Thanks wolfgang, for the info and that workaround.<br>I think there is some off by one error in for loop, or may be some mistake that I didnt notice in my code. the following rule with 3 objects gives index out of bound error. I am attaching java & drl file (package com.example.drools.testing). I am using 5.2.0 final release.<br>
<br>rule "Buy X units of Product A and Get Y units of Product B Free"<br> when<br> $itemsA : ArrayList( $a : size >= 2 ) from collect( CartItem( productId == "A", processed == false) )<br>
$itemsB : ArrayList( $b : size >= 1 ) from collect( CartItem( productId == "B", processed == false) )<br> $m : RuleMessage()<br> then<br> $m.addMessage("sizes- A="+$a + " B="+$b);<br>
int $x = 2;<br> int $y = 1;<br> $m.addMessage("sizes- X="+$x + " Y="+$y);<br> for(int i=0 ; i < $x ; i++){<br> CartItem $ci = (CartItem) $itemsA.get(i);<br>
$m.addMessage( $ci.getId()+")Found item: "+$ci.getProductId());<br> modify((CartItem)$ci){<br> setProcessed(true),<br> setPromoItemDiscount(0D),<br> setPromoId("2"),<br>
setBundleId(bundler.getId()),<br> setAggregatorId(1)<br> };<br> };<br> for(int i=0 ; i < $y ; i++){<br> CartItem $ci = (CartItem) $itemsB.get(i);<br> $m.addMessage( $ci.getId()+")Found item: "+$ci.getProductId());<br>
modify((CartItem)$ci){<br> setProcessed(true),<br> setPromoItemDiscount($ci.getPrice()),<br> setPromoId("2"),<br> setBundleId(bundler.getId()),<br>
setAggregatorId(2)<br> };<br> };<br> bundler.increment();<br>end<br><br><br><b>error</b><br>Exception in thread "main" org.drools.runtime.rule.ConsequenceException: rule: Buy X units of Product A and Get Y units of Product B Free<br>
<br> at org.drools.runtime.rule.impl.DefaultConsequenceExceptionHandler.handleException(DefaultConsequenceExceptionHandler.java:39)<br> at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:916)<br> at org.drools.common.DefaultAgenda.fireNextItem(DefaultAgenda.java:845)<br>
at org.drools.common.DefaultAgenda.fireAllRules(DefaultAgenda.java:1056)<br> at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:733)<br> at org.drools.common.AbstractWorkingMemory.fireAllRules(AbstractWorkingMemory.java:699)<br>
at org.drools.impl.StatefulKnowledgeSessionImpl.fireAllRules(StatefulKnowledgeSessionImpl.java:218)<br> at com.example.drools.testing.Main.main(Main.java:52)<br>Caused by: java.lang.IndexOutOfBoundsException: Index: 1, Size: 1<br>
at java.util.ArrayList.RangeCheck(ArrayList.java:547)<br> at java.util.ArrayList.get(ArrayList.java:322)<br> at com.example.drools.testing.Rule_Buy_X_units_of_Product_A_and_Get_Y_units_of_Product_B_Free_0.defaultConsequence(Rule_Buy_X_units_of_Product_A_and_Get_Y_units_of_Product_B_Free_0.java:12)<br>
at com.example.drools.testing.Rule_Buy_X_units_of_Product_A_and_Get_Y_units_of_Product_B_Free_0DefaultConsequenceInvoker.evaluate(Rule_Buy_X_units_of_Product_A_and_Get_Y_units_of_Product_B_Free_0DefaultConsequenceInvoker.java:44)<br>
at org.drools.common.DefaultAgenda.fireActivation(DefaultAgenda.java:906)<br> ... 6 more<br><br><br><div class="gmail_quote">2011/9/9 Wolfgang Laun <span dir="ltr"><<a href="mailto:wolfgang.laun@gmail.com">wolfgang.laun@gmail.com</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">If the declared type of productId and getProductId() is String, it should be compared to a string literal. (A conversion might be made, but don't rely on that.)<br>
<br>You cannot access components of a global in RHS code using the simplified notation (not unless you use "mvel" - but don't do that.) Here, all accesses should be written the usual Java way, with getter and setter calls.<br>
<br>The problem you have with modify(ci) is a bug (fixed for 5.3.0). As a workaround,use<br><br>modify( (CartItem)ci ){ ... }<br><font color="#888888"><br>-W</font><div><div></div><div class="h5"><br> <br><br>2011/9/9 Sandeep Bandela <span dir="ltr"><<a href="mailto:gibsosmat@gmail.com" target="_blank">gibsosmat@gmail.com</a>></span><br>
<div class="gmail_quote"><blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">some more info for the modify() problem, the CartItem is an interface and the implementation is CartItemImpl. if this info leads to some clues. <br>
</blockquote><blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex"><div><div></div><div><br><br><div class="gmail_quote">On Fri, Sep 9, 2011 at 1:28 PM, Sandeep Bandela <span dir="ltr"><<a href="mailto:gibsosmat@gmail.com" target="_blank">gibsosmat@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">Hi here is the same thing converted to mvl<br><br>// this Bundler.java has integer member that keeps incrementing<br>
global Bundler bundler<div>
<br><br>rule "Apply 10% discount if you purchase 2 items"<br></div> when<br>
$s1 : CartItem( <b>productId == 219759</b>, processed == false)<br> $s2 : CartItem( this != $s1, productId == $s1.productId, processed == false)<div><br> $m : RuleMessage()<br> then<br> $m.addMessage("Found item1: " + $s1.getName() + " id: "+$s1.getId());<br>
$m.addMessage("Found item2: " + $s2.getName() + " id: "+$s2.getId());<br> modify($s1){<br> setProcessed(true),<br> setPromoItemDiscount($s1.getPrice() * 0.1),<br> setPromoId("1"),<br>
setBundleId(bundler.getId()),<br> setAggrigatorId(1)<br> };<br> modify($s2){<br> setProcessed(true),<br> setPromoItemDiscount($s2.getPrice() * 0.1),<br> setPromoId("1"),<br>
setBundleId(bundler.getId()),<br> setAggrigatorId(1)<br> };<br></div> $m.addMessage("bundled ["+<b>bundler.getId()</b>+"] "+$s1.getId()+","+$s2.getId());<br> bundler.increment();<br>
end<br><br>the above rule dosent fire, but if I change the highlighter to getProductId() == 219759, or use productId == "219759", may be this is some edge case but it took long time for me to figure it out productId is String. now consider the <b>bundler.getId()</b>, if I use <b><a href="http://bundler.id" target="_blank">bundler.id</a></b> I get compilation error.<br>
<br>Rule Compilation error : [Rule name='Apply 10% discount if you purchase 2 items']<br> com/example/promotions/promotionEngine/Rule_Apply_10__discount_if_you_purchase_2_items_0.java (23:1592) : The field Bundler.id is not visible<br>
2011-09-09 13:18:39,863 INFO [STDOUT] - 2011-09-09 13:18:39,863 INFO [PromotionsManager] - ksession initialized<br>2011-09-09 13:18:39,863 INFO [STDOUT] - 2011-09-09 13:18:39,863 INFO [PromotionsManager] - Exploding items and inserting cart<br>
2011-09-09 13:18:39,864 INFO [STDOUT] - 2011-09-09 13:18:39,863 ERROR [CheckOutBasedUtilities] - Failed to apply promo offers <br>java.lang.RuntimeException: Unexpected global [bundler]<br> at org.drools.common.AbstractWorkingMemory.setGlobal(AbstractWorkingMemory.java:613)<br>
at org.drools.impl.StatefulKnowledgeSessionImpl.setGlobal(StatefulKnowledgeSessionImpl.java:332)<br> at com.example.promotions.promotionEngine.PromotionsManager.applyOffers(PromotionsManager.java:154)<br> at com.example.promotions.promotionEngine.PromotionsManager.shuffleForOffers(PromotionsManager.java:61)`<br>
<br>lastly my actual problem that I am looking for a solution lets say we have "Buy X items of A and get Y Items of B". X=5 & Y=4 from the original problem I want to template the rule and load the values of X,A,Y,B from database or excel etc. if I use modify the error is as follows<br>
<br><b>my rule</b><div><br><br><br>rule "Buy X units of Product A and Get Y units of Product B Free"<br></div> when<br> $itemsX : ArrayList( size == 2 ) from collect( CartItem( getProductId() == 24257, !isProcessed()))<br>
$itemsY : ArrayList( size == 1) from collect(CartItem( getProductId() == 24260, !isProcessed()))<br> $m : RuleMessage()<br> then<br> for(Object item : $itemsX){<br> CartItem ci = (CartItem) item;<br>
$m.addMessage( ci.getId()+")Found item: "+ci.getItemId()+" name: "+ci.getName());<br> modify(ci){<br> setProcessed(true),<br> setPromoItemDiscount(0),<div>
<br>
setPromoId("2"),<br> setBundleId(bundler.getId()),<br> setAggrigatorId(1)<br> };<br> }<br></div> for(Object item : $itemsY){<br> CartItem ci = (CartItem) item;<br>
$m.addMessage( ci.getId()+")Found item: "+ci.getItemId()+" name: "+ci.getName());<br> modify(ci){<br> setProcessed(true),<br> setPromoItemDiscount(ci.getPrice()),<br>
setPromoId("2"),<br> setBundleId(bundler.getId()),<br> setAggrigatorId(2)<br> };<br> }<br> bundler.increment();<br>end<br><br>Rule Compilation error : [Rule name='Buy X units of Product A and Get Y units of Product B Free']<br>
com/example/promotions/promotionEngine/Rule_Buy_X_units_of_Product_A_and_Get_Y_units_of_Product_B_Free_0.java (11:1236) : The method setProcessed(boolean) is undefined for the type Object<br> com/example/promotions/promotionEngine/Rule_Buy_X_units_of_Product_A_and_Get_Y_units_of_Product_B_Free_0.java (12:1265) : The method setPromoItemDiscount(int) is undefined for the type Object<br>
com/example/promotions/promotionEngine/Rule_Buy_X_units_of_Product_A_and_Get_Y_units_of_Product_B_Free_0.java (13:1299) : The method setPromoId(String) is undefined for the type Object<br> com/example/promotions/promotionEngine/Rule_Buy_X_units_of_Product_A_and_Get_Y_units_of_Product_B_Free_0.java (14:1325) : The method setBundleId(Integer) is undefined for the type Object<br>
com/example/promotions/promotionEngine/Rule_Buy_X_units_of_Product_A_and_Get_Y_units_of_Product_B_Free_0.java (15:1364) : The method setAggrigatorId(int) is undefined for the type Object<br> com/example/promotions/promotionEngine/Rule_Buy_X_units_of_Product_A_and_Get_Y_units_of_Product_B_Free_0.java (22:1702) : The method setProcessed(boolean) is undefined for the type Object<br>
com/example/promotions/promotionEngine/Rule_Buy_X_units_of_Product_A_and_Get_Y_units_of_Product_B_Free_0.java (23:1731) : The method setPromoItemDiscount(Double) is undefined for the type Object<br> com/example/promotions/promotionEngine/Rule_Buy_X_units_of_Product_A_and_Get_Y_units_of_Product_B_Free_0.java (24:1777) : The method setPromoId(String) is undefined for the type Object<br>
com/example/promotions/promotionEngine/Rule_Buy_X_units_of_Product_A_and_Get_Y_units_of_Product_B_Free_0.java (25:1803) : The method setBundleId(Integer) is undefined for the type Object<br> com/example/promotions/promotionEngine/Rule_Buy_X_units_of_Product_A_and_Get_Y_units_of_Product_B_Free_0.java (26:1842) : The method setAggrigatorId(int) is undefined for the type Object<br>
<br>Rule Compilation error : [Rule name='Apply 10% discount if you purchase 2 items']<br> com/example/promotions/promotionEngine/Rule_Apply_10__discount_if_you_purchase_2_items_0.java (23:1592) : The field Bundler.id is not visible<div>
<div></div><div><br>
<br><br><div class="gmail_quote">On Fri, Sep 9, 2011 at 12:40 PM, Sandeep Bandela <span dir="ltr"><<a href="mailto:gibsosmat@gmail.com" target="_blank">gibsosmat@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">
Hi Wolfgang,<br>This is what I did initially but for product > 2 I didnt find a generic way to do this. following is my first rule. I didnt use field names because it was giving error that member is not accessible. I will attach the errors of each case in a few mins.<br>
<br>rule "Apply 10% discount if you purchase 2 items"<br> dialect "java"<br> when<br> $s1 : CartItem( getProductId() == 236061, !isProcessed())<br> $s2 : CartItem( getProductId() == 236061, getId() != $s1.getId(), !isProcessed())<br>
$m : RuleMessage()<br> then<br> $m.addMessage("Found item1: " + $s1.getName() + " id: "+$s1.getId());<br> $m.addMessage("Found item2: " + $s2.getName() + " id: "+$s2.getId());<br>
modify($s1){<br> setProcessed(true),<br> setPromoItemDiscount($s1.getPrice() * 0.1),<br> setPromoId("1"),<br> setBundleId(bundler.getId()),<br> setAggrigatorId(1)<br> };<br>
modify($s2){<br> setProcessed(true),<br> setPromoItemDiscount($s2.getPrice() * 0.1),<br> setPromoId("1"),<br> setBundleId(bundler.getId()),<br> setAggrigatorId(1)<br> };<br>
bundler.increment();<br>end<div><div></div><div><br><br><div class="gmail_quote">2011/9/9 Wolfgang Laun <span dir="ltr"><<a href="mailto:wolfgang.laun@gmail.com" target="_blank">wolfgang.laun@gmail.com</a>></span><br>
<blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">
Your rule exhibits procedural thinking. (For an aspiring rule programmer his is typical teething troubles.) <br><br>There's no need to collect all A's and B's in order to determine their number being greater than one or two - this is achieved automatically by a simple triple match rule. Consider<br>
<br>rule "2A - 1B"<br>when<br> $a1: CartItem( productId == "A", processed == false )<br> $a2: CartItem( this != $a1, productId == "A", processed == false )<br> $b: CartItem( productId == "B", processed == false )<br>
then<br> modify( $a1 ){...}<br> modify( $a2 ){...}<br> modify( $b ){...}<br>end<br><br>Note:<br><ul><li>The modify is essential. (When you say "doesn't work", always provide details.)</li><li>Use the field name rather than the getter call - it improves readability.</li>
<li>I'm not sure whether 5.2.0 final handles boolean fields correctly - IIRC, there were some issues. It's possible that CartItem(..., !processed) works. <br></li></ul>-W<br><br><div class="gmail_quote"><div><div>
</div><div>2011/9/8 Sandeep Bandela <span dir="ltr"><<a href="mailto:gibsosmat@gmail.com" target="_blank">gibsosmat@gmail.com</a>></span><br>
</div></div><blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex"><div><div></div><div>Hi,<br>I am new to rules engine, after going through the examples shipped (shopping.drl, petstore.drl)<br>
I am trying to implement promotional discounting using drools 5.2.0 final, stateful session. assume cart has all the items that customer wants to buy,<br>
I am trying to bundle them together with the existing offers<br><br>rule "Buy X units of Product A and Get Y units of Product B Free"<br> dialect "java"<br>
when<br> $itemsA : ArrayList( size >= 2) from collect( CartItem( getProductId() == "A", !isProcessed()))<br> $itemsB : ArrayList( size >= 1) from collect( CartItem( getProductId() == "B", !isProcessed()))<br>
then<br> // current scenario buy 2*A and get 1*B <br> int x = 2;<br> int y = 1;<br> for(int i=0 ; i < x ; i++){<br> CartItem $ci = (CartItem) $itemsA.get(i);<br> // modify($ci){setProcessed(true) ... } dosent work<br>
$ci.setProcessed(true);<br> $ci.setItemDiscount(0.0);<br> $ci.setBundleId(bundler.getId());<br> }<br> <br> for(int i=0 ; i < y ; i++){<br> CartItem $ci = (CartItem) $itemsB.get(i);<br>
$ci.setProcessed(true);<br> $ci.setItemDiscount($ci.getPrice());<br> $ci.setBundleId(bundler.getId());<br> }<br> // global counter to identify bundled items<br> bundler.increment();<br>end<br>
<br>the above rule calculates only for 1 set of offer i.e first 2*A & 1*B are considered, rest in the cart are not bundled.<br>if customer buys 4*A + 2*B it dosent consider it. am I missing anything? is this the right way to do it?<br>
any feedback is appreciated.<br><br><br><br clear="all"><br>-- <br>Regards,<br><font color="#888888">Sandeep Bandela.<br><br>
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<br></blockquote></div><br><br clear="all"><br></div></div>-- <br>Regards,<br><font color="#888888">Sandeep Bandela.<br><br>
</font></blockquote></div><br><br clear="all"><br></div></div>-- <br>Regards,<br><font color="#888888">Sandeep Bandela.<br><br>
</font></blockquote></div><br><br clear="all"><br></div></div>-- <br>Regards,<br><font color="#888888">Sandeep Bandela.<br><br>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Regards,<br>Sandeep Bandela.<br><br>