Re: [rules-users] Getting Started with an simple sample

Should the creation of the external file depend on the existence of *any* MeasureResult (with the same detector)? No, because:

- There always is one, otherwise the 1st pattern wouldn't be true.

- Apart from that: all existing MeasureResult's could be below 5, and this should not block file creation.

I didn't know that there is another condition to test for. So there has to be a second condition that checks if the detector that returned the result has already created a file. Just add a further field into the MeasureResult object, which now should contain a value and a detector. Now you should change your rules to something like this: rule "Measure >= 5" when $mes:MeasureResult(result >= 5, mes_detector:detector) not MeasureResult(mes_detector == detector) then //insert textfile creation here end

rule "Measure <= 3" when $mes:MeasureResult(result <= 3, mes_detector:detector) not MeasureResult(mes_detector == detector) then //insert textfile deletion here end The first condition again tests for the result and in addition it saves the detector that created the result into the field mes_detector. The second condition now says that there shall not be a MeasureResult which has a detector that already created a result. Note that you have to retract the MeasureResult object from the Session when you remove a file so that the detector can create a file again. Greetings Bojan ----- Ursprüngliche Mail ----- Von: Stefan Schuster <stefan.m.schuster(a)gmail.com&gt; An: Rules Users List <rules-users(a)lists.jboss.org&gt; Gesendet: Fri, 26 Apr 2013 12:22:12 +0200 (CEST) Betreff: Re: [rules-users] Getting Started with an simple sample Hi Bojan, thanks a lot for your fast response. but how can I guarantee that there is only one textfile per detector created, even if the detecor has a value above 5 for a longer time? Obviously the method for textfile-creation could check if there already exists a file on the filesystem, but that doesn't feel "drools-like" to me. further ideas? thanks Stefan 2013/4/26 Bojan Janisch <bojan.janisch(a)scai.fraunhofer.de&gt; > Hi Stefan, > > after you know what in the knowledgesession shall be, you have to think > how you could check the value that the detectors return. For this you > could > create a new class e.g. MeasureResult which contains the result of the > detectors. So instead of inserting the value, you insert the object (that > contains the value) into the session. Now your rule only have to check if > there is a MeasureResult object and depending on the value, do something. > > For example: > > rule "Measure >= 5" > when > MeasureResult(result >= 5) > then > //insert textfile creation here > end > > rule "Measure <= 3" > when > MeasureResult(result <= 3) > then > //insert textfile deletion here > end > > Of course for these rules your MeasureResult class need a variable called > result and getter-Methods for it. > > Greetings > Bojan > > > > ----- Ursprüngliche Mail ----- > Von: "Stefan Schuster" <stefan.m.schuster(a)gmail.com&gt; > An: "Rules Users List" <rules-users(a)lists.jboss.org&gt; > Gesendet: Freitag, 26. April 2013 11:30:40 > Betreff: [rules-users] Getting Started with an simple sample > > > > > > Hello, > > I’m still in the phase of learning the basics with drools. Therefor I > created a simplified problem that I try to realize it with drools: > > I have several detectors, each of them measures something and converts it > into an integer value between 1 one 6. Every Minute a new measurement is > performed. > > When a detector reaches a value of 5 or above, a textfile is created with > the name of the detector as filename and a predefined text as content. > When > the detector reaches a value of 3 or less, the texfile is deleted. > > My problem is that I’m still “thinking in java” and not yet “thinking in > drools”. > > I guess the measured values would be facts that I insert (like the > key-pressed events in the pong-example) to the knowledgebase. But now I > stumble, I have no idea how to continue. Could anyone give me a helping > hand for the next steps? > > Thanks in advance > > Stefan > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users > > _______________________________________________ > rules-users mailing list > rules-users(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/rules-users _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users