Agreed. The explicitly goal here is to avoid the use of an additional system property (well, undo it, or at least hide it behind an API that we'll be able to re-implement some other way).
JBQ On Fri, Jan 16, 2009 at 4:18 PM, Brian Swetland <[email protected]> wrote: > > As a side-note I'd like to try to reduce usage of the underlying system > properties -- they're becoming a dumping ground for all kinds of random > stuff, and they were not really intended as an open-ended registry of > every possible thing we might think to dump in there.... > > [Dave Bort <[email protected]>] >> The major benefit of using static final fields that I see is that it >> becomes very obvious who is using a given flag (e.g., "provisioned"), >> we can track the existence of that flag using our existing API >> checking tools, and the build breaks if a flag is removed but there >> are users of it. >> >> A dictionary-style interface, on the other hand, provides no >> possibility for static checking; there's no way to tell whether or not >> anyone is using a particular flag. This is the main reason we're >> trying to kill the uses of the SystemProperties API. >> >> --dbort >> >> On Fri, Jan 16, 2009 at 3:58 PM, Jean-Baptiste Queru <[email protected]> wrote: >> > As a follow-up to the thread about the "provisioned" bit, I'd like to >> > look at the way some build-time-configurable aspects are exposed to >> > applications. >> > >> > Right now, we're exposing android.os.Build ("Information about the >> > current build, extracted from system properties."). It contains a >> > dozen of fields (mostly strings) that contain information about the >> > source code that was used, the build combo, and who built it, where, >> > and when, i.e. what we often refer to as "the build". >> > >> > Next to that, we also have android.util.Config ("Build configuration. >> > The constants in this class vary depending on [the] build."). It >> > contains a handful of booleans, which were meant to be set according >> > to the build configuration (e.g. DEBUG, PROFILE, LOGV). Given the way >> > we now check API differences for compatibility breaks, we can't >> > actually change those values without introducing what our api-checking >> > tool considers an API breakage. >> > >> > I'd like to introduce a mechanism to allow the build-time side to pass >> > parameters that can be checked at run-time at the SDK API level, for >> > parameters like the "requires_provisioning" bit. >> > >> > Requirements: >> > -Values must be read-only when seen from applications. >> > -Must not involve any API change when the parameters change. >> > -Must allow to document each possible value using the usual mechanism. >> > -Must not involve build-time-generated (or build-dependent) source >> > files written in the java programming language. >> > -Performance and footprint are both important. >> > -Must support at least booleans, integers (int and/or long?) and strings. >> > >> > I'm thinking that Config is a more appropriate location than Build for >> > those parameters. >> > >> > One approach is to do something similar to Build: grab each parameter >> > at init time (i.e. in a static final) from whichever location is >> > appropriate (SystemProperties or any other place). >> > >> > Another approach is to not directly expose individual fields, but >> > instead to expose functions that take string keys and return the >> > values: e.g. boolean getBoolean(String key), int getInt(String key), >> > and expose static final constant strings for the keys. >> > >> > The former feels like it'd be lighter-weight in terms of memory and >> > CPU. The latter feels a lot more automated (so that we could just >> > stick the values in a data file and parse that). >> > >> > What's the preferred option? >> > >> > Thanks, >> > JBQ >> > >> > -- >> > Jean-Baptiste M. "JBQ" Queru >> > Android Engineer, Google. >> > > -- Jean-Baptiste M. "JBQ" Queru Android Engineer, Google. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "android-framework" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/android-framework?hl=en -~----------~----~----~----~------~----~------~--~---
