Subject-Oriented Business Process Management

ion (hiding function details), reuse (use by different consumers), and farreaching autonomy (control over their own environment and resources) (cf. Erl 2008, pp. 86 et seq.) • On the other hand, in the organization, as a rule legacy systems (applications) are in use which usually, especially for economic reasons (protection of investment, capital accumulation), cannot be easily converted in the short term into a modern, from the ground up designed service-oriented landscape (cf. e.g., Friend et al. 2008). Therefore, along the way the goal is to use mostly proven functionalities of existing systems, for instance, in that IT developers encase these functionalities using so-called wrapper programs (LegacyWrapper). These separate functions from the monolithic structure and publish them as Web services, and so provide them as services in the sense mentioned above (cf. Mathas et al. 2008, pp. 111 ff.; Erl et al. 2008, p. 311; SOA Glossary 2011). If access to a legacy application is preprocessed through a subject with wrapper properties, this handles the synchronous access to the functions of the application and provides the requester a usable asynchronous service. The consuming service is so less tightly coupled to the provider, compared to the case of self-contained, synchronous use of the function of the legacy system. This approach especially helps in meeting the demand for loose coupling of services. Fig. 10.5 Integration of services into the subjects of a process 10.6 Relationship to Service-Oriented Architectures 201