petstore.groovy.drl

drools 一个开放源码的规则引擎

<?xml version="1.0"?>

<rule-set name="PetStore Rules"
          xmlns="http://drools.org/rules"
          xmlns:groovy="http://drools.org/semantics/groovy"
          xmlns:xs="http://www.w3.org/2001/XMLSchema-instance"
          xs:schemaLocation="http://drools.org/rules rules.xsd
                             http://drools.org/semantics/groovy groovy.xsd">

   <application-data identifier="frame">javax.swing.JFrame</application-data>

    <!-- assert each item in the shopping cart into the Working Memory -->
    <rule name="Explode Cart" salience="20">
        <parameter identifier="cart">
            <class>org.drools.examples.petstore.ShoppingCart</class>
        </parameter>

        <groovy:condition>cart.getState( "Exploded" ) == false</groovy:condition>

        <groovy:consequence>
            println "Examining each item in the shopping cart." ;

	        cart.getItems().each { item | drools.assertObject( item ) } ;
            cart.setState( "Exploded", true);
            drools.modifyObject( cart );
        </groovy:consequence>
    </rule>

    <!-- Free Fish Food sample when we buy a Gold Fish if we haven't already  bought Fish Food and dont already have a Fish Food Sample-->
    <rule name="Free Fish Food Sample">
        <parameter identifier="cart">
            <class>org.drools.examples.petstore.ShoppingCart</class>
        </parameter>
        <parameter identifier="item">
            <class>org.drools.examples.petstore.CartItem</class>
        </parameter>

        <groovy:condition>cart.getItems( "Fish Food Sample" ).size() == 0</groovy:condition>
        <groovy:condition>cart.getItems( "Fish Food" ).size() == 0</groovy:condition>
        <groovy:condition>item.getName().equals( "Gold Fish" )</groovy:condition>

        <groovy:consequence>
            println "Adding free Fish Food Sample to cart" ;
            cart.addItem( new org.drools.examples.petstore.CartItem( "Fish Food Sample", 0 ) );
            drools.modifyObject( cart );
        </groovy:consequence>

    </rule>

    <!-- Suggest a tank if we have bought more than 5 gold fish and dont already have one-->
    <rule name="Suggest Tank" salience="10">
        <parameter identifier="cart">
            <class>org.drools.examples.petstore.ShoppingCart</class>
        </parameter>

        <groovy:condition>cart.getState( "Suggested Fish Tank" ) == false</groovy:condition>
        <groovy:condition>cart.getItems( "Gold Fish" ).size() &gt;= 5</groovy:condition>
        <groovy:condition>cart.getItems( "Fish Tank" ).size() == 0</groovy:condition>

        <groovy:consequence>
            import javax.swing.JOptionPane;

            Object[] options = ["Yes", "No"];
            int n = JOptionPane.showOptionDialog(frame, "Would you like to buy a tank for your " + cart.getItems( "Gold Fish" ).size() + " fish?","Purchase Suggestion",JOptionPane.YES_NO_OPTION,JOptionPane.QUESTION_MESSAGE,null,options,options[0]);
            println "SUGGESTION: Would you like to buy a tank for your " + cart.getItems( "Gold Fish" ).size() + " fish? - " ;
            if (n == 0) {
              cart.addItem( new org.drools.examples.petstore.CartItem( "Fish Tank", 25 ) );
              println "Yes" ;
            } else {
              println "No" ;
            }

            cart.setState( "Suggested Fish Tank", true );
            drools.modifyObject( cart );
        </groovy:consequence>
    </rule>

    <!-- Give 5% discount if gross cost is more than 20.00 -->
    <rule name="Apply 5% Discount">
        <parameter identifier="cart">
            <class>org.drools.examples.petstore.ShoppingCart</class>
        </parameter>

        <groovy:condition>cart.getGrossCost() &gt;= 10.00</groovy:condition>
        <groovy:condition>cart.getGrossCost() &lt; 19.9</groovy:condition>

        <groovy:condition>cart.getDiscount() &lt; 0.05</groovy:condition>

        <groovy:consequence>
            println "Applying 5% discount to cart" ;
            cart.setDiscount( 0.05 );
        </groovy:consequence>
    </rule>

    <!-- Give 10% discount if gross cost is more than 20.00 -->
    <rule name="Apply 10% Discount">
        <parameter identifier="cart">
            <class>org.drools.examples.petstore.ShoppingCart</class>
        </parameter>

        <groovy:condition>cart.getGrossCost() &gt;= 20.00</groovy:condition>
        <groovy:condition>cart.getDiscount() &lt; 0.10</groovy:condition>

        <groovy:consequence>
            println "Applying 10% discount to cart" ;
            cart.setDiscount( 0.10 );
        </groovy:consequence>
    </rule>
  </rule-set>