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<p class="MsoNormal">What are the benefits of using pluggable operators (implementations of org.drools.base.evaluators.EvaluatorDefinition such str, matches, or before) versus simply making an equivalent function call? I’ve read the
<a href="http://blog.athico.com/2010/06/creating-pluggable-oprators.html">Creating pluggable operators</a> blog post. Apart from saying that the Eclipse plugin can recognize these operators, it doesn’t really make a case for why I’d want to create my own implementation.
One might argue that operators enhance reusability, but a static method offers much the same benefit. Does a pluggable operator have any optimization, caching, or other advantage?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">For example, here are two ways to match the start of a string in a property of a fact, one using the “str[startsWith]” operator and another with Java’s String.startsWith method:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="text-autospace:none"><b><span style="font-size:10.0pt;font-family:Consolas;color:#960000">declare</span></b><span style="font-size:10.0pt;font-family:Consolas;color:black"> Fact</span><span style="font-size:10.0pt;font-family:Consolas"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:Consolas;color:black"> key : String @key</span><span style="font-size:10.0pt;font-family:Consolas"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><b><span style="font-size:10.0pt;font-family:Consolas;color:#960000">end</span></b><span style="font-size:10.0pt;font-family:Consolas"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:Consolas"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><b><span style="font-size:10.0pt;font-family:Consolas;color:#960000">rule</span></b><span style="font-size:10.0pt;font-family:Consolas;color:black">
</span><span style="font-size:10.0pt;font-family:Consolas;color:green">"Use operator"</span><span style="font-size:10.0pt;font-family:Consolas"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:Consolas;color:black">
</span><b><span style="font-size:10.0pt;font-family:Consolas;color:#960000">when</span></b><span style="font-size:10.0pt;font-family:Consolas"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:Consolas;color:black"> Fact(key str[startsWith]
</span><span style="font-size:10.0pt;font-family:Consolas;color:green">"abc"</span><span style="font-size:10.0pt;font-family:Consolas;color:black">)</span><span style="font-size:10.0pt;font-family:Consolas"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:Consolas;color:black">
</span><b><span style="font-size:10.0pt;font-family:Consolas;color:#960000">then</span></b><span style="font-size:10.0pt;font-family:Consolas"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:Consolas;color:black">
</span><span style="font-size:10.0pt;font-family:Consolas;color:olive">// do something</span><span style="font-size:10.0pt;font-family:Consolas"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><b><span style="font-size:10.0pt;font-family:Consolas;color:#960000">end</span></b><span style="font-size:10.0pt;font-family:Consolas"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:Consolas"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><b><span style="font-size:10.0pt;font-family:Consolas;color:#960000">rule</span></b><span style="font-size:10.0pt;font-family:Consolas;color:black">
</span><span style="font-size:10.0pt;font-family:Consolas;color:green">"Use method"</span><span style="font-size:10.0pt;font-family:Consolas"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:Consolas;color:black">
</span><b><span style="font-size:10.0pt;font-family:Consolas;color:#960000">when</span></b><span style="font-size:10.0pt;font-family:Consolas"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:Consolas;color:black"> Fact(key.startsWith(</span><span style="font-size:10.0pt;font-family:Consolas;color:green">"abc"</span><span style="font-size:10.0pt;font-family:Consolas;color:black">))</span><span style="font-size:10.0pt;font-family:Consolas"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:Consolas;color:black">
</span><b><span style="font-size:10.0pt;font-family:Consolas;color:#960000">then</span></b><span style="font-size:10.0pt;font-family:Consolas"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:10.0pt;font-family:Consolas;color:black">
</span><span style="font-size:10.0pt;font-family:Consolas;color:olive">// do something</span><span style="font-size:10.0pt;font-family:Consolas"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><b><span style="font-size:10.0pt;font-family:Consolas;color:#960000">end</span></b><span style="font-size:10.0pt;font-family:Consolas"><o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Does one of these perform better than the other?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Best wishes,<o:p></o:p></p>
<p class="MsoNormal">Tom<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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