Bernard Szlachta: /* 什么时候使用 DSL 。 */

2016-08-25T02:25:32Z

什么时候使用 DSL 。

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{{Cat|Drools}}

<slideshow style="nobleprog" headingmark="⌘" incmark="…" scaled="true" font="Trebuchet MS" lang="中文版" headingmark2="。" >
;title: Drools - DSL
;author: Bernard Szlachta (NobleProg Ltd)
</slideshow>

== What is Domain Specific Language ⌘==
* " a way of creating a rule language that is dedicated to your problem domain"
* DSL is ultimately transformed to rules (mvel or java)
* .dsl file contain the transformations (mapping)
* DSLs have no impact on the rule engine at runtime, they are just a compile time feature

== 什么是领域特定语言。==
* " 创建规则的语言，为你的问题领域而特别设计"
* DSL最终将转换为规则 (mvel or java)
* .dsl文件包含了转换器 (mapping)
* DSLs 在运行时刻（runtime）对规则引擎无影响，他们只用于编译

== When to use DSL ⌘==
* Your requirements should be executable and always in sync with what is actually executed
* Analysts can focus on "logic proper"
* You already have a rules written in SBVR or other standard (which is consistent and detailed enough to be easily translated into executable rules)
* You need "templates" for conditional elements and consequence actions that are used repeatedly in your rules (with minor variations)

== 什么时候使用 DSL 。==
* 你的需求应该能被执行并且和实际执行的要永远同步
* 分析师可以专注于“逻辑准确”（ "logic proper"）
* 你已经有SBVR或者其它标准（一致且足够详细，可以很容易翻译为可执行规则）写的规则
* 你的规则里多处需要条件判断和结果动作（consequence actions），你需要一套模板(需要稍有改动)

== DSL in Guvnor ⌘==
Create New -> New DSL
[when]Order is greater than {totalOrder} = sc :ShoppingCart( $totalPrice : totalPrice > {totalOrder})
[then]Set discount to {discount} = sc.setTotalPrice( $totalPrice * (1-{discount}) ); update(sc);

# Create New -> New Rule
# Type (format) of rule: DSL or Guided Ruls
dilect "mvel"
when
Order is greater than 10000
then
Set discount to 0.1

Use the test created for tall order discount

== Guvnor里的DSL 。==
Create New -> New DSL
[when]Order is greater than {totalOrder} = sc :ShoppingCart( $totalPrice : totalPrice > {totalOrder})
[then]Set discount to {discount} = sc.setTotalPrice( $totalPrice * (1-{discount}) ); update(sc);

# Create New -> New Rule
# Type (format) of rule: DSL or Guided Ruls
dilect "mvel"
when
Order is greater than 10000
then
Set discount to 0.1

Use the test created for tall order discount

== Eclipse ⌘==
See 08.1DSL folder

== Eclipse 。==
见 08.1DSL 文件夹

=== Connecting DSL file with DSRL file⌘===
[[File:ClipCapIt-150716-052324.PNG]]

=== 连接 DSL 文件和 DSRL 文件。===
[[File:ClipCapIt-150716-052324.PNG]]

Drools - DSL - Revision history

Bernard Szlachta: /* 什么时候使用 DSL 。 */