[higgins-dev] run-time configuration changes

[Greg Byrd <gbyrd@xxxxxxxx>]

As discussed in our last phone meeting, a group at IBM has a need to instantiate 
configurable components, and to make their configurations persistent.  I 
promised that I would send some mail to the dev list to (hopefully) kick off a 
conversation.

This particular requirement raises at least two issues:

(1) Asking a configurable component about its configuration settings.  The 
ISettingDescriptor interface was a first effort at this capability, but it never 
got further than that.  Assuming that ISettingDescriptor is descriptive enough, 
there needs to be some mechanism to describe the settings and constraints for a 
particular component type.

That's what this discussion was about: 
http://dev.eclipse.org/mhonarc/lists/higgins-dev/msg04721.html


(2) Once we create the setting for a component, how do we write the settings to 
the configuration file?  This is complicated by the fact that there are multiple 
formats for configuration files, each with its own ConfigurationHandler.  When a 
component is configured, all it sees is a Map that contains settings -- it has 
no idea what sort of file (if any) these settings came from.

One idea that came up during a discussion with the IBM folks was to somehow 
connect a component to the ConfigurationHandler that was responsible for its 
settings -- then we can pass off the responsibility for storing those settings 
to that handler.

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A third issue, which is not necessarily required for the current scenario, is 
how to change a configured components settings at run-time, and save those new 
settings for later use.

Could call getSettings(), change map, and call configure() again with the new 
settings.  Or could be a separate method for changing (e.g., setSettings()), so 
that the component can distinguish a full configuration from an update.


Comments on any and all of these issues are welcomed.

...Greg