GoF’s design patterns are popular structures designed for flexible and reusable object-oriented software. However, their energy impact is not well understood, with contradictory existing results. In this paper, we aim to answer the relation between design patterns and energy consumption through a multi-platform and multi-software stack empirical study, covering all design patterns, and multiple hardware, OS, languages and compilers. We found, with a high confidence level, that none of the GoF’s design patterns has a significant impact on energy consumption. Therefore, they can be considered energy-neutral, allowing eco-friendly developers to continue using them. We argue that software energy efficiency should rather be considered within the business logic embedded by a design pattern, and ultimately raised to a higher perspective of software development.

To face the climate change, Android developers urge to become green software developers. But how to ensure carbon-efficient mobile apps at large? In this paper, we introduce ecoCode, a SonarQube plugin able to highlight code structures that are smelly from an energy perspective. It is based on a curated list of energy code smells likely to impact negatively the battery lifespan of Android-powered devices. The ecoCode plugin enables analysis of any native Android project written in Java in order to enforce green code. — Demo video on https://youtu.be/4XIYGyPEhXQ

International audience

Despite that reuse libraries are now well adopted during software development step, software evolution step is not yet covered by this kind of beneficial approach. In this paper we present the "evolution shelf", a generic infrastructure to achieve for-reuse and by-reuse techniques within the field of software evolution. The basic idea behind that is to propose and encourage the reuse of recurring and reliable evolution expertises to achieve the structural evolution of a software system at the architectural level. For that purpose, the shelf assists architects in classifying, storing and selecting reusable architectural evolution operations. The underlying concept that we propose to capitalize the expertises is called "evolution style" and it mixes a syntactic and a semantic description format. These ideas form a core for a long-term vision in which it is possible to build a business model of evolution-of-the-shelf (EOTS) with the special objective to decrease the efforts and the risks related to the evolution activities.