexicon/concrete-constructor-coupling.md) - [Factory Method Pattern / Inheritance Complexity](https://banes-lab.com/records/tension/factory-method-pattern-inheritance-complexity.md) - [Design Review](https://banes-lab.com/records/architecture/design-review.md) - [Related Product Variants](https://banes-lab.com/records/lexicon/related-product-variants.md) - [Interchangeability](https://banes-lab.com/records/architecture/interchangeability.md) - [Family-Level Replacement](https://banes-lab.com/records/lexicon/family-level-replacement.md) - [Boilerplate](https://banes-lab.com/records/lexicon/boilerplate.md) - [Mixed Product Families](https://banes-lab.com/records/lexicon/mixed-product-families.md) - [Abstract Factory Pattern / Boilerplate](https://banes-lab.com/records/tension/abstract-factory-pattern-boilerplate.md) - [Complex Construction](https://banes-lab.com/records/lexicon/complex-construction.md) - [Intent-Revealing Interface](https://banes-lab.com/records/architecture/intent-revealing-interface.md) - [Valid Object Creation](https://banes-lab.com/records/lexicon/valid-object-creation.md) - [Telescoping Constructor](https://banes-lab.com/records/lexicon/telescoping-constructor.md) - [Builder Pattern / Boilerplate](https://banes-lab.com/records/tension/boilerplate-builder-pattern.md) - [Cloneable Template Object](https://banes-lab.com/records/lexicon/cloneable-template-object.md) - [Runtime Extensibility](https://banes-lab.com/records/architecture/runtime-extensibility.md) - [Dynamic Object Creation](https://banes-lab.com/records/lexicon/dynamic-object-creation.md) - [Copy Semantics](https://banes-lab.com/records/lexicon/copy-semantics.md) - [Complex Factory Hierarchies](https://banes-lab.com/records/lexicon/complex-factory-hierarchies.md) - [Prototype Pattern / Copy Semantics](https://banes-lab.com/records/tension/copy-semantics-prototype-pattern.md) - [discouraged](https://banes-lab.com/records/vocabulary/severity-discouraged.md) - [Single-Instance Need](https://banes-lab.com/records/lexicon/single-instance-need.md) - [Controlled Instantiation](https://banes-lab.com/records/lexicon/controlled-instantiation.md) - [Shared Resource Access](https://banes-lab.com/records/lexicon/shared-resource-access.md) - [Testability](https://banes-lab.com/records/architecture/testability.md) - [Dependency Injection](https://banes-lab.com/records/architecture/dependency-injection.md) - [Global Mutable State](https://banes-lab.com/records/lexicon/global-mutable-state.md) - [Singleton Pattern / Testability](https://banes-lab.com/records/tension/singleton-pattern-testability.md) - [Singleton Pattern / Dependency Injection](https://banes-lab.com/records/tension/dependency-injection-singleton-pattern.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)