>Gregg:
>
>> A vaching topic (String based) mechanism can be just as fast, as it can
>> assign an numeric value to a string based topic on the first use. This
>> allows the numbers to be different between JVMs, but intra-JVM numbering
>> is consistent through the use of a factory.
>
>True, but an inheritence based approach for Events is simpler/faster and has
>the added advantage that events could be sent out of the JVM as well.
In the embedlet system, we can't make serialization and/or classloading a
requirement. Thus, stuff sent between JVMs needs to be repackaged apon exit
and entry to any JVM. This is the fundamental need to meet protocol
neutralization too. Transport has to use a single, trivial to change
representation. XML is one, but is somewhat verbose for very small, low speed
(cheap RF) networks. Byte arrays are compact, but more difficult to manage.
We, historically, have used byte arrays in our solutions. We use XML to
describe the structure of the data, and have a DOM based parser that builds an
expression tree out of the document which is then executed for field
extraction. Slightly more complex, but infinitely flexible because we can
inject user coded evaluators/extractors to get data out of any container, byte
array, or otherwise...
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gr...@cy... (Cyte Technologies Inc)
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