IM3Token<T> class abstract interface

Base interface for all Material Design 3 design tokens.

This interface defines the core contract that all Material Design 3 tokens must implement. Design tokens are the atomic values that define the visual properties of a design system, including colors, typography, spacing, borders, and more.

The generic type T represents the underlying value type of the token, such as Color, double, TextStyle, or custom types.

Design Token Philosophy

Material Design 3 uses a three-tier token architecture:

  1. Reference tokens: Raw values (e.g., primary color palette)
  2. System tokens: Semantic meanings (e.g., primary color role)
  3. Component tokens: Component-specific values (e.g., button color)

This interface serves as the foundation for all token types, ensuring consistency and type safety throughout the design system.

Usage

Typically, you won't implement this interface directly. Instead, use it through concrete token enums like M3SpacingToken or M3BorderWidthToken:

// System tokens implement this interface
IM3Token<double> spacingToken = M3SpacingToken.space16;
double spacing = spacingToken.value; // 16.0

// Generic token handling
T getTokenValue<T>(IM3Token<T> token) => token.value;

Type Safety

The generic type parameter ensures compile-time type safety when working with different token types:

IM3Token<Color> colorToken = M3SysColor.primary;
IM3Token<double> sizeToken = M3SpacingToken.space24;
IM3Token<TextStyle> textToken = M3TextStyle.bodyLarge;

Implementation Guidelines

When implementing this interface in new token types:

  • Use enums for discrete token sets
  • Provide comprehensive documentation for each token value
  • Follow Material Design 3 naming conventions
  • Ensure immutability with the @immutable annotation

Reference: https://m3.material.io/foundations/design-tokens

Implementers
Annotations

Properties

hashCode → int
The hash code for this object.
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
value → T
The actual value represented by this design token.
no setter

Methods

noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited