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<div style="color:rgb(0,0,0)">Hello all,</div>
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<div style="color:rgb(0,0,0)"><br>
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<div style="color:rgb(0,0,0)">I've been reading up about drool-spring integration and have put together a simple project that wires together a KnowledgeBase and KnowledgeSession as follows : </div>
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<p style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; font:normal normal normal 11px/normal Monaco; color:rgb(66,57,246)">
<span style="color:#009292"><span class="Apple-tab-span" style="white-space:pre"></span><</span><span style="color:#4b9191">drools:resource</span><span style="color:#000000">
</span><span style="color:#961f8d">id</span><span style="color:#000000">=</span>"GroupUnit"<span style="color:#000000">
</span><span style="color:#961f8d">type</span><span style="color:#000000">=</span>"DRL"</p>
<p style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; font:normal normal normal 11px/normal Monaco; color:rgb(66,57,246)">
<span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span></span><span style="color:#961f8d">source</span><span style="color:#000000">=</span>"file:/Users/drools/drools-spring-test/src/Rules/drls/GroupUnit.drl"<span style="color:#000000">
</span><span style="color:#009292">/></span></p>
<p style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; font:normal normal normal 11px/normal Monaco; color:rgb(66,57,246)">
<span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span></span><span style="color:#009292"><</span><span style="color:#4b9191">drools:resource</span><span style="color:#000000">
</span><span style="color:#961f8d">id</span><span style="color:#000000">=</span>"GradeUnit"<span style="color:#000000">
</span><span style="color:#961f8d">type</span><span style="color:#000000">=</span>"DRL"</p>
<p style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; font:normal normal normal 11px/normal Monaco; color:rgb(66,57,246)">
<span class="Apple-style-span"><span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span></span><span style="color:#961f8d">source</span><span style="color:#000000">=</span>"</span>file:/Users/drools/drools-spring-test/src/Rules/drls/GradeUnit.drl"<span class="Apple-style-span">"<span style="color:#000000">
</span><span style="color:#009292">/></span></span></p>
<p style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; font:normal normal normal 11px/normal Monaco; color:rgb(66,57,246)">
<span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span></span><span style="color:#009292"><</span><span style="color:#4b9191">drools:resource</span><span style="color:#000000">
</span><span style="color:#961f8d">id</span><span style="color:#000000">=</span>"EvaluateUnit"<span style="color:#000000">
</span><span style="color:#961f8d">type</span><span style="color:#000000">=</span>"DRL"</p>
<p style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; font:normal normal normal 11px/normal Monaco; color:rgb(66,57,246)">
<span class="Apple-style-span"><span class="Apple-style-span"><span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span></span><span style="color:#961f8d">source</span><span style="color:#000000">=</span>"</span>file:/Users/drools/drools-spring-test/src/Rules/drls/</span>EvaluateUnit<span class="Apple-style-span">.drl"<span class="Apple-style-span">"<span style="color:#000000">
</span><span style="color:#009292">/></span></span></span></p>
<p style="margin-top:0px; margin-right:0px; margin-bottom:0px; margin-left:0px; font:normal normal normal 11px/normal Monaco">
</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; color:#4b9191"><span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span></span><span style="color:#009292"><</span>drools:grid-node<span style="color:#000000">
</span><span style="color:#961f8d">id</span><span style="color:#000000">=</span><span style="color:#4239f6">"node1"</span><span style="color:#000000">
</span><span style="color:#009292">/></span></p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; color:#4239f6"><span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span></span><span style="color:#009292"><</span><span style="color:#4b9191">drools:kbase</span><span style="color:#000000">
</span><span style="color:#961f8d">id</span><span style="color:#000000">=</span>"kbase1"<span style="color:#000000">
</span><span style="color:#961f8d">node</span><span style="color:#000000">=</span>"node1"<span style="color:#009292">></span></p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; color:#4b9191"><span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span></span><span style="color:#009292"><</span>drools:resources<span style="color:#009292">></span></p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; color:#4b9191"><span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span></span><span style="color:#009292"><</span>drools:resource<span style="color:#000000">
</span><span style="color:#961f8d">ref</span><span style="color:#000000">=</span><span style="color:#4239f6">"GroupUnit"</span><span style="color:#000000">
</span><span style="color:#009292">/></span></p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; color:#4b9191"><span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span></span><span style="color:#009292"><</span>drools:resource<span style="color:#000000">
</span><span style="color:#961f8d">ref</span><span style="color:#000000">=</span><span style="color:#4239f6">"GradeUnit"</span><span style="color:#000000">
</span><span style="color:#009292">/></span></p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; color:#4b9191"><span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span></span><span style="color:#009292"><</span>drools:resource<span style="color:#000000">
</span><span style="color:#961f8d">ref</span><span style="color:#000000">=</span><span style="color:#4239f6">"EvaluateUnit"</span><span style="color:#000000">
</span><span style="color:#009292">/></span></p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; color:#4239f6"><span class="Apple-style-span" style="color:rgb(75,145,145)"><span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span></span><span style="color:#009292"></</span>drools:resources<span style="color:#009292">></span></span></p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; color:#4b9191"><span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span></span><span style="color:#009292"></</span>drools:kbase<span style="color:#009292">></span></p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; color:#4239f6"><span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span></span><span style="color:#009292"><</span><span style="color:#4b9191">drools:ksession</span><span style="color:#000000">
</span><span style="color:#961f8d">id</span><span style="color:#000000">=</span>"ksession"<span style="color:#000000">
</span><span style="color:#961f8d">type</span><span style="color:#000000">=</span>"stateful"<span style="color:#000000">
</span><span style="color:#961f8d">kbase</span><span style="color:#000000">=</span>"kbase1"</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; color:#4239f6"><span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span></span><span style="color:#961f8d">node</span><span style="color:#000000">=</span>"node1"<span style="color:#000000">
</span><span style="color:#009292">/></span></p>
<div><span style="color:#009292"><br>
</span></div>
<div><font class="Apple-style-span" color="#009292"><span class="Apple-style-span" style="font-size:14px; color:rgb(0,0,0); font-family:Calibri,sans-serif">Then in my Controller call, I 'AutoWire' in the StatefulKnowledgeSession as follows :</span></font></div>
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</span></font></div>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; color:#777777">@Controller</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; color:#777777">@RequestMapping<span style="color:#000000">( value =
</span><span style="color:#4239f6">"foo"</span><span style="color:#000000"> )</span></p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco"><span style="color:#951565">final</span>
<span style="color:#951565">class</span> FooController{</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; min-height:15.0px">
</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; color:#777777"><span style="color:#000000">
</span>@Autowired</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco"> StatefulKnowledgeSession
<span style="color:#162bc4">ksession</span>;</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; min-height:15.0px">
</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco"> <span style="color:#777777">
@RequestMapping</span>( method = RequestMethod.<span style="color:#162bc4">GET</span> )</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; color:#777777"><span style="color:#000000">
</span>@ResponseBody</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco"> <span style="color:#951565">
public</span> String evaluateUnit() {</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; min-height:15.0px">
<span class="Apple-tab-span" style="white-space:pre"></span> </p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco"><span class="Apple-tab-span" style="white-space:pre"></span>Unit unit =
<span style="color:#951565">new</span> Unit(<span style="color:#4239f6">"030"</span>,
<span style="color:#4239f6">"502"</span>, <span style="color:#4239f6">"C"</span>,
<span style="color:#4239f6">"9484"</span>, <span style="color:#4239f6">"45"</span>,
<span style="color:#951565">new</span> String[] {},</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco"><span class="Apple-tab-span" style="white-space:pre"></span><span style="color:#951565">null</span>);</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; min-height:15.0px">
<span class="Apple-tab-span" style="white-space:pre"></span> </p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco"><span class="Apple-tab-span" style="white-space:pre"></span>
<span style="color:#951565">if</span> (<span style="color:#162bc4">ksession</span> !=
<span style="color:#951565">null</span>)<span class="Apple-tab-span" style="white-space:pre">
</span>{</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco"><span class="Apple-tab-span" style="white-space:pre"></span>
<span style="color:#162bc4">ksession</span>.fireAllRules();</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco"><span class="Apple-tab-span" style="white-space:pre"></span>
<span style="color:#162bc4">ksession</span>.insert(unit);</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco"><span class="Apple-tab-span" style="white-space:pre"></span>
<span style="color:#162bc4">ksession</span>.fireAllRules();</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; color:#4239f6"><span class="Apple-style-span"><span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span>
</span><span style="color:#951565">return</span><span style="color:#000000"> </span>
"<UnitCategory>"<span style="color:#000000"> + unit.getUnitCategory() + </span>"</</span>UnitCategory<span class="Apple-style-span">>"<span style="color:#000000">;</span></span></p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco"><span class="Apple-tab-span" style="white-space:pre"></span> }</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco"><span class="Apple-tab-span" style="white-space:pre"></span>
<span style="color:#951565">else</span></p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco; color:#4239f6"><span style="color:#000000"><span class="Apple-tab-span" style="white-space:pre"></span>
</span><span style="color:#951565">return</span><span style="color:#000000"> </span>
"<message> stateful session is null</message>"<span style="color:#000000">;</span></p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco"> }</p>
<p style="margin:0.0px 0.0px 0.0px 0.0px; font:11.0px Monaco"><br>
</p>
<div><font class="Apple-style-span" color="#009292"><span class="Apple-style-span" style="font-size:14px; color:rgb(0,0,0); font-family:Calibri,sans-serif">The main question that I have is that – is this solution thread-safe ? From what I understand of spring
is that beans configured without any additional qualifiers are inherently singletons. And when deployed in a multi-theaded container like tomcat, Spring assumes that the beans being severed up a thread-safe. So from I have read is that KnowledeSessions are
inherently not thread safe. So putting the 2 together, I leaning towards the assessment that this above solution is NOT thread safe and that if I do want it to be thread safe I should set the StatefulKnowledgeSession to 'prototype' and not leave it as a singleton.</span></font></div>
<div><font class="Apple-style-span" color="#009292"><span class="Apple-style-span" style="font-size:14px; color:rgb(0,0,0); font-family:Calibri,sans-serif"><br>
</span></font></div>
<div><font class="Apple-style-span" color="#009292"><span class="Apple-style-span" style="font-size:14px; color:rgb(0,0,0); font-family:Calibri,sans-serif">Please let me know if I'm missing anything in my assessment here !</span></font></div>
<div><font class="Apple-style-span" color="#009292"><span class="Apple-style-span" style="font-size:14px; color:rgb(0,0,0); font-family:Calibri,sans-serif"><br>
</span></font></div>
<div><font class="Apple-style-span" color="#009292"><span class="Apple-style-span" style="font-size:14px; color:rgb(0,0,0); font-family:Calibri,sans-serif">Thanks in advance,</span></font></div>
<div><font class="Apple-style-span" color="#009292"><span class="Apple-style-span" style="font-size:14px; color:rgb(0,0,0); font-family:Calibri,sans-serif">Gurvinder</span></font></div>
<div><font class="Apple-style-span" color="#009292"><span class="Apple-style-span" style="font-size:14px; color:rgb(0,0,0); font-family:Calibri,sans-serif"><br>
</span></font></div>
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