Common Design Patterns for Symbian OS: The Foundations of Smartphone Software

1.5. Symbian OS Patterns

That's all very well but what's this got to do with Symbian OS? Well, one problem with patterns is that, because they have been abstracted away from specific problems, it can be hard to understand how best to apply them. One of the goals of this book is to describe a set of patterns in more tangible terms specific to Symbian OS and so make them easier to apply in a Symbian OS context. This will be done via the following means:

• Each pattern describes how the forces most relevant to an embedded operating system, such as Symbian OS, impact and are changed by the patterns.

• Explanations are given to explain how Symbian OS architectural elements can be re-used in the application of the patterns.

• Code samples are given in terms of Symbian OS APIs and coding standards so that as much as possible of your job of translating a pattern into practice has already been done for you.

• Examples based on Symbian OS are given to show how the patterns have been realized in situations that Symbian OS developers can more easily relate to.

1.5.1. Constraints on Software Based on Symbian OS

The constraints on a mobile device platform means that software development for Symbian OS has to resolve a set of forces that are distinct from those found in desktop or enterprise environments. Consider the following list of constraints imposed by the mobile device environment:

• Constrained hardware

  Compared to mainstream laptops, mobile devices are between 10 and 30 times smaller in terms of ...