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Section: New Software and Platforms
JOLIE
Java Orchestration Language Interpreter Engine
Keyword: Microservices
Scientific Description: Jolie enforces a strict separation of concerns between behaviour, describing the logic of the application, and deployment, describing the communication capabilities. The behaviour is defined using the typical constructs of structured sequential programming, communication primitives, and operators to deal with concurrency (parallel composition and input choice). Jolie communication primitives comprise two modalities of interaction typical of Service-Oriented Architectures (SOAs), namely one-way (sends an asynchronous message) and request-response (sends a message and waits for an answer). A main feature of the Jolie language is that it allows one to switch among many communication media and data protocols in a simple, uniform way. Since it targets the field of SOAs, Jolie supports the main communication media (TCP/IP sockets, Bluetooth L2CAP, Java RMI, and Unix local sockets) and data protocols (HTTP, JSON-RPC, XML-RPC, SOAP and their respective SSL versions) from this area.
Functional Description: Jolie is a language for programming service-oriented and microservice applications. It directly supports service-oriented abstractions such as service, port, and session. Jolie allows to program a service behaviour, possibly obtained by composing existing services, and supports the main communication protocols and data formats used in service-oriented architectures. Differently from other service-oriented programming languages such as WS-BPEL, Jolie is based on a user-friendly Java-like syntax (more readable than the verbose XML syntax of WS-BPEL). Moreover, the kernel of Jolie is equipped with a formal operational semantics. Jolie is used to provide proof of concepts around Focus activities.
Release Functional Description: There are many fixes to the HTTP extension, improvements to the embedding engine for Javascript programs, and improvements to the support tools jolie2java and wsdl2jolie.
News Of The Year: During 2019 the Jolie project saw three major actions.
The first action regards the build system used for the development of the language, which has been transitioned to Maven, the main build automation tool used for Java projects. The move to Maven is dictated by two needs. The first is to streamline the development and release processes of Jolie, as Maven greatly helps in obtaining, updating, and managing library dependencies. The second necessity addressed by Maven is helping in partitioning the many sub-projects that constitute the Jolie codebase, reducing development and testing times. Having Jolie as a Maven project also helps in providing Jolie sub-components (as Maven libraries) to other projects. Finally, the move to Maven is set within a larger effort to expedite the inclusion in the main Jolie development branch of contributions by new members of its growing community.
The second action regards the transition to Netty as a common framework to support communication protocols and data formats in Jolie. Netty is a widely-adopted Java framework for the development of network applications, and it was used in 2018 to successfully support several IoT communication protocols and data formats in a Jolie spin-off project, called JIoT. The work in 2019 integrated into the Jolie codebase the protocols and data format developed within the JIoT project and pushed towards the integration of the Netty development branch into the main branch of the Jolie project (i.e., re-implementing using Netty the many protocol and data-formats already supported by Jolie). The Netty development branch is currently in a beta phase and it is subject to thorough in-production tests, to ensure consistent behaviour with the previous implementation.
The third action regards the development and support for a new official IDE for Jolie. Hence, along with the ones already existing for the Atom and Sublime Text text editors, Jolie developers can use the Jolie plugin (based on the Language Server Protocol) for the Visual Studio Code text editor to obtain syntax highlighting, documentation aids, file navigation, syntax checking, semantic checking, and quick-run shortcuts for their Jolie programs.
In addition to the above actions, in 2019 Jolie transitioned through three minor releases and a major one, from 1.7.1 to 1.8.2. The minor releases mainly fixed bugs, improved performance, and included new protocol/data-format functionalities. The major release included a slim-down of the notation for the composition of statements, types definitions, and tree structures, for a terser codebase. Upgrades to 1.8.2 also introduced: timeouts for solicit-response invocations to handle the interruption of long-standing requests, more user-friendly messages from the Jolie interpreter, including easier-to-parse errors and the pretty-printing of data structures, for a more effective development and debugging experience.
In 2019 Jolie also saw the development of a new Jolie library, called TQuery, which is a query framework integrated into the Jolie language for the data handling/querying of Jolie trees. Tquery is based on a tree-based instantiation (language and semantics) of MQuery, a sound variant of the Aggregation Framework, the query language of the most popular document-oriented database: MongoDB. Usage scenarios for Tquery are (but not limited to) eHealth, the Internet-of-Things, and Edge Computing, where data should be handled in an ephemeral way, i.e., in a real-time manner but with the constraint that data shall not persist in the system.