Choreography and Orchestration Conformance for System Design

Abstract

Abstract. In a previous work we have presented a formal framework devoted to show the relevance of choreography and orchestration in the design of service oriented applications. Even if useful to start a formal investigation of the relationship between choreography and orchestration, the proposed framework was not suitable to specify real case studies. In fact, it simply permitted to specify all possible computations abstracting away from the conditions driving the choice of the actual behaviour. In this paper we tackle this problem by introducing the notion of state variables. The addition of state requires a substantial modification of the entire framework because the same state variable, at the level of choreography, can be actually stored in distributed orchestrators that will need to synchronize in order to maintain consistent views. In order to faithfully investigate this problem we also need to modify the formal model at the orchestration level, moving from synchronous to asynchronous communication as the latter is the communication modality of the ordinary communication infrastructures.

Orchestrating Tuple-Based Languages

“…From the theoretical point of view, the formalisms closest to ours are Orc and Klaim. In fact, to define Korc, we have chosen them as representative of the broader classes of orchestration calculi (as, e.g., [28,10,23,11,7]) and coordination calculi for network-aware and mobility programming (as, e.g., [21,24,12,39]). Relatively to these calculi, Korc does not provide new primitives, but it permits experimenting and reasoning on a novel programming paradigm combining orchestration and coordination operators.…”

“…Orchestration describes how services can interact from the perspective of one party (local descriptions), while choreography tells of the sequence of messages according to a global perspective, where each party describes the part that plays in the choreography (global descriptions). Means to check conformance of local and global descriptions have been defined in [9,10,27], by relying on bisimulation-like relations, and in [25], by relying on session types. In Korc, the Orc part describes the orchestration, while the Klaim part represents a form of collaborative coordination that can be used to enforce the involved parties to adhere to a given protocol, which can be thought of as a sort of choreography.…”

“…Among the many proposed formalisms (see, e.g., [28,8,10,23,11,7]), we will focus on Orc [31,40], a task orchestration language with applications in workflow, business process management, and web service orchestration. Orc is the This work has been partially sponsored by the EU project ASCENS, 257414. result of a tension between simplicity and expressiveness, and its primitives, differently from most the formalisms mentioned above, focus on orchestration rather than on communication.…”

Algorithms Based on Pattern Analysis for Verification and Adapter Creation for Business Process Composition

“…Semantic approaches for adaptation are discussed in [22]. A formal approach for reasoning about interaction patterns is given in [7,12]. Our work is complementary to these efforts since both kinds of adaptation are necessary.…”

Replicating Web Services for Scalability

“…We model the behaviour of the system in the SOCK calculus [1,2]. We have exercised this model using the JOLIE interpreter [3] in order to increase our confidence that the model describes the behaviour which we intended to capture.…”