Chapter 17. Modules and Runtime Shared Libraries
When building Rich Internet Applications, eventually you will have to
consider file sizes and download times. The Flex Framework offers several
alternatives for separating application code into separate SWF files to
enrich the user experience.
Runtime shared libraries (RSLs) are files that
can be downloaded and cached on a client. A downloaded RSL persists on the
client, and multiple applications can access assets from that cached RSL.
Applications can load two types of RSLs: unsigned and signed.
Unsigned RSLs, such as standard and cross-domain SWF
files, are stored in the browser cache. Signed RSLs,
which are libraries that have been signed by Adobe and have the .swz extension, are stored within the Flash
Player cache.
As the name suggests, a RSL is loaded at runtime and is considered a
dynamically linked library. Statically linked libraries are SWC files that
you compile into an application using the library-path and include-libraries compiler options. Application SWF files compiled against statically linked libraries generally have a larger file size and take longer to download, but they have the benefit of running quickly because all the code is available to the application. Applications employing RSLs load faster and have a smaller initial file size, but they may take more time at startup while loading the RSLs and use more memory as a consequence (the entire library of a RSL is loaded by an application without consideration of ...
