Question

我是JESS的新手，并且在Java中适度。

我有＆＃39; cList＆＃39;作为特殊商品清单（包括＆＃39;必要＆＃39;和＆＃39;区域＆＃39;商品），和＆＃39; xList＆＃39;作为所有商品的清单（包括＆＃39;必要＆＃39;和＆＃39;非必要＆＃39;商品）我想制定一个规则：如果＆＃39; x＆＃39;来自＆＃39; xList＆＃39;状态＆＃39;必要＆＃39;在＆＃39; cList＆＃39;中不存在然后打印＆＃34;缺少基本商品＆＃39; x＆＃39;。＃34;

要清楚，我的系统模式与Jess71p2中的pricing_engine示例相同。

cList与CatalogItems相同
xList与OrderItems相同

我从Java类声明deftemplate。这是反击;

    (import com.aisy.entity.*)
    (deftemplate oldList(declare (from-class oldList)))
    (deftemplate xList  (declare (from-class xList)))
    (deftemplate cList  (declare (from-class cList)))

这里是xList.java

    package com.aisy.entity;
    import java.sql.Timestamp;
    public class xList {
            private Long id_commodity;
            private String commodity;
            private String essentiality;
            private Timestamp update;

        public xList() {
            super();
        }

        public xList(Long id_commodity, String commodity, String essentiality, Timestamp update) {
            super();
            this.id_commodity = id_commodity;
            this.commodity = commodity;
            this.essentiality = essentiality;
            this.update = update;
        }

        public Long getId_commodity() {
            return this.id_commodity;
        }

        public void setId_Commodity(Long id_commodity) {
            this.id_commodity = id_commodity;
        }

        public String getCommodity() {
            return this.commoditty;
        }

        ....getter and setter methods for the rest fields
    }

这里是cList.java;

    public class cList {
        private Long id_commodity;
        private String commodity;
        private String price;
        private Double final_price;

        public cList(Long id_commodity, String commodity, String price, Double final_price) {
            super();
            this.id_commodity = id_commodity;
            this.commodity = commodity;
            this.price = price;
            this.final_price = final_price;
        }

        public cList() {
            super();
        }

            ...common getter and setter methods for all fields

这里是warning.java;

    public class warning {
        private final String description;
        public warning(String aDescription) {
        description = aDescription;
        }

        public String getDescription() {
        return description;
        }
    }

这是规则;

    (defrule 
       (xList (commodity ?essential_commodity) (essentiality /essential/))
       (not(cList (commodity ?essential_commodity)))
        => (add ( new warning "Missing essential commodity" ?essential_commodity))
    )

我尝试将一些信息放到Database for xList和cList：

    xList("100000", "PEANUT", "2.45");
    xList("100003", "BREAD", "1.5");

    cList("100000", "PEANUT", "ESSENTIAL");
    cList("100002", "CAKE", "ESSENTIAL");
    cList("100003", "BREAD", "NON ESSENTIAL" );

由此，如果我运行我的规则引擎，结果应为

   "Missing essential commodity 100002"

但我目前的结果是：

    "Missing essential commodity 100000"
    "Missing essential commodity 100002"

如何解决此问题？

编辑：07/22/2016添加了xList.java和cList.java

Answer 1

确切的语法当然取决于您匹配的事实的确切性质。下面的规则是假设有很多＆＃34; xList＆＃34;事实，每个都列出了商品的名称及其在商品中的重要性＆＃34;和＆＃34; essentiality＆＃34;插槽，分别只有一个cList事实，其中包含所有必需商品的列表。空白多字段（＆＃34; $？＆＃34;）在基本商品之前和之后匹配任意数量的列表元素。

(defrule 
   (xList (commodity ?essential_commodity) (essentiality essential))
   (not (cList $? ?essential_commodity $?))
    =>
   (assert (warning
       (str-cat "Missing essential commodity" ?essential_commodity))))

Answer 2

欧内斯特几乎在那里：

(defrule (xList (commodity ?essential_commodity) (essentiality essential)) (not (cList (commodity ?essential_commodity))) => (assert (warning (description ?essential_commodity))) )

注意：调用不是列表但甚至不包含的类“-List”令人不安（并且确实让Ernest感到困惑）。类应该被称为somethingCommodity，字段名称可能被限制为“id”，“name”等。

如何编写JESS defrule＆＃34;如果列表中不存在值，则打印出警告＆＃34;

2 个答案: