Antero Taivalsaari

On the notion of inheritance

One of the most intriguing—and at the same time most problematic—notions in object-oriented programing is inheritance. Inheritance is commonly regarded as the feature that distinguishes object-oriented programming from other modern programming paradigms, but researchers rarely agree on its meaning and usage. Yet inheritance of often hailed as a solution to many problems hampering software development, and many of the alleged benefits of object-oriented programming, such as improved conceptual modeling and reusability, are largely credited to it. This article aims at a comprehensive understanding of inheritance, examining its usage, surveying its varieties, and presenting a simple taxonomy of mechanisms that can be seen as underlying different inheritance models.

Web Applications Spaghetti Code for the 21st Century

The software industry is currently in the middle of a paradigm shift. Applications are increasingly written for the World Wide Web. Unfortunately, the technologies used for Web application development today violate well-known software engineering principles, and they have reintroduced problems that had already been eliminated years ago in the aftermath of the ldquospaghetti code warsrdquo of the 1970s. In this paper, we investigate Web application development from the viewpoint of software engineering principles. We argue that current Web technologies are inadequate in supporting many of these principles, but also that there is no fundamental reason for Web applications to be any worse than conventional applications in any of these areas. Rather, the current inadequacies are an accidental consequence of the poor conceptual and technological foundation of the Web development technologies today.

The Lively Kernel A Self-supporting System on a Web Page

The Lively Kernel is a complete platform for Web programming written in JavaScriptTM using graphics available in leading browsers. A widget set built from these elements provides a user interface kit, and the widget set is also extensible. A window-based IDE allows users to edit their applications and even the system itself.When a user visits the Lively Kernel page, http://research.sun.com/projects/lively/index.xhtml the kernel loads and runs with no installation whatsoever. The user can immediately construct new objects or applications and manipulate the environment. The Lively Kernel is able to save its creations, and even clone itself, onto Web pages. In so doing, it defines a new form of dynamic content on the Web. Moreover, since it can run in todays browsers, it promises that wherever there is the Internet, there can be authoring of Web content. Beyond its utility, the simplicity and completeness of the Lively Kernel make it a practical benchmark of system complexity, and a flexible laboratory for exploring new approaches to security, simplified graphics, and Web technologies in general. Note to Readers: As of this writing, the Lively Kernel runs with no installation in the Firefox 3 beta and Safari 3 browsers. We are preparing an applet that will allow it to run in other browsers until their internal graphics are adequate for install-free operation

The Web as an Application Platform: The Saga Continues

The World Wide Web is the most powerful medium for information sharing and distribution in the history of humankind. In this paper we take a look at the evolution of the Web from a relatively simple document sharing system to a massively popular, general purpose application and content distribution environment. We focus especially on the rapidly increasing use of the Web as a software platform. So far, a number of obstacles have hindered the development and deployment of full-fledged, truly interactive web applications. However, emerging standards such as HTML5 and Web GLare removing the limitations, and transforming the Web into a real application platform. We believe that in the future the use of conventional binary programs will be limited to system software, whereas the vast majority of end user software will be developed using web technologies.

Web Browser as an Application Platform

For better or worse, the web browser has become a widely used target platform for software applications. Desktop-style applications such as word processors, spreadsheets, calendars, games and instant messaging systems that were earlier written for specific operating systems, CPU architectures or devices are now written for the World Wide Web, to be used from a web browser. In this paper we summarize our experiences in using the web browser as a target platform for real applications. As a concrete example, we use the Sun¿ Labs Lively Kernel, a system that implements an exceptionally interactive web programming environment running in a web browser without any plug-in components. Based on this work, we analyze the limitations, challenges and opportunities related to the web browser as an application platform.

Transforming the web into a real application platform: new technologies, emerging trends and missing pieces

The World Wide Web has evolved from a simple document browsing and distribution environment into a rich software platform in which desktop-style applications are increasingly becoming first class citizens. The document-oriented origins of the Web are still evident in many areas, though, and traditionally it has been difficult to compose truly interactive web applications without using plug-in components or browser extensions such as Flash. However, the ongoing standardization work and emerging technologies such as HTML5, JavaScript 2.0 and WebGL are quickly altering the landscape of web application development. In this paper, we present a number of prior challenges and shortcomings, and describe how new technologies can be used for solving many of the problems. The research is based on our hands-on experiences in building various web-based systems in which a number of different web application development technologies have been used extensively.

Liquid Software Manifesto: The Era of Multiple Device Ownership and Its Implications for Software Architecture

Today, the digital life of people in developed markets is dominated by PCs and smart phones. Yet, as successful as PCs and smart phones are, the dominant era of PCs and smart phones is about to come to an end. Device shipment trends indicate that the number of web-enabled devices other than PCs and smart phones will grow rapidly. In the near future, people will commonly use various types of internet-connected devices in their daily lives. Unlike today, no single device will dominate the users digital life. The transition to a world of multiple device ownership is still rife with problems. Since devices are mostly standalone and only stay in sync in limited ways, the users will have to spend a lot of time managing them. These device management chores become much more tedious as the number of devices in a persons life increases. In this paper we look at the ongoing paradigm shift towards multiple device ownership and its implications for software architecture. We argue that the transition to multiple device ownership will eventually lead us to liquid software - an approach that will allow data and applications to seamlessly move between multiple devices and screens. The new era will imply significant changes in the development, deployment and use of software, opening up new opportunities in software engineering research as well.

The Death of Binary Software: End User Software Moves to the Web

The World Wide Web is the most powerful medium for information sharing and distribution in the history of humankind. The use of the Web is rapidly spreading into many new areas outside its original intended use, including its use as a platform for software applications. So far, a number of obstacles have hindered the development and deployment of full-fledged, truly interactive web applications. However, new emerging standards such as HTML5 and WebGL are removing the remaining limitations and transforming the Web into a real software platform. In this paper we argue that the trend towards web-based software will cause a paradigm shift in the software industry from binary applications to dynamically delivered web applications. In the future, the use of conventional binary programs will be limited to system software, whereas the vast majority of end user software will be developed using web technologies. All this will imply significant changes in the development, deployment and use of software, and open up interesting opportunities in software engineering research as well.

Generalized and stationary scrolling

We present a generalized definition of scrolling that unifies a wide range of existing interaction techniques, from conventional scrolling through pan and zoom systems and fish-eye views. Furthermore it suggests a useful class of new scrolling techniques in which objects do not move across the display. These “stationary scrolling” techniques do not exhibit either of two problems that plague spatial scrolling system: discontinuity in salience and the undermining of the users spatial memory.

Mashups and modularity: Towards secure and reusable web applications

The software industry is currently experiencing a paradigm shift towards Web-based software. We argue that Web technologies should evolve in a direction that would allow the developers to easily create ldquomashwarerdquo - mashup software that leverages components and other content from all over the world. In order to accomplish this, improvements are needed especially in two areas: security and modularity. In this paper we summarize our vision for the future of Web applications, focusing especially on these two important areas.