Reo: a channel-based coordination model for component composition

Abstract

In this paper, we present Reo, which forms a paradigm for composition of software components based on the notion of mobile channels. Reo is a channel-based exogenous coordination model in which complex coordinators, called connectors, are compositionally built out of simpler ones. The simplest connectors in Reo are a set of channels with well-defined behaviour supplied by users. Reo can be used as a language for coordination of concurrent processes, or as a ‘glue language’ for compositional construction of connectors that orchestrate component instances in a component-based system. The emphasis in Reo is just on connectors and their composition, and not on the entities that connect to, communicate and cooperate through these connectors. Each connector in Reo imposes a specific coordination pattern on the entities (for example, components) that perform I/O operations through that connector, without the knowledge of those entities. Channel composition in Reo is a very powerful mechanism for construction of connectors. We demonstrate the expressive power of connector composition in Reo through a number of examples. We show that exogenous coordination patterns that can be expressed as (meta-level) regular expressions over I/O operations can be composed in Reo out of a small set of only five primitive channel types.

Can High Throughput Atone for High Latency in Compiler-Generated Protocol Code?

“…The first buffered channel initially contains a dummy data item (i.e., its actual value does not matter); the other buffered channels initially contain nothing. As in the literature [1,2], we call this subconnector Sequencer k . Because no new data items can flow into Sequencer k , only cycles through the buffers-ad infinitum-such that only one buffer holds a data item at any time.…”

“…To study the performance advantages of using coordination languages for multicore programming, in ongoing work, we are developing compilation technology for the coordination language Reo [1,2]. Reo facilitates compositional construction of protocol specifications manifested as connectors: channel-based mediums through which threads can communicate with each other.…”

“…Reo is a language for compositional construction of concurrency protocols, manifested as connectors [1,2]. Connectors consist of channels and nodes, organized in a graph-like structure.…”

Optimized distributed implementation of multiparty interactions with Restriction

“…Reo [2] is a framework where components communicates using a basic set of dataflow connectors that are combined to form a complex connector. At each round, each component enables a set of input and output ports.…”

A Coordination Model for Interactive Components

“…Our approach is based on previous work on formal calculi for component coordination published in [4,2] and closely inspired by Arbab's Reo model [1]. In this paper we propose a particular model wherein complex coordinators, called connectors, are compositionally built out of simpler ones.…”