This document describes a software architecture that satisfies the need for an integrated and flexible interface to multiple, heterogenous computer systems.
Todays developments in user interfaces focus on usability and appeal, which creates an awesome world of great apps and sites. However, from an end user perspective, the user interface (as a whole) suffers from fragmentation and an exaggerated individualism. Most user interfaces adapt to a companies brand and business goals, but not to the users needs.
Looking at how user interfaces are implemented and integrated, the means are quite low-level. The implementation happens in terms of standard and custom-made graphical elements like images, bars, buttons and boxes. If a clear separation from business logic exists, it happens through individually designed interfaces, either consisting of simple method calls, or loosely adhering to communication protocols like SOAP and REST. Most often, these interfaces transport data, but do only offer few (if none at all) hints on the superior structure, relationships and semantics of the data.
This contrasts to the information actually described by the data. The information always obeys to a superior structure, having clear relationships and a well-defined semantics -- because otherwise, no human user would be able to understand and use the interfaces. Therefore, we have a gap between the information transported and the means of transportation. Specifically, there is no general model that describes interfaces between user and business logic. But without a model there might might be no abstract reasoning and no generic logic regarding the user interface.
Filling this gap by providing a common interface model for multiple different, heterogenous backend systems allows us to provide the user with one integrated and flexible user interface. We can develop general logic and reason about how the user interface can adopt to the user's needs, e.g. splitting the display between different devices, without considering the concrete application. Besides, an integrated interface model allows us to develop software operating on these heterogenous backend systems, regardless of the singular interface technologies they use.
Hereby, a computer system is any system that offers its functionality via an interface to third party software. An interface could be e.g. REST, SOAP, RPC or simple commandline calls.
An interface could possibly be
- a graphical user interface (GUI).
- a textual user interface.
- an interface for users with disabilities, for example providing only haptic or acoustic input and output.
- an interface for automatic service discovery through third party software.
- an application programmer's interface (API).
Thus, Universal Gateway aims to integrate multiple systems into one unified interface, and therefore separates service from interface. This allows
- users to use multiple, heterogenous services through one common, unified and then well-known interface.
- developers to focus on service implementation. It is not necessary to go through all the user interface design for every application (but should still be possible, if wanted).
- developers to focus on interface implementation. By improving the interfaces provided through the Universal Gateway, a benefit for users of many different applications can be created.
Possible user stories of an integrated graphical user interface could be as follows.
- The user reconfigures the user interface to adapt it to his habits.
- The user interface proposes automatic reconfiguration to the user, based on how frequent and in what relationship the user interacted with UI elements.
- The user connects multiple of his devices over a network, allowing him to
combine the user interfaces. Examples:
- The user connects is mobile device to his television, so that he can use his mobile device as a remote control.
- The user connects his mobile device to his television, so that he can use the television as a larger screen for data retrieved on the mobile device.
- The user connects his tablet to a couple of virtual machines, controlling the VMs from his tablet.
- OpenAPI Initiative, specifying a common description language for REST services. It's a great source of information about a single REST interface, but does not currently describe interaction/integration between multiple interfaces. It is also not possible to enrich the description, i.e. with presentation information. Moreover, Universal Gateway aims to use the pipes and filters approach, which OpenAPI doesn't.
- IFML, the Interaction Flow Modelling Language, expresses user interaction and content. (Todo: go into more detail. Comparison.)
In Star Trek®, computer systems are accessed using the LCARS, which can be perceived as a unified graphical user interface. Every since I was a child, I wondered whether this could be a valid approach for computer systems. This specification is my attempt to research this idea.
Copyright (c) 2016-17 Felix Neumann.
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