如何实例化.drl文件中的对象

Question

我对这个流口水的工作人员全新.因此,我在这里遇到一些麻烦.

rule "Raise the alarm when we have one or more fires"
    when
exists Fire()
then 
    insert( new Alarm() );  
end

当我有这个代码它工作正常.但我想改变这一点:

rule "Raise the alarm when we have one or more fires"
    when
exists Fire()
then 
    $alarm = new Alarm();
    $alarm.RingBell();
    insert( $alarm );  
end

可能你明白我在这里想做什么.我想实例化Alarm类并激活它的RingBell方法.但它给了我这个错误

Rule Compilation error : [Rule name='Raise the alarm when we have one or more fires']
    com/sample/Rule_Raise_the_alarm_when_we_have_one_or_more_fires_cd7449c70a6a48c78f4e291495d23b05.java (8:436) : alarm cannot be resolved

java.lang.IllegalArgumentException: Could not parse knowledge.
    at com.sample.DroolsTest.readKnowledgeBase(DroolsTest.java:117)
    at com.sample.DroolsTest.main(DroolsTest.java:28)

如果你们帮助我,我会很感激:))

Answer 1

该错误是因为永远不会声明$ alarm变量.尝试执行以下操作:

rule "Raise the alarm when we have one or more fires"
    when
exists Fire()
then 
    Alarm $alarm = new Alarm();
    $alarm.RingBell();
    insert( $alarm );  
end

重要的一行是:报警 $ alarm = new Alarm();