A Petri net Siphon Based Solution

Protocol-level mismatch is one of the most important problems in service composition. The state-of-the-art method to deal with protocol mismatch is to generate adaptors to check deadlock-freeness based on a reachability graph. When this property is violated, the generation process will repeat itself until no deadlock state is found; however, the main drawback of this method is that it does not take into account the future deadlock state and requires many interactions with a developer. In this regard, it suffers from low efficiency. In this paper, the authors model multiple web service interaction with a Petri net called Composition net (C-net). The protocol-level mismatch problem is transformed into the empty siphon problem of a C-net. The authors take future deadlock states into consideration through this model, while finding the optimal solution that involves fewest interactions with a developer. The proposed method is proved to achieve higher efficiency for resolving protocol-level mismatch issues than traditional ones. Interface Mismatches Interface mismatches include message signature mismatches, message split/merge and message missing/extra mismatches (Benatallah, 2005; Benatallah, 2006) as shown in Figure 1. Message signature mismatches can be defined as: a service client’s message has a different name and/or data type and/or data range from that of a service provider. For example, the message with the name “ClientOrder” on the service client’s site may correspond to the message with the name “Order” DOI: 10.4018/jwsr.2010100101 2 International Journal of Web Services Research, 7(4), 1-20, October-December 2010 Copyright © 2010, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. on the provider’s site. Note that, the case when the provider’s message has a different data range from that of the client is also defined as parameter constraint mismatch in (Benatallah, 2005). Message split mismatch can be defined as: a service client requires multiple messages to achieve certain functionality while a service provider can offer only a single message. For example, a provider’s message mp contains n parts, i.e., mp1, mp2, ..., and mpn while a client considers mp1, mp2, ..., and mpn as n separate messages. Message merge mismatch can be defined as: a service client requires a single message to achieve certain functionality while a service provider can offer multiple messages. This is the reverse case of message split mismatch. For example, a client requires message mc that is a combination of messages mc1, mc2, ..., and mcn from a provider. Missing message mismatches can be defined as: a service client expects a message that a service provider does not issue. For example, a client expects an acknowledgement message while although a provider receives the previous message, it does not issue an acknowledgement. Note that, the missing message should not affect the semantics of the client. Extra message mismatches are defined as: a provider issues an extra message that a client does not expect. This is the opposite case of missing message mismatches. For example, a provider is sending an acknowledgement message that a client does not expect. Figure 1 shows the cases for interface mismatches. Services can be composed if there is no interface mismatches. There are significant research results towards service interface level Table 1. Taxonomy of service composition mismatches Service composition mismatches Interface mismatches message signature mismatches message split/merge mismatches message missing/extra mismatches Protocol level mismatches unspecified reception mutual waiting mismatches non-local choice mismatches Figure 1. Illustration for interface mismatches 18 more pages are available in the full version of this document, which may be purchased using the "Add to Cart" button on the product's webpage: www.igi-global.com/article/protocol-level-servicecomposition-mismatches/47040?camid=4v1 This title is available in InfoSci-Journals, InfoSci-Journal Disciplines Computer Science, Security, and Information Technology, InfoSci-Digital Marketing, E-Business, and EServices eJournal Collection, InfoSci-Networking, Mobile Applications, and Web Technologies eJournal Collection, InfoSci-Journal Disciplines Business, Administration, and Management, InfoSci-Select. Recommend this product to your librarian: www.igi-global.com/e-resources/libraryrecommendation/?id=2