Simplify anti-corrosion layer design using Kotlin

Simplifying Anti-Corruption Layer Design Using Kotlin#

Kotlin Reference#

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Java Anti-Corruption Layer#

package Anti-Corruption-Layer {
	component Interface {
		interface InterfaceDefinition
	}
	component Implementation {
		class InterfaceImplementation
	}
	InterfaceImplementation --|> InterfaceDefinition
}
package Application {
	component Feature {
	}
	
	component App {
	}
}
Feature --> Interface
App --> Feature
App --> Implementation

To prevent the Feature component from directly using the Interface Implementation, the Interface Implementation needs to be separated into a standalone Implementation component. The Feature component should only depend on the Interface component.

Kotlin Anti-Corruption Layer#

package Anti-Corruption-Layer {
	interface InterfaceDefinition
	class InterfaceImplementation
	note left: Package visibility
	InterfaceImplementation --|> InterfaceDefinition
}
package Application {
	component App {
	}
	component Feature {
	}
	App --> Feature
	Feature --> Anti-Corruption-Layer
}

Since Kotlin's package visibility can prevent the Feature component from directly using the Interface Implementation, there is no need to separate the Interface Implementation into a separate component when using Kotlin. This reduces the overall number of components, making it easier to understand and maintain.

Note#

Kotlin's package visibility only applies to Kotlin, so when Java uses a library written in Kotlin, it cannot prevent Java from directly using the Interface Implementation.