When SOA practitioners move their efforts to the mobile domain, they find that some things are familiar and some things are different. The successful enterprise services architect must learn to correctly size SOA services.
The basic characteristics of mobile devices are so familiar that they can easily be overlooked. But the fundamental elements of the devices need to be studied when it is time to ''mobile-enable'' enterprise applications. One must remember that mobile devices typically have small screens, mobile bandwidth is relatively limited and mobile users work differently than their desk-bound counterparts.
In the face of small devices' constraints, correct ''services chunking'' is needed, according to long-time industry hand Rashid Khan, now head of Chatty Solutions, maker of cross-platform mobile development tools and middleware for SaaS and Web applications. As he has written in a blog on Smartphone Web application responsiveness, the best approach to mobile app development requires breaking up the user interface into small ''chunks'' of relevant data that are presented to the user in a logical sequence.
Existing applications were designed for full screen machines. ''That model does not work with mobile,'' Khan recently told SearchSOA.com.
''Mobile users work differently. They get interrupted. They have to work in small bursts,'' said Khan. ''As a result, if you are running a business application, you need to be able to stop and restart [it] easily.''
''You have to give people small bits of information and then they can move on to the next piece, and so on. Do not present a whole lot of information at once,'' he advises. ''Instead, present the user with small pieces of information and move them along.'' When working in the mobile realm, Khan indicated, software architects should think about presenting information in a way that makes sense – in a way that the mobile user can take appropriate action.
So, which parts of mobile development will be familiar to the SOA practitioner? Khan agrees with the members of the SOA army who maintain that sound services architecture is the best underpinning for re-spinning enterprise applications as mobile applications.
''The important thing is that the enterprise application exposes its functionality through a Web services approach," he said. ''If architects have done that, exposing applications to mobile devices is not rocket science at all.''
''SOA enables mobile Web applications to access a variety of services running on remote servers in a granular fashion in a sequence without having to recreate all the logic of all the services,'' wrote Khan in a blog entry on SOA and mobile Web applications.
Khan gives project guidance for the SOA practitioner repurposing services in the mobile domain. The selection of the first project is often a key to overall program success.
''Don't do the most complicated thing first. Don't do the simplest thing, either. Do something in the middle,'' he said.
With the middle road approach, Khan said, ''you can demonstrate the results quickly and show value. With a very simple application, no one will care – while a complex application may prove too complex to create on time without [flaws].''
This was first published in September 2011