---
title: "Generation gap (pattern)"
chunk: 1/1
source: "https://en.wikipedia.org/wiki/Generation_gap_(pattern)"
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T11:34:05.887524+00:00"
instance: "kb-cron"
---

Generation gap is a software design pattern documented by John Vlissides that treats automatically generated code differently than code that was written by a developer. Modifications should not be made to generated code, as they would be overwritten if the code generation process was ever re-run, such as during recompilation.  Vlissides proposed creating a subclass of the generated code which contains the desired modification. This might be considered an example of the template method pattern.


== Modern languages ==
Modern byte-code language like Java were in their early stages when Vlissides developed his ideas. In a language like C# or Java, this pattern may be followed by generating an interface, which is a completely abstract class. The developer would then hand-modify a concrete implementation of the generated interface.
C# have support for partial classes which is a class whose definition may be split into multiple pieces, within a single source-code file or across multiple files.


== References ==