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<div dir="ltr"><font color="#000000" size="2" face="Tahoma">I never got an answer, any answer to this question. I really need to know if PropertyChangeSupport actually works. Is anyone out there successfully using it?</font></div>
<div dir="ltr"><font size="2" face="tahoma"></font> </div>
<div dir="ltr"><font size="2" face="tahoma">In one case (using "modify()") I get a NPE. In all cases, the rules run twice unless I explicitly call "update()". Is anyone *not* seeing this behaviour? Is anyone successfully using the PropertyChangeSupport mechanism
without explicit calls to "update()"???</font></div>
<div dir="ltr"><font size="2" face="tahoma"></font> </div>
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<p style="MARGIN: 0in 0in 0pt" class="MsoNormal"><b><span style="FONT-FAMILY: 'Arial','sans-serif'; COLOR: black; FONT-SIZE: 10pt">Jason Smith<br>
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<font size="2" face="Tahoma"><b>From:</b> Jason Smith<br>
<b>Sent:</b> Monday, November 23, 2009 12:36 PM<br>
<b>To:</b> rules-users@lists.jboss.org<br>
<b>Subject:</b> Rule runs twice without explicit call to update($fact).<br>
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<div dir="ltr"><font color="#000000" size="2" face="Tahoma">My colleague has confirmed that this behavior has been around since Drools 4, and it continues to be a problem for Drools 5.0.1 and 5.1.0.M1, assuming it's a problem and not working as intended.</font></div>
<div dir="ltr"><font size="2" face="tahoma"></font> </div>
<div dir="ltr"><font size="2" face="tahoma">$fact.setPath("...") implements the correct PropertyChangeSupport mechanism for Drools. At least Drools is using it and responding mostly as expected.</font></div>
<div dir="ltr"><font color="#000000" size="2" face="Tahoma"></font> </div>
<div dir="ltr"><font color="#000000" size="2" face="Tahoma">This runs once:</font></div>
<div dir="ltr"><b><font color="#960000" size="2"><font color="#960000" size="2">
<p align="left">rule</b></font></font><font size="2"> </font><font color="#008000" size="2"><font color="#008000" size="2">"Constrain to owner or published to public"</p>
</font></font><font size="2">
<p align="left"></font><b><font color="#960000" size="2"><font color="#960000" size="2">when</p>
</b></font></font><font size="2">
<p align="left">$fact : ListFact(</p>
<p align="left">$path : path </font><b><font color="#960000" size="2"><font color="#960000" size="2">not</b></font></font><font size="2">
</font><b><font color="#960000" size="2"><font color="#960000" size="2">matches</b></font></font><font size="2">
</font><font color="#008000" size="2"><font color="#008000" size="2">".*owner.*"</font></font><font size="2">,</p>
<p align="left">noopResponse == </font><b><font color="#960000" size="2"><font color="#960000" size="2">true</p>
</b></font></font><font size="2">
<p align="left">)</p>
<p align="left">$model : Model()</p>
<p align="left"></font><b><font color="#960000" size="2"><font color="#960000" size="2">then</b></font></font><font size="2">
</p>
<p align="left"></font><b><font color="#960000" size="2"><font color="#960000" size="2">modify</b></font></font><font size="2">($fact)</p>
<p align="left">{</p>
<p align="left">setPath($fact.getPath() + </font><font color="#008000" size="2"><font color="#008000" size="2">"[owner]"</font></font><font size="2">)</p>
<p align="left">}</p>
<p align="left"></font><b><font color="#960000" size="2"><font color="#960000" size="2">update</b></font></font><font size="2">($fact);</p>
</font><b><font color="#960000" size="2"><font color="#960000" size="2">
<p>end</p>
</b></font></font></div>
<div dir="ltr"><font size="2" face="tahoma"></font> </div>
<div dir="ltr"><font size="2" face="tahoma">This runs twice:</font></div>
<div dir="ltr"><b><font color="#960000" size="2"><font color="#960000" size="2">
<p align="left">rule</b></font></font><font size="2"> </font><font color="#008000" size="2"><font color="#008000" size="2">"Constrain to owner or published to public"</p>
</font></font><font size="2">
<p align="left"></font><b><font color="#960000" size="2"><font color="#960000" size="2">when</p>
</b></font></font><font size="2">
<p align="left">$fact : ListFact(</p>
<p align="left">$path : path </font><b><font color="#960000" size="2"><font color="#960000" size="2">not</b></font></font><font size="2">
</font><b><font color="#960000" size="2"><font color="#960000" size="2">matches</b></font></font><font size="2">
</font><font color="#008000" size="2"><font color="#008000" size="2">".*owner.*"</font></font><font size="2">,</p>
<p align="left">noopResponse == </font><b><font color="#960000" size="2"><font color="#960000" size="2">true</p>
</b></font></font><font size="2">
<p align="left">)</p>
<p align="left">$model : Model()</p>
<p align="left"></font><b><font color="#960000" size="2"><font color="#960000" size="2">then</b></font></font><font size="2">
</p>
<p align="left"></font><b><font color="#960000" size="2"><font color="#960000" size="2">modify</b></font></font><font size="2">($fact)</p>
<p align="left">{</p>
<p align="left">setPath($fact.getPath() + <font color="#008000" size="2"><font color="#008000" size="2">"[owner]"</font></font><font size="2">)</font></font><font size="2"></p>
<p align="left">}</font><font size="2"></p>
</font><b><font color="#960000" size="2"><font color="#960000" size="2">
<p>end</p>
</b></font></font></div>
<div dir="ltr"><font size="2" face="tahoma"></font> </div>
<div dir="ltr"><font size="2" face="tahoma">If I don't use modify(...) and simply change the $fact bean path property, the same thing occurs. If I explicitly call update($fact), the rule runs once. If I don't it runs twice.</font></div>
<div dir="ltr"><font size="2" face="tahoma"></font> </div>
<div dir="ltr"><font size="2" face="tahoma">I get "/path[owner][owner]" when I actually wanted "/path[owner]", because it ran twice, not once.</font></div>
<div dir="ltr"><font size="2" face="tahoma"></font> </div>
<div dir="ltr"><font size="2" face="tahoma"><strong>Why doe update(...) work differently from the PropertyChangeSupport mechanism??? Shouldn't I be able to depend on Drools to run this rule only one time?</strong></font></div>
<div dir="ltr"><font size="2" face="tahoma"></font> </div>
<div dir="ltr"><font face="times new roman">I am, admittedly, a bit of a noob at this, but I ran this by my local Drools resident expert, and he doesn't know the answer either.</font></div>
<div dir="ltr"><font face="times new roman"></font> </div>
<div dir="ltr"><font face="times new roman">Thanks so much!</font></div>
<div dir="ltr"><font face="times new roman"></font> </div>
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