I know the original poster typically builds.NET applications, but for those times when you want to do this in Java, there are at least two good engines: http://www.mandarax.org/ is a backwards-chained engine (like Prolog), and http://www.drools.org/ is a forward-chained engine (takes action based on input).
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I know the original poster typically builds .NET applications, but for those times when you want to do this in Java, there are at least two good engines: http://www.mandarax.org/ is a backwards-chained engine (like Prolog), and http://www.drools.org/ is a forward-chained engine (takes action based on input).