规则引擎代码

# Rules We shall use a Ruleflow and implement the rules in 3 steps : * Distribute the products in the pallet * Calculate the costs * Calculate and Display the results This is done in the P1.bpmn2.  ## Distribute the products in the pallet This rules will be executed in the rule step "distribution". So we shall add the keyworruleflow-group "distribution". There are 3 types of product : those we have to put individually, the bulk and the others. ### Initialize a counter for each order line First we shall the rule that created the LeftToDistribute object. For each orderline we create and link to the orderline element ``` rule "Create Counter leftToDistribute quantity" ruleflow-group "distribution" when $elt : OrderLine( numberItems >0 ) not (LeftToDistribute(orderLine==$elt)) then LeftToDistribute e= new LeftToDistribute($elt,$elt.getNumberItems()); insert(e); end rule "Create Counter leftToDistribute weight" ruleflow-group "distribution" when $elt : OrderLine( weight >0 ) not (LeftToDistribute(orderLine==$elt)) then LeftToDistribute e= new LeftToDistribute($elt,$elt.getWeight()); insert(e); end ``` So here the rule above for each OrderLine that is not yet connected to a LeftToDistribute fact. Then we create it and initialize the counter with the number of elements in the line. We have one rule when items are ### individual items For each product of type individual, we shall put it on the pallet. And in the then part, we create the pallet, decrease the number of element left and update the objects? ``` rule "Create PalletForIndividual" ruleflow-group "distribution" when $c : CostCalculationRequest() $p : Product(transportType==Product.transportType_individual) $elt : OrderLine(product==$p ) $l : LeftToDistribute(quantityLeft> 0,orderLine==$elt) then Pallet pp = new Pallet(); pp.setPalletType($p.getTransportType()); pp.addContent($p,new Long(1)); insert(pp); $c.getPallets().add(pp); $l.setQuantityLeft($l.getQuantityLeft()-1); update($l); end ``` ### bulk item For the bulk product, we shall do the same way. The first rule files 1400kg on each pallet. The second rule is if there is less than 1400kg left, then we put the rest in the pallet. ``` rule "Create PalletForBulkMore1400Kg" ruleflow-group "distribution" when $c : CostCalculationRequest() $p : Product(transportType==Product.transportType_bulkt) $elt : OrderLine(product==$p ) $l : LeftToDistribute(weightLeft > 1400,orderLine==$elt) then Pallet pp = new Pallet(); pp.setPalletType($p.getTransportType()); pp.addContent($p,new Long(1400)); insert(pp); $c.getPallets().add(pp); $l.setWeightLeft($l.getWeightLeft()-1400); update($l); end rule "Create PalletForBulkless1400Kg" ruleflow-group "distribution" when $c : CostCalculationRequest() $p : Product(transportType==Product.transportType_bulkt) $elt : OrderLine(product==$p ) $l : LeftToDistribute(weightLeft <= 1400,weightLeft > 0,orderLine==$elt) then Pallet pp = new Pallet(); pp.setPalletType($p.getTransportType()); pp.addContent($p,$l.getWeightLeft()); insert(pp); $c.getPallets().add(pp); $l.setWeightLeft(0); update($l); end ``` ### Distribute the other product type. We shall first create a rule that create a new Pallet if none is available ``` rule "Create Empty Pallet" ruleflow-group "distribution" when not (Pallet (palletType == Product.transportType_pallet,full ==false)) then Pallet p = new Pallet(); p.setPalletType(Product.transportType_pallet); insert (p); end ``` As we are going to fill the pallet in height, we shall declare a pallet as full if the place left in height is smaller than the smallest product in height. ``` rule "GetSmallestHeight" ruleflow-group "distribution" when accumulate( Product( $h : height ,transportType==Product.transportType_pallet ); $min : min( $h ); true ) then CalculatedElement elt = new CalculatedElement(); elt.setKey("minValue.product"); elt.setDoubleValue((Double)$min); insert(elt); end ``` And then the rule that sets the pallet as filled (full has the true value). We only set the value of a pallet that has been filled by one type of product by adding constranint heightLeft!= 2.0. ``` rule "FillPalletIfNoProductGoesIn" ruleflow-group "distribution" when CalculatedElement($min : doubleValue ,key=="minValue.product") $p : Pallet(heightLeft!= 2.0,$hl : heightLeft < $min ,full ==false,palletType == Product.transportType_pallet) then $p.setFull(true); System.out.println("MinValue="+$min); update($p); end ``` Then the rule that fills the pallet with product depending on the size of the product. ``` rule "Create PalletFortransportType_pallet" ruleflow-group "distribution" when $c : CostCalculationRequest() $pp : Pallet($hl : heightLeft ,full ==false,palletType == Product.transportType_pallet) $p : Product(height <= $hl,transportType==Product.transportType_pallet) $elt : OrderLine(product==$p ) $l : LeftToDistribute(quantityLeft > 0,orderLine==$elt) then long a = (long) Math.round($pp.getWidth()/$p.getWidth()); long b = (long) Math.round($pp.getDepth()/$p.getDepth()); long n = Math.min(a*b,$l.getQuantityLeft()); $pp.addContent($p,n); $pp.setHeightLeft($pp.getHeightLeft()-$p.getHeight()); update($pp); $l.setQuantityLeft($l.getQuantityLeft()-n); update($l); end ``` ## Calculate the costs Now we take each cost and add a CostElement depending on the number of pallets we created in previous step ### Transport cost For each step type we calculate the cost ``` rule "boatTransportCost" ruleflow-group "calculate" when $c : CostCalculationRequest( ) $s : Step(transportType ==Step.Ship_TransportType) then TransportCostElement t = new TransportCostElement(); t.setStep($s); t.setAmount($c.getPallets().size()*$s.getDistance()*0.2); $c.getCostElements().add(t); insert(t); end rule "trainTransportCost" ruleflow-group "calculate" when $c : CostCalculationRequest( ) $s : Step(transportType ==Step.train_TransportType) then TransportCostElement t = new TransportCostElement(); t.setStep($s); t.setAmount($c.getPallets().size()*$s.getDistance()*0.5); $c.getCostElements().add(t); insert(t); end rule "truckTransportCost" ruleflow-group "calculate" when $c : CostCalculationRequest( ) $s : Step(transportType ==Step.truck_TransportType) then TransportCostElement t = new TransportCostElement(); t.setStep($s); t.setAmount($c.getPallets().size()*$s.getDistance()*1.0); $c.getCostElements().add(t); insert(t); end ``` ### Taxes Cost For each City we go through, we calculate the cost (Shangai and Rotterdam) As sometimes it depends on the weight, we have to sum the total amount of weigh on all pallets. Here we chose not to put all calculation in the drools session, so we do the sum in the them part of the rules. Se here how we obtain the list of Pallet we want in an ArrayList. In the then part we then iterate on the founded pallet and in the pallet we go through all the products to sum the weight. ``` rule "ShangaiTaxesCost_bulk" ruleflow-group "calculate" when $c : CostCalculationRequest( ) $ci : City(name==City.ShangaiCityName) $listPallet : ArrayList( ) from collect( Pallet(palletType == Product.transportType_bulkt) ) then TaxesCostElement t = new TaxesCostElement(); t.setCity($c