An absolutely watertight and foolproof system would know which attributes (or getter methods) change due to which setter method calls (and, beyond that, whether the setter really <i>changes </i>the value). This, and only this, would be the summit of "fidelity".<br>
<br>Anything else is an approximation, and, depending on the measure you apply, one procedure may be better than another one. Missing a change is more difficult to circumvent with legacy techniques than it is to avoid spurious firings.<br>
<br>Given that the aforementioned analysis is extremely difficult, it is obvious that a truly high-fidelity reaction to changes can't be done without users providing dependency information by means of annotations or some similar technique<br>
<br>-W<br> <br><br><br><div class="gmail_quote">On 16 January 2012 14:46, Swindells, Thomas <span dir="ltr"><<a href="mailto:TSwindells@nds.com">TSwindells@nds.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">The change is reducing the coarseness of the system and so making it more sensitive to the scope of the change so I’d say high fidelity is the correct term.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">I agree with you I’m concerned how this works with non-pure java beans where some of the setters may update multiple fields, or there may be none bean methods
like a reset() method – I don’t understand how these would interact in the system, is there a mechanism to explicitly invalidate a property or mark the whole lot as dirty.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Thomas<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> <a href="mailto:rules-dev-bounces@lists.jboss.org" target="_blank">rules-dev-bounces@lists.jboss.org</a> [mailto:<a href="mailto:rules-dev-bounces@lists.jboss.org" target="_blank">rules-dev-bounces@lists.jboss.org</a>]
<b>On Behalf Of </b>Wolfgang Laun<br>
<b>Sent:</b> 14 January 2012 08:59<br>
<b>To:</b> Rules Dev List<br>
<b>Subject:</b> Re: [rules-dev] Fine Grained Property Change Listeners (Slot Specific)<u></u><u></u></span></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">You really should follow naming conventions Java programmers are familiar<u></u><u></u></p>
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<p class="MsoNormal">with. javax.xml.bind.annotation.XmlAccessType, for instance, uses the<u></u><u></u></p>
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<p class="MsoNormal">term "member" for referring to "public getter/setter pairs", and this comes<u></u><u></u></p>
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<p class="MsoNormal">close to what Drools does. Alternatively, there's "field" and "property",<u></u><u></u></p>
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<p class="MsoNormal">and I wouldn't worry about the extra lip mileage - you can always abbreviate<u></u><u></u></p>
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<p class="MsoNormal">to "prop-specific".<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">Is this new feature in some way configurable for the KnowledgeBase?<u></u><u></u></p>
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<p class="MsoNormal">There are fact types where modifying one member results in the change<u></u><u></u></p>
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<p class="MsoNormal">of more than one member. Consider the very plausible case:<u></u><u></u></p>
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<p class="MsoNormal"> $f: Fact(...)<u></u><u></u></p>
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<p class="MsoNormal"> then<u></u><u></u></p>
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<p class="MsoNormal"> modify( $f ){ getList().add( $x ) }<u></u><u></u></p>
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<p class="MsoNormal"> end<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal"> when<u></u><u></u></p>
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<p class="MsoNormal"> Fact( size > 10 ) # size implemented as getList().size()<u></u><u></u></p>
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<p class="MsoNormal"> then<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">Wolfgang<u></u><u></u></p>
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<p class="MsoNormal"><u></u> <u></u></p>
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<p class="MsoNormal">PS: The new feature is actually <i>restricting the sensitivity of the system.</i><u></u><u></u></p>
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<p class="MsoNormal">Therefore, I feel that "high-fidelity" is actually counter-intuitive!<u></u><u></u></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><u></u> <u></u></p>
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<p class="MsoNormal">On 13 January 2012 23:30, Mark Proctor <<a href="mailto:mproctor@codehaus.org" target="_blank">mproctor@codehaus.org</a>> wrote:<u></u><u></u></p>
<p class="MsoNormal">Mario just got a first cut working for fine grained property change<br>
listeners. Previously when you call update() it will trigger revaluation<br>
of all Patterns of the matching object type in the knowledeg base.<br>
<br>
As some have found this can be a problem, forcing you to split up your<br>
objects into smaller 1 to 1 objects, to avoid unwanted evaluation of<br>
objects - i.e. recursion or excessive evaluation problems.<br>
<br>
The new approach now means the pattern's will only react to fields<br>
constrained or bound inside of the pattern. This will help with<br>
performance and recursion and avoid artificial object splitting. We<br>
previously discussed this here:<br>
<a href="http://blog.athico.com/2010/07/slot-specific-and-refraction.html" target="_blank">http://blog.athico.com/2010/07/slot-specific-and-refraction.html</a><br>
You can see the unit test here:<br>
<a href="https://github.com/droolsjbpm/drools/blob/ca55c78429cbc0f14167c604c413cdc3faaf6988/drools-compiler/src/test/java/org/drools/integrationtests/MiscTest.java" target="_blank">https://github.com/droolsjbpm/drools/blob/ca55c78429cbc0f14167c604c413cdc3faaf6988/drools-compiler/src/test/java/org/drools/integrationtests/MiscTest.java</a><br>
<br>
The implementation is bit mask based, so very efficient. When the engine<br>
executes a modify statement it uses a bit mask of fields being changed,<br>
the pattern will only respond if it has an overlapping bit mask. This<br>
does not work for update(), and is one of the reason why we promote<br>
modify() as it encapsulates the field changes within the statement. You<br>
can follow Mario's chain of work on this at his github activity feed:<br>
<a href="https://github.com/mariofusco.atom" target="_blank">https://github.com/mariofusco.atom</a><br>
<br>
The adventerous amoung you can pick this up from hudson, or from maven,<br>
and start playing now. My hope is that this will make drools much easier<br>
to use:<br>
<a href="https://hudson.jboss.org/hudson/job/drools/lastSuccessfulBuild/artifact/drools-distribution/target/" target="_blank">https://hudson.jboss.org/hudson/job/drools/lastSuccessfulBuild/artifact/drools-distribution/target/</a><br>
<br>
Btw we are after a name. Drools is not a frame based system, so "slot<br>
specific" doesn't seem appropropriate. Property Specific seems a bit of<br>
a mouth full. I'm quite liking High Fidelity Change Listeners :) any<br>
other suggestions?<br>
<br>
slot-specific is the name used by Jess for this feature,<br>
<a href="http://www.jessrules.com/docs/71/constructs.html" target="_blank">http://www.jessrules.com/docs/71/constructs.html</a>. It's also the standard<br>
way that Clips COOL works, which is the Clips OO module. Although that's<br>
partly a side effect of the triple representation of properties used in<br>
COOL, and the modifications are triple based. I don't know what<br>
mechanism Jess is using to enable this.<br>
<br>
Mark<br>
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