I can highly recommend joda-time library (<a href="http://joda-time.sourceforge.net/">http://joda-time.sourceforge.net/</a>)<div><br></div><div>I'd insert current date as a fact.</div><div><br></div><div>I haven't tried this but you might be able to do:</div>
<div>SomeFact( date == (current.plusDays(3)) )</div><div><br></div><div><br><br><div class="gmail_quote">On Thu, Jan 29, 2009 at 11:57 AM, Anstis, Michael (M.) <span dir="ltr"><<a href="mailto:manstis1@ford.com">manstis1@ford.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">
<div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2">Hi David,</font></span></div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2"></font></span> </div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2">Sorry it was of little help.</font></span></div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2"></font></span> </div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2">A rule of thumb is to stay away from "eval" as it kills
performance (the patterns can't be indexed).</font></span></div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2"></font></span> </div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2">I'm not sure if Drools can handle Date variables (the docs
state it handles Data literals formatted as "dd-mmm-yyyy" so Cheese( date ==
"27-Oct-2008") works).</font></span></div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2"></font></span> </div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2">I guess you could look at something like this (gees, this
is going to show how "green" I am with Drools now):-</font></span></div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2"></font></span> </div>
<div dir="ltr" align="left"><span><font face="Courier New" color="#0000ff" size="2">rule "yuck"</font></span></div>
<div dir="ltr" align="left"><span><font face="Courier New"><font color="#0000ff" size="2">
when</font></font></span></div>
<div dir="ltr" align="left"><span><font face="Courier New"><font color="#0000ff" size="2"> DateFactory($today :
today )</font></font></span></div>
<div dir="ltr" align="left"><span><font face="Courier New"><font color="#0000ff" size="2"> $c : CreditCard( $expires :
expirationDate )</font></font></span></div>
<div dir="ltr" align="left"><span><font face="Courier New" color="#0000ff" size="2"> ArrayList( size
>= 0 ) from collect( Day( date >= $today, date <= $expires
))<br> then</font></span></div>
<div dir="ltr" align="left"><span><font face="Courier New"><font color="#0000ff" size="2"> //Difference between "today"
and "expiry date" is more than zero days</font></font></span></div>
<div dir="ltr" align="left"><font size="2"><font color="#0000ff"><font face="Courier New"><span>end</span><span></span></font></font></font></div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2"></font></span> </div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2">This does require the insertion of (possibly) huge amounts
of Day facts. Yuck. There must be a better way (in fact your eval looks soooo
much cleaner). I'm just throwing out ideas. </font></span></div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2"></font></span> </div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2">Good luck with your adventures with
Drools.</font></span></div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2"></font></span> </div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2">Mike</font></span></div><br>
<blockquote style="margin-right:0px">
<div lang="en-us" dir="ltr" align="left">
<hr>
<font face="Tahoma" size="2"><div class="Ih2E3d"><b>From:</b> <a href="mailto:rules-users-bounces@lists.jboss.org" target="_blank">rules-users-bounces@lists.jboss.org</a>
[mailto:<a href="mailto:rules-users-bounces@lists.jboss.org" target="_blank">rules-users-bounces@lists.jboss.org</a>] <b>On Behalf Of </b>David
Siefert<br></div><b>Sent:</b> 29 January 2009 11:31<br><b>To:</b> Rules Users
List<br><b>Subject:</b> Re: [rules-users] Working with dates in
rules<br></font><br></div><div><div></div><div class="Wj3C7c">
<div></div>
<div>Not sure--Drools 5 temporal reasoning looks like it would be the
answer. Only problem is that I need a solution now, so I am stuck with
Drools 4.</div>
<div> </div>
<div>This did give me some ideas though. I created myself a class called
TemporalReasoner. This has a few methods, namely to roll a date (so I
can tell it x amount of time from now), and then compare it to another
date.</div>
<div> </div>
<div>So in my rule, lets say I have a fact CreditCard with property
expiration:Date (speaking uml-ishly for "a property named 'expiration' of
type Date"):</div>
<div> </div>
<div><font face="courier new,monospace">rule "Fires when expiration less than
today"</font></div>
<div><font face="courier new,monospace"> when</font></div>
<div><font face="courier new,monospace"> $c:
CreditCard($expires : expirationDate)</font></div>
<div><font face="courier new,monospace"> eval(new
TemporalReasoner(Calendar.getInstance()).lessThan($expires))</font></div>
<div><font face="courier new,monospace"> then</font></div>
<div><font face="courier new,monospace"> // do something for
when credit card is still valid</font></div>
<div><font face="courier new,monospace">end</font></div>
<div> </div>
<div>Now, I'm still generally a noob with BRs, so I'm not sure how this will
affect performance. Any advice?</div>
<div> </div>
<div>Thanks,</div>
<div>David<br><br></div>
<div class="gmail_quote">On Thu, Jan 29, 2009 at 3:50 AM, Anstis, Michael (M.)
<span dir="ltr"><<a href="mailto:manstis1@ford.com" target="_blank">manstis1@ford.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="padding-left:1ex;margin:0px 0px 0px 0.8ex;border-left:#ccc 1px solid">
<div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2">Hi,</font></span></div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2"></font></span> </div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2">I wonder
whether Drools 5 "Complex Event Processing Support (Temporal Reasoning)"
might be what you're looking for?</font></span></div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2"></font></span> </div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2"><a href="http://blog.athico.com/2008/07/drools-50-m1-new-and-noteworthy.html" target="_blank">http://blog.athico.com/2008/07/drools-50-m1-new-and-noteworthy.html</a></font></span></div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2"></font></span> </div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2">With
kind regards,</font></span></div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2"></font></span> </div>
<div dir="ltr" align="left"><span><font face="Arial" color="#0000ff" size="2">Mike</font></span></div><br>
<blockquote dir="ltr" style="margin-right:0px">
<div lang="en-us" dir="ltr" align="left">
<hr>
<font face="Tahoma" size="2"><b>From:</b> <a href="mailto:rules-users-bounces@lists.jboss.org" target="_blank">rules-users-bounces@lists.jboss.org</a> [mailto:<a href="mailto:rules-users-bounces@lists.jboss.org" target="_blank">rules-users-bounces@lists.jboss.org</a>] <b>On Behalf Of
</b>David Siefert<br><b>Sent:</b> 29 January 2009 09:40<br><b>To:</b>
Rules Users List<br><b>Subject:</b> [rules-users] Working with dates in
rules<br></font><br></div>
<div>
<div></div>
<div>
<div></div>
<div>Hi-</div>
<div> </div>
<div>I'm wondering how it would be possible to compare a part of a date in
the lhs condition of a rule in a Drool. In other words, I need to
compare a date to see if it is <em>x</em> days from the current
date, <em>n</em> hours from current time, etc. Would anyone be
kind enough to provide an example? I'm thinking I may have to
implement something of my own to offer that functionality?</div>
<div> </div>
<div>Big thanks,</div>
<div>David</div></div></div></blockquote></div><br>_______________________________________________<br>rules-users
mailing list<br><a href="mailto:rules-users@lists.jboss.org" target="_blank">rules-users@lists.jboss.org</a><br><a href="https://lists.jboss.org/mailman/listinfo/rules-users" target="_blank">https://lists.jboss.org/mailman/listinfo/rules-users</a><br>
<br></blockquote></div><br></div></div></blockquote></div>
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