well, if you have both room and thermometer asserted as seperate facts, you need to modify each one if you want their changes to be re-considered (not always the case). The engine will then re-check all the combinations and create activations for modified facts - basically its the same as if you retracted and asserted those facts anew. On 2/22/07, seeker <janko.dimitroff(a)dai-labor.de&gt; wrote: > > I have a fact which holds a reference to another fact. I wonder which one > do I have to modify in my RHS. > My Objects are Room and Thermometer. Room holds reference to Thermometer > (and that has a property describing the value). > > When my rule fires I want to decrease the temperature level to simulate > that the room gets colder until a certain value A is reached. So the rule > should be called several times until the actual level equals A. > > This works ONE time when I set the new value on Thermometer and modify > Thermometer, not reaching A (the rule isnt fired again). > But works as expected when I modify Room instead of Thermometer (rules is > fired several times). > > I'm new to drools and wonder if that is desired or if I do something > wrong. > > To make things more confusing: When several rules met the same > conditions, > does only one rule gets fired or do all get fired (as I read it from > Figure 1.19 of the documention). > > If I modify Room my other rules _dont_ get fired. When I had modified > Thermometer my other rules _do_ get fired.