java Drools 规则：如何在“何时”部分使用方法？
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Drools Rules: How can I use a method on "when" section?
提问by manoelhc
I need to execute a method on "when" section of a DSLR file and I′m not sure if it′s possible. Example:
我需要在 DSLR 文件的“何时”部分执行一个方法，我不确定是否可行。例子：
rule "WNPRules_10"
when
$reminder:Reminder(source == "HMI")
$user:User(isInAgeRange("30-100")==true)
Reminder(clickPercentual >= 10)
User(haveAtLeastOptIns("1,2,3,4") == true)
then
$reminder.setPriority(1);update($reminder);
end
(note: isInAgeRange() and haveAtLeastOptIns() are methods of User)
（注意：isInAgeRange() 和 haveAtLeastOptIns() 是 User 的方法）
I tried with eval() and no errors appeared, but it didn′t execute. Like this:
我尝试了 eval() 并且没有出现错误，但它没有执行。像这样：
rule "WNPRules_10"
when
$reminder:Reminder(source == "HMI")
$user:User(eval($user.isInAgeRange("30-100")==true))
Reminder(clickPercentual >= 10)
User(eval($user.haveAtLeastOptIns("1,2,3,4") == true))
then
$reminder.setPriority(1);update($reminder);
end
How can I resolve this problem?
我该如何解决这个问题？
回答by Michael Neale
Your second attempt looks fairly confused - also - do you have so User patterns - do you want them to refer to the same instance of user? or can they be separate instances (or must they be separate?) - that will change things a bit in some cases depending on your intent.
你的第二次尝试看起来相当混乱——还有——你有这样的用户模式——你想让它们引用同一个用户实例吗？或者它们可以是单独的实例（或者它们必须是单独的？） - 在某些情况下会根据您的意图改变一些事情。
In terms of the simplest rewrite I can think of:
就我能想到的最简单的重写而言：
rule "WNPRules_10"
when
$reminder:Reminder(source == "HMI")
$user:User()
eval($user.isInAgeRange("30-100") && $user.haveAtLeastOptIns("1,2,3,4"))
Reminder(clickPercentual >= 10)
then
$reminder.setPriority(1);update($reminder);
end
Note the use of the eval() top level element - it also uses only one user pattern - and then applies the constraints to it. (In a future version inline evals will work without having to write eval !).
请注意 eval() 顶级元素的使用 - 它也仅使用一种用户模式 - 然后对其应用约束。（在未来的版本中，内联 eval 无需编写 eval 即可工作！）。
