Interacto: A Modern User Interaction Processing Model

TL;DR

Interacto introduces a high-level user interaction processing model that enhances modularity, reusability, and testability of modern UIs by reifying user interactions and supporting advanced features like undo/redo.

Contribution

It proposes Interacto, a novel high-level interaction model that addresses flaws of traditional low-level UI event processing frameworks, enabling better design and testing of complex UIs.

Findings

Successful implementation in open source projects for Java/JavaFX and TypeScript/Angular.

Positive evaluation through a real-world case study since 2013.

Controlled experiment with 44 students showing advantages over traditional frameworks.

Abstract

Since most software systems provide their users with interactive features, building user interfaces (UI) is one of the core software engineering tasks. It consists in designing, implementing and testing ever more sophisticated and versatile ways for users to interact with software systems, and safely connecting these interactions with commands querying or modifying their state. However, most UI frameworks still rely on a low level model, the bare bone UI event processing model. This model was suitable for the rather simple UIs of the early 80s (menus, buttons, keyboards, mouse clicks), but now exhibits major software engineering flaws for modern, highly interactive UIs. These flaws include lack of separation of concerns, weak modularity and thus low reusability of code for advanced interactions, as well as low testability. To mitigate these flaws, we propose Interacto as a high level user interaction processing model. By reifying the concept of user interaction, Interacto makes it easy to design, implement and test modular and reusable advanced user interactions, and to connect them to commands with built-in undo/redo support. To demonstrate its applicability and generality, we briefly present two open source implementations of Interacto for Java/JavaFX and TypeScript/Angular. We evaluate Interacto interest (1) on a real world case study, where it has been used since 2013, and with (2) a controlled experiment with 44 master students, comparing it with traditionnal UI frameworks.