SCOOP – Concurrency Made Easy
The metaphor of objects as entities encompassing both logic and state, simplifying the design and development of particularly large-scale applications, is well established in the industry. However, large applications are rarely monolithic components that carry out a single sequential task; most applications are composed of many components running in parallel. Yet, the vast majority of such applications are built in a rather ad-hoc manner, typically by making use of threading libraries and explicit synchronization through low-level mechanisms such as semaphores, locks, or monitors layered on top of objects.
The Simple Concurrent Object-Oriented Programming (SCOOP) model strives for a higher-level abstraction for concurrency, naturally woven into “traditional” object-oriented constructs. Thanks to the full support for contracts and other object-oriented mechanisms and techniques — inheritance, polymorphism, dynamic binding, genericity, and agents — SCOOP offers the programmer a simple yet powerful framework for efficient development of concurrent systems.
This paper presents a survey of SCOOP, including (1) the foundations of the SCOOP paradigm, its computation and synchronization models (focusing on simplicity), and our more recent developments. These are (2) an extended type system for eliminating synchronization defects (improving safety), (3) support for transactional semantics for subcomputations (enforcing atomicity), and (4) an event library for programming real-time concurrent tasks (allowing for predictability).
KeywordsConcurrent Programming Typing Rule Atomic Feature Separate Object Aperiodic Task
Unable to display preview. Download preview PDF.
- 3.Butler, M., Hoare, C., Ferreira, C.: A Trace Semantics for Long-Running Transactions. In: 25 Years Communicating Sequential Processes, pp. 133–150 (2004)Google Scholar
- 6.Burdy, L., Cheon, Y., Cok, D., Ernst, M., Kiniry, J., Leavens, G., Leino, K.R.M., Poll, E.: An Overview of JML Tools and Applications. In: Eighth International Workshop on Formal Methods for Industrial Critical Systems (FMICS 2003) (2003)Google Scholar
- 11.ECMA: Eiffel Analysis, Design and Programming Language. ECMA Standard 367 (2005)Google Scholar
- 13.Weikum, G., Vossen, G.: Transactional Information Systems: Theory, Algorithms, and the Practice of Concurrency Control and Recovery. Morgan Kaufmann Publishers, San Francisco (2002)Google Scholar
- 14.Moss, J.E.B.: Nested Transactions: an Approach to Reliable Distributed Computing. Technical Report 260, Massachusetts Institute of Technology, Laboratory for Computer Science (1981)Google Scholar
- 15.Vaucouleur, S., Eugster, P.: Atomic Features. In: Proceedings of the Workshop on Synchronization in Concurrent Object-Oriented Languages (SCOOL), OOPSLA (October 2005)Google Scholar
- 16.Arslan, V., Eugster, P.: Modeling Embedded Real-time Applications with Objects and Events. In: Proceedings of the 3rd Workshop on Object-Oriented Modelling of Embedded Real-Time Systems (OMER-3) (to appear, 2005)Google Scholar
- 17.Brega, R.: A Combination of System Software Techniques Aimed at Raising the Runtime-Safety of Complex Mechatronic Applications. PhD thesis, ETH Zurich, Switzerland (2002)Google Scholar