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Add a note about using messages for data storage. Thanks to mlotz for telling me this functionality was underexposed in the current docs.

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Niels Sascha Reedijk 2007-12-27 13:30:30 +00:00
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17
docs/user/app/Message.dox
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@ -95,17 +95,24 @@
This class is at the center of the web of messaging classes, in the sense
that it defines the actual structure of the messages. Messages have two
important elements: the #what identifer, and the data members. The first
can be directly manipulated, the latter can be manipulated through
<b>important elements</b>: the #what identifer, and the data members. The
first can be directly manipulated, the latter can be manipulated through
AddData(), FindData() and ReplaceData() and their deratives. Neither of
these elements are mandatory.
The second important role of BMessage is that it stores meta data: who sent
the message and with what intention? The methods of BMessage will disclose
if the message was a reply (IsReply()), where it came from
The second important role of BMessage is that it stores <b>meta data</b>:
who sent the message and with what intention? The methods of BMessage will
disclose if the message was a reply (IsReply()), where it came from
(IsSourceRemote()), whether a reply is expected (IsSourceWaiting()), and in
case the message is a reply, what it's a reply to (Previous()).
Mostly, messages are used to pass information between the the objects in
your application, but because messages are such flexible data containers,
they are also often used for other <b>data storage purposes</b>. Many
applications store their settings as messages. Because messages can be
flattened to data streams (such as files), they provide an easy but
powerful tool for data storage.
All methods can be classified in these areas:
- Adding, Finding, Replacing and Removing Data.
- Statistics and Miscelanous information.