Recaf: Java dialects as libraries

Mainstream programming languages like Java have limited support for language extensibility. Without mechanisms for syntactic abstraction, new programming styles can only be embedded in the form of libraries, limiting expressiveness. In this paper, we present Recaf, a lightweight tool for creating Java dialects; effectively extending Java with new language constructs and user defined semantics. The Recaf compiler generically transforms designated method bodies to code that is parameterized by a semantic factory (Object Algebra), defined in plain Java. The implementation of such a factory defines the desired runtime semantics. We applied our design to produce several examples from a diverse set of programming styles and two case studies: We define i) extensions for generators, asynchronous computations and asynchronous streams and ii) a Domain-Specific Language (DSL) for Parsing Expression Grammars (PEGs), in a few lines of code

Recaf: Java dialects as libraries

Mainstream programming languages like Java have limited support for language extensibility. Without mechanisms for syntactic abstraction, new programming styles can only be embedded in the form of libraries, limiting expressiveness. In this paper, we present Recaf, a lightweight tool for creating Java dialects; effectively extending Java with new language constructs and user defined semantics. The Recaf compiler generically transforms designated method bodies to code that is parameterized by a semantic factory (Object Algebra), defined in plain Java. The implementation of such a factory defines the desired runtime semantics. We applied our design to produce several examples from a diverse set of programming styles and two case studies: We define i) extensions for generators, asynchronous computations and asynchronous streams and ii) a Domain-Specific Language (DSL) for Parsing Expression Grammars (PEGs), in a few lines of code

Darwinian Data Structure Selection

Data structure selection and tuning is laborious but can vastly improve an application's performance and memory footprint. Some data structures share a common interface and enjoy multiple implementations. We call them Darwinian Data Structures (DDS), since we can subject their implementations to survival of the fittest. We introduce ARTEMIS a multi-objective, cloud-based search-based optimisation framework that automatically finds optimal, tuned DDS modulo a test suite, then changes an application to use that DDS. ARTEMIS achieves substantial performance improvements for \emph{every} project in $5$ Java projects from DaCapo benchmark, $8$ popular projects and $30$ uniformly sampled projects from GitHub. For execution time, CPU usage, and memory consumption, ARTEMIS finds at least one solution that improves \emph{all} measures for $86\%$ ($37/43$) of the projects. The median improvement across the best solutions is $4.8\%$, $10.1\%$, $5.1\%$ for runtime, memory and CPU usage. These aggregate results understate ARTEMIS's potential impact. Some of the benchmarks it improves are libraries or utility functions. Two examples are gson, a ubiquitous Java serialization framework, and xalan, Apache's XML transformation tool. ARTEMIS improves gson by $16.5$\%, $1\%$ and $2.2\%$ for memory, runtime, and CPU; ARTEMIS improves xalan's memory consumption by $23.5$\%. \emph{Every} client of these projects will benefit from these performance improvements.Comment: 11 page

Design Patterns: Elements of Reusable Object-Oriented Software

The book is an introduction to the idea of design patterns in software engineering, and a catalog of twenty-three common patterns. The nice thing is, most experienced OOP designers will find out they've known about patterns all along. It's just that they've never considered them as such, or tried to centralize the idea behind a given pattern so that it will be easily reusable.

Verily: a web framework for creating more reasonable web applications

The complexity of web application construction is increasing at an astounding rate. Developing for the web typically crosses multiple application tiers in a variety of languages, which can result in disjoint code bases. This lack of standardization introduces new challenges for reasoning. In this paper we introduce Verily, a new web framework for Java that supports the development of verifiable web applications. Rather than requiring that programs be verified in separate a posteriori analysis, Verily supports construction via a series of Recipes, which are properties of an application that are enforced at compile time. In addition to introducing the Verily framework, we also present two Recipes: the Core Recipe, an application architecture for web applications designed to replace traditional server-side Model View Controller, and the Global Mutable State Recipe, which enables developers to use sessions within their applications without resorting to the use of unrestricted global mutable state. Copyright © 2014 ACM