On 26 July 2011 21:42, Edson Tirelli <span dir="ltr"><<a href="mailto:ed.tirelli@gmail.com">ed.tirelli@gmail.com</a>></span> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div><br></div><div> Hi all,</div><div><br></div><div> As you all know, we use "entry-points" to represent streams in Drools, but in fact, entry points are a much more general abstraction than just streams. For instance, they create partitions in the RETE's alpha network, they support all Rete concepts like truth maintenance, they share a centralized fact handle factory (that is possibly a contention point), etc.</div>
<div><br></div><div> Event Streams in general can have a much more specialized implementation. For instance, as events are immutable,</div></blockquote><div><br>"Immutable" certainly not by a Drools definition? Something with @role(event) is just a fact, and I can modify an event as required by my application.<br>
</div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div> there is no need for truth maintenance;</div></blockquote><div><br>A fact derived from events could be managed by the TMS - why not? Or do you mean <a href="http://s.th">s.th</a>. else? <br>
<br> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div> streams should be 100% parallelizable (does this word exist?);</div></blockquote>
<div><br>If it didn't exist before, it exists now ;-)<br> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div>some algorithms like event sequencing can be run before injecting events into the main engine instead of injecting and then coordinating back with the sequencing algorithm. </div>
<div><br></div><div> Because of things like the ones above, I was considering creating an explicit concept for streams in Drools. They would be a first class concept in the engine and would be handled appropriately. They would be orthogonal to entry-points, and be used exclusively for events. </div>
</blockquote><div><br>It's difficult (for me) to see what a "stream" should imply. Can you provide a concise definition? A "stream" should be for role event only, and its facts should be immutable (?) - what else? <br>
<br>Are there any good use cases for these "streams" that cannot be readily dealt with using events?<br><br></div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div><br></div><div> The other option that we have would be to continue to hide the implementation behind the concept of entry-points and to select algorithm details by compile time analysis. Although it seems like a simpler solution, it has the potential of confusing users</div>
</blockquote><div><br>Most of the time, the confusion of Drools users stems from the lack of clear documentation - not from the complexitiy of features. <br><br>Cheers<br>Wolfgang<br> </div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div> that would not know exactly when something is being executed as a regular entry point (with TMS, and all the stuff mentioned above) or as a specific stream (that has features that would be specific for events).</div>
<div><br></div><div> Thoughts?</div><div> Edson</div><br clear="all"><font color="#888888"><br>-- <br> Edson Tirelli<br> JBoss Drools Core Development<br> JBoss by Red Hat @ <a href="http://www.jboss.com" target="_blank">www.jboss.com</a><br>
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