Tutorials Oracle SOAThere are five primary options for modernization, and all are worthy of deep exploration. In the next section, we will review each of these options at a high level. However, this book is a deep technical dive on two approaches for Legacy Modernization, namely SOA enablement and rearchitecture. These two options are selected for two reasons. First, it gives a modernization option for staying on the mainframe (SOA enablement) and moving off the mainframe (rearchitecture).
Second, many organizations around the world are engaged on one of these two paths, or both in many cases. Although either modernization option can be chosen independently, together they provide a smooth and measured path to a modern environment without the risk of a big bang approach. We also cover a rehostingbased approach to modernization, which minimizes the upfront risk and supports SOA enablement and selective rearchitecture during or following the automated platform migration. We will cover more of this later.
There are five primary approaches to legacy modernization:
Rearchitecting to a new environment
SOA integration and enablement
Replatforming through rehosting and automated migration
Replacement with COTS solutions
Data Modernization
Other organizations may have different nomenclature for what they call each type of modernization, but any of these options can generally fit into one of these five categories. Each of the options can be carried out in concert with the others, or as a standalone effort. They are not mutually exclusive endeavors. Further, in a large modernization project, multiple approaches are often used for parts of the larger modernization initiative.
The right mix of approaches is determined by the business needs driving the modernization, organization's risk tolerance and time constraints, the nature of the source environment and legacy applications. Where the applications no longer meet business needs and require significant changes, rearchitecture might be the best way forward. On the other hand, for very large applications that mostly meet the business needs, SOA enablement or replatforming might be lower risk options.
You will notice that the first thing we talk about in this section the Legacy Understanding phase isn't listed as one of the modernization options. It is mentioned at this stage because it is a critical step that is done as a precursor to any option your organization chooses.
Once we have identified our business drivers and the first steps in this process, we must understand what we have before we go ahead and modernize it. Legacy environments are very complex and quite often have little or no current documentation. This introduces a concept of analysis and discovery that is valuable for any modernization technique.
Application Portfolio Analysis (APA)
In order to make use of any modernization approach, the first step an organization must take is to carry out an APA of the current applications and their environment. This process has many names. You may hear terms such as Legacy Understanding, Application Relearn, or Portfolio Understanding. All these activities provide a clear view of the current state of the computing environment.
This process equips the organization with the information that it needs to identify the best areas for modernization. For example, this process can reveal process flows, data flows, how screens interact with transactions and programs, program complexity and maintainability metrics and can even generate pseudocode to redocument candidate business rules. Additionally, the physical repositories that are created as a result of the analysis can be used in the next stages of modernization, be it in SOA enablement, rearchitecture, or replatforming. Efforts are currently underway by the Object Management Group (OMG) to create a standard method to exchange this data between applications. The following screenshot shows the Legacy Portfolio Analysis:
Next Page: APA Macroanalysis and APA Microanalysis
