Bottom-up and top-down COBOL system migration to Web Services: An experience report

Abstract

Moving from mainframe systems to Service-Oriented Architecture (SOA) using Web Services is an attractive but daunting task. The bottom-up or Direct Migration approach enables the e↵ective modernization of legacy systems to Web Services. Conversely, bringing migration into fruition with the top-down or Indirect Migration approach is recognized as being comparatively harder but achieves better migration results. In practice, it is very uncommon to employ both approaches to the same large enterprise system, which leaves no room for comparison. This paper reports the outcomes of applying both migration approaches on a real COBOL system, presents the followed migration processes, their costs, and reports on the discoverability and reusability of target Web Services.

A tool to improve code‐first Web services discoverability through text mining techniques

“…This practice is precisely promoted by code first. Although thoughtfully designed contract‐first WSDL documents have been proven to be affected by less anti‐patterns than code‐first WSDL documents, even when using anti‐pattern aware tools , code‐first Web service development is widely used because is it is cheaper and provides faster time to market . In addition, developing contract‐first Web services requires experts to write WSDL documents, instead of generating them automatically.…”

Service selection based on a practical interface assessment scheme

“…Necessarily, this approach relies on service providers that develop Web Services in a contract-first manner, a method that encourages designers to first derive a service's WSDL document to then supply an implementation, achieving better and highly discoverable services. However, the most used approach to build Web Services by the industry is code-first (Rodriguez et al, 2013b). This means that a developer first implements a service and then generates the corresponding WSDL document by using language-specific tools that automatically derive the interface from the service code.…”

“…In terms of architectural principles, conceptual decisions and technological decisions, the authors in (Pautasso et al, 2008) recommend using REST for ad-hoc integration and using WS-* for enterprise-level application integration where transactions, reliability, and message-level security are critical. Recent efforts in large-scale legacy system migration to SOA have demonstrated the suitability of WS-* technologies and standards (Rodriguez et al, 2013b). First, some proposals rely on semantic descriptions of services (Di Martino, 2009) that generally are not available, since publishers must put extra effort into describing services by means of semantic meta-data .…”

“…SOC lets developers dynamically grow application portfolios rapidly by creating compound solutions using organizational software assets -including enterprise information and legacy systems (Rodriguez et al, 2013b) -and combining them with external components residing in remote networks. From a business perspective, a service-oriented application implies a business facing solution which consumes services from one or more providers and integrates them into the business process (Sprott and L., 2004).…”

Best practices for describing, consuming, and discovering web services: a comprehensive toolset

“…It is worth mentioning that a step towards experimentally assessing the effects of simultaneously following our guidelines can be found in [15], in which we described the results of combining both the guidelines to generate effective queries and shield applications from specific services. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 In addition, the guidelines for defining easily understandable have been applied in a real-life development [8]. This development consisted in migrating a COBOL legacy system to a SOC system.…”